xref: /openbsd-src/gnu/usr.bin/perl/sv.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*    sv.c
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, by Larry Wall and others
5  *
6  *    You may distribute under the terms of either the GNU General Public
7  *    License or the Artistic License, as specified in the README file.
8  *
9  * "I wonder what the Entish is for 'yes' and 'no'," he thought.
10  *
11  *
12  * This file contains the code that creates, manipulates and destroys
13  * scalar values (SVs). The other types (AV, HV, GV, etc.) reuse the
14  * structure of an SV, so their creation and destruction is handled
15  * here; higher-level functions are in av.c, hv.c, and so on. Opcode
16  * level functions (eg. substr, split, join) for each of the types are
17  * in the pp*.c files.
18  */
19 
20 #include "EXTERN.h"
21 #define PERL_IN_SV_C
22 #include "perl.h"
23 #include "regcomp.h"
24 
25 #define FCALL *f
26 
27 #ifdef __Lynx__
28 /* Missing proto on LynxOS */
29   char *gconvert(double, int, int,  char *);
30 #endif
31 
32 #ifdef PERL_UTF8_CACHE_ASSERT
33 /* if adding more checks watch out for the following tests:
34  *   t/op/index.t t/op/length.t t/op/pat.t t/op/substr.t
35  *   lib/utf8.t lib/Unicode/Collate/t/index.t
36  * --jhi
37  */
38 #   define ASSERT_UTF8_CACHE(cache) \
39     STMT_START { if (cache) { assert((cache)[0] <= (cache)[1]); \
40 			      assert((cache)[2] <= (cache)[3]); \
41 			      assert((cache)[3] <= (cache)[1]);} \
42 			      } STMT_END
43 #else
44 #   define ASSERT_UTF8_CACHE(cache) NOOP
45 #endif
46 
47 #ifdef PERL_OLD_COPY_ON_WRITE
48 #define SV_COW_NEXT_SV(sv)	INT2PTR(SV *,SvUVX(sv))
49 #define SV_COW_NEXT_SV_SET(current,next)	SvUV_set(current, PTR2UV(next))
50 /* This is a pessimistic view. Scalar must be purely a read-write PV to copy-
51    on-write.  */
52 #endif
53 
54 /* ============================================================================
55 
56 =head1 Allocation and deallocation of SVs.
57 
58 An SV (or AV, HV, etc.) is allocated in two parts: the head (struct
59 sv, av, hv...) contains type and reference count information, and for
60 many types, a pointer to the body (struct xrv, xpv, xpviv...), which
61 contains fields specific to each type.  Some types store all they need
62 in the head, so don't have a body.
63 
64 In all but the most memory-paranoid configuations (ex: PURIFY), heads
65 and bodies are allocated out of arenas, which by default are
66 approximately 4K chunks of memory parcelled up into N heads or bodies.
67 Sv-bodies are allocated by their sv-type, guaranteeing size
68 consistency needed to allocate safely from arrays.
69 
70 For SV-heads, the first slot in each arena is reserved, and holds a
71 link to the next arena, some flags, and a note of the number of slots.
72 Snaked through each arena chain is a linked list of free items; when
73 this becomes empty, an extra arena is allocated and divided up into N
74 items which are threaded into the free list.
75 
76 SV-bodies are similar, but they use arena-sets by default, which
77 separate the link and info from the arena itself, and reclaim the 1st
78 slot in the arena.  SV-bodies are further described later.
79 
80 The following global variables are associated with arenas:
81 
82     PL_sv_arenaroot	pointer to list of SV arenas
83     PL_sv_root		pointer to list of free SV structures
84 
85     PL_body_arenas	head of linked-list of body arenas
86     PL_body_roots[]	array of pointers to list of free bodies of svtype
87 			arrays are indexed by the svtype needed
88 
89 A few special SV heads are not allocated from an arena, but are
90 instead directly created in the interpreter structure, eg PL_sv_undef.
91 The size of arenas can be changed from the default by setting
92 PERL_ARENA_SIZE appropriately at compile time.
93 
94 The SV arena serves the secondary purpose of allowing still-live SVs
95 to be located and destroyed during final cleanup.
96 
97 At the lowest level, the macros new_SV() and del_SV() grab and free
98 an SV head.  (If debugging with -DD, del_SV() calls the function S_del_sv()
99 to return the SV to the free list with error checking.) new_SV() calls
100 more_sv() / sv_add_arena() to add an extra arena if the free list is empty.
101 SVs in the free list have their SvTYPE field set to all ones.
102 
103 At the time of very final cleanup, sv_free_arenas() is called from
104 perl_destruct() to physically free all the arenas allocated since the
105 start of the interpreter.
106 
107 The function visit() scans the SV arenas list, and calls a specified
108 function for each SV it finds which is still live - ie which has an SvTYPE
109 other than all 1's, and a non-zero SvREFCNT. visit() is used by the
110 following functions (specified as [function that calls visit()] / [function
111 called by visit() for each SV]):
112 
113     sv_report_used() / do_report_used()
114 			dump all remaining SVs (debugging aid)
115 
116     sv_clean_objs() / do_clean_objs(),do_clean_named_objs()
117 			Attempt to free all objects pointed to by RVs,
118 			and, unless DISABLE_DESTRUCTOR_KLUDGE is defined,
119 			try to do the same for all objects indirectly
120 			referenced by typeglobs too.  Called once from
121 			perl_destruct(), prior to calling sv_clean_all()
122 			below.
123 
124     sv_clean_all() / do_clean_all()
125 			SvREFCNT_dec(sv) each remaining SV, possibly
126 			triggering an sv_free(). It also sets the
127 			SVf_BREAK flag on the SV to indicate that the
128 			refcnt has been artificially lowered, and thus
129 			stopping sv_free() from giving spurious warnings
130 			about SVs which unexpectedly have a refcnt
131 			of zero.  called repeatedly from perl_destruct()
132 			until there are no SVs left.
133 
134 =head2 Arena allocator API Summary
135 
136 Private API to rest of sv.c
137 
138     new_SV(),  del_SV(),
139 
140     new_XIV(), del_XIV(),
141     new_XNV(), del_XNV(),
142     etc
143 
144 Public API:
145 
146     sv_report_used(), sv_clean_objs(), sv_clean_all(), sv_free_arenas()
147 
148 =cut
149 
150 ============================================================================ */
151 
152 /*
153  * "A time to plant, and a time to uproot what was planted..."
154  */
155 
156 void
157 Perl_offer_nice_chunk(pTHX_ void *chunk, U32 chunk_size)
158 {
159     dVAR;
160     void *new_chunk;
161     U32 new_chunk_size;
162     new_chunk = (void *)(chunk);
163     new_chunk_size = (chunk_size);
164     if (new_chunk_size > PL_nice_chunk_size) {
165 	Safefree(PL_nice_chunk);
166 	PL_nice_chunk = (char *) new_chunk;
167 	PL_nice_chunk_size = new_chunk_size;
168     } else {
169 	Safefree(chunk);
170     }
171 }
172 
173 #ifdef DEBUG_LEAKING_SCALARS
174 #  define FREE_SV_DEBUG_FILE(sv) Safefree((sv)->sv_debug_file)
175 #else
176 #  define FREE_SV_DEBUG_FILE(sv)
177 #endif
178 
179 #ifdef PERL_POISON
180 #  define SvARENA_CHAIN(sv)	((sv)->sv_u.svu_rv)
181 /* Whilst I'd love to do this, it seems that things like to check on
182    unreferenced scalars
183 #  define POSION_SV_HEAD(sv)	PoisonNew(sv, 1, struct STRUCT_SV)
184 */
185 #  define POSION_SV_HEAD(sv)	PoisonNew(&SvANY(sv), 1, void *), \
186 				PoisonNew(&SvREFCNT(sv), 1, U32)
187 #else
188 #  define SvARENA_CHAIN(sv)	SvANY(sv)
189 #  define POSION_SV_HEAD(sv)
190 #endif
191 
192 #define plant_SV(p) \
193     STMT_START {					\
194 	FREE_SV_DEBUG_FILE(p);				\
195 	POSION_SV_HEAD(p);				\
196 	SvARENA_CHAIN(p) = (void *)PL_sv_root;		\
197 	SvFLAGS(p) = SVTYPEMASK;			\
198 	PL_sv_root = (p);				\
199 	--PL_sv_count;					\
200     } STMT_END
201 
202 #define uproot_SV(p) \
203     STMT_START {					\
204 	(p) = PL_sv_root;				\
205 	PL_sv_root = (SV*)SvARENA_CHAIN(p);		\
206 	++PL_sv_count;					\
207     } STMT_END
208 
209 
210 /* make some more SVs by adding another arena */
211 
212 STATIC SV*
213 S_more_sv(pTHX)
214 {
215     dVAR;
216     SV* sv;
217 
218     if (PL_nice_chunk) {
219 	sv_add_arena(PL_nice_chunk, PL_nice_chunk_size, 0);
220 	PL_nice_chunk = NULL;
221         PL_nice_chunk_size = 0;
222     }
223     else {
224 	char *chunk;                /* must use New here to match call to */
225 	Newx(chunk,PERL_ARENA_SIZE,char);  /* Safefree() in sv_free_arenas() */
226 	sv_add_arena(chunk, PERL_ARENA_SIZE, 0);
227     }
228     uproot_SV(sv);
229     return sv;
230 }
231 
232 /* new_SV(): return a new, empty SV head */
233 
234 #ifdef DEBUG_LEAKING_SCALARS
235 /* provide a real function for a debugger to play with */
236 STATIC SV*
237 S_new_SV(pTHX)
238 {
239     SV* sv;
240 
241     if (PL_sv_root)
242 	uproot_SV(sv);
243     else
244 	sv = S_more_sv(aTHX);
245     SvANY(sv) = 0;
246     SvREFCNT(sv) = 1;
247     SvFLAGS(sv) = 0;
248     sv->sv_debug_optype = PL_op ? PL_op->op_type : 0;
249     sv->sv_debug_line = (U16) (PL_parser
250 	    ?  PL_parser->copline == NOLINE
251 		?  PL_curcop
252 		    ? CopLINE(PL_curcop)
253 		    : 0
254 		: PL_parser->copline
255 	    : 0);
256     sv->sv_debug_inpad = 0;
257     sv->sv_debug_cloned = 0;
258     sv->sv_debug_file = PL_curcop ? savepv(CopFILE(PL_curcop)): NULL;
259 
260     return sv;
261 }
262 #  define new_SV(p) (p)=S_new_SV(aTHX)
263 
264 #else
265 #  define new_SV(p) \
266     STMT_START {					\
267 	if (PL_sv_root)					\
268 	    uproot_SV(p);				\
269 	else						\
270 	    (p) = S_more_sv(aTHX);			\
271 	SvANY(p) = 0;					\
272 	SvREFCNT(p) = 1;				\
273 	SvFLAGS(p) = 0;					\
274     } STMT_END
275 #endif
276 
277 
278 /* del_SV(): return an empty SV head to the free list */
279 
280 #ifdef DEBUGGING
281 
282 #define del_SV(p) \
283     STMT_START {					\
284 	if (DEBUG_D_TEST)				\
285 	    del_sv(p);					\
286 	else						\
287 	    plant_SV(p);				\
288     } STMT_END
289 
290 STATIC void
291 S_del_sv(pTHX_ SV *p)
292 {
293     dVAR;
294     if (DEBUG_D_TEST) {
295 	SV* sva;
296 	bool ok = 0;
297 	for (sva = PL_sv_arenaroot; sva; sva = (SV *) SvANY(sva)) {
298 	    const SV * const sv = sva + 1;
299 	    const SV * const svend = &sva[SvREFCNT(sva)];
300 	    if (p >= sv && p < svend) {
301 		ok = 1;
302 		break;
303 	    }
304 	}
305 	if (!ok) {
306 	    if (ckWARN_d(WARN_INTERNAL))
307 	        Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
308 			    "Attempt to free non-arena SV: 0x%"UVxf
309                             pTHX__FORMAT, PTR2UV(p) pTHX__VALUE);
310 	    return;
311 	}
312     }
313     plant_SV(p);
314 }
315 
316 #else /* ! DEBUGGING */
317 
318 #define del_SV(p)   plant_SV(p)
319 
320 #endif /* DEBUGGING */
321 
322 
323 /*
324 =head1 SV Manipulation Functions
325 
326 =for apidoc sv_add_arena
327 
328 Given a chunk of memory, link it to the head of the list of arenas,
329 and split it into a list of free SVs.
330 
331 =cut
332 */
333 
334 void
335 Perl_sv_add_arena(pTHX_ char *ptr, U32 size, U32 flags)
336 {
337     dVAR;
338     SV* const sva = (SV*)ptr;
339     register SV* sv;
340     register SV* svend;
341 
342     /* The first SV in an arena isn't an SV. */
343     SvANY(sva) = (void *) PL_sv_arenaroot;		/* ptr to next arena */
344     SvREFCNT(sva) = size / sizeof(SV);		/* number of SV slots */
345     SvFLAGS(sva) = flags;			/* FAKE if not to be freed */
346 
347     PL_sv_arenaroot = sva;
348     PL_sv_root = sva + 1;
349 
350     svend = &sva[SvREFCNT(sva) - 1];
351     sv = sva + 1;
352     while (sv < svend) {
353 	SvARENA_CHAIN(sv) = (void *)(SV*)(sv + 1);
354 #ifdef DEBUGGING
355 	SvREFCNT(sv) = 0;
356 #endif
357 	/* Must always set typemask because it's always checked in on cleanup
358 	   when the arenas are walked looking for objects.  */
359 	SvFLAGS(sv) = SVTYPEMASK;
360 	sv++;
361     }
362     SvARENA_CHAIN(sv) = 0;
363 #ifdef DEBUGGING
364     SvREFCNT(sv) = 0;
365 #endif
366     SvFLAGS(sv) = SVTYPEMASK;
367 }
368 
369 /* visit(): call the named function for each non-free SV in the arenas
370  * whose flags field matches the flags/mask args. */
371 
372 STATIC I32
373 S_visit(pTHX_ SVFUNC_t f, U32 flags, U32 mask)
374 {
375     dVAR;
376     SV* sva;
377     I32 visited = 0;
378 
379     for (sva = PL_sv_arenaroot; sva; sva = (SV*)SvANY(sva)) {
380 	register const SV * const svend = &sva[SvREFCNT(sva)];
381 	register SV* sv;
382 	for (sv = sva + 1; sv < svend; ++sv) {
383 	    if (SvTYPE(sv) != SVTYPEMASK
384 		    && (sv->sv_flags & mask) == flags
385 		    && SvREFCNT(sv))
386 	    {
387 		(FCALL)(aTHX_ sv);
388 		++visited;
389 	    }
390 	}
391     }
392     return visited;
393 }
394 
395 #ifdef DEBUGGING
396 
397 /* called by sv_report_used() for each live SV */
398 
399 static void
400 do_report_used(pTHX_ SV *sv)
401 {
402     if (SvTYPE(sv) != SVTYPEMASK) {
403 	PerlIO_printf(Perl_debug_log, "****\n");
404 	sv_dump(sv);
405     }
406 }
407 #endif
408 
409 /*
410 =for apidoc sv_report_used
411 
412 Dump the contents of all SVs not yet freed. (Debugging aid).
413 
414 =cut
415 */
416 
417 void
418 Perl_sv_report_used(pTHX)
419 {
420 #ifdef DEBUGGING
421     visit(do_report_used, 0, 0);
422 #else
423     PERL_UNUSED_CONTEXT;
424 #endif
425 }
426 
427 /* called by sv_clean_objs() for each live SV */
428 
429 static void
430 do_clean_objs(pTHX_ SV *ref)
431 {
432     dVAR;
433     assert (SvROK(ref));
434     {
435 	SV * const target = SvRV(ref);
436 	if (SvOBJECT(target)) {
437 	    DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning object ref:\n "), sv_dump(ref)));
438 	    if (SvWEAKREF(ref)) {
439 		sv_del_backref(target, ref);
440 		SvWEAKREF_off(ref);
441 		SvRV_set(ref, NULL);
442 	    } else {
443 		SvROK_off(ref);
444 		SvRV_set(ref, NULL);
445 		SvREFCNT_dec(target);
446 	    }
447 	}
448     }
449 
450     /* XXX Might want to check arrays, etc. */
451 }
452 
453 /* called by sv_clean_objs() for each live SV */
454 
455 #ifndef DISABLE_DESTRUCTOR_KLUDGE
456 static void
457 do_clean_named_objs(pTHX_ SV *sv)
458 {
459     dVAR;
460     assert(SvTYPE(sv) == SVt_PVGV);
461     assert(isGV_with_GP(sv));
462     if (GvGP(sv)) {
463 	if ((
464 #ifdef PERL_DONT_CREATE_GVSV
465 	     GvSV(sv) &&
466 #endif
467 	     SvOBJECT(GvSV(sv))) ||
468 	     (GvAV(sv) && SvOBJECT(GvAV(sv))) ||
469 	     (GvHV(sv) && SvOBJECT(GvHV(sv))) ||
470 	     /* In certain rare cases GvIOp(sv) can be NULL, which would make SvOBJECT(GvIO(sv)) dereference NULL. */
471 	     (GvIO(sv) ? (SvFLAGS(GvIOp(sv)) & SVs_OBJECT) : 0) ||
472 	     (GvCV(sv) && SvOBJECT(GvCV(sv))) )
473 	{
474 	    DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning named glob object:\n "), sv_dump(sv)));
475 	    SvFLAGS(sv) |= SVf_BREAK;
476 	    SvREFCNT_dec(sv);
477 	}
478     }
479 }
480 #endif
481 
482 /*
483 =for apidoc sv_clean_objs
484 
485 Attempt to destroy all objects not yet freed
486 
487 =cut
488 */
489 
490 void
491 Perl_sv_clean_objs(pTHX)
492 {
493     dVAR;
494     PL_in_clean_objs = TRUE;
495     visit(do_clean_objs, SVf_ROK, SVf_ROK);
496 #ifndef DISABLE_DESTRUCTOR_KLUDGE
497     /* some barnacles may yet remain, clinging to typeglobs */
498     visit(do_clean_named_objs, SVt_PVGV|SVpgv_GP, SVTYPEMASK|SVp_POK|SVpgv_GP);
499 #endif
500     PL_in_clean_objs = FALSE;
501 }
502 
503 /* called by sv_clean_all() for each live SV */
504 
505 static void
506 do_clean_all(pTHX_ SV *sv)
507 {
508     dVAR;
509     DEBUG_D((PerlIO_printf(Perl_debug_log, "Cleaning loops: SV at 0x%"UVxf"\n", PTR2UV(sv)) ));
510     SvFLAGS(sv) |= SVf_BREAK;
511     SvREFCNT_dec(sv);
512 }
513 
514 /*
515 =for apidoc sv_clean_all
516 
517 Decrement the refcnt of each remaining SV, possibly triggering a
518 cleanup. This function may have to be called multiple times to free
519 SVs which are in complex self-referential hierarchies.
520 
521 =cut
522 */
523 
524 I32
525 Perl_sv_clean_all(pTHX)
526 {
527     dVAR;
528     I32 cleaned;
529     PL_in_clean_all = TRUE;
530     cleaned = visit(do_clean_all, 0,0);
531     PL_in_clean_all = FALSE;
532     return cleaned;
533 }
534 
535 /*
536   ARENASETS: a meta-arena implementation which separates arena-info
537   into struct arena_set, which contains an array of struct
538   arena_descs, each holding info for a single arena.  By separating
539   the meta-info from the arena, we recover the 1st slot, formerly
540   borrowed for list management.  The arena_set is about the size of an
541   arena, avoiding the needless malloc overhead of a naive linked-list.
542 
543   The cost is 1 arena-set malloc per ~320 arena-mallocs, + the unused
544   memory in the last arena-set (1/2 on average).  In trade, we get
545   back the 1st slot in each arena (ie 1.7% of a CV-arena, less for
546   smaller types).  The recovery of the wasted space allows use of
547   small arenas for large, rare body types, by changing array* fields
548   in body_details_by_type[] below.
549 */
550 struct arena_desc {
551     char       *arena;		/* the raw storage, allocated aligned */
552     size_t      size;		/* its size ~4k typ */
553     U32		misc;		/* type, and in future other things. */
554 };
555 
556 struct arena_set;
557 
558 /* Get the maximum number of elements in set[] such that struct arena_set
559    will fit within PERL_ARENA_SIZE, which is probably just under 4K, and
560    therefore likely to be 1 aligned memory page.  */
561 
562 #define ARENAS_PER_SET  ((PERL_ARENA_SIZE - sizeof(struct arena_set*) \
563 			  - 2 * sizeof(int)) / sizeof (struct arena_desc))
564 
565 struct arena_set {
566     struct arena_set* next;
567     unsigned int   set_size;	/* ie ARENAS_PER_SET */
568     unsigned int   curr;	/* index of next available arena-desc */
569     struct arena_desc set[ARENAS_PER_SET];
570 };
571 
572 /*
573 =for apidoc sv_free_arenas
574 
575 Deallocate the memory used by all arenas. Note that all the individual SV
576 heads and bodies within the arenas must already have been freed.
577 
578 =cut
579 */
580 void
581 Perl_sv_free_arenas(pTHX)
582 {
583     dVAR;
584     SV* sva;
585     SV* svanext;
586     unsigned int i;
587 
588     /* Free arenas here, but be careful about fake ones.  (We assume
589        contiguity of the fake ones with the corresponding real ones.) */
590 
591     for (sva = PL_sv_arenaroot; sva; sva = svanext) {
592 	svanext = (SV*) SvANY(sva);
593 	while (svanext && SvFAKE(svanext))
594 	    svanext = (SV*) SvANY(svanext);
595 
596 	if (!SvFAKE(sva))
597 	    Safefree(sva);
598     }
599 
600     {
601 	struct arena_set *aroot = (struct arena_set*) PL_body_arenas;
602 
603 	while (aroot) {
604 	    struct arena_set *current = aroot;
605 	    i = aroot->curr;
606 	    while (i--) {
607 		assert(aroot->set[i].arena);
608 		Safefree(aroot->set[i].arena);
609 	    }
610 	    aroot = aroot->next;
611 	    Safefree(current);
612 	}
613     }
614     PL_body_arenas = 0;
615 
616     i = PERL_ARENA_ROOTS_SIZE;
617     while (i--)
618 	PL_body_roots[i] = 0;
619 
620     Safefree(PL_nice_chunk);
621     PL_nice_chunk = NULL;
622     PL_nice_chunk_size = 0;
623     PL_sv_arenaroot = 0;
624     PL_sv_root = 0;
625 }
626 
627 /*
628   Here are mid-level routines that manage the allocation of bodies out
629   of the various arenas.  There are 5 kinds of arenas:
630 
631   1. SV-head arenas, which are discussed and handled above
632   2. regular body arenas
633   3. arenas for reduced-size bodies
634   4. Hash-Entry arenas
635   5. pte arenas (thread related)
636 
637   Arena types 2 & 3 are chained by body-type off an array of
638   arena-root pointers, which is indexed by svtype.  Some of the
639   larger/less used body types are malloced singly, since a large
640   unused block of them is wasteful.  Also, several svtypes dont have
641   bodies; the data fits into the sv-head itself.  The arena-root
642   pointer thus has a few unused root-pointers (which may be hijacked
643   later for arena types 4,5)
644 
645   3 differs from 2 as an optimization; some body types have several
646   unused fields in the front of the structure (which are kept in-place
647   for consistency).  These bodies can be allocated in smaller chunks,
648   because the leading fields arent accessed.  Pointers to such bodies
649   are decremented to point at the unused 'ghost' memory, knowing that
650   the pointers are used with offsets to the real memory.
651 
652   HE, HEK arenas are managed separately, with separate code, but may
653   be merge-able later..
654 
655   PTE arenas are not sv-bodies, but they share these mid-level
656   mechanics, so are considered here.  The new mid-level mechanics rely
657   on the sv_type of the body being allocated, so we just reserve one
658   of the unused body-slots for PTEs, then use it in those (2) PTE
659   contexts below (line ~10k)
660 */
661 
662 /* get_arena(size): this creates custom-sized arenas
663    TBD: export properly for hv.c: S_more_he().
664 */
665 void*
666 Perl_get_arena(pTHX_ size_t arena_size, U32 misc)
667 {
668     dVAR;
669     struct arena_desc* adesc;
670     struct arena_set *aroot = (struct arena_set*) PL_body_arenas;
671     unsigned int curr;
672 
673     /* shouldnt need this
674     if (!arena_size)	arena_size = PERL_ARENA_SIZE;
675     */
676 
677     /* may need new arena-set to hold new arena */
678     if (!aroot || aroot->curr >= aroot->set_size) {
679 	struct arena_set *newroot;
680 	Newxz(newroot, 1, struct arena_set);
681 	newroot->set_size = ARENAS_PER_SET;
682 	newroot->next = aroot;
683 	aroot = newroot;
684 	PL_body_arenas = (void *) newroot;
685 	DEBUG_m(PerlIO_printf(Perl_debug_log, "new arenaset %p\n", (void*)aroot));
686     }
687 
688     /* ok, now have arena-set with at least 1 empty/available arena-desc */
689     curr = aroot->curr++;
690     adesc = &(aroot->set[curr]);
691     assert(!adesc->arena);
692 
693     Newx(adesc->arena, arena_size, char);
694     adesc->size = arena_size;
695     adesc->misc = misc;
696     DEBUG_m(PerlIO_printf(Perl_debug_log, "arena %d added: %p size %"UVuf"\n",
697 			  curr, (void*)adesc->arena, (UV)arena_size));
698 
699     return adesc->arena;
700 }
701 
702 
703 /* return a thing to the free list */
704 
705 #define del_body(thing, root)			\
706     STMT_START {				\
707 	void ** const thing_copy = (void **)thing;\
708 	*thing_copy = *root;			\
709 	*root = (void*)thing_copy;		\
710     } STMT_END
711 
712 /*
713 
714 =head1 SV-Body Allocation
715 
716 Allocation of SV-bodies is similar to SV-heads, differing as follows;
717 the allocation mechanism is used for many body types, so is somewhat
718 more complicated, it uses arena-sets, and has no need for still-live
719 SV detection.
720 
721 At the outermost level, (new|del)_X*V macros return bodies of the
722 appropriate type.  These macros call either (new|del)_body_type or
723 (new|del)_body_allocated macro pairs, depending on specifics of the
724 type.  Most body types use the former pair, the latter pair is used to
725 allocate body types with "ghost fields".
726 
727 "ghost fields" are fields that are unused in certain types, and
728 consequently dont need to actually exist.  They are declared because
729 they're part of a "base type", which allows use of functions as
730 methods.  The simplest examples are AVs and HVs, 2 aggregate types
731 which don't use the fields which support SCALAR semantics.
732 
733 For these types, the arenas are carved up into *_allocated size
734 chunks, we thus avoid wasted memory for those unaccessed members.
735 When bodies are allocated, we adjust the pointer back in memory by the
736 size of the bit not allocated, so it's as if we allocated the full
737 structure.  (But things will all go boom if you write to the part that
738 is "not there", because you'll be overwriting the last members of the
739 preceding structure in memory.)
740 
741 We calculate the correction using the STRUCT_OFFSET macro. For
742 example, if xpv_allocated is the same structure as XPV then the two
743 OFFSETs sum to zero, and the pointer is unchanged. If the allocated
744 structure is smaller (no initial NV actually allocated) then the net
745 effect is to subtract the size of the NV from the pointer, to return a
746 new pointer as if an initial NV were actually allocated.
747 
748 This is the same trick as was used for NV and IV bodies. Ironically it
749 doesn't need to be used for NV bodies any more, because NV is now at
750 the start of the structure. IV bodies don't need it either, because
751 they are no longer allocated.
752 
753 In turn, the new_body_* allocators call S_new_body(), which invokes
754 new_body_inline macro, which takes a lock, and takes a body off the
755 linked list at PL_body_roots[sv_type], calling S_more_bodies() if
756 necessary to refresh an empty list.  Then the lock is released, and
757 the body is returned.
758 
759 S_more_bodies calls get_arena(), and carves it up into an array of N
760 bodies, which it strings into a linked list.  It looks up arena-size
761 and body-size from the body_details table described below, thus
762 supporting the multiple body-types.
763 
764 If PURIFY is defined, or PERL_ARENA_SIZE=0, arenas are not used, and
765 the (new|del)_X*V macros are mapped directly to malloc/free.
766 
767 */
768 
769 /*
770 
771 For each sv-type, struct body_details bodies_by_type[] carries
772 parameters which control these aspects of SV handling:
773 
774 Arena_size determines whether arenas are used for this body type, and if
775 so, how big they are.  PURIFY or PERL_ARENA_SIZE=0 set this field to
776 zero, forcing individual mallocs and frees.
777 
778 Body_size determines how big a body is, and therefore how many fit into
779 each arena.  Offset carries the body-pointer adjustment needed for
780 *_allocated body types, and is used in *_allocated macros.
781 
782 But its main purpose is to parameterize info needed in
783 Perl_sv_upgrade().  The info here dramatically simplifies the function
784 vs the implementation in 5.8.7, making it table-driven.  All fields
785 are used for this, except for arena_size.
786 
787 For the sv-types that have no bodies, arenas are not used, so those
788 PL_body_roots[sv_type] are unused, and can be overloaded.  In
789 something of a special case, SVt_NULL is borrowed for HE arenas;
790 PL_body_roots[HE_SVSLOT=SVt_NULL] is filled by S_more_he, but the
791 bodies_by_type[SVt_NULL] slot is not used, as the table is not
792 available in hv.c.
793 
794 PTEs also use arenas, but are never seen in Perl_sv_upgrade. Nonetheless,
795 they get their own slot in bodies_by_type[PTE_SVSLOT =SVt_IV], so they can
796 just use the same allocation semantics.  At first, PTEs were also
797 overloaded to a non-body sv-type, but this yielded hard-to-find malloc
798 bugs, so was simplified by claiming a new slot.  This choice has no
799 consequence at this time.
800 
801 */
802 
803 struct body_details {
804     U8 body_size;	/* Size to allocate  */
805     U8 copy;		/* Size of structure to copy (may be shorter)  */
806     U8 offset;
807     unsigned int type : 4;	    /* We have space for a sanity check.  */
808     unsigned int cant_upgrade : 1;  /* Cannot upgrade this type */
809     unsigned int zero_nv : 1;	    /* zero the NV when upgrading from this */
810     unsigned int arena : 1;	    /* Allocated from an arena */
811     size_t arena_size;		    /* Size of arena to allocate */
812 };
813 
814 #define HADNV FALSE
815 #define NONV TRUE
816 
817 
818 #ifdef PURIFY
819 /* With -DPURFIY we allocate everything directly, and don't use arenas.
820    This seems a rather elegant way to simplify some of the code below.  */
821 #define HASARENA FALSE
822 #else
823 #define HASARENA TRUE
824 #endif
825 #define NOARENA FALSE
826 
827 /* Size the arenas to exactly fit a given number of bodies.  A count
828    of 0 fits the max number bodies into a PERL_ARENA_SIZE.block,
829    simplifying the default.  If count > 0, the arena is sized to fit
830    only that many bodies, allowing arenas to be used for large, rare
831    bodies (XPVFM, XPVIO) without undue waste.  The arena size is
832    limited by PERL_ARENA_SIZE, so we can safely oversize the
833    declarations.
834  */
835 #define FIT_ARENA0(body_size)				\
836     ((size_t)(PERL_ARENA_SIZE / body_size) * body_size)
837 #define FIT_ARENAn(count,body_size)			\
838     ( count * body_size <= PERL_ARENA_SIZE)		\
839     ? count * body_size					\
840     : FIT_ARENA0 (body_size)
841 #define FIT_ARENA(count,body_size)			\
842     count 						\
843     ? FIT_ARENAn (count, body_size)			\
844     : FIT_ARENA0 (body_size)
845 
846 /* A macro to work out the offset needed to subtract from a pointer to (say)
847 
848 typedef struct {
849     STRLEN	xpv_cur;
850     STRLEN	xpv_len;
851 } xpv_allocated;
852 
853 to make its members accessible via a pointer to (say)
854 
855 struct xpv {
856     NV		xnv_nv;
857     STRLEN	xpv_cur;
858     STRLEN	xpv_len;
859 };
860 
861 */
862 
863 #define relative_STRUCT_OFFSET(longer, shorter, member) \
864     (STRUCT_OFFSET(shorter, member) - STRUCT_OFFSET(longer, member))
865 
866 /* Calculate the length to copy. Specifically work out the length less any
867    final padding the compiler needed to add.  See the comment in sv_upgrade
868    for why copying the padding proved to be a bug.  */
869 
870 #define copy_length(type, last_member) \
871 	STRUCT_OFFSET(type, last_member) \
872 	+ sizeof (((type*)SvANY((SV*)0))->last_member)
873 
874 static const struct body_details bodies_by_type[] = {
875     { sizeof(HE), 0, 0, SVt_NULL,
876       FALSE, NONV, NOARENA, FIT_ARENA(0, sizeof(HE)) },
877 
878     /* The bind placeholder pretends to be an RV for now.
879        Also it's marked as "can't upgrade" to stop anyone using it before it's
880        implemented.  */
881     { 0, 0, 0, SVt_BIND, TRUE, NONV, NOARENA, 0 },
882 
883     /* IVs are in the head, so the allocation size is 0.
884        However, the slot is overloaded for PTEs.  */
885     { sizeof(struct ptr_tbl_ent), /* This is used for PTEs.  */
886       sizeof(IV), /* This is used to copy out the IV body.  */
887       STRUCT_OFFSET(XPVIV, xiv_iv), SVt_IV, FALSE, NONV,
888       NOARENA /* IVS don't need an arena  */,
889       /* But PTEs need to know the size of their arena  */
890       FIT_ARENA(0, sizeof(struct ptr_tbl_ent))
891     },
892 
893     /* 8 bytes on most ILP32 with IEEE doubles */
894     { sizeof(NV), sizeof(NV), 0, SVt_NV, FALSE, HADNV, HASARENA,
895       FIT_ARENA(0, sizeof(NV)) },
896 
897     /* RVs are in the head now.  */
898     { 0, 0, 0, SVt_RV, FALSE, NONV, NOARENA, 0 },
899 
900     /* 8 bytes on most ILP32 with IEEE doubles */
901     { sizeof(xpv_allocated),
902       copy_length(XPV, xpv_len)
903       - relative_STRUCT_OFFSET(xpv_allocated, XPV, xpv_cur),
904       + relative_STRUCT_OFFSET(xpv_allocated, XPV, xpv_cur),
905       SVt_PV, FALSE, NONV, HASARENA, FIT_ARENA(0, sizeof(xpv_allocated)) },
906 
907     /* 12 */
908     { sizeof(xpviv_allocated),
909       copy_length(XPVIV, xiv_u)
910       - relative_STRUCT_OFFSET(xpviv_allocated, XPVIV, xpv_cur),
911       + relative_STRUCT_OFFSET(xpviv_allocated, XPVIV, xpv_cur),
912       SVt_PVIV, FALSE, NONV, HASARENA, FIT_ARENA(0, sizeof(xpviv_allocated)) },
913 
914     /* 20 */
915     { sizeof(XPVNV), copy_length(XPVNV, xiv_u), 0, SVt_PVNV, FALSE, HADNV,
916       HASARENA, FIT_ARENA(0, sizeof(XPVNV)) },
917 
918     /* 28 */
919     { sizeof(XPVMG), copy_length(XPVMG, xmg_stash), 0, SVt_PVMG, FALSE, HADNV,
920       HASARENA, FIT_ARENA(0, sizeof(XPVMG)) },
921 
922     /* 48 */
923     { sizeof(XPVGV), sizeof(XPVGV), 0, SVt_PVGV, TRUE, HADNV,
924       HASARENA, FIT_ARENA(0, sizeof(XPVGV)) },
925 
926     /* 64 */
927     { sizeof(XPVLV), sizeof(XPVLV), 0, SVt_PVLV, TRUE, HADNV,
928       HASARENA, FIT_ARENA(0, sizeof(XPVLV)) },
929 
930     { sizeof(xpvav_allocated),
931       copy_length(XPVAV, xmg_stash)
932       - relative_STRUCT_OFFSET(xpvav_allocated, XPVAV, xav_fill),
933       + relative_STRUCT_OFFSET(xpvav_allocated, XPVAV, xav_fill),
934       SVt_PVAV, TRUE, NONV, HASARENA, FIT_ARENA(0, sizeof(xpvav_allocated)) },
935 
936     { sizeof(xpvhv_allocated),
937       copy_length(XPVHV, xmg_stash)
938       - relative_STRUCT_OFFSET(xpvhv_allocated, XPVHV, xhv_fill),
939       + relative_STRUCT_OFFSET(xpvhv_allocated, XPVHV, xhv_fill),
940       SVt_PVHV, TRUE, NONV, HASARENA, FIT_ARENA(0, sizeof(xpvhv_allocated)) },
941 
942     /* 56 */
943     { sizeof(xpvcv_allocated), sizeof(xpvcv_allocated),
944       + relative_STRUCT_OFFSET(xpvcv_allocated, XPVCV, xpv_cur),
945       SVt_PVCV, TRUE, NONV, HASARENA, FIT_ARENA(0, sizeof(xpvcv_allocated)) },
946 
947     { sizeof(xpvfm_allocated), sizeof(xpvfm_allocated),
948       + relative_STRUCT_OFFSET(xpvfm_allocated, XPVFM, xpv_cur),
949       SVt_PVFM, TRUE, NONV, NOARENA, FIT_ARENA(20, sizeof(xpvfm_allocated)) },
950 
951     /* XPVIO is 84 bytes, fits 48x */
952     { sizeof(XPVIO), sizeof(XPVIO), 0, SVt_PVIO, TRUE, HADNV,
953       HASARENA, FIT_ARENA(24, sizeof(XPVIO)) },
954 };
955 
956 #define new_body_type(sv_type)		\
957     (void *)((char *)S_new_body(aTHX_ sv_type))
958 
959 #define del_body_type(p, sv_type)	\
960     del_body(p, &PL_body_roots[sv_type])
961 
962 
963 #define new_body_allocated(sv_type)		\
964     (void *)((char *)S_new_body(aTHX_ sv_type)	\
965 	     - bodies_by_type[sv_type].offset)
966 
967 #define del_body_allocated(p, sv_type)		\
968     del_body(p + bodies_by_type[sv_type].offset, &PL_body_roots[sv_type])
969 
970 
971 #define my_safemalloc(s)	(void*)safemalloc(s)
972 #define my_safecalloc(s)	(void*)safecalloc(s, 1)
973 #define my_safefree(p)	safefree((char*)p)
974 
975 #ifdef PURIFY
976 
977 #define new_XNV()	my_safemalloc(sizeof(XPVNV))
978 #define del_XNV(p)	my_safefree(p)
979 
980 #define new_XPVNV()	my_safemalloc(sizeof(XPVNV))
981 #define del_XPVNV(p)	my_safefree(p)
982 
983 #define new_XPVAV()	my_safemalloc(sizeof(XPVAV))
984 #define del_XPVAV(p)	my_safefree(p)
985 
986 #define new_XPVHV()	my_safemalloc(sizeof(XPVHV))
987 #define del_XPVHV(p)	my_safefree(p)
988 
989 #define new_XPVMG()	my_safemalloc(sizeof(XPVMG))
990 #define del_XPVMG(p)	my_safefree(p)
991 
992 #define new_XPVGV()	my_safemalloc(sizeof(XPVGV))
993 #define del_XPVGV(p)	my_safefree(p)
994 
995 #else /* !PURIFY */
996 
997 #define new_XNV()	new_body_type(SVt_NV)
998 #define del_XNV(p)	del_body_type(p, SVt_NV)
999 
1000 #define new_XPVNV()	new_body_type(SVt_PVNV)
1001 #define del_XPVNV(p)	del_body_type(p, SVt_PVNV)
1002 
1003 #define new_XPVAV()	new_body_allocated(SVt_PVAV)
1004 #define del_XPVAV(p)	del_body_allocated(p, SVt_PVAV)
1005 
1006 #define new_XPVHV()	new_body_allocated(SVt_PVHV)
1007 #define del_XPVHV(p)	del_body_allocated(p, SVt_PVHV)
1008 
1009 #define new_XPVMG()	new_body_type(SVt_PVMG)
1010 #define del_XPVMG(p)	del_body_type(p, SVt_PVMG)
1011 
1012 #define new_XPVGV()	new_body_type(SVt_PVGV)
1013 #define del_XPVGV(p)	del_body_type(p, SVt_PVGV)
1014 
1015 #endif /* PURIFY */
1016 
1017 /* no arena for you! */
1018 
1019 #define new_NOARENA(details) \
1020 	my_safemalloc((details)->body_size + (details)->offset)
1021 #define new_NOARENAZ(details) \
1022 	my_safecalloc((details)->body_size + (details)->offset)
1023 
1024 STATIC void *
1025 S_more_bodies (pTHX_ svtype sv_type)
1026 {
1027     dVAR;
1028     void ** const root = &PL_body_roots[sv_type];
1029     const struct body_details * const bdp = &bodies_by_type[sv_type];
1030     const size_t body_size = bdp->body_size;
1031     char *start;
1032     const char *end;
1033 #if defined(DEBUGGING) && !defined(PERL_GLOBAL_STRUCT_PRIVATE)
1034     static bool done_sanity_check;
1035 
1036     /* PERL_GLOBAL_STRUCT_PRIVATE cannot coexist with global
1037      * variables like done_sanity_check. */
1038     if (!done_sanity_check) {
1039 	unsigned int i = SVt_LAST;
1040 
1041 	done_sanity_check = TRUE;
1042 
1043 	while (i--)
1044 	    assert (bodies_by_type[i].type == i);
1045     }
1046 #endif
1047 
1048     assert(bdp->arena_size);
1049 
1050     start = (char*) Perl_get_arena(aTHX_ bdp->arena_size, sv_type);
1051 
1052     end = start + bdp->arena_size - body_size;
1053 
1054     /* computed count doesnt reflect the 1st slot reservation */
1055     DEBUG_m(PerlIO_printf(Perl_debug_log,
1056 			  "arena %p end %p arena-size %d type %d size %d ct %d\n",
1057 			  (void*)start, (void*)end,
1058 			  (int)bdp->arena_size, sv_type, (int)body_size,
1059 			  (int)bdp->arena_size / (int)body_size));
1060 
1061     *root = (void *)start;
1062 
1063     while (start < end) {
1064 	char * const next = start + body_size;
1065 	*(void**) start = (void *)next;
1066 	start = next;
1067     }
1068     *(void **)start = 0;
1069 
1070     return *root;
1071 }
1072 
1073 /* grab a new thing from the free list, allocating more if necessary.
1074    The inline version is used for speed in hot routines, and the
1075    function using it serves the rest (unless PURIFY).
1076 */
1077 #define new_body_inline(xpv, sv_type) \
1078     STMT_START { \
1079 	void ** const r3wt = &PL_body_roots[sv_type]; \
1080 	xpv = (PTR_TBL_ENT_t*) (*((void **)(r3wt))      \
1081 	  ? *((void **)(r3wt)) : more_bodies(sv_type)); \
1082 	*(r3wt) = *(void**)(xpv); \
1083     } STMT_END
1084 
1085 #ifndef PURIFY
1086 
1087 STATIC void *
1088 S_new_body(pTHX_ svtype sv_type)
1089 {
1090     dVAR;
1091     void *xpv;
1092     new_body_inline(xpv, sv_type);
1093     return xpv;
1094 }
1095 
1096 #endif
1097 
1098 /*
1099 =for apidoc sv_upgrade
1100 
1101 Upgrade an SV to a more complex form.  Generally adds a new body type to the
1102 SV, then copies across as much information as possible from the old body.
1103 You generally want to use the C<SvUPGRADE> macro wrapper. See also C<svtype>.
1104 
1105 =cut
1106 */
1107 
1108 void
1109 Perl_sv_upgrade(pTHX_ register SV *sv, svtype new_type)
1110 {
1111     dVAR;
1112     void*	old_body;
1113     void*	new_body;
1114     const svtype old_type = SvTYPE(sv);
1115     const struct body_details *new_type_details;
1116     const struct body_details *const old_type_details
1117 	= bodies_by_type + old_type;
1118 
1119     if (new_type != SVt_PV && SvIsCOW(sv)) {
1120 	sv_force_normal_flags(sv, 0);
1121     }
1122 
1123     if (old_type == new_type)
1124 	return;
1125 
1126     if (old_type > new_type)
1127 	Perl_croak(aTHX_ "sv_upgrade from type %d down to type %d",
1128 		(int)old_type, (int)new_type);
1129 
1130 
1131     old_body = SvANY(sv);
1132 
1133     /* Copying structures onto other structures that have been neatly zeroed
1134        has a subtle gotcha. Consider XPVMG
1135 
1136        +------+------+------+------+------+-------+-------+
1137        |     NV      | CUR  | LEN  |  IV  | MAGIC | STASH |
1138        +------+------+------+------+------+-------+-------+
1139        0      4      8     12     16     20      24      28
1140 
1141        where NVs are aligned to 8 bytes, so that sizeof that structure is
1142        actually 32 bytes long, with 4 bytes of padding at the end:
1143 
1144        +------+------+------+------+------+-------+-------+------+
1145        |     NV      | CUR  | LEN  |  IV  | MAGIC | STASH | ???  |
1146        +------+------+------+------+------+-------+-------+------+
1147        0      4      8     12     16     20      24      28     32
1148 
1149        so what happens if you allocate memory for this structure:
1150 
1151        +------+------+------+------+------+-------+-------+------+------+...
1152        |     NV      | CUR  | LEN  |  IV  | MAGIC | STASH |  GP  | NAME |
1153        +------+------+------+------+------+-------+-------+------+------+...
1154        0      4      8     12     16     20      24      28     32     36
1155 
1156        zero it, then copy sizeof(XPVMG) bytes on top of it? Not quite what you
1157        expect, because you copy the area marked ??? onto GP. Now, ??? may have
1158        started out as zero once, but it's quite possible that it isn't. So now,
1159        rather than a nicely zeroed GP, you have it pointing somewhere random.
1160        Bugs ensue.
1161 
1162        (In fact, GP ends up pointing at a previous GP structure, because the
1163        principle cause of the padding in XPVMG getting garbage is a copy of
1164        sizeof(XPVMG) bytes from a XPVGV structure in sv_unglob. Right now
1165        this happens to be moot because XPVGV has been re-ordered, with GP
1166        no longer after STASH)
1167 
1168        So we are careful and work out the size of used parts of all the
1169        structures.  */
1170 
1171     switch (old_type) {
1172     case SVt_NULL:
1173 	break;
1174     case SVt_IV:
1175 	if (new_type < SVt_PVIV) {
1176 	    new_type = (new_type == SVt_NV)
1177 		? SVt_PVNV : SVt_PVIV;
1178 	}
1179 	break;
1180     case SVt_NV:
1181 	if (new_type < SVt_PVNV) {
1182 	    new_type = SVt_PVNV;
1183 	}
1184 	break;
1185     case SVt_RV:
1186 	break;
1187     case SVt_PV:
1188 	assert(new_type > SVt_PV);
1189 	assert(SVt_IV < SVt_PV);
1190 	assert(SVt_NV < SVt_PV);
1191 	break;
1192     case SVt_PVIV:
1193 	break;
1194     case SVt_PVNV:
1195 	break;
1196     case SVt_PVMG:
1197 	/* Because the XPVMG of PL_mess_sv isn't allocated from the arena,
1198 	   there's no way that it can be safely upgraded, because perl.c
1199 	   expects to Safefree(SvANY(PL_mess_sv))  */
1200 	assert(sv != PL_mess_sv);
1201 	/* This flag bit is used to mean other things in other scalar types.
1202 	   Given that it only has meaning inside the pad, it shouldn't be set
1203 	   on anything that can get upgraded.  */
1204 	assert(!SvPAD_TYPED(sv));
1205 	break;
1206     default:
1207 	if (old_type_details->cant_upgrade)
1208 	    Perl_croak(aTHX_ "Can't upgrade %s (%" UVuf ") to %" UVuf,
1209 		       sv_reftype(sv, 0), (UV) old_type, (UV) new_type);
1210     }
1211     new_type_details = bodies_by_type + new_type;
1212 
1213     SvFLAGS(sv) &= ~SVTYPEMASK;
1214     SvFLAGS(sv) |= new_type;
1215 
1216     /* This can't happen, as SVt_NULL is <= all values of new_type, so one of
1217        the return statements above will have triggered.  */
1218     assert (new_type != SVt_NULL);
1219     switch (new_type) {
1220     case SVt_IV:
1221 	assert(old_type == SVt_NULL);
1222 	SvANY(sv) = (XPVIV*)((char*)&(sv->sv_u.svu_iv) - STRUCT_OFFSET(XPVIV, xiv_iv));
1223 	SvIV_set(sv, 0);
1224 	return;
1225     case SVt_NV:
1226 	assert(old_type == SVt_NULL);
1227 	SvANY(sv) = new_XNV();
1228 	SvNV_set(sv, 0);
1229 	return;
1230     case SVt_RV:
1231 	assert(old_type == SVt_NULL);
1232 	SvANY(sv) = &sv->sv_u.svu_rv;
1233 	SvRV_set(sv, 0);
1234 	return;
1235     case SVt_PVHV:
1236     case SVt_PVAV:
1237 	assert(new_type_details->body_size);
1238 
1239 #ifndef PURIFY
1240 	assert(new_type_details->arena);
1241 	assert(new_type_details->arena_size);
1242 	/* This points to the start of the allocated area.  */
1243 	new_body_inline(new_body, new_type);
1244 	Zero(new_body, new_type_details->body_size, char);
1245 	new_body = ((char *)new_body) - new_type_details->offset;
1246 #else
1247 	/* We always allocated the full length item with PURIFY. To do this
1248 	   we fake things so that arena is false for all 16 types..  */
1249 	new_body = new_NOARENAZ(new_type_details);
1250 #endif
1251 	SvANY(sv) = new_body;
1252 	if (new_type == SVt_PVAV) {
1253 	    AvMAX(sv)	= -1;
1254 	    AvFILLp(sv)	= -1;
1255 	    AvREAL_only(sv);
1256 	}
1257 
1258 	/* SVt_NULL isn't the only thing upgraded to AV or HV.
1259 	   The target created by newSVrv also is, and it can have magic.
1260 	   However, it never has SvPVX set.
1261 	*/
1262 	if (old_type >= SVt_RV) {
1263 	    assert(SvPVX_const(sv) == 0);
1264 	}
1265 
1266 	if (old_type >= SVt_PVMG) {
1267 	    SvMAGIC_set(sv, ((XPVMG*)old_body)->xmg_u.xmg_magic);
1268 	    SvSTASH_set(sv, ((XPVMG*)old_body)->xmg_stash);
1269 	} else {
1270 	    sv->sv_u.svu_array = NULL; /* or svu_hash  */
1271 	}
1272 	break;
1273 
1274 
1275     case SVt_PVIV:
1276 	/* XXX Is this still needed?  Was it ever needed?   Surely as there is
1277 	   no route from NV to PVIV, NOK can never be true  */
1278 	assert(!SvNOKp(sv));
1279 	assert(!SvNOK(sv));
1280     case SVt_PVIO:
1281     case SVt_PVFM:
1282     case SVt_PVGV:
1283     case SVt_PVCV:
1284     case SVt_PVLV:
1285     case SVt_PVMG:
1286     case SVt_PVNV:
1287     case SVt_PV:
1288 
1289 	assert(new_type_details->body_size);
1290 	/* We always allocated the full length item with PURIFY. To do this
1291 	   we fake things so that arena is false for all 16 types..  */
1292 	if(new_type_details->arena) {
1293 	    /* This points to the start of the allocated area.  */
1294 	    new_body_inline(new_body, new_type);
1295 	    Zero(new_body, new_type_details->body_size, char);
1296 	    new_body = ((char *)new_body) - new_type_details->offset;
1297 	} else {
1298 	    new_body = new_NOARENAZ(new_type_details);
1299 	}
1300 	SvANY(sv) = new_body;
1301 
1302 	if (old_type_details->copy) {
1303 	    /* There is now the potential for an upgrade from something without
1304 	       an offset (PVNV or PVMG) to something with one (PVCV, PVFM)  */
1305 	    int offset = old_type_details->offset;
1306 	    int length = old_type_details->copy;
1307 
1308 	    if (new_type_details->offset > old_type_details->offset) {
1309 		const int difference
1310 		    = new_type_details->offset - old_type_details->offset;
1311 		offset += difference;
1312 		length -= difference;
1313 	    }
1314 	    assert (length >= 0);
1315 
1316 	    Copy((char *)old_body + offset, (char *)new_body + offset, length,
1317 		 char);
1318 	}
1319 
1320 #ifndef NV_ZERO_IS_ALLBITS_ZERO
1321 	/* If NV 0.0 is stores as all bits 0 then Zero() already creates a
1322 	 * correct 0.0 for us.  Otherwise, if the old body didn't have an
1323 	 * NV slot, but the new one does, then we need to initialise the
1324 	 * freshly created NV slot with whatever the correct bit pattern is
1325 	 * for 0.0  */
1326 	if (old_type_details->zero_nv && !new_type_details->zero_nv
1327 	    && !isGV_with_GP(sv))
1328 	    SvNV_set(sv, 0);
1329 #endif
1330 
1331 	if (new_type == SVt_PVIO)
1332 	    IoPAGE_LEN(sv) = 60;
1333 	if (old_type < SVt_RV)
1334 	    SvPV_set(sv, NULL);
1335 	break;
1336     default:
1337 	Perl_croak(aTHX_ "panic: sv_upgrade to unknown type %lu",
1338 		   (unsigned long)new_type);
1339     }
1340 
1341     if (old_type_details->arena) {
1342 	/* If there was an old body, then we need to free it.
1343 	   Note that there is an assumption that all bodies of types that
1344 	   can be upgraded came from arenas. Only the more complex non-
1345 	   upgradable types are allowed to be directly malloc()ed.  */
1346 #ifdef PURIFY
1347 	my_safefree(old_body);
1348 #else
1349 	del_body((void*)((char*)old_body + old_type_details->offset),
1350 		 &PL_body_roots[old_type]);
1351 #endif
1352     }
1353 }
1354 
1355 /*
1356 =for apidoc sv_backoff
1357 
1358 Remove any string offset. You should normally use the C<SvOOK_off> macro
1359 wrapper instead.
1360 
1361 =cut
1362 */
1363 
1364 int
1365 Perl_sv_backoff(pTHX_ register SV *sv)
1366 {
1367     PERL_UNUSED_CONTEXT;
1368     assert(SvOOK(sv));
1369     assert(SvTYPE(sv) != SVt_PVHV);
1370     assert(SvTYPE(sv) != SVt_PVAV);
1371     if (SvIVX(sv)) {
1372 	const char * const s = SvPVX_const(sv);
1373 	SvLEN_set(sv, SvLEN(sv) + SvIVX(sv));
1374 	SvPV_set(sv, SvPVX(sv) - SvIVX(sv));
1375 	SvIV_set(sv, 0);
1376 	Move(s, SvPVX(sv), SvCUR(sv)+1, char);
1377     }
1378     SvFLAGS(sv) &= ~SVf_OOK;
1379     return 0;
1380 }
1381 
1382 /*
1383 =for apidoc sv_grow
1384 
1385 Expands the character buffer in the SV.  If necessary, uses C<sv_unref> and
1386 upgrades the SV to C<SVt_PV>.  Returns a pointer to the character buffer.
1387 Use the C<SvGROW> wrapper instead.
1388 
1389 =cut
1390 */
1391 
1392 char *
1393 Perl_sv_grow(pTHX_ register SV *sv, register STRLEN newlen)
1394 {
1395     register char *s;
1396 
1397     if (PL_madskills && newlen >= 0x100000) {
1398 	PerlIO_printf(Perl_debug_log,
1399 		      "Allocation too large: %"UVxf"\n", (UV)newlen);
1400     }
1401 #ifdef HAS_64K_LIMIT
1402     if (newlen >= 0x10000) {
1403 	PerlIO_printf(Perl_debug_log,
1404 		      "Allocation too large: %"UVxf"\n", (UV)newlen);
1405 	my_exit(1);
1406     }
1407 #endif /* HAS_64K_LIMIT */
1408     if (SvROK(sv))
1409 	sv_unref(sv);
1410     if (SvTYPE(sv) < SVt_PV) {
1411 	sv_upgrade(sv, SVt_PV);
1412 	s = SvPVX_mutable(sv);
1413     }
1414     else if (SvOOK(sv)) {	/* pv is offset? */
1415 	sv_backoff(sv);
1416 	s = SvPVX_mutable(sv);
1417 	if (newlen > SvLEN(sv))
1418 	    newlen += 10 * (newlen - SvCUR(sv)); /* avoid copy each time */
1419 #ifdef HAS_64K_LIMIT
1420 	if (newlen >= 0x10000)
1421 	    newlen = 0xFFFF;
1422 #endif
1423     }
1424     else
1425 	s = SvPVX_mutable(sv);
1426 
1427     if (newlen > SvLEN(sv)) {		/* need more room? */
1428 	newlen = PERL_STRLEN_ROUNDUP(newlen);
1429 	if (SvLEN(sv) && s) {
1430 #ifdef MYMALLOC
1431 	    const STRLEN l = malloced_size((void*)SvPVX_const(sv));
1432 	    if (newlen <= l) {
1433 		SvLEN_set(sv, l);
1434 		return s;
1435 	    } else
1436 #endif
1437 	    s = (char*)saferealloc(s, newlen);
1438 	}
1439 	else {
1440 	    s = (char*)safemalloc(newlen);
1441 	    if (SvPVX_const(sv) && SvCUR(sv)) {
1442 	        Move(SvPVX_const(sv), s, (newlen < SvCUR(sv)) ? newlen : SvCUR(sv), char);
1443 	    }
1444 	}
1445 	SvPV_set(sv, s);
1446         SvLEN_set(sv, newlen);
1447     }
1448     return s;
1449 }
1450 
1451 /*
1452 =for apidoc sv_setiv
1453 
1454 Copies an integer into the given SV, upgrading first if necessary.
1455 Does not handle 'set' magic.  See also C<sv_setiv_mg>.
1456 
1457 =cut
1458 */
1459 
1460 void
1461 Perl_sv_setiv(pTHX_ register SV *sv, IV i)
1462 {
1463     dVAR;
1464     SV_CHECK_THINKFIRST_COW_DROP(sv);
1465     switch (SvTYPE(sv)) {
1466     case SVt_NULL:
1467 	sv_upgrade(sv, SVt_IV);
1468 	break;
1469     case SVt_NV:
1470 	sv_upgrade(sv, SVt_PVNV);
1471 	break;
1472     case SVt_RV:
1473     case SVt_PV:
1474 	sv_upgrade(sv, SVt_PVIV);
1475 	break;
1476 
1477     case SVt_PVGV:
1478     case SVt_PVAV:
1479     case SVt_PVHV:
1480     case SVt_PVCV:
1481     case SVt_PVFM:
1482     case SVt_PVIO:
1483 	Perl_croak(aTHX_ "Can't coerce %s to integer in %s", sv_reftype(sv,0),
1484 		   OP_DESC(PL_op));
1485     default: NOOP;
1486     }
1487     (void)SvIOK_only(sv);			/* validate number */
1488     SvIV_set(sv, i);
1489     SvTAINT(sv);
1490 }
1491 
1492 /*
1493 =for apidoc sv_setiv_mg
1494 
1495 Like C<sv_setiv>, but also handles 'set' magic.
1496 
1497 =cut
1498 */
1499 
1500 void
1501 Perl_sv_setiv_mg(pTHX_ register SV *sv, IV i)
1502 {
1503     sv_setiv(sv,i);
1504     SvSETMAGIC(sv);
1505 }
1506 
1507 /*
1508 =for apidoc sv_setuv
1509 
1510 Copies an unsigned integer into the given SV, upgrading first if necessary.
1511 Does not handle 'set' magic.  See also C<sv_setuv_mg>.
1512 
1513 =cut
1514 */
1515 
1516 void
1517 Perl_sv_setuv(pTHX_ register SV *sv, UV u)
1518 {
1519     /* With these two if statements:
1520        u=1.49  s=0.52  cu=72.49  cs=10.64  scripts=270  tests=20865
1521 
1522        without
1523        u=1.35  s=0.47  cu=73.45  cs=11.43  scripts=270  tests=20865
1524 
1525        If you wish to remove them, please benchmark to see what the effect is
1526     */
1527     if (u <= (UV)IV_MAX) {
1528        sv_setiv(sv, (IV)u);
1529        return;
1530     }
1531     sv_setiv(sv, 0);
1532     SvIsUV_on(sv);
1533     SvUV_set(sv, u);
1534 }
1535 
1536 /*
1537 =for apidoc sv_setuv_mg
1538 
1539 Like C<sv_setuv>, but also handles 'set' magic.
1540 
1541 =cut
1542 */
1543 
1544 void
1545 Perl_sv_setuv_mg(pTHX_ register SV *sv, UV u)
1546 {
1547     sv_setuv(sv,u);
1548     SvSETMAGIC(sv);
1549 }
1550 
1551 /*
1552 =for apidoc sv_setnv
1553 
1554 Copies a double into the given SV, upgrading first if necessary.
1555 Does not handle 'set' magic.  See also C<sv_setnv_mg>.
1556 
1557 =cut
1558 */
1559 
1560 void
1561 Perl_sv_setnv(pTHX_ register SV *sv, NV num)
1562 {
1563     dVAR;
1564     SV_CHECK_THINKFIRST_COW_DROP(sv);
1565     switch (SvTYPE(sv)) {
1566     case SVt_NULL:
1567     case SVt_IV:
1568 	sv_upgrade(sv, SVt_NV);
1569 	break;
1570     case SVt_RV:
1571     case SVt_PV:
1572     case SVt_PVIV:
1573 	sv_upgrade(sv, SVt_PVNV);
1574 	break;
1575 
1576     case SVt_PVGV:
1577     case SVt_PVAV:
1578     case SVt_PVHV:
1579     case SVt_PVCV:
1580     case SVt_PVFM:
1581     case SVt_PVIO:
1582 	Perl_croak(aTHX_ "Can't coerce %s to number in %s", sv_reftype(sv,0),
1583 		   OP_NAME(PL_op));
1584     default: NOOP;
1585     }
1586     SvNV_set(sv, num);
1587     (void)SvNOK_only(sv);			/* validate number */
1588     SvTAINT(sv);
1589 }
1590 
1591 /*
1592 =for apidoc sv_setnv_mg
1593 
1594 Like C<sv_setnv>, but also handles 'set' magic.
1595 
1596 =cut
1597 */
1598 
1599 void
1600 Perl_sv_setnv_mg(pTHX_ register SV *sv, NV num)
1601 {
1602     sv_setnv(sv,num);
1603     SvSETMAGIC(sv);
1604 }
1605 
1606 /* Print an "isn't numeric" warning, using a cleaned-up,
1607  * printable version of the offending string
1608  */
1609 
1610 STATIC void
1611 S_not_a_number(pTHX_ SV *sv)
1612 {
1613      dVAR;
1614      SV *dsv;
1615      char tmpbuf[64];
1616      const char *pv;
1617 
1618      if (DO_UTF8(sv)) {
1619           dsv = sv_2mortal(newSVpvs(""));
1620           pv = sv_uni_display(dsv, sv, 10, 0);
1621      } else {
1622 	  char *d = tmpbuf;
1623 	  const char * const limit = tmpbuf + sizeof(tmpbuf) - 8;
1624 	  /* each *s can expand to 4 chars + "...\0",
1625 	     i.e. need room for 8 chars */
1626 
1627 	  const char *s = SvPVX_const(sv);
1628 	  const char * const end = s + SvCUR(sv);
1629 	  for ( ; s < end && d < limit; s++ ) {
1630 	       int ch = *s & 0xFF;
1631 	       if (ch & 128 && !isPRINT_LC(ch)) {
1632 		    *d++ = 'M';
1633 		    *d++ = '-';
1634 		    ch &= 127;
1635 	       }
1636 	       if (ch == '\n') {
1637 		    *d++ = '\\';
1638 		    *d++ = 'n';
1639 	       }
1640 	       else if (ch == '\r') {
1641 		    *d++ = '\\';
1642 		    *d++ = 'r';
1643 	       }
1644 	       else if (ch == '\f') {
1645 		    *d++ = '\\';
1646 		    *d++ = 'f';
1647 	       }
1648 	       else if (ch == '\\') {
1649 		    *d++ = '\\';
1650 		    *d++ = '\\';
1651 	       }
1652 	       else if (ch == '\0') {
1653 		    *d++ = '\\';
1654 		    *d++ = '0';
1655 	       }
1656 	       else if (isPRINT_LC(ch))
1657 		    *d++ = ch;
1658 	       else {
1659 		    *d++ = '^';
1660 		    *d++ = toCTRL(ch);
1661 	       }
1662 	  }
1663 	  if (s < end) {
1664 	       *d++ = '.';
1665 	       *d++ = '.';
1666 	       *d++ = '.';
1667 	  }
1668 	  *d = '\0';
1669 	  pv = tmpbuf;
1670     }
1671 
1672     if (PL_op)
1673 	Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
1674 		    "Argument \"%s\" isn't numeric in %s", pv,
1675 		    OP_DESC(PL_op));
1676     else
1677 	Perl_warner(aTHX_ packWARN(WARN_NUMERIC),
1678 		    "Argument \"%s\" isn't numeric", pv);
1679 }
1680 
1681 /*
1682 =for apidoc looks_like_number
1683 
1684 Test if the content of an SV looks like a number (or is a number).
1685 C<Inf> and C<Infinity> are treated as numbers (so will not issue a
1686 non-numeric warning), even if your atof() doesn't grok them.
1687 
1688 =cut
1689 */
1690 
1691 I32
1692 Perl_looks_like_number(pTHX_ SV *sv)
1693 {
1694     register const char *sbegin;
1695     STRLEN len;
1696 
1697     if (SvPOK(sv)) {
1698 	sbegin = SvPVX_const(sv);
1699 	len = SvCUR(sv);
1700     }
1701     else if (SvPOKp(sv))
1702 	sbegin = SvPV_const(sv, len);
1703     else
1704 	return SvFLAGS(sv) & (SVf_NOK|SVp_NOK|SVf_IOK|SVp_IOK);
1705     return grok_number(sbegin, len, NULL);
1706 }
1707 
1708 STATIC bool
1709 S_glob_2number(pTHX_ GV * const gv)
1710 {
1711     const U32 wasfake = SvFLAGS(gv) & SVf_FAKE;
1712     SV *const buffer = sv_newmortal();
1713 
1714     /* FAKE globs can get coerced, so need to turn this off temporarily if it
1715        is on.  */
1716     SvFAKE_off(gv);
1717     gv_efullname3(buffer, gv, "*");
1718     SvFLAGS(gv) |= wasfake;
1719 
1720     /* We know that all GVs stringify to something that is not-a-number,
1721 	so no need to test that.  */
1722     if (ckWARN(WARN_NUMERIC))
1723 	not_a_number(buffer);
1724     /* We just want something true to return, so that S_sv_2iuv_common
1725 	can tail call us and return true.  */
1726     return TRUE;
1727 }
1728 
1729 STATIC char *
1730 S_glob_2pv(pTHX_ GV * const gv, STRLEN * const len)
1731 {
1732     const U32 wasfake = SvFLAGS(gv) & SVf_FAKE;
1733     SV *const buffer = sv_newmortal();
1734 
1735     /* FAKE globs can get coerced, so need to turn this off temporarily if it
1736        is on.  */
1737     SvFAKE_off(gv);
1738     gv_efullname3(buffer, gv, "*");
1739     SvFLAGS(gv) |= wasfake;
1740 
1741     assert(SvPOK(buffer));
1742     if (len) {
1743 	*len = SvCUR(buffer);
1744     }
1745     return SvPVX(buffer);
1746 }
1747 
1748 /* Actually, ISO C leaves conversion of UV to IV undefined, but
1749    until proven guilty, assume that things are not that bad... */
1750 
1751 /*
1752    NV_PRESERVES_UV:
1753 
1754    As 64 bit platforms often have an NV that doesn't preserve all bits of
1755    an IV (an assumption perl has been based on to date) it becomes necessary
1756    to remove the assumption that the NV always carries enough precision to
1757    recreate the IV whenever needed, and that the NV is the canonical form.
1758    Instead, IV/UV and NV need to be given equal rights. So as to not lose
1759    precision as a side effect of conversion (which would lead to insanity
1760    and the dragon(s) in t/op/numconvert.t getting very angry) the intent is
1761    1) to distinguish between IV/UV/NV slots that have cached a valid
1762       conversion where precision was lost and IV/UV/NV slots that have a
1763       valid conversion which has lost no precision
1764    2) to ensure that if a numeric conversion to one form is requested that
1765       would lose precision, the precise conversion (or differently
1766       imprecise conversion) is also performed and cached, to prevent
1767       requests for different numeric formats on the same SV causing
1768       lossy conversion chains. (lossless conversion chains are perfectly
1769       acceptable (still))
1770 
1771 
1772    flags are used:
1773    SvIOKp is true if the IV slot contains a valid value
1774    SvIOK  is true only if the IV value is accurate (UV if SvIOK_UV true)
1775    SvNOKp is true if the NV slot contains a valid value
1776    SvNOK  is true only if the NV value is accurate
1777 
1778    so
1779    while converting from PV to NV, check to see if converting that NV to an
1780    IV(or UV) would lose accuracy over a direct conversion from PV to
1781    IV(or UV). If it would, cache both conversions, return NV, but mark
1782    SV as IOK NOKp (ie not NOK).
1783 
1784    While converting from PV to IV, check to see if converting that IV to an
1785    NV would lose accuracy over a direct conversion from PV to NV. If it
1786    would, cache both conversions, flag similarly.
1787 
1788    Before, the SV value "3.2" could become NV=3.2 IV=3 NOK, IOK quite
1789    correctly because if IV & NV were set NV *always* overruled.
1790    Now, "3.2" will become NV=3.2 IV=3 NOK, IOKp, because the flag's meaning
1791    changes - now IV and NV together means that the two are interchangeable:
1792    SvIVX == (IV) SvNVX && SvNVX == (NV) SvIVX;
1793 
1794    The benefit of this is that operations such as pp_add know that if
1795    SvIOK is true for both left and right operands, then integer addition
1796    can be used instead of floating point (for cases where the result won't
1797    overflow). Before, floating point was always used, which could lead to
1798    loss of precision compared with integer addition.
1799 
1800    * making IV and NV equal status should make maths accurate on 64 bit
1801      platforms
1802    * may speed up maths somewhat if pp_add and friends start to use
1803      integers when possible instead of fp. (Hopefully the overhead in
1804      looking for SvIOK and checking for overflow will not outweigh the
1805      fp to integer speedup)
1806    * will slow down integer operations (callers of SvIV) on "inaccurate"
1807      values, as the change from SvIOK to SvIOKp will cause a call into
1808      sv_2iv each time rather than a macro access direct to the IV slot
1809    * should speed up number->string conversion on integers as IV is
1810      favoured when IV and NV are equally accurate
1811 
1812    ####################################################################
1813    You had better be using SvIOK_notUV if you want an IV for arithmetic:
1814    SvIOK is true if (IV or UV), so you might be getting (IV)SvUV.
1815    On the other hand, SvUOK is true iff UV.
1816    ####################################################################
1817 
1818    Your mileage will vary depending your CPU's relative fp to integer
1819    performance ratio.
1820 */
1821 
1822 #ifndef NV_PRESERVES_UV
1823 #  define IS_NUMBER_UNDERFLOW_IV 1
1824 #  define IS_NUMBER_UNDERFLOW_UV 2
1825 #  define IS_NUMBER_IV_AND_UV    2
1826 #  define IS_NUMBER_OVERFLOW_IV  4
1827 #  define IS_NUMBER_OVERFLOW_UV  5
1828 
1829 /* sv_2iuv_non_preserve(): private routine for use by sv_2iv() and sv_2uv() */
1830 
1831 /* For sv_2nv these three cases are "SvNOK and don't bother casting"  */
1832 STATIC int
1833 S_sv_2iuv_non_preserve(pTHX_ register SV *sv, I32 numtype)
1834 {
1835     dVAR;
1836     PERL_UNUSED_ARG(numtype); /* Used only under DEBUGGING? */
1837     DEBUG_c(PerlIO_printf(Perl_debug_log,"sv_2iuv_non '%s', IV=0x%"UVxf" NV=%"NVgf" inttype=%"UVXf"\n", SvPVX_const(sv), SvIVX(sv), SvNVX(sv), (UV)numtype));
1838     if (SvNVX(sv) < (NV)IV_MIN) {
1839 	(void)SvIOKp_on(sv);
1840 	(void)SvNOK_on(sv);
1841 	SvIV_set(sv, IV_MIN);
1842 	return IS_NUMBER_UNDERFLOW_IV;
1843     }
1844     if (SvNVX(sv) > (NV)UV_MAX) {
1845 	(void)SvIOKp_on(sv);
1846 	(void)SvNOK_on(sv);
1847 	SvIsUV_on(sv);
1848 	SvUV_set(sv, UV_MAX);
1849 	return IS_NUMBER_OVERFLOW_UV;
1850     }
1851     (void)SvIOKp_on(sv);
1852     (void)SvNOK_on(sv);
1853     /* Can't use strtol etc to convert this string.  (See truth table in
1854        sv_2iv  */
1855     if (SvNVX(sv) <= (UV)IV_MAX) {
1856         SvIV_set(sv, I_V(SvNVX(sv)));
1857         if ((NV)(SvIVX(sv)) == SvNVX(sv)) {
1858             SvIOK_on(sv); /* Integer is precise. NOK, IOK */
1859         } else {
1860             /* Integer is imprecise. NOK, IOKp */
1861         }
1862         return SvNVX(sv) < 0 ? IS_NUMBER_UNDERFLOW_UV : IS_NUMBER_IV_AND_UV;
1863     }
1864     SvIsUV_on(sv);
1865     SvUV_set(sv, U_V(SvNVX(sv)));
1866     if ((NV)(SvUVX(sv)) == SvNVX(sv)) {
1867         if (SvUVX(sv) == UV_MAX) {
1868             /* As we know that NVs don't preserve UVs, UV_MAX cannot
1869                possibly be preserved by NV. Hence, it must be overflow.
1870                NOK, IOKp */
1871             return IS_NUMBER_OVERFLOW_UV;
1872         }
1873         SvIOK_on(sv); /* Integer is precise. NOK, UOK */
1874     } else {
1875         /* Integer is imprecise. NOK, IOKp */
1876     }
1877     return IS_NUMBER_OVERFLOW_IV;
1878 }
1879 #endif /* !NV_PRESERVES_UV*/
1880 
1881 STATIC bool
1882 S_sv_2iuv_common(pTHX_ SV *sv) {
1883     dVAR;
1884     if (SvNOKp(sv)) {
1885 	/* erm. not sure. *should* never get NOKp (without NOK) from sv_2nv
1886 	 * without also getting a cached IV/UV from it at the same time
1887 	 * (ie PV->NV conversion should detect loss of accuracy and cache
1888 	 * IV or UV at same time to avoid this. */
1889 	/* IV-over-UV optimisation - choose to cache IV if possible */
1890 
1891 	if (SvTYPE(sv) == SVt_NV)
1892 	    sv_upgrade(sv, SVt_PVNV);
1893 
1894 	(void)SvIOKp_on(sv);	/* Must do this first, to clear any SvOOK */
1895 	/* < not <= as for NV doesn't preserve UV, ((NV)IV_MAX+1) will almost
1896 	   certainly cast into the IV range at IV_MAX, whereas the correct
1897 	   answer is the UV IV_MAX +1. Hence < ensures that dodgy boundary
1898 	   cases go to UV */
1899 #if defined(NAN_COMPARE_BROKEN) && defined(Perl_isnan)
1900 	if (Perl_isnan(SvNVX(sv))) {
1901 	    SvUV_set(sv, 0);
1902 	    SvIsUV_on(sv);
1903 	    return FALSE;
1904 	}
1905 #endif
1906 	if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
1907 	    SvIV_set(sv, I_V(SvNVX(sv)));
1908 	    if (SvNVX(sv) == (NV) SvIVX(sv)
1909 #ifndef NV_PRESERVES_UV
1910 		&& (((UV)1 << NV_PRESERVES_UV_BITS) >
1911 		    (UV)(SvIVX(sv) > 0 ? SvIVX(sv) : -SvIVX(sv)))
1912 		/* Don't flag it as "accurately an integer" if the number
1913 		   came from a (by definition imprecise) NV operation, and
1914 		   we're outside the range of NV integer precision */
1915 #endif
1916 		) {
1917 		SvIOK_on(sv);  /* Can this go wrong with rounding? NWC */
1918 		DEBUG_c(PerlIO_printf(Perl_debug_log,
1919 				      "0x%"UVxf" iv(%"NVgf" => %"IVdf") (precise)\n",
1920 				      PTR2UV(sv),
1921 				      SvNVX(sv),
1922 				      SvIVX(sv)));
1923 
1924 	    } else {
1925 		/* IV not precise.  No need to convert from PV, as NV
1926 		   conversion would already have cached IV if it detected
1927 		   that PV->IV would be better than PV->NV->IV
1928 		   flags already correct - don't set public IOK.  */
1929 		DEBUG_c(PerlIO_printf(Perl_debug_log,
1930 				      "0x%"UVxf" iv(%"NVgf" => %"IVdf") (imprecise)\n",
1931 				      PTR2UV(sv),
1932 				      SvNVX(sv),
1933 				      SvIVX(sv)));
1934 	    }
1935 	    /* Can the above go wrong if SvIVX == IV_MIN and SvNVX < IV_MIN,
1936 	       but the cast (NV)IV_MIN rounds to a the value less (more
1937 	       negative) than IV_MIN which happens to be equal to SvNVX ??
1938 	       Analogous to 0xFFFFFFFFFFFFFFFF rounding up to NV (2**64) and
1939 	       NV rounding back to 0xFFFFFFFFFFFFFFFF, so UVX == UV(NVX) and
1940 	       (NV)UVX == NVX are both true, but the values differ. :-(
1941 	       Hopefully for 2s complement IV_MIN is something like
1942 	       0x8000000000000000 which will be exact. NWC */
1943 	}
1944 	else {
1945 	    SvUV_set(sv, U_V(SvNVX(sv)));
1946 	    if (
1947 		(SvNVX(sv) == (NV) SvUVX(sv))
1948 #ifndef  NV_PRESERVES_UV
1949 		/* Make sure it's not 0xFFFFFFFFFFFFFFFF */
1950 		/*&& (SvUVX(sv) != UV_MAX) irrelevant with code below */
1951 		&& (((UV)1 << NV_PRESERVES_UV_BITS) > SvUVX(sv))
1952 		/* Don't flag it as "accurately an integer" if the number
1953 		   came from a (by definition imprecise) NV operation, and
1954 		   we're outside the range of NV integer precision */
1955 #endif
1956 		)
1957 		SvIOK_on(sv);
1958 	    SvIsUV_on(sv);
1959 	    DEBUG_c(PerlIO_printf(Perl_debug_log,
1960 				  "0x%"UVxf" 2iv(%"UVuf" => %"IVdf") (as unsigned)\n",
1961 				  PTR2UV(sv),
1962 				  SvUVX(sv),
1963 				  SvUVX(sv)));
1964 	}
1965     }
1966     else if (SvPOKp(sv) && SvLEN(sv)) {
1967 	UV value;
1968 	const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), &value);
1969 	/* We want to avoid a possible problem when we cache an IV/ a UV which
1970 	   may be later translated to an NV, and the resulting NV is not
1971 	   the same as the direct translation of the initial string
1972 	   (eg 123.456 can shortcut to the IV 123 with atol(), but we must
1973 	   be careful to ensure that the value with the .456 is around if the
1974 	   NV value is requested in the future).
1975 
1976 	   This means that if we cache such an IV/a UV, we need to cache the
1977 	   NV as well.  Moreover, we trade speed for space, and do not
1978 	   cache the NV if we are sure it's not needed.
1979 	 */
1980 
1981 	/* SVt_PVNV is one higher than SVt_PVIV, hence this order  */
1982 	if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
1983 	     == IS_NUMBER_IN_UV) {
1984 	    /* It's definitely an integer, only upgrade to PVIV */
1985 	    if (SvTYPE(sv) < SVt_PVIV)
1986 		sv_upgrade(sv, SVt_PVIV);
1987 	    (void)SvIOK_on(sv);
1988 	} else if (SvTYPE(sv) < SVt_PVNV)
1989 	    sv_upgrade(sv, SVt_PVNV);
1990 
1991 	/* If NVs preserve UVs then we only use the UV value if we know that
1992 	   we aren't going to call atof() below. If NVs don't preserve UVs
1993 	   then the value returned may have more precision than atof() will
1994 	   return, even though value isn't perfectly accurate.  */
1995 	if ((numtype & (IS_NUMBER_IN_UV
1996 #ifdef NV_PRESERVES_UV
1997 			| IS_NUMBER_NOT_INT
1998 #endif
1999 	    )) == IS_NUMBER_IN_UV) {
2000 	    /* This won't turn off the public IOK flag if it was set above  */
2001 	    (void)SvIOKp_on(sv);
2002 
2003 	    if (!(numtype & IS_NUMBER_NEG)) {
2004 		/* positive */;
2005 		if (value <= (UV)IV_MAX) {
2006 		    SvIV_set(sv, (IV)value);
2007 		} else {
2008 		    /* it didn't overflow, and it was positive. */
2009 		    SvUV_set(sv, value);
2010 		    SvIsUV_on(sv);
2011 		}
2012 	    } else {
2013 		/* 2s complement assumption  */
2014 		if (value <= (UV)IV_MIN) {
2015 		    SvIV_set(sv, -(IV)value);
2016 		} else {
2017 		    /* Too negative for an IV.  This is a double upgrade, but
2018 		       I'm assuming it will be rare.  */
2019 		    if (SvTYPE(sv) < SVt_PVNV)
2020 			sv_upgrade(sv, SVt_PVNV);
2021 		    SvNOK_on(sv);
2022 		    SvIOK_off(sv);
2023 		    SvIOKp_on(sv);
2024 		    SvNV_set(sv, -(NV)value);
2025 		    SvIV_set(sv, IV_MIN);
2026 		}
2027 	    }
2028 	}
2029 	/* For !NV_PRESERVES_UV and IS_NUMBER_IN_UV and IS_NUMBER_NOT_INT we
2030            will be in the previous block to set the IV slot, and the next
2031            block to set the NV slot.  So no else here.  */
2032 
2033 	if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2034 	    != IS_NUMBER_IN_UV) {
2035 	    /* It wasn't an (integer that doesn't overflow the UV). */
2036 	    SvNV_set(sv, Atof(SvPVX_const(sv)));
2037 
2038 	    if (! numtype && ckWARN(WARN_NUMERIC))
2039 		not_a_number(sv);
2040 
2041 #if defined(USE_LONG_DOUBLE)
2042 	    DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2iv(%" PERL_PRIgldbl ")\n",
2043 				  PTR2UV(sv), SvNVX(sv)));
2044 #else
2045 	    DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2iv(%"NVgf")\n",
2046 				  PTR2UV(sv), SvNVX(sv)));
2047 #endif
2048 
2049 #ifdef NV_PRESERVES_UV
2050             (void)SvIOKp_on(sv);
2051             (void)SvNOK_on(sv);
2052             if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
2053                 SvIV_set(sv, I_V(SvNVX(sv)));
2054                 if ((NV)(SvIVX(sv)) == SvNVX(sv)) {
2055                     SvIOK_on(sv);
2056                 } else {
2057 		    NOOP;  /* Integer is imprecise. NOK, IOKp */
2058                 }
2059                 /* UV will not work better than IV */
2060             } else {
2061                 if (SvNVX(sv) > (NV)UV_MAX) {
2062                     SvIsUV_on(sv);
2063                     /* Integer is inaccurate. NOK, IOKp, is UV */
2064                     SvUV_set(sv, UV_MAX);
2065                 } else {
2066                     SvUV_set(sv, U_V(SvNVX(sv)));
2067                     /* 0xFFFFFFFFFFFFFFFF not an issue in here, NVs
2068                        NV preservse UV so can do correct comparison.  */
2069                     if ((NV)(SvUVX(sv)) == SvNVX(sv)) {
2070                         SvIOK_on(sv);
2071                     } else {
2072 			NOOP;   /* Integer is imprecise. NOK, IOKp, is UV */
2073                     }
2074                 }
2075 		SvIsUV_on(sv);
2076             }
2077 #else /* NV_PRESERVES_UV */
2078             if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2079                 == (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT)) {
2080                 /* The IV/UV slot will have been set from value returned by
2081                    grok_number above.  The NV slot has just been set using
2082                    Atof.  */
2083 	        SvNOK_on(sv);
2084                 assert (SvIOKp(sv));
2085             } else {
2086                 if (((UV)1 << NV_PRESERVES_UV_BITS) >
2087                     U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))) {
2088                     /* Small enough to preserve all bits. */
2089                     (void)SvIOKp_on(sv);
2090                     SvNOK_on(sv);
2091                     SvIV_set(sv, I_V(SvNVX(sv)));
2092                     if ((NV)(SvIVX(sv)) == SvNVX(sv))
2093                         SvIOK_on(sv);
2094                     /* Assumption: first non-preserved integer is < IV_MAX,
2095                        this NV is in the preserved range, therefore: */
2096                     if (!(U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))
2097                           < (UV)IV_MAX)) {
2098                         Perl_croak(aTHX_ "sv_2iv assumed (U_V(fabs((double)SvNVX(sv))) < (UV)IV_MAX) but SvNVX(sv)=%"NVgf" U_V is 0x%"UVxf", IV_MAX is 0x%"UVxf"\n", SvNVX(sv), U_V(SvNVX(sv)), (UV)IV_MAX);
2099                     }
2100                 } else {
2101                     /* IN_UV NOT_INT
2102                          0      0	already failed to read UV.
2103                          0      1       already failed to read UV.
2104                          1      0       you won't get here in this case. IV/UV
2105                          	        slot set, public IOK, Atof() unneeded.
2106                          1      1       already read UV.
2107                        so there's no point in sv_2iuv_non_preserve() attempting
2108                        to use atol, strtol, strtoul etc.  */
2109                     sv_2iuv_non_preserve (sv, numtype);
2110                 }
2111             }
2112 #endif /* NV_PRESERVES_UV */
2113 	}
2114     }
2115     else  {
2116 	if (isGV_with_GP(sv))
2117 	    return glob_2number((GV *)sv);
2118 
2119 	if (!(SvFLAGS(sv) & SVs_PADTMP)) {
2120 	    if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
2121 		report_uninit(sv);
2122 	}
2123 	if (SvTYPE(sv) < SVt_IV)
2124 	    /* Typically the caller expects that sv_any is not NULL now.  */
2125 	    sv_upgrade(sv, SVt_IV);
2126 	/* Return 0 from the caller.  */
2127 	return TRUE;
2128     }
2129     return FALSE;
2130 }
2131 
2132 /*
2133 =for apidoc sv_2iv_flags
2134 
2135 Return the integer value of an SV, doing any necessary string
2136 conversion.  If flags includes SV_GMAGIC, does an mg_get() first.
2137 Normally used via the C<SvIV(sv)> and C<SvIVx(sv)> macros.
2138 
2139 =cut
2140 */
2141 
2142 IV
2143 Perl_sv_2iv_flags(pTHX_ register SV *sv, I32 flags)
2144 {
2145     dVAR;
2146     if (!sv)
2147 	return 0;
2148     if (SvGMAGICAL(sv) || (SvTYPE(sv) == SVt_PVGV && SvVALID(sv))) {
2149 	/* FBMs use the same flag bit as SVf_IVisUV, so must let them
2150 	   cache IVs just in case. In practice it seems that they never
2151 	   actually anywhere accessible by user Perl code, let alone get used
2152 	   in anything other than a string context.  */
2153 	if (flags & SV_GMAGIC)
2154 	    mg_get(sv);
2155 	if (SvIOKp(sv))
2156 	    return SvIVX(sv);
2157 	if (SvNOKp(sv)) {
2158 	    return I_V(SvNVX(sv));
2159 	}
2160 	if (SvPOKp(sv) && SvLEN(sv)) {
2161 	    UV value;
2162 	    const int numtype
2163 		= grok_number(SvPVX_const(sv), SvCUR(sv), &value);
2164 
2165 	    if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2166 		== IS_NUMBER_IN_UV) {
2167 		/* It's definitely an integer */
2168 		if (numtype & IS_NUMBER_NEG) {
2169 		    if (value < (UV)IV_MIN)
2170 			return -(IV)value;
2171 		} else {
2172 		    if (value < (UV)IV_MAX)
2173 			return (IV)value;
2174 		}
2175 	    }
2176 	    if (!numtype) {
2177 		if (ckWARN(WARN_NUMERIC))
2178 		    not_a_number(sv);
2179 	    }
2180 	    return I_V(Atof(SvPVX_const(sv)));
2181 	}
2182         if (SvROK(sv)) {
2183 	    goto return_rok;
2184 	}
2185 	assert(SvTYPE(sv) >= SVt_PVMG);
2186 	/* This falls through to the report_uninit inside S_sv_2iuv_common.  */
2187     } else if (SvTHINKFIRST(sv)) {
2188 	if (SvROK(sv)) {
2189 	return_rok:
2190 	    if (SvAMAGIC(sv)) {
2191 		SV * const tmpstr=AMG_CALLun(sv,numer);
2192 		if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2193 		    return SvIV(tmpstr);
2194 		}
2195 	    }
2196 	    return PTR2IV(SvRV(sv));
2197 	}
2198 	if (SvIsCOW(sv)) {
2199 	    sv_force_normal_flags(sv, 0);
2200 	}
2201 	if (SvREADONLY(sv) && !SvOK(sv)) {
2202 	    if (ckWARN(WARN_UNINITIALIZED))
2203 		report_uninit(sv);
2204 	    return 0;
2205 	}
2206     }
2207     if (!SvIOKp(sv)) {
2208 	if (S_sv_2iuv_common(aTHX_ sv))
2209 	    return 0;
2210     }
2211     DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2iv(%"IVdf")\n",
2212 	PTR2UV(sv),SvIVX(sv)));
2213     return SvIsUV(sv) ? (IV)SvUVX(sv) : SvIVX(sv);
2214 }
2215 
2216 /*
2217 =for apidoc sv_2uv_flags
2218 
2219 Return the unsigned integer value of an SV, doing any necessary string
2220 conversion.  If flags includes SV_GMAGIC, does an mg_get() first.
2221 Normally used via the C<SvUV(sv)> and C<SvUVx(sv)> macros.
2222 
2223 =cut
2224 */
2225 
2226 UV
2227 Perl_sv_2uv_flags(pTHX_ register SV *sv, I32 flags)
2228 {
2229     dVAR;
2230     if (!sv)
2231 	return 0;
2232     if (SvGMAGICAL(sv) || (SvTYPE(sv) == SVt_PVGV && SvVALID(sv))) {
2233 	/* FBMs use the same flag bit as SVf_IVisUV, so must let them
2234 	   cache IVs just in case.  */
2235 	if (flags & SV_GMAGIC)
2236 	    mg_get(sv);
2237 	if (SvIOKp(sv))
2238 	    return SvUVX(sv);
2239 	if (SvNOKp(sv))
2240 	    return U_V(SvNVX(sv));
2241 	if (SvPOKp(sv) && SvLEN(sv)) {
2242 	    UV value;
2243 	    const int numtype
2244 		= grok_number(SvPVX_const(sv), SvCUR(sv), &value);
2245 
2246 	    if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2247 		== IS_NUMBER_IN_UV) {
2248 		/* It's definitely an integer */
2249 		if (!(numtype & IS_NUMBER_NEG))
2250 		    return value;
2251 	    }
2252 	    if (!numtype) {
2253 		if (ckWARN(WARN_NUMERIC))
2254 		    not_a_number(sv);
2255 	    }
2256 	    return U_V(Atof(SvPVX_const(sv)));
2257 	}
2258         if (SvROK(sv)) {
2259 	    goto return_rok;
2260 	}
2261 	assert(SvTYPE(sv) >= SVt_PVMG);
2262 	/* This falls through to the report_uninit inside S_sv_2iuv_common.  */
2263     } else if (SvTHINKFIRST(sv)) {
2264 	if (SvROK(sv)) {
2265 	return_rok:
2266 	    if (SvAMAGIC(sv)) {
2267 		SV *const tmpstr = AMG_CALLun(sv,numer);
2268 		if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2269 		    return SvUV(tmpstr);
2270 		}
2271 	    }
2272 	    return PTR2UV(SvRV(sv));
2273 	}
2274 	if (SvIsCOW(sv)) {
2275 	    sv_force_normal_flags(sv, 0);
2276 	}
2277 	if (SvREADONLY(sv) && !SvOK(sv)) {
2278 	    if (ckWARN(WARN_UNINITIALIZED))
2279 		report_uninit(sv);
2280 	    return 0;
2281 	}
2282     }
2283     if (!SvIOKp(sv)) {
2284 	if (S_sv_2iuv_common(aTHX_ sv))
2285 	    return 0;
2286     }
2287 
2288     DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2uv(%"UVuf")\n",
2289 			  PTR2UV(sv),SvUVX(sv)));
2290     return SvIsUV(sv) ? SvUVX(sv) : (UV)SvIVX(sv);
2291 }
2292 
2293 /*
2294 =for apidoc sv_2nv
2295 
2296 Return the num value of an SV, doing any necessary string or integer
2297 conversion, magic etc. Normally used via the C<SvNV(sv)> and C<SvNVx(sv)>
2298 macros.
2299 
2300 =cut
2301 */
2302 
2303 NV
2304 Perl_sv_2nv(pTHX_ register SV *sv)
2305 {
2306     dVAR;
2307     if (!sv)
2308 	return 0.0;
2309     if (SvGMAGICAL(sv) || (SvTYPE(sv) == SVt_PVGV && SvVALID(sv))) {
2310 	/* FBMs use the same flag bit as SVf_IVisUV, so must let them
2311 	   cache IVs just in case.  */
2312 	mg_get(sv);
2313 	if (SvNOKp(sv))
2314 	    return SvNVX(sv);
2315 	if ((SvPOKp(sv) && SvLEN(sv)) && !SvIOKp(sv)) {
2316 	    if (!SvIOKp(sv) && ckWARN(WARN_NUMERIC) &&
2317 		!grok_number(SvPVX_const(sv), SvCUR(sv), NULL))
2318 		not_a_number(sv);
2319 	    return Atof(SvPVX_const(sv));
2320 	}
2321 	if (SvIOKp(sv)) {
2322 	    if (SvIsUV(sv))
2323 		return (NV)SvUVX(sv);
2324 	    else
2325 		return (NV)SvIVX(sv);
2326 	}
2327         if (SvROK(sv)) {
2328 	    goto return_rok;
2329 	}
2330 	assert(SvTYPE(sv) >= SVt_PVMG);
2331 	/* This falls through to the report_uninit near the end of the
2332 	   function. */
2333     } else if (SvTHINKFIRST(sv)) {
2334 	if (SvROK(sv)) {
2335 	return_rok:
2336 	    if (SvAMAGIC(sv)) {
2337 		SV *const tmpstr = AMG_CALLun(sv,numer);
2338                 if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2339 		    return SvNV(tmpstr);
2340 		}
2341 	    }
2342 	    return PTR2NV(SvRV(sv));
2343 	}
2344 	if (SvIsCOW(sv)) {
2345 	    sv_force_normal_flags(sv, 0);
2346 	}
2347 	if (SvREADONLY(sv) && !SvOK(sv)) {
2348 	    if (ckWARN(WARN_UNINITIALIZED))
2349 		report_uninit(sv);
2350 	    return 0.0;
2351 	}
2352     }
2353     if (SvTYPE(sv) < SVt_NV) {
2354 	/* The logic to use SVt_PVNV if necessary is in sv_upgrade.  */
2355 	sv_upgrade(sv, SVt_NV);
2356 #ifdef USE_LONG_DOUBLE
2357 	DEBUG_c({
2358 	    STORE_NUMERIC_LOCAL_SET_STANDARD();
2359 	    PerlIO_printf(Perl_debug_log,
2360 			  "0x%"UVxf" num(%" PERL_PRIgldbl ")\n",
2361 			  PTR2UV(sv), SvNVX(sv));
2362 	    RESTORE_NUMERIC_LOCAL();
2363 	});
2364 #else
2365 	DEBUG_c({
2366 	    STORE_NUMERIC_LOCAL_SET_STANDARD();
2367 	    PerlIO_printf(Perl_debug_log, "0x%"UVxf" num(%"NVgf")\n",
2368 			  PTR2UV(sv), SvNVX(sv));
2369 	    RESTORE_NUMERIC_LOCAL();
2370 	});
2371 #endif
2372     }
2373     else if (SvTYPE(sv) < SVt_PVNV)
2374 	sv_upgrade(sv, SVt_PVNV);
2375     if (SvNOKp(sv)) {
2376         return SvNVX(sv);
2377     }
2378     if (SvIOKp(sv)) {
2379 	SvNV_set(sv, SvIsUV(sv) ? (NV)SvUVX(sv) : (NV)SvIVX(sv));
2380 #ifdef NV_PRESERVES_UV
2381 	SvNOK_on(sv);
2382 #else
2383 	/* Only set the public NV OK flag if this NV preserves the IV  */
2384 	/* Check it's not 0xFFFFFFFFFFFFFFFF */
2385 	if (SvIsUV(sv) ? ((SvUVX(sv) != UV_MAX)&&(SvUVX(sv) == U_V(SvNVX(sv))))
2386 		       : (SvIVX(sv) == I_V(SvNVX(sv))))
2387 	    SvNOK_on(sv);
2388 	else
2389 	    SvNOKp_on(sv);
2390 #endif
2391     }
2392     else if (SvPOKp(sv) && SvLEN(sv)) {
2393 	UV value;
2394 	const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), &value);
2395 	if (!SvIOKp(sv) && !numtype && ckWARN(WARN_NUMERIC))
2396 	    not_a_number(sv);
2397 #ifdef NV_PRESERVES_UV
2398 	if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
2399 	    == IS_NUMBER_IN_UV) {
2400 	    /* It's definitely an integer */
2401 	    SvNV_set(sv, (numtype & IS_NUMBER_NEG) ? -(NV)value : (NV)value);
2402 	} else
2403 	    SvNV_set(sv, Atof(SvPVX_const(sv)));
2404 	SvNOK_on(sv);
2405 #else
2406 	SvNV_set(sv, Atof(SvPVX_const(sv)));
2407 	/* Only set the public NV OK flag if this NV preserves the value in
2408 	   the PV at least as well as an IV/UV would.
2409 	   Not sure how to do this 100% reliably. */
2410 	/* if that shift count is out of range then Configure's test is
2411 	   wonky. We shouldn't be in here with NV_PRESERVES_UV_BITS ==
2412 	   UV_BITS */
2413 	if (((UV)1 << NV_PRESERVES_UV_BITS) >
2414 	    U_V(SvNVX(sv) > 0 ? SvNVX(sv) : -SvNVX(sv))) {
2415 	    SvNOK_on(sv); /* Definitely small enough to preserve all bits */
2416 	} else if (!(numtype & IS_NUMBER_IN_UV)) {
2417             /* Can't use strtol etc to convert this string, so don't try.
2418                sv_2iv and sv_2uv will use the NV to convert, not the PV.  */
2419             SvNOK_on(sv);
2420         } else {
2421             /* value has been set.  It may not be precise.  */
2422 	    if ((numtype & IS_NUMBER_NEG) && (value > (UV)IV_MIN)) {
2423 		/* 2s complement assumption for (UV)IV_MIN  */
2424                 SvNOK_on(sv); /* Integer is too negative.  */
2425             } else {
2426                 SvNOKp_on(sv);
2427                 SvIOKp_on(sv);
2428 
2429                 if (numtype & IS_NUMBER_NEG) {
2430                     SvIV_set(sv, -(IV)value);
2431                 } else if (value <= (UV)IV_MAX) {
2432 		    SvIV_set(sv, (IV)value);
2433 		} else {
2434 		    SvUV_set(sv, value);
2435 		    SvIsUV_on(sv);
2436 		}
2437 
2438                 if (numtype & IS_NUMBER_NOT_INT) {
2439                     /* I believe that even if the original PV had decimals,
2440                        they are lost beyond the limit of the FP precision.
2441                        However, neither is canonical, so both only get p
2442                        flags.  NWC, 2000/11/25 */
2443                     /* Both already have p flags, so do nothing */
2444                 } else {
2445 		    const NV nv = SvNVX(sv);
2446                     if (SvNVX(sv) < (NV)IV_MAX + 0.5) {
2447                         if (SvIVX(sv) == I_V(nv)) {
2448                             SvNOK_on(sv);
2449                         } else {
2450                             /* It had no "." so it must be integer.  */
2451                         }
2452 			SvIOK_on(sv);
2453                     } else {
2454                         /* between IV_MAX and NV(UV_MAX).
2455                            Could be slightly > UV_MAX */
2456 
2457                         if (numtype & IS_NUMBER_NOT_INT) {
2458                             /* UV and NV both imprecise.  */
2459                         } else {
2460 			    const UV nv_as_uv = U_V(nv);
2461 
2462                             if (value == nv_as_uv && SvUVX(sv) != UV_MAX) {
2463                                 SvNOK_on(sv);
2464                             }
2465 			    SvIOK_on(sv);
2466                         }
2467                     }
2468                 }
2469             }
2470         }
2471 #endif /* NV_PRESERVES_UV */
2472     }
2473     else  {
2474 	if (isGV_with_GP(sv)) {
2475 	    glob_2number((GV *)sv);
2476 	    return 0.0;
2477 	}
2478 
2479 	if (!PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP) && ckWARN(WARN_UNINITIALIZED))
2480 	    report_uninit(sv);
2481 	assert (SvTYPE(sv) >= SVt_NV);
2482 	/* Typically the caller expects that sv_any is not NULL now.  */
2483 	/* XXX Ilya implies that this is a bug in callers that assume this
2484 	   and ideally should be fixed.  */
2485 	return 0.0;
2486     }
2487 #if defined(USE_LONG_DOUBLE)
2488     DEBUG_c({
2489 	STORE_NUMERIC_LOCAL_SET_STANDARD();
2490 	PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2nv(%" PERL_PRIgldbl ")\n",
2491 		      PTR2UV(sv), SvNVX(sv));
2492 	RESTORE_NUMERIC_LOCAL();
2493     });
2494 #else
2495     DEBUG_c({
2496 	STORE_NUMERIC_LOCAL_SET_STANDARD();
2497 	PerlIO_printf(Perl_debug_log, "0x%"UVxf" 1nv(%"NVgf")\n",
2498 		      PTR2UV(sv), SvNVX(sv));
2499 	RESTORE_NUMERIC_LOCAL();
2500     });
2501 #endif
2502     return SvNVX(sv);
2503 }
2504 
2505 /*
2506 =for apidoc sv_2num
2507 
2508 Return an SV with the numeric value of the source SV, doing any necessary
2509 reference or overload conversion.  You must use the C<SvNUM(sv)> macro to
2510 access this function.
2511 
2512 =cut
2513 */
2514 
2515 SV *
2516 Perl_sv_2num(pTHX_ register SV *sv)
2517 {
2518     if (!SvROK(sv))
2519 	return sv;
2520     if (SvAMAGIC(sv)) {
2521 	SV * const tmpsv = AMG_CALLun(sv,numer);
2522 	if (tmpsv && (!SvROK(tmpsv) || (SvRV(tmpsv) != SvRV(sv))))
2523 	    return sv_2num(tmpsv);
2524     }
2525     return sv_2mortal(newSVuv(PTR2UV(SvRV(sv))));
2526 }
2527 
2528 /* uiv_2buf(): private routine for use by sv_2pv_flags(): print an IV or
2529  * UV as a string towards the end of buf, and return pointers to start and
2530  * end of it.
2531  *
2532  * We assume that buf is at least TYPE_CHARS(UV) long.
2533  */
2534 
2535 static char *
2536 S_uiv_2buf(char *buf, IV iv, UV uv, int is_uv, char **peob)
2537 {
2538     char *ptr = buf + TYPE_CHARS(UV);
2539     char * const ebuf = ptr;
2540     int sign;
2541 
2542     if (is_uv)
2543 	sign = 0;
2544     else if (iv >= 0) {
2545 	uv = iv;
2546 	sign = 0;
2547     } else {
2548 	uv = -iv;
2549 	sign = 1;
2550     }
2551     do {
2552 	*--ptr = '0' + (char)(uv % 10);
2553     } while (uv /= 10);
2554     if (sign)
2555 	*--ptr = '-';
2556     *peob = ebuf;
2557     return ptr;
2558 }
2559 
2560 /*
2561 =for apidoc sv_2pv_flags
2562 
2563 Returns a pointer to the string value of an SV, and sets *lp to its length.
2564 If flags includes SV_GMAGIC, does an mg_get() first. Coerces sv to a string
2565 if necessary.
2566 Normally invoked via the C<SvPV_flags> macro. C<sv_2pv()> and C<sv_2pv_nomg>
2567 usually end up here too.
2568 
2569 =cut
2570 */
2571 
2572 char *
2573 Perl_sv_2pv_flags(pTHX_ register SV *sv, STRLEN *lp, I32 flags)
2574 {
2575     dVAR;
2576     register char *s;
2577 
2578     if (!sv) {
2579 	if (lp)
2580 	    *lp = 0;
2581 	return (char *)"";
2582     }
2583     if (SvGMAGICAL(sv)) {
2584 	if (flags & SV_GMAGIC)
2585 	    mg_get(sv);
2586 	if (SvPOKp(sv)) {
2587 	    if (lp)
2588 		*lp = SvCUR(sv);
2589 	    if (flags & SV_MUTABLE_RETURN)
2590 		return SvPVX_mutable(sv);
2591 	    if (flags & SV_CONST_RETURN)
2592 		return (char *)SvPVX_const(sv);
2593 	    return SvPVX(sv);
2594 	}
2595 	if (SvIOKp(sv) || SvNOKp(sv)) {
2596 	    char tbuf[64];  /* Must fit sprintf/Gconvert of longest IV/NV */
2597 	    STRLEN len;
2598 
2599 	    if (SvIOKp(sv)) {
2600 		len = SvIsUV(sv)
2601 		    ? my_snprintf(tbuf, sizeof(tbuf), "%"UVuf, (UV)SvUVX(sv))
2602 		    : my_snprintf(tbuf, sizeof(tbuf), "%"IVdf, (IV)SvIVX(sv));
2603 	    } else {
2604 		Gconvert(SvNVX(sv), NV_DIG, 0, tbuf);
2605 		len = strlen(tbuf);
2606 	    }
2607 	    assert(!SvROK(sv));
2608 	    {
2609 		dVAR;
2610 
2611 #ifdef FIXNEGATIVEZERO
2612 		if (len == 2 && tbuf[0] == '-' && tbuf[1] == '0') {
2613 		    tbuf[0] = '0';
2614 		    tbuf[1] = 0;
2615 		    len = 1;
2616 		}
2617 #endif
2618 		SvUPGRADE(sv, SVt_PV);
2619 		if (lp)
2620 		    *lp = len;
2621 		s = SvGROW_mutable(sv, len + 1);
2622 		SvCUR_set(sv, len);
2623 		SvPOKp_on(sv);
2624 		return (char*)memcpy(s, tbuf, len + 1);
2625 	    }
2626 	}
2627         if (SvROK(sv)) {
2628 	    goto return_rok;
2629 	}
2630 	assert(SvTYPE(sv) >= SVt_PVMG);
2631 	/* This falls through to the report_uninit near the end of the
2632 	   function. */
2633     } else if (SvTHINKFIRST(sv)) {
2634 	if (SvROK(sv)) {
2635 	return_rok:
2636             if (SvAMAGIC(sv)) {
2637 		SV *const tmpstr = AMG_CALLun(sv,string);
2638 		if (tmpstr && (!SvROK(tmpstr) || (SvRV(tmpstr) != SvRV(sv)))) {
2639 		    /* Unwrap this:  */
2640 		    /* char *pv = lp ? SvPV(tmpstr, *lp) : SvPV_nolen(tmpstr);
2641 		     */
2642 
2643 		    char *pv;
2644 		    if ((SvFLAGS(tmpstr) & (SVf_POK)) == SVf_POK) {
2645 			if (flags & SV_CONST_RETURN) {
2646 			    pv = (char *) SvPVX_const(tmpstr);
2647 			} else {
2648 			    pv = (flags & SV_MUTABLE_RETURN)
2649 				? SvPVX_mutable(tmpstr) : SvPVX(tmpstr);
2650 			}
2651 			if (lp)
2652 			    *lp = SvCUR(tmpstr);
2653 		    } else {
2654 			pv = sv_2pv_flags(tmpstr, lp, flags);
2655 		    }
2656 		    if (SvUTF8(tmpstr))
2657 			SvUTF8_on(sv);
2658 		    else
2659 			SvUTF8_off(sv);
2660 		    return pv;
2661 		}
2662 	    }
2663 	    {
2664 		STRLEN len;
2665 		char *retval;
2666 		char *buffer;
2667 		MAGIC *mg;
2668 		const SV *const referent = (SV*)SvRV(sv);
2669 
2670 		if (!referent) {
2671 		    len = 7;
2672 		    retval = buffer = savepvn("NULLREF", len);
2673 		} else if (SvTYPE(referent) == SVt_PVMG
2674 			   && ((SvFLAGS(referent) &
2675 				(SVs_OBJECT|SVf_OK|SVs_GMG|SVs_SMG|SVs_RMG))
2676 			       == (SVs_OBJECT|SVs_SMG))
2677 			   && (mg = mg_find(referent, PERL_MAGIC_qr)))
2678                 {
2679                     char *str = NULL;
2680                     I32 haseval = 0;
2681                     U32 flags = 0;
2682                     (str) = CALLREG_AS_STR(mg,lp,&flags,&haseval);
2683                     if (flags & 1)
2684 	                SvUTF8_on(sv);
2685                     else
2686 	                SvUTF8_off(sv);
2687                     PL_reginterp_cnt += haseval;
2688 		    return str;
2689 		} else {
2690 		    const char *const typestr = sv_reftype(referent, 0);
2691 		    const STRLEN typelen = strlen(typestr);
2692 		    UV addr = PTR2UV(referent);
2693 		    const char *stashname = NULL;
2694 		    STRLEN stashnamelen = 0; /* hush, gcc */
2695 		    const char *buffer_end;
2696 
2697 		    if (SvOBJECT(referent)) {
2698 			const HEK *const name = HvNAME_HEK(SvSTASH(referent));
2699 
2700 			if (name) {
2701 			    stashname = HEK_KEY(name);
2702 			    stashnamelen = HEK_LEN(name);
2703 
2704 			    if (HEK_UTF8(name)) {
2705 				SvUTF8_on(sv);
2706 			    } else {
2707 				SvUTF8_off(sv);
2708 			    }
2709 			} else {
2710 			    stashname = "__ANON__";
2711 			    stashnamelen = 8;
2712 			}
2713 			len = stashnamelen + 1 /* = */ + typelen + 3 /* (0x */
2714 			    + 2 * sizeof(UV) + 2 /* )\0 */;
2715 		    } else {
2716 			len = typelen + 3 /* (0x */
2717 			    + 2 * sizeof(UV) + 2 /* )\0 */;
2718 		    }
2719 
2720 		    Newx(buffer, len, char);
2721 		    buffer_end = retval = buffer + len;
2722 
2723 		    /* Working backwards  */
2724 		    *--retval = '\0';
2725 		    *--retval = ')';
2726 		    do {
2727 			*--retval = PL_hexdigit[addr & 15];
2728 		    } while (addr >>= 4);
2729 		    *--retval = 'x';
2730 		    *--retval = '0';
2731 		    *--retval = '(';
2732 
2733 		    retval -= typelen;
2734 		    memcpy(retval, typestr, typelen);
2735 
2736 		    if (stashname) {
2737 			*--retval = '=';
2738 			retval -= stashnamelen;
2739 			memcpy(retval, stashname, stashnamelen);
2740 		    }
2741 		    /* retval may not neccesarily have reached the start of the
2742 		       buffer here.  */
2743 		    assert (retval >= buffer);
2744 
2745 		    len = buffer_end - retval - 1; /* -1 for that \0  */
2746 		}
2747 		if (lp)
2748 		    *lp = len;
2749 		SAVEFREEPV(buffer);
2750 		return retval;
2751 	    }
2752 	}
2753 	if (SvREADONLY(sv) && !SvOK(sv)) {
2754 	    if (ckWARN(WARN_UNINITIALIZED))
2755 		report_uninit(sv);
2756 	    if (lp)
2757 		*lp = 0;
2758 	    return (char *)"";
2759 	}
2760     }
2761     if (SvIOK(sv) || ((SvIOKp(sv) && !SvNOKp(sv)))) {
2762 	/* I'm assuming that if both IV and NV are equally valid then
2763 	   converting the IV is going to be more efficient */
2764 	const U32 isUIOK = SvIsUV(sv);
2765 	char buf[TYPE_CHARS(UV)];
2766 	char *ebuf, *ptr;
2767 	STRLEN len;
2768 
2769 	if (SvTYPE(sv) < SVt_PVIV)
2770 	    sv_upgrade(sv, SVt_PVIV);
2771  	ptr = uiv_2buf(buf, SvIVX(sv), SvUVX(sv), isUIOK, &ebuf);
2772 	len = ebuf - ptr;
2773 	/* inlined from sv_setpvn */
2774 	s = SvGROW_mutable(sv, len + 1);
2775 	Move(ptr, s, len, char);
2776 	s += len;
2777 	*s = '\0';
2778     }
2779     else if (SvNOKp(sv)) {
2780 	const int olderrno = errno;
2781 	if (SvTYPE(sv) < SVt_PVNV)
2782 	    sv_upgrade(sv, SVt_PVNV);
2783 	/* The +20 is pure guesswork.  Configure test needed. --jhi */
2784 	s = SvGROW_mutable(sv, NV_DIG + 20);
2785 	/* some Xenix systems wipe out errno here */
2786 #ifdef apollo
2787 	if (SvNVX(sv) == 0.0)
2788 	    my_strlcpy(s, "0", SvLEN(sv));
2789 	else
2790 #endif /*apollo*/
2791 	{
2792 	    Gconvert(SvNVX(sv), NV_DIG, 0, s);
2793 	}
2794 	errno = olderrno;
2795 #ifdef FIXNEGATIVEZERO
2796         if (*s == '-' && s[1] == '0' && !s[2]) {
2797 	    s[0] = '0';
2798 	    s[1] = 0;
2799 	}
2800 #endif
2801 	while (*s) s++;
2802 #ifdef hcx
2803 	if (s[-1] == '.')
2804 	    *--s = '\0';
2805 #endif
2806     }
2807     else {
2808 	if (isGV_with_GP(sv))
2809 	    return glob_2pv((GV *)sv, lp);
2810 
2811 	if (!PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP) && ckWARN(WARN_UNINITIALIZED))
2812 	    report_uninit(sv);
2813 	if (lp)
2814 	    *lp = 0;
2815 	if (SvTYPE(sv) < SVt_PV)
2816 	    /* Typically the caller expects that sv_any is not NULL now.  */
2817 	    sv_upgrade(sv, SVt_PV);
2818 	return (char *)"";
2819     }
2820     {
2821 	const STRLEN len = s - SvPVX_const(sv);
2822 	if (lp)
2823 	    *lp = len;
2824 	SvCUR_set(sv, len);
2825     }
2826     SvPOK_on(sv);
2827     DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2pv(%s)\n",
2828 			  PTR2UV(sv),SvPVX_const(sv)));
2829     if (flags & SV_CONST_RETURN)
2830 	return (char *)SvPVX_const(sv);
2831     if (flags & SV_MUTABLE_RETURN)
2832 	return SvPVX_mutable(sv);
2833     return SvPVX(sv);
2834 }
2835 
2836 /*
2837 =for apidoc sv_copypv
2838 
2839 Copies a stringified representation of the source SV into the
2840 destination SV.  Automatically performs any necessary mg_get and
2841 coercion of numeric values into strings.  Guaranteed to preserve
2842 UTF8 flag even from overloaded objects.  Similar in nature to
2843 sv_2pv[_flags] but operates directly on an SV instead of just the
2844 string.  Mostly uses sv_2pv_flags to do its work, except when that
2845 would lose the UTF-8'ness of the PV.
2846 
2847 =cut
2848 */
2849 
2850 void
2851 Perl_sv_copypv(pTHX_ SV *dsv, register SV *ssv)
2852 {
2853     STRLEN len;
2854     const char * const s = SvPV_const(ssv,len);
2855     sv_setpvn(dsv,s,len);
2856     if (SvUTF8(ssv))
2857 	SvUTF8_on(dsv);
2858     else
2859 	SvUTF8_off(dsv);
2860 }
2861 
2862 /*
2863 =for apidoc sv_2pvbyte
2864 
2865 Return a pointer to the byte-encoded representation of the SV, and set *lp
2866 to its length.  May cause the SV to be downgraded from UTF-8 as a
2867 side-effect.
2868 
2869 Usually accessed via the C<SvPVbyte> macro.
2870 
2871 =cut
2872 */
2873 
2874 char *
2875 Perl_sv_2pvbyte(pTHX_ register SV *sv, STRLEN *lp)
2876 {
2877     sv_utf8_downgrade(sv,0);
2878     return lp ? SvPV(sv,*lp) : SvPV_nolen(sv);
2879 }
2880 
2881 /*
2882 =for apidoc sv_2pvutf8
2883 
2884 Return a pointer to the UTF-8-encoded representation of the SV, and set *lp
2885 to its length.  May cause the SV to be upgraded to UTF-8 as a side-effect.
2886 
2887 Usually accessed via the C<SvPVutf8> macro.
2888 
2889 =cut
2890 */
2891 
2892 char *
2893 Perl_sv_2pvutf8(pTHX_ register SV *sv, STRLEN *lp)
2894 {
2895     sv_utf8_upgrade(sv);
2896     return lp ? SvPV(sv,*lp) : SvPV_nolen(sv);
2897 }
2898 
2899 
2900 /*
2901 =for apidoc sv_2bool
2902 
2903 This function is only called on magical items, and is only used by
2904 sv_true() or its macro equivalent.
2905 
2906 =cut
2907 */
2908 
2909 bool
2910 Perl_sv_2bool(pTHX_ register SV *sv)
2911 {
2912     dVAR;
2913     SvGETMAGIC(sv);
2914 
2915     if (!SvOK(sv))
2916 	return 0;
2917     if (SvROK(sv)) {
2918 	if (SvAMAGIC(sv)) {
2919 	    SV * const tmpsv = AMG_CALLun(sv,bool_);
2920 	    if (tmpsv && (!SvROK(tmpsv) || (SvRV(tmpsv) != SvRV(sv))))
2921 		return (bool)SvTRUE(tmpsv);
2922 	}
2923 	return SvRV(sv) != 0;
2924     }
2925     if (SvPOKp(sv)) {
2926 	register XPV* const Xpvtmp = (XPV*)SvANY(sv);
2927 	if (Xpvtmp &&
2928 		(*sv->sv_u.svu_pv > '0' ||
2929 		Xpvtmp->xpv_cur > 1 ||
2930 		(Xpvtmp->xpv_cur && *sv->sv_u.svu_pv != '0')))
2931 	    return 1;
2932 	else
2933 	    return 0;
2934     }
2935     else {
2936 	if (SvIOKp(sv))
2937 	    return SvIVX(sv) != 0;
2938 	else {
2939 	    if (SvNOKp(sv))
2940 		return SvNVX(sv) != 0.0;
2941 	    else {
2942 		if (isGV_with_GP(sv))
2943 		    return TRUE;
2944 		else
2945 		    return FALSE;
2946 	    }
2947 	}
2948     }
2949 }
2950 
2951 /*
2952 =for apidoc sv_utf8_upgrade
2953 
2954 Converts the PV of an SV to its UTF-8-encoded form.
2955 Forces the SV to string form if it is not already.
2956 Always sets the SvUTF8 flag to avoid future validity checks even
2957 if all the bytes have hibit clear.
2958 
2959 This is not as a general purpose byte encoding to Unicode interface:
2960 use the Encode extension for that.
2961 
2962 =for apidoc sv_utf8_upgrade_flags
2963 
2964 Converts the PV of an SV to its UTF-8-encoded form.
2965 Forces the SV to string form if it is not already.
2966 Always sets the SvUTF8 flag to avoid future validity checks even
2967 if all the bytes have hibit clear. If C<flags> has C<SV_GMAGIC> bit set,
2968 will C<mg_get> on C<sv> if appropriate, else not. C<sv_utf8_upgrade> and
2969 C<sv_utf8_upgrade_nomg> are implemented in terms of this function.
2970 
2971 This is not as a general purpose byte encoding to Unicode interface:
2972 use the Encode extension for that.
2973 
2974 =cut
2975 */
2976 
2977 STRLEN
2978 Perl_sv_utf8_upgrade_flags(pTHX_ register SV *sv, I32 flags)
2979 {
2980     dVAR;
2981     if (sv == &PL_sv_undef)
2982 	return 0;
2983     if (!SvPOK(sv)) {
2984 	STRLEN len = 0;
2985 	if (SvREADONLY(sv) && (SvPOKp(sv) || SvIOKp(sv) || SvNOKp(sv))) {
2986 	    (void) sv_2pv_flags(sv,&len, flags);
2987 	    if (SvUTF8(sv))
2988 		return len;
2989 	} else {
2990 	    (void) SvPV_force(sv,len);
2991 	}
2992     }
2993 
2994     if (SvUTF8(sv)) {
2995 	return SvCUR(sv);
2996     }
2997 
2998     if (SvIsCOW(sv)) {
2999         sv_force_normal_flags(sv, 0);
3000     }
3001 
3002     if (PL_encoding && !(flags & SV_UTF8_NO_ENCODING))
3003         sv_recode_to_utf8(sv, PL_encoding);
3004     else { /* Assume Latin-1/EBCDIC */
3005 	/* This function could be much more efficient if we
3006 	 * had a FLAG in SVs to signal if there are any hibit
3007 	 * chars in the PV.  Given that there isn't such a flag
3008 	 * make the loop as fast as possible. */
3009 	const U8 * const s = (U8 *) SvPVX_const(sv);
3010 	const U8 * const e = (U8 *) SvEND(sv);
3011 	const U8 *t = s;
3012 
3013 	while (t < e) {
3014 	    const U8 ch = *t++;
3015 	    /* Check for hi bit */
3016 	    if (!NATIVE_IS_INVARIANT(ch)) {
3017 		STRLEN len = SvCUR(sv) + 1; /* Plus the \0 */
3018 		U8 * const recoded = bytes_to_utf8((U8*)s, &len);
3019 
3020 		SvPV_free(sv); /* No longer using what was there before. */
3021 		SvPV_set(sv, (char*)recoded);
3022 		SvCUR_set(sv, len - 1);
3023 		SvLEN_set(sv, len); /* No longer know the real size. */
3024 		break;
3025 	    }
3026 	}
3027 	/* Mark as UTF-8 even if no hibit - saves scanning loop */
3028 	SvUTF8_on(sv);
3029     }
3030     return SvCUR(sv);
3031 }
3032 
3033 /*
3034 =for apidoc sv_utf8_downgrade
3035 
3036 Attempts to convert the PV of an SV from characters to bytes.
3037 If the PV contains a character beyond byte, this conversion will fail;
3038 in this case, either returns false or, if C<fail_ok> is not
3039 true, croaks.
3040 
3041 This is not as a general purpose Unicode to byte encoding interface:
3042 use the Encode extension for that.
3043 
3044 =cut
3045 */
3046 
3047 bool
3048 Perl_sv_utf8_downgrade(pTHX_ register SV* sv, bool fail_ok)
3049 {
3050     dVAR;
3051     if (SvPOKp(sv) && SvUTF8(sv)) {
3052         if (SvCUR(sv)) {
3053 	    U8 *s;
3054 	    STRLEN len;
3055 
3056             if (SvIsCOW(sv)) {
3057                 sv_force_normal_flags(sv, 0);
3058             }
3059 	    s = (U8 *) SvPV(sv, len);
3060 	    if (!utf8_to_bytes(s, &len)) {
3061 	        if (fail_ok)
3062 		    return FALSE;
3063 		else {
3064 		    if (PL_op)
3065 		        Perl_croak(aTHX_ "Wide character in %s",
3066 				   OP_DESC(PL_op));
3067 		    else
3068 		        Perl_croak(aTHX_ "Wide character");
3069 		}
3070 	    }
3071 	    SvCUR_set(sv, len);
3072 	}
3073     }
3074     SvUTF8_off(sv);
3075     return TRUE;
3076 }
3077 
3078 /*
3079 =for apidoc sv_utf8_encode
3080 
3081 Converts the PV of an SV to UTF-8, but then turns the C<SvUTF8>
3082 flag off so that it looks like octets again.
3083 
3084 =cut
3085 */
3086 
3087 void
3088 Perl_sv_utf8_encode(pTHX_ register SV *sv)
3089 {
3090     if (SvIsCOW(sv)) {
3091         sv_force_normal_flags(sv, 0);
3092     }
3093     if (SvREADONLY(sv)) {
3094 	Perl_croak(aTHX_ PL_no_modify);
3095     }
3096     (void) sv_utf8_upgrade(sv);
3097     SvUTF8_off(sv);
3098 }
3099 
3100 /*
3101 =for apidoc sv_utf8_decode
3102 
3103 If the PV of the SV is an octet sequence in UTF-8
3104 and contains a multiple-byte character, the C<SvUTF8> flag is turned on
3105 so that it looks like a character. If the PV contains only single-byte
3106 characters, the C<SvUTF8> flag stays being off.
3107 Scans PV for validity and returns false if the PV is invalid UTF-8.
3108 
3109 =cut
3110 */
3111 
3112 bool
3113 Perl_sv_utf8_decode(pTHX_ register SV *sv)
3114 {
3115     if (SvPOKp(sv)) {
3116         const U8 *c;
3117         const U8 *e;
3118 
3119 	/* The octets may have got themselves encoded - get them back as
3120 	 * bytes
3121 	 */
3122 	if (!sv_utf8_downgrade(sv, TRUE))
3123 	    return FALSE;
3124 
3125         /* it is actually just a matter of turning the utf8 flag on, but
3126          * we want to make sure everything inside is valid utf8 first.
3127          */
3128         c = (const U8 *) SvPVX_const(sv);
3129 	if (!is_utf8_string(c, SvCUR(sv)+1))
3130 	    return FALSE;
3131         e = (const U8 *) SvEND(sv);
3132         while (c < e) {
3133 	    const U8 ch = *c++;
3134             if (!UTF8_IS_INVARIANT(ch)) {
3135 		SvUTF8_on(sv);
3136 		break;
3137 	    }
3138         }
3139     }
3140     return TRUE;
3141 }
3142 
3143 /*
3144 =for apidoc sv_setsv
3145 
3146 Copies the contents of the source SV C<ssv> into the destination SV
3147 C<dsv>.  The source SV may be destroyed if it is mortal, so don't use this
3148 function if the source SV needs to be reused. Does not handle 'set' magic.
3149 Loosely speaking, it performs a copy-by-value, obliterating any previous
3150 content of the destination.
3151 
3152 You probably want to use one of the assortment of wrappers, such as
3153 C<SvSetSV>, C<SvSetSV_nosteal>, C<SvSetMagicSV> and
3154 C<SvSetMagicSV_nosteal>.
3155 
3156 =for apidoc sv_setsv_flags
3157 
3158 Copies the contents of the source SV C<ssv> into the destination SV
3159 C<dsv>.  The source SV may be destroyed if it is mortal, so don't use this
3160 function if the source SV needs to be reused. Does not handle 'set' magic.
3161 Loosely speaking, it performs a copy-by-value, obliterating any previous
3162 content of the destination.
3163 If the C<flags> parameter has the C<SV_GMAGIC> bit set, will C<mg_get> on
3164 C<ssv> if appropriate, else not. If the C<flags> parameter has the
3165 C<NOSTEAL> bit set then the buffers of temps will not be stolen. <sv_setsv>
3166 and C<sv_setsv_nomg> are implemented in terms of this function.
3167 
3168 You probably want to use one of the assortment of wrappers, such as
3169 C<SvSetSV>, C<SvSetSV_nosteal>, C<SvSetMagicSV> and
3170 C<SvSetMagicSV_nosteal>.
3171 
3172 This is the primary function for copying scalars, and most other
3173 copy-ish functions and macros use this underneath.
3174 
3175 =cut
3176 */
3177 
3178 static void
3179 S_glob_assign_glob(pTHX_ SV *dstr, SV *sstr, const int dtype)
3180 {
3181     I32 mro_changes = 0; /* 1 = method, 2 = isa */
3182 
3183     if (dtype != SVt_PVGV) {
3184 	const char * const name = GvNAME(sstr);
3185 	const STRLEN len = GvNAMELEN(sstr);
3186 	{
3187 	    if (dtype >= SVt_PV) {
3188 		SvPV_free(dstr);
3189 		SvPV_set(dstr, 0);
3190 		SvLEN_set(dstr, 0);
3191 		SvCUR_set(dstr, 0);
3192 	    }
3193 	    SvUPGRADE(dstr, SVt_PVGV);
3194 	    (void)SvOK_off(dstr);
3195 	    /* FIXME - why are we doing this, then turning it off and on again
3196 	       below?  */
3197 	    isGV_with_GP_on(dstr);
3198 	}
3199 	GvSTASH(dstr) = GvSTASH(sstr);
3200 	if (GvSTASH(dstr))
3201 	    Perl_sv_add_backref(aTHX_ (SV*)GvSTASH(dstr), dstr);
3202 	gv_name_set((GV *)dstr, name, len, GV_ADD);
3203 	SvFAKE_on(dstr);	/* can coerce to non-glob */
3204     }
3205 
3206 #ifdef GV_UNIQUE_CHECK
3207     if (GvUNIQUE((GV*)dstr)) {
3208 	Perl_croak(aTHX_ PL_no_modify);
3209     }
3210 #endif
3211 
3212     if(GvGP((GV*)sstr)) {
3213         /* If source has method cache entry, clear it */
3214         if(GvCVGEN(sstr)) {
3215             SvREFCNT_dec(GvCV(sstr));
3216             GvCV(sstr) = NULL;
3217             GvCVGEN(sstr) = 0;
3218         }
3219         /* If source has a real method, then a method is
3220            going to change */
3221         else if(GvCV((GV*)sstr)) {
3222             mro_changes = 1;
3223         }
3224     }
3225 
3226     /* If dest already had a real method, that's a change as well */
3227     if(!mro_changes && GvGP((GV*)dstr) && GvCVu((GV*)dstr)) {
3228         mro_changes = 1;
3229     }
3230 
3231     if(strEQ(GvNAME((GV*)dstr),"ISA"))
3232         mro_changes = 2;
3233 
3234     gp_free((GV*)dstr);
3235     isGV_with_GP_off(dstr);
3236     (void)SvOK_off(dstr);
3237     isGV_with_GP_on(dstr);
3238     GvINTRO_off(dstr);		/* one-shot flag */
3239     GvGP(dstr) = gp_ref(GvGP(sstr));
3240     if (SvTAINTED(sstr))
3241 	SvTAINT(dstr);
3242     if (GvIMPORTED(dstr) != GVf_IMPORTED
3243 	&& CopSTASH_ne(PL_curcop, GvSTASH(dstr)))
3244 	{
3245 	    GvIMPORTED_on(dstr);
3246 	}
3247     GvMULTI_on(dstr);
3248     if(mro_changes == 2) mro_isa_changed_in(GvSTASH(dstr));
3249     else if(mro_changes) mro_method_changed_in(GvSTASH(dstr));
3250     return;
3251 }
3252 
3253 static void
3254 S_glob_assign_ref(pTHX_ SV *dstr, SV *sstr) {
3255     SV * const sref = SvREFCNT_inc(SvRV(sstr));
3256     SV *dref = NULL;
3257     const int intro = GvINTRO(dstr);
3258     SV **location;
3259     U8 import_flag = 0;
3260     const U32 stype = SvTYPE(sref);
3261 
3262 
3263 #ifdef GV_UNIQUE_CHECK
3264     if (GvUNIQUE((GV*)dstr)) {
3265 	Perl_croak(aTHX_ PL_no_modify);
3266     }
3267 #endif
3268 
3269     if (intro) {
3270 	GvINTRO_off(dstr);	/* one-shot flag */
3271 	GvLINE(dstr) = CopLINE(PL_curcop);
3272 	GvEGV(dstr) = (GV*)dstr;
3273     }
3274     GvMULTI_on(dstr);
3275     switch (stype) {
3276     case SVt_PVCV:
3277 	location = (SV **) &GvCV(dstr);
3278 	import_flag = GVf_IMPORTED_CV;
3279 	goto common;
3280     case SVt_PVHV:
3281 	location = (SV **) &GvHV(dstr);
3282 	import_flag = GVf_IMPORTED_HV;
3283 	goto common;
3284     case SVt_PVAV:
3285 	location = (SV **) &GvAV(dstr);
3286 	import_flag = GVf_IMPORTED_AV;
3287 	goto common;
3288     case SVt_PVIO:
3289 	location = (SV **) &GvIOp(dstr);
3290 	goto common;
3291     case SVt_PVFM:
3292 	location = (SV **) &GvFORM(dstr);
3293     default:
3294 	location = &GvSV(dstr);
3295 	import_flag = GVf_IMPORTED_SV;
3296     common:
3297 	if (intro) {
3298 	    if (stype == SVt_PVCV) {
3299 		/*if (GvCVGEN(dstr) && (GvCV(dstr) != (CV*)sref || GvCVGEN(dstr))) {*/
3300 		if (GvCVGEN(dstr)) {
3301 		    SvREFCNT_dec(GvCV(dstr));
3302 		    GvCV(dstr) = NULL;
3303 		    GvCVGEN(dstr) = 0; /* Switch off cacheness. */
3304 		}
3305 	    }
3306 	    SAVEGENERICSV(*location);
3307 	}
3308 	else
3309 	    dref = *location;
3310 	if (stype == SVt_PVCV && (*location != sref || GvCVGEN(dstr))) {
3311 	    CV* const cv = (CV*)*location;
3312 	    if (cv) {
3313 		if (!GvCVGEN((GV*)dstr) &&
3314 		    (CvROOT(cv) || CvXSUB(cv)))
3315 		    {
3316 			/* Redefining a sub - warning is mandatory if
3317 			   it was a const and its value changed. */
3318 			if (CvCONST(cv)	&& CvCONST((CV*)sref)
3319 			    && cv_const_sv(cv) == cv_const_sv((CV*)sref)) {
3320 			    NOOP;
3321 			    /* They are 2 constant subroutines generated from
3322 			       the same constant. This probably means that
3323 			       they are really the "same" proxy subroutine
3324 			       instantiated in 2 places. Most likely this is
3325 			       when a constant is exported twice.  Don't warn.
3326 			    */
3327 			}
3328 			else if (ckWARN(WARN_REDEFINE)
3329 				 || (CvCONST(cv)
3330 				     && (!CvCONST((CV*)sref)
3331 					 || sv_cmp(cv_const_sv(cv),
3332 						   cv_const_sv((CV*)sref))))) {
3333 			    Perl_warner(aTHX_ packWARN(WARN_REDEFINE),
3334 					(const char *)
3335 					(CvCONST(cv)
3336 					 ? "Constant subroutine %s::%s redefined"
3337 					 : "Subroutine %s::%s redefined"),
3338 					HvNAME_get(GvSTASH((GV*)dstr)),
3339 					GvENAME((GV*)dstr));
3340 			}
3341 		    }
3342 		if (!intro)
3343 		    cv_ckproto_len(cv, (GV*)dstr,
3344 				   SvPOK(sref) ? SvPVX_const(sref) : NULL,
3345 				   SvPOK(sref) ? SvCUR(sref) : 0);
3346 	    }
3347 	    GvCVGEN(dstr) = 0; /* Switch off cacheness. */
3348 	    GvASSUMECV_on(dstr);
3349 	    if(GvSTASH(dstr)) mro_method_changed_in(GvSTASH(dstr)); /* sub foo { 1 } sub bar { 2 } *bar = \&foo */
3350 	}
3351 	*location = sref;
3352 	if (import_flag && !(GvFLAGS(dstr) & import_flag)
3353 	    && CopSTASH_ne(PL_curcop, GvSTASH(dstr))) {
3354 	    GvFLAGS(dstr) |= import_flag;
3355 	}
3356 	break;
3357     }
3358     SvREFCNT_dec(dref);
3359     if (SvTAINTED(sstr))
3360 	SvTAINT(dstr);
3361     return;
3362 }
3363 
3364 void
3365 Perl_sv_setsv_flags(pTHX_ SV *dstr, register SV *sstr, I32 flags)
3366 {
3367     dVAR;
3368     register U32 sflags;
3369     register int dtype;
3370     register svtype stype;
3371 
3372     if (sstr == dstr)
3373 	return;
3374 
3375     if (SvIS_FREED(dstr)) {
3376 	Perl_croak(aTHX_ "panic: attempt to copy value %" SVf
3377 		   " to a freed scalar %p", SVfARG(sstr), (void *)dstr);
3378     }
3379     SV_CHECK_THINKFIRST_COW_DROP(dstr);
3380     if (!sstr)
3381 	sstr = &PL_sv_undef;
3382     if (SvIS_FREED(sstr)) {
3383 	Perl_croak(aTHX_ "panic: attempt to copy freed scalar %p to %p",
3384 		   (void*)sstr, (void*)dstr);
3385     }
3386     stype = SvTYPE(sstr);
3387     dtype = SvTYPE(dstr);
3388 
3389     (void)SvAMAGIC_off(dstr);
3390     if ( SvVOK(dstr) )
3391     {
3392 	/* need to nuke the magic */
3393 	mg_free(dstr);
3394 	SvRMAGICAL_off(dstr);
3395     }
3396 
3397     /* There's a lot of redundancy below but we're going for speed here */
3398 
3399     switch (stype) {
3400     case SVt_NULL:
3401       undef_sstr:
3402 	if (dtype != SVt_PVGV) {
3403 	    (void)SvOK_off(dstr);
3404 	    return;
3405 	}
3406 	break;
3407     case SVt_IV:
3408 	if (SvIOK(sstr)) {
3409 	    switch (dtype) {
3410 	    case SVt_NULL:
3411 		sv_upgrade(dstr, SVt_IV);
3412 		break;
3413 	    case SVt_NV:
3414 	    case SVt_RV:
3415 	    case SVt_PV:
3416 		sv_upgrade(dstr, SVt_PVIV);
3417 		break;
3418 	    case SVt_PVGV:
3419 		goto end_of_first_switch;
3420 	    }
3421 	    (void)SvIOK_only(dstr);
3422 	    SvIV_set(dstr,  SvIVX(sstr));
3423 	    if (SvIsUV(sstr))
3424 		SvIsUV_on(dstr);
3425 	    /* SvTAINTED can only be true if the SV has taint magic, which in
3426 	       turn means that the SV type is PVMG (or greater). This is the
3427 	       case statement for SVt_IV, so this cannot be true (whatever gcov
3428 	       may say).  */
3429 	    assert(!SvTAINTED(sstr));
3430 	    return;
3431 	}
3432 	goto undef_sstr;
3433 
3434     case SVt_NV:
3435 	if (SvNOK(sstr)) {
3436 	    switch (dtype) {
3437 	    case SVt_NULL:
3438 	    case SVt_IV:
3439 		sv_upgrade(dstr, SVt_NV);
3440 		break;
3441 	    case SVt_RV:
3442 	    case SVt_PV:
3443 	    case SVt_PVIV:
3444 		sv_upgrade(dstr, SVt_PVNV);
3445 		break;
3446 	    case SVt_PVGV:
3447 		goto end_of_first_switch;
3448 	    }
3449 	    SvNV_set(dstr, SvNVX(sstr));
3450 	    (void)SvNOK_only(dstr);
3451 	    /* SvTAINTED can only be true if the SV has taint magic, which in
3452 	       turn means that the SV type is PVMG (or greater). This is the
3453 	       case statement for SVt_NV, so this cannot be true (whatever gcov
3454 	       may say).  */
3455 	    assert(!SvTAINTED(sstr));
3456 	    return;
3457 	}
3458 	goto undef_sstr;
3459 
3460     case SVt_RV:
3461 	if (dtype < SVt_RV)
3462 	    sv_upgrade(dstr, SVt_RV);
3463 	break;
3464     case SVt_PVFM:
3465 #ifdef PERL_OLD_COPY_ON_WRITE
3466 	if ((SvFLAGS(sstr) & CAN_COW_MASK) == CAN_COW_FLAGS) {
3467 	    if (dtype < SVt_PVIV)
3468 		sv_upgrade(dstr, SVt_PVIV);
3469 	    break;
3470 	}
3471 	/* Fall through */
3472 #endif
3473     case SVt_PV:
3474 	if (dtype < SVt_PV)
3475 	    sv_upgrade(dstr, SVt_PV);
3476 	break;
3477     case SVt_PVIV:
3478 	if (dtype < SVt_PVIV)
3479 	    sv_upgrade(dstr, SVt_PVIV);
3480 	break;
3481     case SVt_PVNV:
3482 	if (dtype < SVt_PVNV)
3483 	    sv_upgrade(dstr, SVt_PVNV);
3484 	break;
3485     default:
3486 	{
3487 	const char * const type = sv_reftype(sstr,0);
3488 	if (PL_op)
3489 	    Perl_croak(aTHX_ "Bizarre copy of %s in %s", type, OP_NAME(PL_op));
3490 	else
3491 	    Perl_croak(aTHX_ "Bizarre copy of %s", type);
3492 	}
3493 	break;
3494 
3495 	/* case SVt_BIND: */
3496     case SVt_PVLV:
3497     case SVt_PVGV:
3498 	if (isGV_with_GP(sstr) && dtype <= SVt_PVGV) {
3499 	    glob_assign_glob(dstr, sstr, dtype);
3500 	    return;
3501 	}
3502 	/* SvVALID means that this PVGV is playing at being an FBM.  */
3503 	/*FALLTHROUGH*/
3504 
3505     case SVt_PVMG:
3506 	if (SvGMAGICAL(sstr) && (flags & SV_GMAGIC)) {
3507 	    mg_get(sstr);
3508 	    if (SvTYPE(sstr) != stype) {
3509 		stype = SvTYPE(sstr);
3510 		if (isGV_with_GP(sstr) && stype == SVt_PVGV && dtype <= SVt_PVGV) {
3511 		    glob_assign_glob(dstr, sstr, dtype);
3512 		    return;
3513 		}
3514 	    }
3515 	}
3516 	if (stype == SVt_PVLV)
3517 	    SvUPGRADE(dstr, SVt_PVNV);
3518 	else
3519 	    SvUPGRADE(dstr, (svtype)stype);
3520     }
3521  end_of_first_switch:
3522 
3523     /* dstr may have been upgraded.  */
3524     dtype = SvTYPE(dstr);
3525     sflags = SvFLAGS(sstr);
3526 
3527     if (dtype == SVt_PVCV || dtype == SVt_PVFM) {
3528 	/* Assigning to a subroutine sets the prototype.  */
3529 	if (SvOK(sstr)) {
3530 	    STRLEN len;
3531 	    const char *const ptr = SvPV_const(sstr, len);
3532 
3533             SvGROW(dstr, len + 1);
3534             Copy(ptr, SvPVX(dstr), len + 1, char);
3535             SvCUR_set(dstr, len);
3536 	    SvPOK_only(dstr);
3537 	    SvFLAGS(dstr) |= sflags & SVf_UTF8;
3538 	} else {
3539 	    SvOK_off(dstr);
3540 	}
3541     } else if (dtype == SVt_PVAV || dtype == SVt_PVHV) {
3542 	const char * const type = sv_reftype(dstr,0);
3543 	if (PL_op)
3544 	    Perl_croak(aTHX_ "Cannot copy to %s in %s", type, OP_NAME(PL_op));
3545 	else
3546 	    Perl_croak(aTHX_ "Cannot copy to %s", type);
3547     } else if (sflags & SVf_ROK) {
3548 	if (isGV_with_GP(dstr) && dtype == SVt_PVGV
3549 	    && SvTYPE(SvRV(sstr)) == SVt_PVGV) {
3550 	    sstr = SvRV(sstr);
3551 	    if (sstr == dstr) {
3552 		if (GvIMPORTED(dstr) != GVf_IMPORTED
3553 		    && CopSTASH_ne(PL_curcop, GvSTASH(dstr)))
3554 		{
3555 		    GvIMPORTED_on(dstr);
3556 		}
3557 		GvMULTI_on(dstr);
3558 		return;
3559 	    }
3560 	    glob_assign_glob(dstr, sstr, dtype);
3561 	    return;
3562 	}
3563 
3564 	if (dtype >= SVt_PV) {
3565 	    if (dtype == SVt_PVGV && isGV_with_GP(dstr)) {
3566 		glob_assign_ref(dstr, sstr);
3567 		return;
3568 	    }
3569 	    if (SvPVX_const(dstr)) {
3570 		SvPV_free(dstr);
3571 		SvLEN_set(dstr, 0);
3572                 SvCUR_set(dstr, 0);
3573 	    }
3574 	}
3575 	(void)SvOK_off(dstr);
3576 	SvRV_set(dstr, SvREFCNT_inc(SvRV(sstr)));
3577 	SvFLAGS(dstr) |= sflags & SVf_ROK;
3578 	assert(!(sflags & SVp_NOK));
3579 	assert(!(sflags & SVp_IOK));
3580 	assert(!(sflags & SVf_NOK));
3581 	assert(!(sflags & SVf_IOK));
3582     }
3583     else if (dtype == SVt_PVGV && isGV_with_GP(dstr)) {
3584 	if (!(sflags & SVf_OK)) {
3585 	    if (ckWARN(WARN_MISC))
3586 		Perl_warner(aTHX_ packWARN(WARN_MISC),
3587 			    "Undefined value assigned to typeglob");
3588 	}
3589 	else {
3590 	    GV *gv = gv_fetchsv(sstr, GV_ADD, SVt_PVGV);
3591 	    if (dstr != (SV*)gv) {
3592 		if (GvGP(dstr))
3593 		    gp_free((GV*)dstr);
3594 		GvGP(dstr) = gp_ref(GvGP(gv));
3595 	    }
3596 	}
3597     }
3598     else if (sflags & SVp_POK) {
3599         bool isSwipe = 0;
3600 
3601 	/*
3602 	 * Check to see if we can just swipe the string.  If so, it's a
3603 	 * possible small lose on short strings, but a big win on long ones.
3604 	 * It might even be a win on short strings if SvPVX_const(dstr)
3605 	 * has to be allocated and SvPVX_const(sstr) has to be freed.
3606 	 * Likewise if we can set up COW rather than doing an actual copy, we
3607 	 * drop to the else clause, as the swipe code and the COW setup code
3608 	 * have much in common.
3609 	 */
3610 
3611 	/* Whichever path we take through the next code, we want this true,
3612 	   and doing it now facilitates the COW check.  */
3613 	(void)SvPOK_only(dstr);
3614 
3615 	if (
3616 	    /* If we're already COW then this clause is not true, and if COW
3617 	       is allowed then we drop down to the else and make dest COW
3618 	       with us.  If caller hasn't said that we're allowed to COW
3619 	       shared hash keys then we don't do the COW setup, even if the
3620 	       source scalar is a shared hash key scalar.  */
3621             (((flags & SV_COW_SHARED_HASH_KEYS)
3622 	       ? (sflags & (SVf_FAKE|SVf_READONLY)) != (SVf_FAKE|SVf_READONLY)
3623 	       : 1 /* If making a COW copy is forbidden then the behaviour we
3624 		       desire is as if the source SV isn't actually already
3625 		       COW, even if it is.  So we act as if the source flags
3626 		       are not COW, rather than actually testing them.  */
3627 	      )
3628 #ifndef PERL_OLD_COPY_ON_WRITE
3629 	     /* The change that added SV_COW_SHARED_HASH_KEYS makes the logic
3630 		when PERL_OLD_COPY_ON_WRITE is defined a little wrong.
3631 		Conceptually PERL_OLD_COPY_ON_WRITE being defined should
3632 		override SV_COW_SHARED_HASH_KEYS, because it means "always COW"
3633 		but in turn, it's somewhat dead code, never expected to go
3634 		live, but more kept as a placeholder on how to do it better
3635 		in a newer implementation.  */
3636 	     /* If we are COW and dstr is a suitable target then we drop down
3637 		into the else and make dest a COW of us.  */
3638 	     || (SvFLAGS(dstr) & CAN_COW_MASK) != CAN_COW_FLAGS
3639 #endif
3640 	     )
3641             &&
3642             !(isSwipe =
3643                  (sflags & SVs_TEMP) &&   /* slated for free anyway? */
3644                  !(sflags & SVf_OOK) &&   /* and not involved in OOK hack? */
3645 	         (!(flags & SV_NOSTEAL)) &&
3646 					/* and we're allowed to steal temps */
3647                  SvREFCNT(sstr) == 1 &&   /* and no other references to it? */
3648                  SvLEN(sstr) 	&&	  /* and really is a string */
3649 	    			/* and won't be needed again, potentially */
3650 	      !(PL_op && PL_op->op_type == OP_AASSIGN))
3651 #ifdef PERL_OLD_COPY_ON_WRITE
3652             && ((flags & SV_COW_SHARED_HASH_KEYS)
3653 		? (!((sflags & CAN_COW_MASK) == CAN_COW_FLAGS
3654 		     && (SvFLAGS(dstr) & CAN_COW_MASK) == CAN_COW_FLAGS
3655 		     && SvTYPE(sstr) >= SVt_PVIV))
3656 		: 1)
3657 #endif
3658             ) {
3659             /* Failed the swipe test, and it's not a shared hash key either.
3660                Have to copy the string.  */
3661 	    STRLEN len = SvCUR(sstr);
3662             SvGROW(dstr, len + 1);	/* inlined from sv_setpvn */
3663             Move(SvPVX_const(sstr),SvPVX(dstr),len,char);
3664             SvCUR_set(dstr, len);
3665             *SvEND(dstr) = '\0';
3666         } else {
3667             /* If PERL_OLD_COPY_ON_WRITE is not defined, then isSwipe will always
3668                be true in here.  */
3669             /* Either it's a shared hash key, or it's suitable for
3670                copy-on-write or we can swipe the string.  */
3671             if (DEBUG_C_TEST) {
3672                 PerlIO_printf(Perl_debug_log, "Copy on write: sstr --> dstr\n");
3673                 sv_dump(sstr);
3674                 sv_dump(dstr);
3675             }
3676 #ifdef PERL_OLD_COPY_ON_WRITE
3677             if (!isSwipe) {
3678                 /* I believe I should acquire a global SV mutex if
3679                    it's a COW sv (not a shared hash key) to stop
3680                    it going un copy-on-write.
3681                    If the source SV has gone un copy on write between up there
3682                    and down here, then (assert() that) it is of the correct
3683                    form to make it copy on write again */
3684                 if ((sflags & (SVf_FAKE | SVf_READONLY))
3685                     != (SVf_FAKE | SVf_READONLY)) {
3686                     SvREADONLY_on(sstr);
3687                     SvFAKE_on(sstr);
3688                     /* Make the source SV into a loop of 1.
3689                        (about to become 2) */
3690                     SV_COW_NEXT_SV_SET(sstr, sstr);
3691                 }
3692             }
3693 #endif
3694             /* Initial code is common.  */
3695 	    if (SvPVX_const(dstr)) {	/* we know that dtype >= SVt_PV */
3696 		SvPV_free(dstr);
3697 	    }
3698 
3699             if (!isSwipe) {
3700                 /* making another shared SV.  */
3701                 STRLEN cur = SvCUR(sstr);
3702                 STRLEN len = SvLEN(sstr);
3703 #ifdef PERL_OLD_COPY_ON_WRITE
3704                 if (len) {
3705 		    assert (SvTYPE(dstr) >= SVt_PVIV);
3706                     /* SvIsCOW_normal */
3707                     /* splice us in between source and next-after-source.  */
3708                     SV_COW_NEXT_SV_SET(dstr, SV_COW_NEXT_SV(sstr));
3709                     SV_COW_NEXT_SV_SET(sstr, dstr);
3710                     SvPV_set(dstr, SvPVX_mutable(sstr));
3711                 } else
3712 #endif
3713 		{
3714                     /* SvIsCOW_shared_hash */
3715                     DEBUG_C(PerlIO_printf(Perl_debug_log,
3716                                           "Copy on write: Sharing hash\n"));
3717 
3718 		    assert (SvTYPE(dstr) >= SVt_PV);
3719                     SvPV_set(dstr,
3720 			     HEK_KEY(share_hek_hek(SvSHARED_HEK_FROM_PV(SvPVX_const(sstr)))));
3721 		}
3722                 SvLEN_set(dstr, len);
3723                 SvCUR_set(dstr, cur);
3724                 SvREADONLY_on(dstr);
3725                 SvFAKE_on(dstr);
3726                 /* Relesase a global SV mutex.  */
3727             }
3728             else
3729                 {	/* Passes the swipe test.  */
3730                 SvPV_set(dstr, SvPVX_mutable(sstr));
3731                 SvLEN_set(dstr, SvLEN(sstr));
3732                 SvCUR_set(dstr, SvCUR(sstr));
3733 
3734                 SvTEMP_off(dstr);
3735                 (void)SvOK_off(sstr);	/* NOTE: nukes most SvFLAGS on sstr */
3736                 SvPV_set(sstr, NULL);
3737                 SvLEN_set(sstr, 0);
3738                 SvCUR_set(sstr, 0);
3739                 SvTEMP_off(sstr);
3740             }
3741         }
3742 	if (sflags & SVp_NOK) {
3743 	    SvNV_set(dstr, SvNVX(sstr));
3744 	}
3745 	if (sflags & SVp_IOK) {
3746 	    SvOOK_off(dstr);
3747 	    SvIV_set(dstr, SvIVX(sstr));
3748 	    /* Must do this otherwise some other overloaded use of 0x80000000
3749 	       gets confused. I guess SVpbm_VALID */
3750 	    if (sflags & SVf_IVisUV)
3751 		SvIsUV_on(dstr);
3752 	}
3753 	SvFLAGS(dstr) |= sflags & (SVf_IOK|SVp_IOK|SVf_NOK|SVp_NOK|SVf_UTF8);
3754 	{
3755 	    const MAGIC * const smg = SvVSTRING_mg(sstr);
3756 	    if (smg) {
3757 		sv_magic(dstr, NULL, PERL_MAGIC_vstring,
3758 			 smg->mg_ptr, smg->mg_len);
3759 		SvRMAGICAL_on(dstr);
3760 	    }
3761 	}
3762     }
3763     else if (sflags & (SVp_IOK|SVp_NOK)) {
3764 	(void)SvOK_off(dstr);
3765 	SvFLAGS(dstr) |= sflags & (SVf_IOK|SVp_IOK|SVf_IVisUV|SVf_NOK|SVp_NOK);
3766 	if (sflags & SVp_IOK) {
3767 	    /* XXXX Do we want to set IsUV for IV(ROK)?  Be extra safe... */
3768 	    SvIV_set(dstr, SvIVX(sstr));
3769 	}
3770 	if (sflags & SVp_NOK) {
3771 	    SvNV_set(dstr, SvNVX(sstr));
3772 	}
3773     }
3774     else {
3775 	if (isGV_with_GP(sstr)) {
3776 	    /* This stringification rule for globs is spread in 3 places.
3777 	       This feels bad. FIXME.  */
3778 	    const U32 wasfake = sflags & SVf_FAKE;
3779 
3780 	    /* FAKE globs can get coerced, so need to turn this off
3781 	       temporarily if it is on.  */
3782 	    SvFAKE_off(sstr);
3783 	    gv_efullname3(dstr, (GV *)sstr, "*");
3784 	    SvFLAGS(sstr) |= wasfake;
3785 	}
3786 	else
3787 	    (void)SvOK_off(dstr);
3788     }
3789     if (SvTAINTED(sstr))
3790 	SvTAINT(dstr);
3791 }
3792 
3793 /*
3794 =for apidoc sv_setsv_mg
3795 
3796 Like C<sv_setsv>, but also handles 'set' magic.
3797 
3798 =cut
3799 */
3800 
3801 void
3802 Perl_sv_setsv_mg(pTHX_ SV *dstr, register SV *sstr)
3803 {
3804     sv_setsv(dstr,sstr);
3805     SvSETMAGIC(dstr);
3806 }
3807 
3808 #ifdef PERL_OLD_COPY_ON_WRITE
3809 SV *
3810 Perl_sv_setsv_cow(pTHX_ SV *dstr, SV *sstr)
3811 {
3812     STRLEN cur = SvCUR(sstr);
3813     STRLEN len = SvLEN(sstr);
3814     register char *new_pv;
3815 
3816     if (DEBUG_C_TEST) {
3817 	PerlIO_printf(Perl_debug_log, "Fast copy on write: %p -> %p\n",
3818 		      (void*)sstr, (void*)dstr);
3819 	sv_dump(sstr);
3820 	if (dstr)
3821 		    sv_dump(dstr);
3822     }
3823 
3824     if (dstr) {
3825 	if (SvTHINKFIRST(dstr))
3826 	    sv_force_normal_flags(dstr, SV_COW_DROP_PV);
3827 	else if (SvPVX_const(dstr))
3828 	    Safefree(SvPVX_const(dstr));
3829     }
3830     else
3831 	new_SV(dstr);
3832     SvUPGRADE(dstr, SVt_PVIV);
3833 
3834     assert (SvPOK(sstr));
3835     assert (SvPOKp(sstr));
3836     assert (!SvIOK(sstr));
3837     assert (!SvIOKp(sstr));
3838     assert (!SvNOK(sstr));
3839     assert (!SvNOKp(sstr));
3840 
3841     if (SvIsCOW(sstr)) {
3842 
3843 	if (SvLEN(sstr) == 0) {
3844 	    /* source is a COW shared hash key.  */
3845 	    DEBUG_C(PerlIO_printf(Perl_debug_log,
3846 				  "Fast copy on write: Sharing hash\n"));
3847 	    new_pv = HEK_KEY(share_hek_hek(SvSHARED_HEK_FROM_PV(SvPVX_const(sstr))));
3848 	    goto common_exit;
3849 	}
3850 	SV_COW_NEXT_SV_SET(dstr, SV_COW_NEXT_SV(sstr));
3851     } else {
3852 	assert ((SvFLAGS(sstr) & CAN_COW_MASK) == CAN_COW_FLAGS);
3853 	SvUPGRADE(sstr, SVt_PVIV);
3854 	SvREADONLY_on(sstr);
3855 	SvFAKE_on(sstr);
3856 	DEBUG_C(PerlIO_printf(Perl_debug_log,
3857 			      "Fast copy on write: Converting sstr to COW\n"));
3858 	SV_COW_NEXT_SV_SET(dstr, sstr);
3859     }
3860     SV_COW_NEXT_SV_SET(sstr, dstr);
3861     new_pv = SvPVX_mutable(sstr);
3862 
3863   common_exit:
3864     SvPV_set(dstr, new_pv);
3865     SvFLAGS(dstr) = (SVt_PVIV|SVf_POK|SVp_POK|SVf_FAKE|SVf_READONLY);
3866     if (SvUTF8(sstr))
3867 	SvUTF8_on(dstr);
3868     SvLEN_set(dstr, len);
3869     SvCUR_set(dstr, cur);
3870     if (DEBUG_C_TEST) {
3871 	sv_dump(dstr);
3872     }
3873     return dstr;
3874 }
3875 #endif
3876 
3877 /*
3878 =for apidoc sv_setpvn
3879 
3880 Copies a string into an SV.  The C<len> parameter indicates the number of
3881 bytes to be copied.  If the C<ptr> argument is NULL the SV will become
3882 undefined.  Does not handle 'set' magic.  See C<sv_setpvn_mg>.
3883 
3884 =cut
3885 */
3886 
3887 void
3888 Perl_sv_setpvn(pTHX_ register SV *sv, register const char *ptr, register STRLEN len)
3889 {
3890     dVAR;
3891     register char *dptr;
3892 
3893     SV_CHECK_THINKFIRST_COW_DROP(sv);
3894     if (!ptr) {
3895 	(void)SvOK_off(sv);
3896 	return;
3897     }
3898     else {
3899         /* len is STRLEN which is unsigned, need to copy to signed */
3900 	const IV iv = len;
3901 	if (iv < 0)
3902 	    Perl_croak(aTHX_ "panic: sv_setpvn called with negative strlen");
3903     }
3904     SvUPGRADE(sv, SVt_PV);
3905 
3906     dptr = SvGROW(sv, len + 1);
3907     Move(ptr,dptr,len,char);
3908     dptr[len] = '\0';
3909     SvCUR_set(sv, len);
3910     (void)SvPOK_only_UTF8(sv);		/* validate pointer */
3911     SvTAINT(sv);
3912 }
3913 
3914 /*
3915 =for apidoc sv_setpvn_mg
3916 
3917 Like C<sv_setpvn>, but also handles 'set' magic.
3918 
3919 =cut
3920 */
3921 
3922 void
3923 Perl_sv_setpvn_mg(pTHX_ register SV *sv, register const char *ptr, register STRLEN len)
3924 {
3925     sv_setpvn(sv,ptr,len);
3926     SvSETMAGIC(sv);
3927 }
3928 
3929 /*
3930 =for apidoc sv_setpv
3931 
3932 Copies a string into an SV.  The string must be null-terminated.  Does not
3933 handle 'set' magic.  See C<sv_setpv_mg>.
3934 
3935 =cut
3936 */
3937 
3938 void
3939 Perl_sv_setpv(pTHX_ register SV *sv, register const char *ptr)
3940 {
3941     dVAR;
3942     register STRLEN len;
3943 
3944     SV_CHECK_THINKFIRST_COW_DROP(sv);
3945     if (!ptr) {
3946 	(void)SvOK_off(sv);
3947 	return;
3948     }
3949     len = strlen(ptr);
3950     SvUPGRADE(sv, SVt_PV);
3951 
3952     SvGROW(sv, len + 1);
3953     Move(ptr,SvPVX(sv),len+1,char);
3954     SvCUR_set(sv, len);
3955     (void)SvPOK_only_UTF8(sv);		/* validate pointer */
3956     SvTAINT(sv);
3957 }
3958 
3959 /*
3960 =for apidoc sv_setpv_mg
3961 
3962 Like C<sv_setpv>, but also handles 'set' magic.
3963 
3964 =cut
3965 */
3966 
3967 void
3968 Perl_sv_setpv_mg(pTHX_ register SV *sv, register const char *ptr)
3969 {
3970     sv_setpv(sv,ptr);
3971     SvSETMAGIC(sv);
3972 }
3973 
3974 /*
3975 =for apidoc sv_usepvn_flags
3976 
3977 Tells an SV to use C<ptr> to find its string value.  Normally the
3978 string is stored inside the SV but sv_usepvn allows the SV to use an
3979 outside string.  The C<ptr> should point to memory that was allocated
3980 by C<malloc>.  The string length, C<len>, must be supplied.  By default
3981 this function will realloc (i.e. move) the memory pointed to by C<ptr>,
3982 so that pointer should not be freed or used by the programmer after
3983 giving it to sv_usepvn, and neither should any pointers from "behind"
3984 that pointer (e.g. ptr + 1) be used.
3985 
3986 If C<flags> & SV_SMAGIC is true, will call SvSETMAGIC. If C<flags> &
3987 SV_HAS_TRAILING_NUL is true, then C<ptr[len]> must be NUL, and the realloc
3988 will be skipped. (i.e. the buffer is actually at least 1 byte longer than
3989 C<len>, and already meets the requirements for storing in C<SvPVX>)
3990 
3991 =cut
3992 */
3993 
3994 void
3995 Perl_sv_usepvn_flags(pTHX_ SV *sv, char *ptr, STRLEN len, U32 flags)
3996 {
3997     dVAR;
3998     STRLEN allocate;
3999     SV_CHECK_THINKFIRST_COW_DROP(sv);
4000     SvUPGRADE(sv, SVt_PV);
4001     if (!ptr) {
4002 	(void)SvOK_off(sv);
4003 	if (flags & SV_SMAGIC)
4004 	    SvSETMAGIC(sv);
4005 	return;
4006     }
4007     if (SvPVX_const(sv))
4008 	SvPV_free(sv);
4009 
4010 #ifdef DEBUGGING
4011     if (flags & SV_HAS_TRAILING_NUL)
4012 	assert(ptr[len] == '\0');
4013 #endif
4014 
4015     allocate = (flags & SV_HAS_TRAILING_NUL)
4016 	? len + 1: PERL_STRLEN_ROUNDUP(len + 1);
4017     if (flags & SV_HAS_TRAILING_NUL) {
4018 	/* It's long enough - do nothing.
4019 	   Specfically Perl_newCONSTSUB is relying on this.  */
4020     } else {
4021 #ifdef DEBUGGING
4022 	/* Force a move to shake out bugs in callers.  */
4023 	char *new_ptr = (char*)safemalloc(allocate);
4024 	Copy(ptr, new_ptr, len, char);
4025 	PoisonFree(ptr,len,char);
4026 	Safefree(ptr);
4027 	ptr = new_ptr;
4028 #else
4029 	ptr = (char*) saferealloc (ptr, allocate);
4030 #endif
4031     }
4032     SvPV_set(sv, ptr);
4033     SvCUR_set(sv, len);
4034     SvLEN_set(sv, allocate);
4035     if (!(flags & SV_HAS_TRAILING_NUL)) {
4036 	ptr[len] = '\0';
4037     }
4038     (void)SvPOK_only_UTF8(sv);		/* validate pointer */
4039     SvTAINT(sv);
4040     if (flags & SV_SMAGIC)
4041 	SvSETMAGIC(sv);
4042 }
4043 
4044 #ifdef PERL_OLD_COPY_ON_WRITE
4045 /* Need to do this *after* making the SV normal, as we need the buffer
4046    pointer to remain valid until after we've copied it.  If we let go too early,
4047    another thread could invalidate it by unsharing last of the same hash key
4048    (which it can do by means other than releasing copy-on-write Svs)
4049    or by changing the other copy-on-write SVs in the loop.  */
4050 STATIC void
4051 S_sv_release_COW(pTHX_ register SV *sv, const char *pvx, SV *after)
4052 {
4053     { /* this SV was SvIsCOW_normal(sv) */
4054          /* we need to find the SV pointing to us.  */
4055         SV *current = SV_COW_NEXT_SV(after);
4056 
4057         if (current == sv) {
4058             /* The SV we point to points back to us (there were only two of us
4059                in the loop.)
4060                Hence other SV is no longer copy on write either.  */
4061             SvFAKE_off(after);
4062             SvREADONLY_off(after);
4063         } else {
4064             /* We need to follow the pointers around the loop.  */
4065             SV *next;
4066             while ((next = SV_COW_NEXT_SV(current)) != sv) {
4067                 assert (next);
4068                 current = next;
4069                  /* don't loop forever if the structure is bust, and we have
4070                     a pointer into a closed loop.  */
4071                 assert (current != after);
4072                 assert (SvPVX_const(current) == pvx);
4073             }
4074             /* Make the SV before us point to the SV after us.  */
4075             SV_COW_NEXT_SV_SET(current, after);
4076         }
4077     }
4078 }
4079 #endif
4080 /*
4081 =for apidoc sv_force_normal_flags
4082 
4083 Undo various types of fakery on an SV: if the PV is a shared string, make
4084 a private copy; if we're a ref, stop refing; if we're a glob, downgrade to
4085 an xpvmg; if we're a copy-on-write scalar, this is the on-write time when
4086 we do the copy, and is also used locally. If C<SV_COW_DROP_PV> is set
4087 then a copy-on-write scalar drops its PV buffer (if any) and becomes
4088 SvPOK_off rather than making a copy. (Used where this scalar is about to be
4089 set to some other value.) In addition, the C<flags> parameter gets passed to
4090 C<sv_unref_flags()> when unrefing. C<sv_force_normal> calls this function
4091 with flags set to 0.
4092 
4093 =cut
4094 */
4095 
4096 void
4097 Perl_sv_force_normal_flags(pTHX_ register SV *sv, U32 flags)
4098 {
4099     dVAR;
4100 #ifdef PERL_OLD_COPY_ON_WRITE
4101     if (SvREADONLY(sv)) {
4102         /* At this point I believe I should acquire a global SV mutex.  */
4103 	if (SvFAKE(sv)) {
4104 	    const char * const pvx = SvPVX_const(sv);
4105 	    const STRLEN len = SvLEN(sv);
4106 	    const STRLEN cur = SvCUR(sv);
4107 	    /* next COW sv in the loop.  If len is 0 then this is a shared-hash
4108 	       key scalar, so we mustn't attempt to call SV_COW_NEXT_SV(), as
4109 	       we'll fail an assertion.  */
4110 	    SV * const next = len ? SV_COW_NEXT_SV(sv) : 0;
4111 
4112             if (DEBUG_C_TEST) {
4113                 PerlIO_printf(Perl_debug_log,
4114                               "Copy on write: Force normal %ld\n",
4115                               (long) flags);
4116                 sv_dump(sv);
4117             }
4118             SvFAKE_off(sv);
4119             SvREADONLY_off(sv);
4120             /* This SV doesn't own the buffer, so need to Newx() a new one:  */
4121             SvPV_set(sv, NULL);
4122             SvLEN_set(sv, 0);
4123             if (flags & SV_COW_DROP_PV) {
4124                 /* OK, so we don't need to copy our buffer.  */
4125                 SvPOK_off(sv);
4126             } else {
4127                 SvGROW(sv, cur + 1);
4128                 Move(pvx,SvPVX(sv),cur,char);
4129                 SvCUR_set(sv, cur);
4130                 *SvEND(sv) = '\0';
4131             }
4132 	    if (len) {
4133 		sv_release_COW(sv, pvx, next);
4134 	    } else {
4135 		unshare_hek(SvSHARED_HEK_FROM_PV(pvx));
4136 	    }
4137             if (DEBUG_C_TEST) {
4138                 sv_dump(sv);
4139             }
4140 	}
4141 	else if (IN_PERL_RUNTIME)
4142 	    Perl_croak(aTHX_ PL_no_modify);
4143         /* At this point I believe that I can drop the global SV mutex.  */
4144     }
4145 #else
4146     if (SvREADONLY(sv)) {
4147 	if (SvFAKE(sv)) {
4148 	    const char * const pvx = SvPVX_const(sv);
4149 	    const STRLEN len = SvCUR(sv);
4150 	    SvFAKE_off(sv);
4151 	    SvREADONLY_off(sv);
4152 	    SvPV_set(sv, NULL);
4153 	    SvLEN_set(sv, 0);
4154 	    SvGROW(sv, len + 1);
4155 	    Move(pvx,SvPVX(sv),len,char);
4156 	    *SvEND(sv) = '\0';
4157 	    unshare_hek(SvSHARED_HEK_FROM_PV(pvx));
4158 	}
4159 	else if (IN_PERL_RUNTIME)
4160 	    Perl_croak(aTHX_ PL_no_modify);
4161     }
4162 #endif
4163     if (SvROK(sv))
4164 	sv_unref_flags(sv, flags);
4165     else if (SvFAKE(sv) && SvTYPE(sv) == SVt_PVGV)
4166 	sv_unglob(sv);
4167 }
4168 
4169 /*
4170 =for apidoc sv_chop
4171 
4172 Efficient removal of characters from the beginning of the string buffer.
4173 SvPOK(sv) must be true and the C<ptr> must be a pointer to somewhere inside
4174 the string buffer.  The C<ptr> becomes the first character of the adjusted
4175 string. Uses the "OOK hack".
4176 Beware: after this function returns, C<ptr> and SvPVX_const(sv) may no longer
4177 refer to the same chunk of data.
4178 
4179 =cut
4180 */
4181 
4182 void
4183 Perl_sv_chop(pTHX_ register SV *sv, register const char *ptr)
4184 {
4185     register STRLEN delta;
4186     if (!ptr || !SvPOKp(sv))
4187 	return;
4188     delta = ptr - SvPVX_const(sv);
4189     SV_CHECK_THINKFIRST(sv);
4190     if (SvTYPE(sv) < SVt_PVIV)
4191 	sv_upgrade(sv,SVt_PVIV);
4192 
4193     if (!SvOOK(sv)) {
4194 	if (!SvLEN(sv)) { /* make copy of shared string */
4195 	    const char *pvx = SvPVX_const(sv);
4196 	    const STRLEN len = SvCUR(sv);
4197 	    SvGROW(sv, len + 1);
4198 	    Move(pvx,SvPVX(sv),len,char);
4199 	    *SvEND(sv) = '\0';
4200 	}
4201 	SvIV_set(sv, 0);
4202 	/* Same SvOOK_on but SvOOK_on does a SvIOK_off
4203 	   and we do that anyway inside the SvNIOK_off
4204 	*/
4205 	SvFLAGS(sv) |= SVf_OOK;
4206     }
4207     SvNIOK_off(sv);
4208     SvLEN_set(sv, SvLEN(sv) - delta);
4209     SvCUR_set(sv, SvCUR(sv) - delta);
4210     SvPV_set(sv, SvPVX(sv) + delta);
4211     SvIV_set(sv, SvIVX(sv) + delta);
4212 }
4213 
4214 /*
4215 =for apidoc sv_catpvn
4216 
4217 Concatenates the string onto the end of the string which is in the SV.  The
4218 C<len> indicates number of bytes to copy.  If the SV has the UTF-8
4219 status set, then the bytes appended should be valid UTF-8.
4220 Handles 'get' magic, but not 'set' magic.  See C<sv_catpvn_mg>.
4221 
4222 =for apidoc sv_catpvn_flags
4223 
4224 Concatenates the string onto the end of the string which is in the SV.  The
4225 C<len> indicates number of bytes to copy.  If the SV has the UTF-8
4226 status set, then the bytes appended should be valid UTF-8.
4227 If C<flags> has C<SV_GMAGIC> bit set, will C<mg_get> on C<dsv> if
4228 appropriate, else not. C<sv_catpvn> and C<sv_catpvn_nomg> are implemented
4229 in terms of this function.
4230 
4231 =cut
4232 */
4233 
4234 void
4235 Perl_sv_catpvn_flags(pTHX_ register SV *dsv, register const char *sstr, register STRLEN slen, I32 flags)
4236 {
4237     dVAR;
4238     STRLEN dlen;
4239     const char * const dstr = SvPV_force_flags(dsv, dlen, flags);
4240 
4241     SvGROW(dsv, dlen + slen + 1);
4242     if (sstr == dstr)
4243 	sstr = SvPVX_const(dsv);
4244     Move(sstr, SvPVX(dsv) + dlen, slen, char);
4245     SvCUR_set(dsv, SvCUR(dsv) + slen);
4246     *SvEND(dsv) = '\0';
4247     (void)SvPOK_only_UTF8(dsv);		/* validate pointer */
4248     SvTAINT(dsv);
4249     if (flags & SV_SMAGIC)
4250 	SvSETMAGIC(dsv);
4251 }
4252 
4253 /*
4254 =for apidoc sv_catsv
4255 
4256 Concatenates the string from SV C<ssv> onto the end of the string in
4257 SV C<dsv>.  Modifies C<dsv> but not C<ssv>.  Handles 'get' magic, but
4258 not 'set' magic.  See C<sv_catsv_mg>.
4259 
4260 =for apidoc sv_catsv_flags
4261 
4262 Concatenates the string from SV C<ssv> onto the end of the string in
4263 SV C<dsv>.  Modifies C<dsv> but not C<ssv>.  If C<flags> has C<SV_GMAGIC>
4264 bit set, will C<mg_get> on the SVs if appropriate, else not. C<sv_catsv>
4265 and C<sv_catsv_nomg> are implemented in terms of this function.
4266 
4267 =cut */
4268 
4269 void
4270 Perl_sv_catsv_flags(pTHX_ SV *dsv, register SV *ssv, I32 flags)
4271 {
4272     dVAR;
4273     if (ssv) {
4274 	STRLEN slen;
4275 	const char *spv = SvPV_const(ssv, slen);
4276 	if (spv) {
4277 	    /*  sutf8 and dutf8 were type bool, but under USE_ITHREADS,
4278 		gcc version 2.95.2 20000220 (Debian GNU/Linux) for
4279 		Linux xxx 2.2.17 on sparc64 with gcc -O2, we erroneously
4280 		get dutf8 = 0x20000000, (i.e.  SVf_UTF8) even though
4281 		dsv->sv_flags doesn't have that bit set.
4282 		Andy Dougherty  12 Oct 2001
4283 	    */
4284 	    const I32 sutf8 = DO_UTF8(ssv);
4285 	    I32 dutf8;
4286 
4287 	    if (SvGMAGICAL(dsv) && (flags & SV_GMAGIC))
4288 		mg_get(dsv);
4289 	    dutf8 = DO_UTF8(dsv);
4290 
4291 	    if (dutf8 != sutf8) {
4292 		if (dutf8) {
4293 		    /* Not modifying source SV, so taking a temporary copy. */
4294 		    SV* const csv = sv_2mortal(newSVpvn(spv, slen));
4295 
4296 		    sv_utf8_upgrade(csv);
4297 		    spv = SvPV_const(csv, slen);
4298 		}
4299 		else
4300 		    sv_utf8_upgrade_nomg(dsv);
4301 	    }
4302 	    sv_catpvn_nomg(dsv, spv, slen);
4303 	}
4304     }
4305     if (flags & SV_SMAGIC)
4306 	SvSETMAGIC(dsv);
4307 }
4308 
4309 /*
4310 =for apidoc sv_catpv
4311 
4312 Concatenates the string onto the end of the string which is in the SV.
4313 If the SV has the UTF-8 status set, then the bytes appended should be
4314 valid UTF-8.  Handles 'get' magic, but not 'set' magic.  See C<sv_catpv_mg>.
4315 
4316 =cut */
4317 
4318 void
4319 Perl_sv_catpv(pTHX_ register SV *sv, register const char *ptr)
4320 {
4321     dVAR;
4322     register STRLEN len;
4323     STRLEN tlen;
4324     char *junk;
4325 
4326     if (!ptr)
4327 	return;
4328     junk = SvPV_force(sv, tlen);
4329     len = strlen(ptr);
4330     SvGROW(sv, tlen + len + 1);
4331     if (ptr == junk)
4332 	ptr = SvPVX_const(sv);
4333     Move(ptr,SvPVX(sv)+tlen,len+1,char);
4334     SvCUR_set(sv, SvCUR(sv) + len);
4335     (void)SvPOK_only_UTF8(sv);		/* validate pointer */
4336     SvTAINT(sv);
4337 }
4338 
4339 /*
4340 =for apidoc sv_catpv_mg
4341 
4342 Like C<sv_catpv>, but also handles 'set' magic.
4343 
4344 =cut
4345 */
4346 
4347 void
4348 Perl_sv_catpv_mg(pTHX_ register SV *sv, register const char *ptr)
4349 {
4350     sv_catpv(sv,ptr);
4351     SvSETMAGIC(sv);
4352 }
4353 
4354 /*
4355 =for apidoc newSV
4356 
4357 Creates a new SV.  A non-zero C<len> parameter indicates the number of
4358 bytes of preallocated string space the SV should have.  An extra byte for a
4359 trailing NUL is also reserved.  (SvPOK is not set for the SV even if string
4360 space is allocated.)  The reference count for the new SV is set to 1.
4361 
4362 In 5.9.3, newSV() replaces the older NEWSV() API, and drops the first
4363 parameter, I<x>, a debug aid which allowed callers to identify themselves.
4364 This aid has been superseded by a new build option, PERL_MEM_LOG (see
4365 L<perlhack/PERL_MEM_LOG>).  The older API is still there for use in XS
4366 modules supporting older perls.
4367 
4368 =cut
4369 */
4370 
4371 SV *
4372 Perl_newSV(pTHX_ STRLEN len)
4373 {
4374     dVAR;
4375     register SV *sv;
4376 
4377     new_SV(sv);
4378     if (len) {
4379 	sv_upgrade(sv, SVt_PV);
4380 	SvGROW(sv, len + 1);
4381     }
4382     return sv;
4383 }
4384 /*
4385 =for apidoc sv_magicext
4386 
4387 Adds magic to an SV, upgrading it if necessary. Applies the
4388 supplied vtable and returns a pointer to the magic added.
4389 
4390 Note that C<sv_magicext> will allow things that C<sv_magic> will not.
4391 In particular, you can add magic to SvREADONLY SVs, and add more than
4392 one instance of the same 'how'.
4393 
4394 If C<namlen> is greater than zero then a C<savepvn> I<copy> of C<name> is
4395 stored, if C<namlen> is zero then C<name> is stored as-is and - as another
4396 special case - if C<(name && namlen == HEf_SVKEY)> then C<name> is assumed
4397 to contain an C<SV*> and is stored as-is with its REFCNT incremented.
4398 
4399 (This is now used as a subroutine by C<sv_magic>.)
4400 
4401 =cut
4402 */
4403 MAGIC *
4404 Perl_sv_magicext(pTHX_ SV* sv, SV* obj, int how, const MGVTBL *vtable,
4405 		 const char* name, I32 namlen)
4406 {
4407     dVAR;
4408     MAGIC* mg;
4409 
4410     SvUPGRADE(sv, SVt_PVMG);
4411     Newxz(mg, 1, MAGIC);
4412     mg->mg_moremagic = SvMAGIC(sv);
4413     SvMAGIC_set(sv, mg);
4414 
4415     /* Sometimes a magic contains a reference loop, where the sv and
4416        object refer to each other.  To prevent a reference loop that
4417        would prevent such objects being freed, we look for such loops
4418        and if we find one we avoid incrementing the object refcount.
4419 
4420        Note we cannot do this to avoid self-tie loops as intervening RV must
4421        have its REFCNT incremented to keep it in existence.
4422 
4423     */
4424     if (!obj || obj == sv ||
4425 	how == PERL_MAGIC_arylen ||
4426 	how == PERL_MAGIC_qr ||
4427 	how == PERL_MAGIC_symtab ||
4428 	(SvTYPE(obj) == SVt_PVGV &&
4429 	    (GvSV(obj) == sv || GvHV(obj) == (HV*)sv || GvAV(obj) == (AV*)sv ||
4430 	    GvCV(obj) == (CV*)sv || GvIOp(obj) == (IO*)sv ||
4431 	    GvFORM(obj) == (CV*)sv)))
4432     {
4433 	mg->mg_obj = obj;
4434     }
4435     else {
4436 	mg->mg_obj = SvREFCNT_inc_simple(obj);
4437 	mg->mg_flags |= MGf_REFCOUNTED;
4438     }
4439 
4440     /* Normal self-ties simply pass a null object, and instead of
4441        using mg_obj directly, use the SvTIED_obj macro to produce a
4442        new RV as needed.  For glob "self-ties", we are tieing the PVIO
4443        with an RV obj pointing to the glob containing the PVIO.  In
4444        this case, to avoid a reference loop, we need to weaken the
4445        reference.
4446     */
4447 
4448     if (how == PERL_MAGIC_tiedscalar && SvTYPE(sv) == SVt_PVIO &&
4449         obj && SvROK(obj) && GvIO(SvRV(obj)) == (IO*)sv)
4450     {
4451       sv_rvweaken(obj);
4452     }
4453 
4454     mg->mg_type = how;
4455     mg->mg_len = namlen;
4456     if (name) {
4457 	if (namlen > 0)
4458 	    mg->mg_ptr = savepvn(name, namlen);
4459 	else if (namlen == HEf_SVKEY)
4460 	    mg->mg_ptr = (char*)SvREFCNT_inc_simple_NN((SV*)name);
4461 	else
4462 	    mg->mg_ptr = (char *) name;
4463     }
4464     mg->mg_virtual = (MGVTBL *) vtable;
4465 
4466     mg_magical(sv);
4467     if (SvGMAGICAL(sv))
4468 	SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK|SVf_POK);
4469     return mg;
4470 }
4471 
4472 /*
4473 =for apidoc sv_magic
4474 
4475 Adds magic to an SV. First upgrades C<sv> to type C<SVt_PVMG> if necessary,
4476 then adds a new magic item of type C<how> to the head of the magic list.
4477 
4478 See C<sv_magicext> (which C<sv_magic> now calls) for a description of the
4479 handling of the C<name> and C<namlen> arguments.
4480 
4481 You need to use C<sv_magicext> to add magic to SvREADONLY SVs and also
4482 to add more than one instance of the same 'how'.
4483 
4484 =cut
4485 */
4486 
4487 void
4488 Perl_sv_magic(pTHX_ register SV *sv, SV *obj, int how, const char *name, I32 namlen)
4489 {
4490     dVAR;
4491     const MGVTBL *vtable;
4492     MAGIC* mg;
4493 
4494 #ifdef PERL_OLD_COPY_ON_WRITE
4495     if (SvIsCOW(sv))
4496         sv_force_normal_flags(sv, 0);
4497 #endif
4498     if (SvREADONLY(sv)) {
4499 	if (
4500 	    /* its okay to attach magic to shared strings; the subsequent
4501 	     * upgrade to PVMG will unshare the string */
4502 	    !(SvFAKE(sv) && SvTYPE(sv) < SVt_PVMG)
4503 
4504 	    && IN_PERL_RUNTIME
4505 	    && how != PERL_MAGIC_regex_global
4506 	    && how != PERL_MAGIC_bm
4507 	    && how != PERL_MAGIC_fm
4508 	    && how != PERL_MAGIC_sv
4509 	    && how != PERL_MAGIC_backref
4510 	   )
4511 	{
4512 	    Perl_croak(aTHX_ PL_no_modify);
4513 	}
4514     }
4515     if (SvMAGICAL(sv) || (how == PERL_MAGIC_taint && SvTYPE(sv) >= SVt_PVMG)) {
4516 	if (SvMAGIC(sv) && (mg = mg_find(sv, how))) {
4517 	    /* sv_magic() refuses to add a magic of the same 'how' as an
4518 	       existing one
4519 	     */
4520 	    if (how == PERL_MAGIC_taint) {
4521 		mg->mg_len |= 1;
4522 		/* Any scalar which already had taint magic on which someone
4523 		   (erroneously?) did SvIOK_on() or similar will now be
4524 		   incorrectly sporting public "OK" flags.  */
4525 		SvFLAGS(sv) &= ~(SVf_IOK|SVf_NOK|SVf_POK);
4526 	    }
4527 	    return;
4528 	}
4529     }
4530 
4531     switch (how) {
4532     case PERL_MAGIC_sv:
4533 	vtable = &PL_vtbl_sv;
4534 	break;
4535     case PERL_MAGIC_overload:
4536         vtable = &PL_vtbl_amagic;
4537         break;
4538     case PERL_MAGIC_overload_elem:
4539         vtable = &PL_vtbl_amagicelem;
4540         break;
4541     case PERL_MAGIC_overload_table:
4542         vtable = &PL_vtbl_ovrld;
4543         break;
4544     case PERL_MAGIC_bm:
4545 	vtable = &PL_vtbl_bm;
4546 	break;
4547     case PERL_MAGIC_regdata:
4548 	vtable = &PL_vtbl_regdata;
4549 	break;
4550     case PERL_MAGIC_regdatum:
4551 	vtable = &PL_vtbl_regdatum;
4552 	break;
4553     case PERL_MAGIC_env:
4554 	vtable = &PL_vtbl_env;
4555 	break;
4556     case PERL_MAGIC_fm:
4557 	vtable = &PL_vtbl_fm;
4558 	break;
4559     case PERL_MAGIC_envelem:
4560 	vtable = &PL_vtbl_envelem;
4561 	break;
4562     case PERL_MAGIC_regex_global:
4563 	vtable = &PL_vtbl_mglob;
4564 	break;
4565     case PERL_MAGIC_isa:
4566 	vtable = &PL_vtbl_isa;
4567 	break;
4568     case PERL_MAGIC_isaelem:
4569 	vtable = &PL_vtbl_isaelem;
4570 	break;
4571     case PERL_MAGIC_nkeys:
4572 	vtable = &PL_vtbl_nkeys;
4573 	break;
4574     case PERL_MAGIC_dbfile:
4575 	vtable = NULL;
4576 	break;
4577     case PERL_MAGIC_dbline:
4578 	vtable = &PL_vtbl_dbline;
4579 	break;
4580 #ifdef USE_LOCALE_COLLATE
4581     case PERL_MAGIC_collxfrm:
4582         vtable = &PL_vtbl_collxfrm;
4583         break;
4584 #endif /* USE_LOCALE_COLLATE */
4585     case PERL_MAGIC_tied:
4586 	vtable = &PL_vtbl_pack;
4587 	break;
4588     case PERL_MAGIC_tiedelem:
4589     case PERL_MAGIC_tiedscalar:
4590 	vtable = &PL_vtbl_packelem;
4591 	break;
4592     case PERL_MAGIC_qr:
4593 	vtable = &PL_vtbl_regexp;
4594 	break;
4595     case PERL_MAGIC_hints:
4596 	/* As this vtable is all NULL, we can reuse it.  */
4597     case PERL_MAGIC_sig:
4598 	vtable = &PL_vtbl_sig;
4599 	break;
4600     case PERL_MAGIC_sigelem:
4601 	vtable = &PL_vtbl_sigelem;
4602 	break;
4603     case PERL_MAGIC_taint:
4604 	vtable = &PL_vtbl_taint;
4605 	break;
4606     case PERL_MAGIC_uvar:
4607 	vtable = &PL_vtbl_uvar;
4608 	break;
4609     case PERL_MAGIC_vec:
4610 	vtable = &PL_vtbl_vec;
4611 	break;
4612     case PERL_MAGIC_arylen_p:
4613     case PERL_MAGIC_rhash:
4614     case PERL_MAGIC_symtab:
4615     case PERL_MAGIC_vstring:
4616 	vtable = NULL;
4617 	break;
4618     case PERL_MAGIC_utf8:
4619 	vtable = &PL_vtbl_utf8;
4620 	break;
4621     case PERL_MAGIC_substr:
4622 	vtable = &PL_vtbl_substr;
4623 	break;
4624     case PERL_MAGIC_defelem:
4625 	vtable = &PL_vtbl_defelem;
4626 	break;
4627     case PERL_MAGIC_arylen:
4628 	vtable = &PL_vtbl_arylen;
4629 	break;
4630     case PERL_MAGIC_pos:
4631 	vtable = &PL_vtbl_pos;
4632 	break;
4633     case PERL_MAGIC_backref:
4634 	vtable = &PL_vtbl_backref;
4635 	break;
4636     case PERL_MAGIC_hintselem:
4637 	vtable = &PL_vtbl_hintselem;
4638 	break;
4639     case PERL_MAGIC_ext:
4640 	/* Reserved for use by extensions not perl internals.	        */
4641 	/* Useful for attaching extension internal data to perl vars.	*/
4642 	/* Note that multiple extensions may clash if magical scalars	*/
4643 	/* etc holding private data from one are passed to another.	*/
4644 	vtable = NULL;
4645 	break;
4646     default:
4647 	Perl_croak(aTHX_ "Don't know how to handle magic of type \\%o", how);
4648     }
4649 
4650     /* Rest of work is done else where */
4651     mg = sv_magicext(sv,obj,how,vtable,name,namlen);
4652 
4653     switch (how) {
4654     case PERL_MAGIC_taint:
4655 	mg->mg_len = 1;
4656 	break;
4657     case PERL_MAGIC_ext:
4658     case PERL_MAGIC_dbfile:
4659 	SvRMAGICAL_on(sv);
4660 	break;
4661     }
4662 }
4663 
4664 /*
4665 =for apidoc sv_unmagic
4666 
4667 Removes all magic of type C<type> from an SV.
4668 
4669 =cut
4670 */
4671 
4672 int
4673 Perl_sv_unmagic(pTHX_ SV *sv, int type)
4674 {
4675     MAGIC* mg;
4676     MAGIC** mgp;
4677     if (SvTYPE(sv) < SVt_PVMG || !SvMAGIC(sv))
4678 	return 0;
4679     mgp = &(((XPVMG*) SvANY(sv))->xmg_u.xmg_magic);
4680     for (mg = *mgp; mg; mg = *mgp) {
4681 	if (mg->mg_type == type) {
4682             const MGVTBL* const vtbl = mg->mg_virtual;
4683 	    *mgp = mg->mg_moremagic;
4684 	    if (vtbl && vtbl->svt_free)
4685 		CALL_FPTR(vtbl->svt_free)(aTHX_ sv, mg);
4686 	    if (mg->mg_ptr && mg->mg_type != PERL_MAGIC_regex_global) {
4687 		if (mg->mg_len > 0)
4688 		    Safefree(mg->mg_ptr);
4689 		else if (mg->mg_len == HEf_SVKEY)
4690 		    SvREFCNT_dec((SV*)mg->mg_ptr);
4691 		else if (mg->mg_type == PERL_MAGIC_utf8)
4692 		    Safefree(mg->mg_ptr);
4693             }
4694 	    if (mg->mg_flags & MGf_REFCOUNTED)
4695 		SvREFCNT_dec(mg->mg_obj);
4696 	    Safefree(mg);
4697 	}
4698 	else
4699 	    mgp = &mg->mg_moremagic;
4700     }
4701     if (!SvMAGIC(sv)) {
4702 	SvMAGICAL_off(sv);
4703 	SvFLAGS(sv) |= (SvFLAGS(sv) & (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
4704 	SvMAGIC_set(sv, NULL);
4705     }
4706 
4707     return 0;
4708 }
4709 
4710 /*
4711 =for apidoc sv_rvweaken
4712 
4713 Weaken a reference: set the C<SvWEAKREF> flag on this RV; give the
4714 referred-to SV C<PERL_MAGIC_backref> magic if it hasn't already; and
4715 push a back-reference to this RV onto the array of backreferences
4716 associated with that magic. If the RV is magical, set magic will be
4717 called after the RV is cleared.
4718 
4719 =cut
4720 */
4721 
4722 SV *
4723 Perl_sv_rvweaken(pTHX_ SV *sv)
4724 {
4725     SV *tsv;
4726     if (!SvOK(sv))  /* let undefs pass */
4727 	return sv;
4728     if (!SvROK(sv))
4729 	Perl_croak(aTHX_ "Can't weaken a nonreference");
4730     else if (SvWEAKREF(sv)) {
4731 	if (ckWARN(WARN_MISC))
4732 	    Perl_warner(aTHX_ packWARN(WARN_MISC), "Reference is already weak");
4733 	return sv;
4734     }
4735     tsv = SvRV(sv);
4736     Perl_sv_add_backref(aTHX_ tsv, sv);
4737     SvWEAKREF_on(sv);
4738     SvREFCNT_dec(tsv);
4739     return sv;
4740 }
4741 
4742 /* Give tsv backref magic if it hasn't already got it, then push a
4743  * back-reference to sv onto the array associated with the backref magic.
4744  */
4745 
4746 void
4747 Perl_sv_add_backref(pTHX_ SV *tsv, SV *sv)
4748 {
4749     dVAR;
4750     AV *av;
4751 
4752     if (SvTYPE(tsv) == SVt_PVHV) {
4753 	AV **const avp = Perl_hv_backreferences_p(aTHX_ (HV*)tsv);
4754 
4755 	av = *avp;
4756 	if (!av) {
4757 	    /* There is no AV in the offical place - try a fixup.  */
4758 	    MAGIC *const mg = mg_find(tsv, PERL_MAGIC_backref);
4759 
4760 	    if (mg) {
4761 		/* Aha. They've got it stowed in magic.  Bring it back.  */
4762 		av = (AV*)mg->mg_obj;
4763 		/* Stop mg_free decreasing the refernce count.  */
4764 		mg->mg_obj = NULL;
4765 		/* Stop mg_free even calling the destructor, given that
4766 		   there's no AV to free up.  */
4767 		mg->mg_virtual = 0;
4768 		sv_unmagic(tsv, PERL_MAGIC_backref);
4769 	    } else {
4770 		av = newAV();
4771 		AvREAL_off(av);
4772 		SvREFCNT_inc_simple_void(av);
4773 	    }
4774 	    *avp = av;
4775 	}
4776     } else {
4777 	const MAGIC *const mg
4778 	    = SvMAGICAL(tsv) ? mg_find(tsv, PERL_MAGIC_backref) : NULL;
4779 	if (mg)
4780 	    av = (AV*)mg->mg_obj;
4781 	else {
4782 	    av = newAV();
4783 	    AvREAL_off(av);
4784 	    sv_magic(tsv, (SV*)av, PERL_MAGIC_backref, NULL, 0);
4785 	    /* av now has a refcnt of 2, which avoids it getting freed
4786 	     * before us during global cleanup. The extra ref is removed
4787 	     * by magic_killbackrefs() when tsv is being freed */
4788 	}
4789     }
4790     if (AvFILLp(av) >= AvMAX(av)) {
4791         av_extend(av, AvFILLp(av)+1);
4792     }
4793     AvARRAY(av)[++AvFILLp(av)] = sv; /* av_push() */
4794 }
4795 
4796 /* delete a back-reference to ourselves from the backref magic associated
4797  * with the SV we point to.
4798  */
4799 
4800 STATIC void
4801 S_sv_del_backref(pTHX_ SV *tsv, SV *sv)
4802 {
4803     dVAR;
4804     AV *av = NULL;
4805     SV **svp;
4806     I32 i;
4807 
4808     if (SvTYPE(tsv) == SVt_PVHV && SvOOK(tsv)) {
4809 	av = *Perl_hv_backreferences_p(aTHX_ (HV*)tsv);
4810 	/* We mustn't attempt to "fix up" the hash here by moving the
4811 	   backreference array back to the hv_aux structure, as that is stored
4812 	   in the main HvARRAY(), and hfreentries assumes that no-one
4813 	   reallocates HvARRAY() while it is running.  */
4814     }
4815     if (!av) {
4816 	const MAGIC *const mg
4817 	    = SvMAGICAL(tsv) ? mg_find(tsv, PERL_MAGIC_backref) : NULL;
4818 	if (mg)
4819 	    av = (AV *)mg->mg_obj;
4820     }
4821     if (!av) {
4822 	if (PL_in_clean_all)
4823 	    return;
4824 	Perl_croak(aTHX_ "panic: del_backref");
4825     }
4826 
4827     if (SvIS_FREED(av))
4828 	return;
4829 
4830     svp = AvARRAY(av);
4831     /* We shouldn't be in here more than once, but for paranoia reasons lets
4832        not assume this.  */
4833     for (i = AvFILLp(av); i >= 0; i--) {
4834 	if (svp[i] == sv) {
4835 	    const SSize_t fill = AvFILLp(av);
4836 	    if (i != fill) {
4837 		/* We weren't the last entry.
4838 		   An unordered list has this property that you can take the
4839 		   last element off the end to fill the hole, and it's still
4840 		   an unordered list :-)
4841 		*/
4842 		svp[i] = svp[fill];
4843 	    }
4844 	    svp[fill] = NULL;
4845 	    AvFILLp(av) = fill - 1;
4846 	}
4847     }
4848 }
4849 
4850 int
4851 Perl_sv_kill_backrefs(pTHX_ SV *sv, AV *av)
4852 {
4853     SV **svp = AvARRAY(av);
4854 
4855     PERL_UNUSED_ARG(sv);
4856 
4857     /* Not sure why the av can get freed ahead of its sv, but somehow it does
4858        in ext/B/t/bytecode.t test 15 (involving print <DATA>)  */
4859     if (svp && !SvIS_FREED(av)) {
4860 	SV *const *const last = svp + AvFILLp(av);
4861 
4862 	while (svp <= last) {
4863 	    if (*svp) {
4864 		SV *const referrer = *svp;
4865 		if (SvWEAKREF(referrer)) {
4866 		    /* XXX Should we check that it hasn't changed? */
4867 		    SvRV_set(referrer, 0);
4868 		    SvOK_off(referrer);
4869 		    SvWEAKREF_off(referrer);
4870 		    SvSETMAGIC(referrer);
4871 		} else if (SvTYPE(referrer) == SVt_PVGV ||
4872 			   SvTYPE(referrer) == SVt_PVLV) {
4873 		    /* You lookin' at me?  */
4874 		    assert(GvSTASH(referrer));
4875 		    assert(GvSTASH(referrer) == (HV*)sv);
4876 		    GvSTASH(referrer) = 0;
4877 		} else {
4878 		    Perl_croak(aTHX_
4879 			       "panic: magic_killbackrefs (flags=%"UVxf")",
4880 			       (UV)SvFLAGS(referrer));
4881 		}
4882 
4883 		*svp = NULL;
4884 	    }
4885 	    svp++;
4886 	}
4887     }
4888     SvREFCNT_dec(av); /* remove extra count added by sv_add_backref() */
4889     return 0;
4890 }
4891 
4892 /*
4893 =for apidoc sv_insert
4894 
4895 Inserts a string at the specified offset/length within the SV. Similar to
4896 the Perl substr() function.
4897 
4898 =cut
4899 */
4900 
4901 void
4902 Perl_sv_insert(pTHX_ SV *bigstr, STRLEN offset, STRLEN len, const char *little, STRLEN littlelen)
4903 {
4904     dVAR;
4905     register char *big;
4906     register char *mid;
4907     register char *midend;
4908     register char *bigend;
4909     register I32 i;
4910     STRLEN curlen;
4911 
4912 
4913     if (!bigstr)
4914 	Perl_croak(aTHX_ "Can't modify non-existent substring");
4915     SvPV_force(bigstr, curlen);
4916     (void)SvPOK_only_UTF8(bigstr);
4917     if (offset + len > curlen) {
4918 	SvGROW(bigstr, offset+len+1);
4919 	Zero(SvPVX(bigstr)+curlen, offset+len-curlen, char);
4920 	SvCUR_set(bigstr, offset+len);
4921     }
4922 
4923     SvTAINT(bigstr);
4924     i = littlelen - len;
4925     if (i > 0) {			/* string might grow */
4926 	big = SvGROW(bigstr, SvCUR(bigstr) + i + 1);
4927 	mid = big + offset + len;
4928 	midend = bigend = big + SvCUR(bigstr);
4929 	bigend += i;
4930 	*bigend = '\0';
4931 	while (midend > mid)		/* shove everything down */
4932 	    *--bigend = *--midend;
4933 	Move(little,big+offset,littlelen,char);
4934 	SvCUR_set(bigstr, SvCUR(bigstr) + i);
4935 	SvSETMAGIC(bigstr);
4936 	return;
4937     }
4938     else if (i == 0) {
4939 	Move(little,SvPVX(bigstr)+offset,len,char);
4940 	SvSETMAGIC(bigstr);
4941 	return;
4942     }
4943 
4944     big = SvPVX(bigstr);
4945     mid = big + offset;
4946     midend = mid + len;
4947     bigend = big + SvCUR(bigstr);
4948 
4949     if (midend > bigend)
4950 	Perl_croak(aTHX_ "panic: sv_insert");
4951 
4952     if (mid - big > bigend - midend) {	/* faster to shorten from end */
4953 	if (littlelen) {
4954 	    Move(little, mid, littlelen,char);
4955 	    mid += littlelen;
4956 	}
4957 	i = bigend - midend;
4958 	if (i > 0) {
4959 	    Move(midend, mid, i,char);
4960 	    mid += i;
4961 	}
4962 	*mid = '\0';
4963 	SvCUR_set(bigstr, mid - big);
4964     }
4965     else if ((i = mid - big)) {	/* faster from front */
4966 	midend -= littlelen;
4967 	mid = midend;
4968 	sv_chop(bigstr,midend-i);
4969 	big += i;
4970 	while (i--)
4971 	    *--midend = *--big;
4972 	if (littlelen)
4973 	    Move(little, mid, littlelen,char);
4974     }
4975     else if (littlelen) {
4976 	midend -= littlelen;
4977 	sv_chop(bigstr,midend);
4978 	Move(little,midend,littlelen,char);
4979     }
4980     else {
4981 	sv_chop(bigstr,midend);
4982     }
4983     SvSETMAGIC(bigstr);
4984 }
4985 
4986 /*
4987 =for apidoc sv_replace
4988 
4989 Make the first argument a copy of the second, then delete the original.
4990 The target SV physically takes over ownership of the body of the source SV
4991 and inherits its flags; however, the target keeps any magic it owns,
4992 and any magic in the source is discarded.
4993 Note that this is a rather specialist SV copying operation; most of the
4994 time you'll want to use C<sv_setsv> or one of its many macro front-ends.
4995 
4996 =cut
4997 */
4998 
4999 void
5000 Perl_sv_replace(pTHX_ register SV *sv, register SV *nsv)
5001 {
5002     dVAR;
5003     const U32 refcnt = SvREFCNT(sv);
5004     SV_CHECK_THINKFIRST_COW_DROP(sv);
5005     if (SvREFCNT(nsv) != 1) {
5006 	Perl_croak(aTHX_ "panic: reference miscount on nsv in sv_replace() (%"
5007 		   UVuf " != 1)", (UV) SvREFCNT(nsv));
5008     }
5009     if (SvMAGICAL(sv)) {
5010 	if (SvMAGICAL(nsv))
5011 	    mg_free(nsv);
5012 	else
5013 	    sv_upgrade(nsv, SVt_PVMG);
5014 	SvMAGIC_set(nsv, SvMAGIC(sv));
5015 	SvFLAGS(nsv) |= SvMAGICAL(sv);
5016 	SvMAGICAL_off(sv);
5017 	SvMAGIC_set(sv, NULL);
5018     }
5019     SvREFCNT(sv) = 0;
5020     sv_clear(sv);
5021     assert(!SvREFCNT(sv));
5022 #ifdef DEBUG_LEAKING_SCALARS
5023     sv->sv_flags  = nsv->sv_flags;
5024     sv->sv_any    = nsv->sv_any;
5025     sv->sv_refcnt = nsv->sv_refcnt;
5026     sv->sv_u      = nsv->sv_u;
5027 #else
5028     StructCopy(nsv,sv,SV);
5029 #endif
5030     /* Currently could join these into one piece of pointer arithmetic, but
5031        it would be unclear.  */
5032     if(SvTYPE(sv) == SVt_IV)
5033 	SvANY(sv)
5034 	    = (XPVIV*)((char*)&(sv->sv_u.svu_iv) - STRUCT_OFFSET(XPVIV, xiv_iv));
5035     else if (SvTYPE(sv) == SVt_RV) {
5036 	SvANY(sv) = &sv->sv_u.svu_rv;
5037     }
5038 
5039 
5040 #ifdef PERL_OLD_COPY_ON_WRITE
5041     if (SvIsCOW_normal(nsv)) {
5042 	/* We need to follow the pointers around the loop to make the
5043 	   previous SV point to sv, rather than nsv.  */
5044 	SV *next;
5045 	SV *current = nsv;
5046 	while ((next = SV_COW_NEXT_SV(current)) != nsv) {
5047 	    assert(next);
5048 	    current = next;
5049 	    assert(SvPVX_const(current) == SvPVX_const(nsv));
5050 	}
5051 	/* Make the SV before us point to the SV after us.  */
5052 	if (DEBUG_C_TEST) {
5053 	    PerlIO_printf(Perl_debug_log, "previous is\n");
5054 	    sv_dump(current);
5055 	    PerlIO_printf(Perl_debug_log,
5056                           "move it from 0x%"UVxf" to 0x%"UVxf"\n",
5057 			  (UV) SV_COW_NEXT_SV(current), (UV) sv);
5058 	}
5059 	SV_COW_NEXT_SV_SET(current, sv);
5060     }
5061 #endif
5062     SvREFCNT(sv) = refcnt;
5063     SvFLAGS(nsv) |= SVTYPEMASK;		/* Mark as freed */
5064     SvREFCNT(nsv) = 0;
5065     del_SV(nsv);
5066 }
5067 
5068 /*
5069 =for apidoc sv_clear
5070 
5071 Clear an SV: call any destructors, free up any memory used by the body,
5072 and free the body itself. The SV's head is I<not> freed, although
5073 its type is set to all 1's so that it won't inadvertently be assumed
5074 to be live during global destruction etc.
5075 This function should only be called when REFCNT is zero. Most of the time
5076 you'll want to call C<sv_free()> (or its macro wrapper C<SvREFCNT_dec>)
5077 instead.
5078 
5079 =cut
5080 */
5081 
5082 void
5083 Perl_sv_clear(pTHX_ register SV *sv)
5084 {
5085     dVAR;
5086     const U32 type = SvTYPE(sv);
5087     const struct body_details *const sv_type_details
5088 	= bodies_by_type + type;
5089     HV *stash;
5090 
5091     assert(sv);
5092     assert(SvREFCNT(sv) == 0);
5093 
5094     if (type <= SVt_IV) {
5095 	/* See the comment in sv.h about the collusion between this early
5096 	   return and the overloading of the NULL and IV slots in the size
5097 	   table.  */
5098 	return;
5099     }
5100 
5101     if (SvOBJECT(sv)) {
5102 	if (PL_defstash &&	/* Still have a symbol table? */
5103 	    SvDESTROYABLE(sv))
5104 	{
5105 	    dSP;
5106 	    HV* stash;
5107 	    do {
5108 		CV* destructor;
5109 		stash = SvSTASH(sv);
5110 		destructor = StashHANDLER(stash,DESTROY);
5111 		if (destructor) {
5112 		    SV* const tmpref = newRV(sv);
5113 	            SvREADONLY_on(tmpref);   /* DESTROY() could be naughty */
5114 		    ENTER;
5115 		    PUSHSTACKi(PERLSI_DESTROY);
5116 		    EXTEND(SP, 2);
5117 		    PUSHMARK(SP);
5118 		    PUSHs(tmpref);
5119 		    PUTBACK;
5120 		    call_sv((SV*)destructor, G_DISCARD|G_EVAL|G_KEEPERR|G_VOID);
5121 
5122 
5123 		    POPSTACK;
5124 		    SPAGAIN;
5125 		    LEAVE;
5126 		    if(SvREFCNT(tmpref) < 2) {
5127 		        /* tmpref is not kept alive! */
5128 		        SvREFCNT(sv)--;
5129 			SvRV_set(tmpref, NULL);
5130 			SvROK_off(tmpref);
5131 		    }
5132 		    SvREFCNT_dec(tmpref);
5133 		}
5134 	    } while (SvOBJECT(sv) && SvSTASH(sv) != stash);
5135 
5136 
5137 	    if (SvREFCNT(sv)) {
5138 		if (PL_in_clean_objs)
5139 		    Perl_croak(aTHX_ "DESTROY created new reference to dead object '%s'",
5140 			  HvNAME_get(stash));
5141 		/* DESTROY gave object new lease on life */
5142 		return;
5143 	    }
5144 	}
5145 
5146 	if (SvOBJECT(sv)) {
5147 	    SvREFCNT_dec(SvSTASH(sv));	/* possibly of changed persuasion */
5148 	    SvOBJECT_off(sv);	/* Curse the object. */
5149 	    if (type != SVt_PVIO)
5150 		--PL_sv_objcount;	/* XXX Might want something more general */
5151 	}
5152     }
5153     if (type >= SVt_PVMG) {
5154 	if (type == SVt_PVMG && SvPAD_OUR(sv)) {
5155 	    SvREFCNT_dec(SvOURSTASH(sv));
5156 	} else if (SvMAGIC(sv))
5157 	    mg_free(sv);
5158 	if (type == SVt_PVMG && SvPAD_TYPED(sv))
5159 	    SvREFCNT_dec(SvSTASH(sv));
5160     }
5161     switch (type) {
5162 	/* case SVt_BIND: */
5163     case SVt_PVIO:
5164 	if (IoIFP(sv) &&
5165 	    IoIFP(sv) != PerlIO_stdin() &&
5166 	    IoIFP(sv) != PerlIO_stdout() &&
5167 	    IoIFP(sv) != PerlIO_stderr())
5168 	{
5169 	    io_close((IO*)sv, FALSE);
5170 	}
5171 	if (IoDIRP(sv) && !(IoFLAGS(sv) & IOf_FAKE_DIRP))
5172 	    PerlDir_close(IoDIRP(sv));
5173 	IoDIRP(sv) = (DIR*)NULL;
5174 	Safefree(IoTOP_NAME(sv));
5175 	Safefree(IoFMT_NAME(sv));
5176 	Safefree(IoBOTTOM_NAME(sv));
5177 	goto freescalar;
5178     case SVt_PVCV:
5179     case SVt_PVFM:
5180 	cv_undef((CV*)sv);
5181 	goto freescalar;
5182     case SVt_PVHV:
5183 	Perl_hv_kill_backrefs(aTHX_ (HV*)sv);
5184 	hv_undef((HV*)sv);
5185 	break;
5186     case SVt_PVAV:
5187 	if (PL_comppad == (AV*)sv) {
5188 	    PL_comppad = NULL;
5189 	    PL_curpad = NULL;
5190 	}
5191 	av_undef((AV*)sv);
5192 	break;
5193     case SVt_PVLV:
5194 	if (LvTYPE(sv) == 'T') { /* for tie: return HE to pool */
5195 	    SvREFCNT_dec(HeKEY_sv((HE*)LvTARG(sv)));
5196 	    HeNEXT((HE*)LvTARG(sv)) = PL_hv_fetch_ent_mh;
5197 	    PL_hv_fetch_ent_mh = (HE*)LvTARG(sv);
5198 	}
5199 	else if (LvTYPE(sv) != 't') /* unless tie: unrefcnted fake SV**  */
5200 	    SvREFCNT_dec(LvTARG(sv));
5201     case SVt_PVGV:
5202 	if (isGV_with_GP(sv)) {
5203             if(GvCVu((GV*)sv) && (stash = GvSTASH((GV*)sv)) && HvNAME_get(stash))
5204                 mro_method_changed_in(stash);
5205 	    gp_free((GV*)sv);
5206 	    if (GvNAME_HEK(sv))
5207 		unshare_hek(GvNAME_HEK(sv));
5208 	    /* If we're in a stash, we don't own a reference to it. However it does
5209 	       have a back reference to us, which needs to be cleared.  */
5210 	    if (!SvVALID(sv) && (stash = GvSTASH(sv)))
5211 		    sv_del_backref((SV*)stash, sv);
5212 	}
5213 	/* FIXME. There are probably more unreferenced pointers to SVs in the
5214 	   interpreter struct that we should check and tidy in a similar
5215 	   fashion to this:  */
5216 	if ((GV*)sv == PL_last_in_gv)
5217 	    PL_last_in_gv = NULL;
5218     case SVt_PVMG:
5219     case SVt_PVNV:
5220     case SVt_PVIV:
5221       freescalar:
5222 	/* Don't bother with SvOOK_off(sv); as we're only going to free it.  */
5223 	if (SvOOK(sv)) {
5224 	    SvPV_set(sv, SvPVX_mutable(sv) - SvIVX(sv));
5225 	    /* Don't even bother with turning off the OOK flag.  */
5226 	}
5227     case SVt_PV:
5228     case SVt_RV:
5229 	if (SvROK(sv)) {
5230 	    SV * const target = SvRV(sv);
5231 	    if (SvWEAKREF(sv))
5232 	        sv_del_backref(target, sv);
5233 	    else
5234 	        SvREFCNT_dec(target);
5235 	}
5236 #ifdef PERL_OLD_COPY_ON_WRITE
5237 	else if (SvPVX_const(sv)) {
5238             if (SvIsCOW(sv)) {
5239                 /* I believe I need to grab the global SV mutex here and
5240                    then recheck the COW status.  */
5241                 if (DEBUG_C_TEST) {
5242                     PerlIO_printf(Perl_debug_log, "Copy on write: clear\n");
5243                     sv_dump(sv);
5244                 }
5245 		if (SvLEN(sv)) {
5246 		    sv_release_COW(sv, SvPVX_const(sv), SV_COW_NEXT_SV(sv));
5247 		} else {
5248 		    unshare_hek(SvSHARED_HEK_FROM_PV(SvPVX_const(sv)));
5249 		}
5250 
5251                 /* And drop it here.  */
5252                 SvFAKE_off(sv);
5253             } else if (SvLEN(sv)) {
5254                 Safefree(SvPVX_const(sv));
5255             }
5256 	}
5257 #else
5258 	else if (SvPVX_const(sv) && SvLEN(sv))
5259 	    Safefree(SvPVX_mutable(sv));
5260 	else if (SvPVX_const(sv) && SvREADONLY(sv) && SvFAKE(sv)) {
5261 	    unshare_hek(SvSHARED_HEK_FROM_PV(SvPVX_const(sv)));
5262 	    SvFAKE_off(sv);
5263 	}
5264 #endif
5265 	break;
5266     case SVt_NV:
5267 	break;
5268     }
5269 
5270     SvFLAGS(sv) &= SVf_BREAK;
5271     SvFLAGS(sv) |= SVTYPEMASK;
5272 
5273     if (sv_type_details->arena) {
5274 	del_body(((char *)SvANY(sv) + sv_type_details->offset),
5275 		 &PL_body_roots[type]);
5276     }
5277     else if (sv_type_details->body_size) {
5278 	my_safefree(SvANY(sv));
5279     }
5280 }
5281 
5282 /*
5283 =for apidoc sv_newref
5284 
5285 Increment an SV's reference count. Use the C<SvREFCNT_inc()> wrapper
5286 instead.
5287 
5288 =cut
5289 */
5290 
5291 SV *
5292 Perl_sv_newref(pTHX_ SV *sv)
5293 {
5294     PERL_UNUSED_CONTEXT;
5295     if (sv)
5296 	(SvREFCNT(sv))++;
5297     return sv;
5298 }
5299 
5300 /*
5301 =for apidoc sv_free
5302 
5303 Decrement an SV's reference count, and if it drops to zero, call
5304 C<sv_clear> to invoke destructors and free up any memory used by
5305 the body; finally, deallocate the SV's head itself.
5306 Normally called via a wrapper macro C<SvREFCNT_dec>.
5307 
5308 =cut
5309 */
5310 
5311 void
5312 Perl_sv_free(pTHX_ SV *sv)
5313 {
5314     dVAR;
5315     if (!sv)
5316 	return;
5317     if (SvREFCNT(sv) == 0) {
5318 	if (SvFLAGS(sv) & SVf_BREAK)
5319 	    /* this SV's refcnt has been artificially decremented to
5320 	     * trigger cleanup */
5321 	    return;
5322 	if (PL_in_clean_all) /* All is fair */
5323 	    return;
5324 	if (SvREADONLY(sv) && SvIMMORTAL(sv)) {
5325 	    /* make sure SvREFCNT(sv)==0 happens very seldom */
5326 	    SvREFCNT(sv) = (~(U32)0)/2;
5327 	    return;
5328 	}
5329 	if (ckWARN_d(WARN_INTERNAL)) {
5330 	    Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
5331                         "Attempt to free unreferenced scalar: SV 0x%"UVxf
5332                         pTHX__FORMAT, PTR2UV(sv) pTHX__VALUE);
5333 #ifdef DEBUG_LEAKING_SCALARS_FORK_DUMP
5334 	    Perl_dump_sv_child(aTHX_ sv);
5335 #else
5336   #ifdef DEBUG_LEAKING_SCALARS
5337 	sv_dump(sv);
5338   #endif
5339 #endif
5340 	}
5341 	return;
5342     }
5343     if (--(SvREFCNT(sv)) > 0)
5344 	return;
5345     Perl_sv_free2(aTHX_ sv);
5346 }
5347 
5348 void
5349 Perl_sv_free2(pTHX_ SV *sv)
5350 {
5351     dVAR;
5352 #ifdef DEBUGGING
5353     if (SvTEMP(sv)) {
5354 	if (ckWARN_d(WARN_DEBUGGING))
5355 	    Perl_warner(aTHX_ packWARN(WARN_DEBUGGING),
5356 			"Attempt to free temp prematurely: SV 0x%"UVxf
5357                         pTHX__FORMAT, PTR2UV(sv) pTHX__VALUE);
5358 	return;
5359     }
5360 #endif
5361     if (SvREADONLY(sv) && SvIMMORTAL(sv)) {
5362 	/* make sure SvREFCNT(sv)==0 happens very seldom */
5363 	SvREFCNT(sv) = (~(U32)0)/2;
5364 	return;
5365     }
5366     sv_clear(sv);
5367     if (! SvREFCNT(sv))
5368 	del_SV(sv);
5369 }
5370 
5371 /*
5372 =for apidoc sv_len
5373 
5374 Returns the length of the string in the SV. Handles magic and type
5375 coercion.  See also C<SvCUR>, which gives raw access to the xpv_cur slot.
5376 
5377 =cut
5378 */
5379 
5380 STRLEN
5381 Perl_sv_len(pTHX_ register SV *sv)
5382 {
5383     STRLEN len;
5384 
5385     if (!sv)
5386 	return 0;
5387 
5388     if (SvGMAGICAL(sv))
5389 	len = mg_length(sv);
5390     else
5391         (void)SvPV_const(sv, len);
5392     return len;
5393 }
5394 
5395 /*
5396 =for apidoc sv_len_utf8
5397 
5398 Returns the number of characters in the string in an SV, counting wide
5399 UTF-8 bytes as a single character. Handles magic and type coercion.
5400 
5401 =cut
5402 */
5403 
5404 /*
5405  * The length is cached in PERL_UTF8_magic, in the mg_len field.  Also the
5406  * mg_ptr is used, by sv_pos_u2b() and sv_pos_b2u() - see the comments below.
5407  * (Note that the mg_len is not the length of the mg_ptr field.
5408  * This allows the cache to store the character length of the string without
5409  * needing to malloc() extra storage to attach to the mg_ptr.)
5410  *
5411  */
5412 
5413 STRLEN
5414 Perl_sv_len_utf8(pTHX_ register SV *sv)
5415 {
5416     if (!sv)
5417 	return 0;
5418 
5419     if (SvGMAGICAL(sv))
5420 	return mg_length(sv);
5421     else
5422     {
5423 	STRLEN len;
5424 	const U8 *s = (U8*)SvPV_const(sv, len);
5425 
5426 	if (PL_utf8cache) {
5427 	    STRLEN ulen;
5428 	    MAGIC *mg = SvMAGICAL(sv) ? mg_find(sv, PERL_MAGIC_utf8) : NULL;
5429 
5430 	    if (mg && mg->mg_len != -1) {
5431 		ulen = mg->mg_len;
5432 		if (PL_utf8cache < 0) {
5433 		    const STRLEN real = Perl_utf8_length(aTHX_ s, s + len);
5434 		    if (real != ulen) {
5435 			/* Need to turn the assertions off otherwise we may
5436 			   recurse infinitely while printing error messages.
5437 			*/
5438 			SAVEI8(PL_utf8cache);
5439 			PL_utf8cache = 0;
5440 			Perl_croak(aTHX_ "panic: sv_len_utf8 cache %"UVuf
5441 				   " real %"UVuf" for %"SVf,
5442 				   (UV) ulen, (UV) real, SVfARG(sv));
5443 		    }
5444 		}
5445 	    }
5446 	    else {
5447 		ulen = Perl_utf8_length(aTHX_ s, s + len);
5448 		if (!SvREADONLY(sv)) {
5449 		    if (!mg) {
5450 			mg = sv_magicext(sv, 0, PERL_MAGIC_utf8,
5451 					 &PL_vtbl_utf8, 0, 0);
5452 		    }
5453 		    assert(mg);
5454 		    mg->mg_len = ulen;
5455 		}
5456 	    }
5457 	    return ulen;
5458 	}
5459 	return Perl_utf8_length(aTHX_ s, s + len);
5460     }
5461 }
5462 
5463 /* Walk forwards to find the byte corresponding to the passed in UTF-8
5464    offset.  */
5465 static STRLEN
5466 S_sv_pos_u2b_forwards(const U8 *const start, const U8 *const send,
5467 		      STRLEN uoffset)
5468 {
5469     const U8 *s = start;
5470 
5471     while (s < send && uoffset--)
5472 	s += UTF8SKIP(s);
5473     if (s > send) {
5474 	/* This is the existing behaviour. Possibly it should be a croak, as
5475 	   it's actually a bounds error  */
5476 	s = send;
5477     }
5478     return s - start;
5479 }
5480 
5481 /* Given the length of the string in both bytes and UTF-8 characters, decide
5482    whether to walk forwards or backwards to find the byte corresponding to
5483    the passed in UTF-8 offset.  */
5484 static STRLEN
5485 S_sv_pos_u2b_midway(const U8 *const start, const U8 *send,
5486 		      STRLEN uoffset, STRLEN uend)
5487 {
5488     STRLEN backw = uend - uoffset;
5489     if (uoffset < 2 * backw) {
5490 	/* The assumption is that going forwards is twice the speed of going
5491 	   forward (that's where the 2 * backw comes from).
5492 	   (The real figure of course depends on the UTF-8 data.)  */
5493 	return sv_pos_u2b_forwards(start, send, uoffset);
5494     }
5495 
5496     while (backw--) {
5497 	send--;
5498 	while (UTF8_IS_CONTINUATION(*send))
5499 	    send--;
5500     }
5501     return send - start;
5502 }
5503 
5504 /* For the string representation of the given scalar, find the byte
5505    corresponding to the passed in UTF-8 offset.  uoffset0 and boffset0
5506    give another position in the string, *before* the sought offset, which
5507    (which is always true, as 0, 0 is a valid pair of positions), which should
5508    help reduce the amount of linear searching.
5509    If *mgp is non-NULL, it should point to the UTF-8 cache magic, which
5510    will be used to reduce the amount of linear searching. The cache will be
5511    created if necessary, and the found value offered to it for update.  */
5512 static STRLEN
5513 S_sv_pos_u2b_cached(pTHX_ SV *sv, MAGIC **mgp, const U8 *const start,
5514 		    const U8 *const send, STRLEN uoffset,
5515 		    STRLEN uoffset0, STRLEN boffset0) {
5516     STRLEN boffset = 0; /* Actually always set, but let's keep gcc happy.  */
5517     bool found = FALSE;
5518 
5519     assert (uoffset >= uoffset0);
5520 
5521     if (SvMAGICAL(sv) && !SvREADONLY(sv) && PL_utf8cache
5522 	&& (*mgp || (*mgp = mg_find(sv, PERL_MAGIC_utf8)))) {
5523 	if ((*mgp)->mg_ptr) {
5524 	    STRLEN *cache = (STRLEN *) (*mgp)->mg_ptr;
5525 	    if (cache[0] == uoffset) {
5526 		/* An exact match. */
5527 		return cache[1];
5528 	    }
5529 	    if (cache[2] == uoffset) {
5530 		/* An exact match. */
5531 		return cache[3];
5532 	    }
5533 
5534 	    if (cache[0] < uoffset) {
5535 		/* The cache already knows part of the way.   */
5536 		if (cache[0] > uoffset0) {
5537 		    /* The cache knows more than the passed in pair  */
5538 		    uoffset0 = cache[0];
5539 		    boffset0 = cache[1];
5540 		}
5541 		if ((*mgp)->mg_len != -1) {
5542 		    /* And we know the end too.  */
5543 		    boffset = boffset0
5544 			+ sv_pos_u2b_midway(start + boffset0, send,
5545 					      uoffset - uoffset0,
5546 					      (*mgp)->mg_len - uoffset0);
5547 		} else {
5548 		    boffset = boffset0
5549 			+ sv_pos_u2b_forwards(start + boffset0,
5550 						send, uoffset - uoffset0);
5551 		}
5552 	    }
5553 	    else if (cache[2] < uoffset) {
5554 		/* We're between the two cache entries.  */
5555 		if (cache[2] > uoffset0) {
5556 		    /* and the cache knows more than the passed in pair  */
5557 		    uoffset0 = cache[2];
5558 		    boffset0 = cache[3];
5559 		}
5560 
5561 		boffset = boffset0
5562 		    + sv_pos_u2b_midway(start + boffset0,
5563 					  start + cache[1],
5564 					  uoffset - uoffset0,
5565 					  cache[0] - uoffset0);
5566 	    } else {
5567 		boffset = boffset0
5568 		    + sv_pos_u2b_midway(start + boffset0,
5569 					  start + cache[3],
5570 					  uoffset - uoffset0,
5571 					  cache[2] - uoffset0);
5572 	    }
5573 	    found = TRUE;
5574 	}
5575 	else if ((*mgp)->mg_len != -1) {
5576 	    /* If we can take advantage of a passed in offset, do so.  */
5577 	    /* In fact, offset0 is either 0, or less than offset, so don't
5578 	       need to worry about the other possibility.  */
5579 	    boffset = boffset0
5580 		+ sv_pos_u2b_midway(start + boffset0, send,
5581 				      uoffset - uoffset0,
5582 				      (*mgp)->mg_len - uoffset0);
5583 	    found = TRUE;
5584 	}
5585     }
5586 
5587     if (!found || PL_utf8cache < 0) {
5588 	const STRLEN real_boffset
5589 	    = boffset0 + sv_pos_u2b_forwards(start + boffset0,
5590 					       send, uoffset - uoffset0);
5591 
5592 	if (found && PL_utf8cache < 0) {
5593 	    if (real_boffset != boffset) {
5594 		/* Need to turn the assertions off otherwise we may recurse
5595 		   infinitely while printing error messages.  */
5596 		SAVEI8(PL_utf8cache);
5597 		PL_utf8cache = 0;
5598 		Perl_croak(aTHX_ "panic: sv_pos_u2b_cache cache %"UVuf
5599 			   " real %"UVuf" for %"SVf,
5600 			   (UV) boffset, (UV) real_boffset, SVfARG(sv));
5601 	    }
5602 	}
5603 	boffset = real_boffset;
5604     }
5605 
5606     S_utf8_mg_pos_cache_update(aTHX_ sv, mgp, boffset, uoffset, send - start);
5607     return boffset;
5608 }
5609 
5610 
5611 /*
5612 =for apidoc sv_pos_u2b
5613 
5614 Converts the value pointed to by offsetp from a count of UTF-8 chars from
5615 the start of the string, to a count of the equivalent number of bytes; if
5616 lenp is non-zero, it does the same to lenp, but this time starting from
5617 the offset, rather than from the start of the string. Handles magic and
5618 type coercion.
5619 
5620 =cut
5621 */
5622 
5623 /*
5624  * sv_pos_u2b() uses, like sv_pos_b2u(), the mg_ptr of the potential
5625  * PERL_UTF8_magic of the sv to store the mapping between UTF-8 and
5626  * byte offsets.  See also the comments of S_utf8_mg_pos_cache_update().
5627  *
5628  */
5629 
5630 void
5631 Perl_sv_pos_u2b(pTHX_ register SV *sv, I32* offsetp, I32* lenp)
5632 {
5633     const U8 *start;
5634     STRLEN len;
5635 
5636     if (!sv)
5637 	return;
5638 
5639     start = (U8*)SvPV_const(sv, len);
5640     if (len) {
5641 	STRLEN uoffset = (STRLEN) *offsetp;
5642 	const U8 * const send = start + len;
5643 	MAGIC *mg = NULL;
5644 	const STRLEN boffset = sv_pos_u2b_cached(sv, &mg, start, send,
5645 					     uoffset, 0, 0);
5646 
5647 	*offsetp = (I32) boffset;
5648 
5649 	if (lenp) {
5650 	    /* Convert the relative offset to absolute.  */
5651 	    const STRLEN uoffset2 = uoffset + (STRLEN) *lenp;
5652 	    const STRLEN boffset2
5653 		= sv_pos_u2b_cached(sv, &mg, start, send, uoffset2,
5654 				      uoffset, boffset) - boffset;
5655 
5656 	    *lenp = boffset2;
5657 	}
5658     }
5659     else {
5660 	 *offsetp = 0;
5661 	 if (lenp)
5662 	      *lenp = 0;
5663     }
5664 
5665     return;
5666 }
5667 
5668 /* Create and update the UTF8 magic offset cache, with the proffered utf8/
5669    byte length pairing. The (byte) length of the total SV is passed in too,
5670    as blen, because for some (more esoteric) SVs, the call to SvPV_const()
5671    may not have updated SvCUR, so we can't rely on reading it directly.
5672 
5673    The proffered utf8/byte length pairing isn't used if the cache already has
5674    two pairs, and swapping either for the proffered pair would increase the
5675    RMS of the intervals between known byte offsets.
5676 
5677    The cache itself consists of 4 STRLEN values
5678    0: larger UTF-8 offset
5679    1: corresponding byte offset
5680    2: smaller UTF-8 offset
5681    3: corresponding byte offset
5682 
5683    Unused cache pairs have the value 0, 0.
5684    Keeping the cache "backwards" means that the invariant of
5685    cache[0] >= cache[2] is maintained even with empty slots, which means that
5686    the code that uses it doesn't need to worry if only 1 entry has actually
5687    been set to non-zero.  It also makes the "position beyond the end of the
5688    cache" logic much simpler, as the first slot is always the one to start
5689    from.
5690 */
5691 static void
5692 S_utf8_mg_pos_cache_update(pTHX_ SV *sv, MAGIC **mgp, STRLEN byte, STRLEN utf8,
5693 			   STRLEN blen)
5694 {
5695     STRLEN *cache;
5696     if (SvREADONLY(sv))
5697 	return;
5698 
5699     if (!*mgp) {
5700 	*mgp = sv_magicext(sv, 0, PERL_MAGIC_utf8, (MGVTBL*)&PL_vtbl_utf8, 0,
5701 			   0);
5702 	(*mgp)->mg_len = -1;
5703     }
5704     assert(*mgp);
5705 
5706     if (!(cache = (STRLEN *)(*mgp)->mg_ptr)) {
5707 	Newxz(cache, PERL_MAGIC_UTF8_CACHESIZE * 2, STRLEN);
5708 	(*mgp)->mg_ptr = (char *) cache;
5709     }
5710     assert(cache);
5711 
5712     if (PL_utf8cache < 0) {
5713 	const U8 *start = (const U8 *) SvPVX_const(sv);
5714 	const STRLEN realutf8 = utf8_length(start, start + byte);
5715 
5716 	if (realutf8 != utf8) {
5717 	    /* Need to turn the assertions off otherwise we may recurse
5718 	       infinitely while printing error messages.  */
5719 	    SAVEI8(PL_utf8cache);
5720 	    PL_utf8cache = 0;
5721 	    Perl_croak(aTHX_ "panic: utf8_mg_pos_cache_update cache %"UVuf
5722 		       " real %"UVuf" for %"SVf, (UV) utf8, (UV) realutf8, SVfARG(sv));
5723 	}
5724     }
5725 
5726     /* Cache is held with the later position first, to simplify the code
5727        that deals with unbounded ends.  */
5728 
5729     ASSERT_UTF8_CACHE(cache);
5730     if (cache[1] == 0) {
5731 	/* Cache is totally empty  */
5732 	cache[0] = utf8;
5733 	cache[1] = byte;
5734     } else if (cache[3] == 0) {
5735 	if (byte > cache[1]) {
5736 	    /* New one is larger, so goes first.  */
5737 	    cache[2] = cache[0];
5738 	    cache[3] = cache[1];
5739 	    cache[0] = utf8;
5740 	    cache[1] = byte;
5741 	} else {
5742 	    cache[2] = utf8;
5743 	    cache[3] = byte;
5744 	}
5745     } else {
5746 #define THREEWAY_SQUARE(a,b,c,d) \
5747 	    ((float)((d) - (c))) * ((float)((d) - (c))) \
5748 	    + ((float)((c) - (b))) * ((float)((c) - (b))) \
5749 	       + ((float)((b) - (a))) * ((float)((b) - (a)))
5750 
5751 	/* Cache has 2 slots in use, and we know three potential pairs.
5752 	   Keep the two that give the lowest RMS distance. Do the
5753 	   calcualation in bytes simply because we always know the byte
5754 	   length.  squareroot has the same ordering as the positive value,
5755 	   so don't bother with the actual square root.  */
5756 	const float existing = THREEWAY_SQUARE(0, cache[3], cache[1], blen);
5757 	if (byte > cache[1]) {
5758 	    /* New position is after the existing pair of pairs.  */
5759 	    const float keep_earlier
5760 		= THREEWAY_SQUARE(0, cache[3], byte, blen);
5761 	    const float keep_later
5762 		= THREEWAY_SQUARE(0, cache[1], byte, blen);
5763 
5764 	    if (keep_later < keep_earlier) {
5765 		if (keep_later < existing) {
5766 		    cache[2] = cache[0];
5767 		    cache[3] = cache[1];
5768 		    cache[0] = utf8;
5769 		    cache[1] = byte;
5770 		}
5771 	    }
5772 	    else {
5773 		if (keep_earlier < existing) {
5774 		    cache[0] = utf8;
5775 		    cache[1] = byte;
5776 		}
5777 	    }
5778 	}
5779 	else if (byte > cache[3]) {
5780 	    /* New position is between the existing pair of pairs.  */
5781 	    const float keep_earlier
5782 		= THREEWAY_SQUARE(0, cache[3], byte, blen);
5783 	    const float keep_later
5784 		= THREEWAY_SQUARE(0, byte, cache[1], blen);
5785 
5786 	    if (keep_later < keep_earlier) {
5787 		if (keep_later < existing) {
5788 		    cache[2] = utf8;
5789 		    cache[3] = byte;
5790 		}
5791 	    }
5792 	    else {
5793 		if (keep_earlier < existing) {
5794 		    cache[0] = utf8;
5795 		    cache[1] = byte;
5796 		}
5797 	    }
5798 	}
5799 	else {
5800  	    /* New position is before the existing pair of pairs.  */
5801 	    const float keep_earlier
5802 		= THREEWAY_SQUARE(0, byte, cache[3], blen);
5803 	    const float keep_later
5804 		= THREEWAY_SQUARE(0, byte, cache[1], blen);
5805 
5806 	    if (keep_later < keep_earlier) {
5807 		if (keep_later < existing) {
5808 		    cache[2] = utf8;
5809 		    cache[3] = byte;
5810 		}
5811 	    }
5812 	    else {
5813 		if (keep_earlier < existing) {
5814 		    cache[0] = cache[2];
5815 		    cache[1] = cache[3];
5816 		    cache[2] = utf8;
5817 		    cache[3] = byte;
5818 		}
5819 	    }
5820 	}
5821     }
5822     ASSERT_UTF8_CACHE(cache);
5823 }
5824 
5825 /* We already know all of the way, now we may be able to walk back.  The same
5826    assumption is made as in S_sv_pos_u2b_midway(), namely that walking
5827    backward is half the speed of walking forward. */
5828 static STRLEN
5829 S_sv_pos_b2u_midway(pTHX_ const U8 *s, const U8 *const target, const U8 *end,
5830 		    STRLEN endu)
5831 {
5832     const STRLEN forw = target - s;
5833     STRLEN backw = end - target;
5834 
5835     if (forw < 2 * backw) {
5836 	return utf8_length(s, target);
5837     }
5838 
5839     while (end > target) {
5840 	end--;
5841 	while (UTF8_IS_CONTINUATION(*end)) {
5842 	    end--;
5843 	}
5844 	endu--;
5845     }
5846     return endu;
5847 }
5848 
5849 /*
5850 =for apidoc sv_pos_b2u
5851 
5852 Converts the value pointed to by offsetp from a count of bytes from the
5853 start of the string, to a count of the equivalent number of UTF-8 chars.
5854 Handles magic and type coercion.
5855 
5856 =cut
5857 */
5858 
5859 /*
5860  * sv_pos_b2u() uses, like sv_pos_u2b(), the mg_ptr of the potential
5861  * PERL_UTF8_magic of the sv to store the mapping between UTF-8 and
5862  * byte offsets.
5863  *
5864  */
5865 void
5866 Perl_sv_pos_b2u(pTHX_ register SV* sv, I32* offsetp)
5867 {
5868     const U8* s;
5869     const STRLEN byte = *offsetp;
5870     STRLEN len = 0; /* Actually always set, but let's keep gcc happy.  */
5871     STRLEN blen;
5872     MAGIC* mg = NULL;
5873     const U8* send;
5874     bool found = FALSE;
5875 
5876     if (!sv)
5877 	return;
5878 
5879     s = (const U8*)SvPV_const(sv, blen);
5880 
5881     if (blen < byte)
5882 	Perl_croak(aTHX_ "panic: sv_pos_b2u: bad byte offset");
5883 
5884     send = s + byte;
5885 
5886     if (SvMAGICAL(sv) && !SvREADONLY(sv) && PL_utf8cache
5887 	&& (mg = mg_find(sv, PERL_MAGIC_utf8))) {
5888 	if (mg->mg_ptr) {
5889 	    STRLEN * const cache = (STRLEN *) mg->mg_ptr;
5890 	    if (cache[1] == byte) {
5891 		/* An exact match. */
5892 		*offsetp = cache[0];
5893 		return;
5894 	    }
5895 	    if (cache[3] == byte) {
5896 		/* An exact match. */
5897 		*offsetp = cache[2];
5898 		return;
5899 	    }
5900 
5901 	    if (cache[1] < byte) {
5902 		/* We already know part of the way. */
5903 		if (mg->mg_len != -1) {
5904 		    /* Actually, we know the end too.  */
5905 		    len = cache[0]
5906 			+ S_sv_pos_b2u_midway(aTHX_ s + cache[1], send,
5907 					      s + blen, mg->mg_len - cache[0]);
5908 		} else {
5909 		    len = cache[0] + utf8_length(s + cache[1], send);
5910 		}
5911 	    }
5912 	    else if (cache[3] < byte) {
5913 		/* We're between the two cached pairs, so we do the calculation
5914 		   offset by the byte/utf-8 positions for the earlier pair,
5915 		   then add the utf-8 characters from the string start to
5916 		   there.  */
5917 		len = S_sv_pos_b2u_midway(aTHX_ s + cache[3], send,
5918 					  s + cache[1], cache[0] - cache[2])
5919 		    + cache[2];
5920 
5921 	    }
5922 	    else { /* cache[3] > byte */
5923 		len = S_sv_pos_b2u_midway(aTHX_ s, send, s + cache[3],
5924 					  cache[2]);
5925 
5926 	    }
5927 	    ASSERT_UTF8_CACHE(cache);
5928 	    found = TRUE;
5929 	} else if (mg->mg_len != -1) {
5930 	    len = S_sv_pos_b2u_midway(aTHX_ s, send, s + blen, mg->mg_len);
5931 	    found = TRUE;
5932 	}
5933     }
5934     if (!found || PL_utf8cache < 0) {
5935 	const STRLEN real_len = utf8_length(s, send);
5936 
5937 	if (found && PL_utf8cache < 0) {
5938 	    if (len != real_len) {
5939 		/* Need to turn the assertions off otherwise we may recurse
5940 		   infinitely while printing error messages.  */
5941 		SAVEI8(PL_utf8cache);
5942 		PL_utf8cache = 0;
5943 		Perl_croak(aTHX_ "panic: sv_pos_b2u cache %"UVuf
5944 			   " real %"UVuf" for %"SVf,
5945 			   (UV) len, (UV) real_len, SVfARG(sv));
5946 	    }
5947 	}
5948 	len = real_len;
5949     }
5950     *offsetp = len;
5951 
5952     S_utf8_mg_pos_cache_update(aTHX_ sv, &mg, byte, len, blen);
5953 }
5954 
5955 /*
5956 =for apidoc sv_eq
5957 
5958 Returns a boolean indicating whether the strings in the two SVs are
5959 identical. Is UTF-8 and 'use bytes' aware, handles get magic, and will
5960 coerce its args to strings if necessary.
5961 
5962 =cut
5963 */
5964 
5965 I32
5966 Perl_sv_eq(pTHX_ register SV *sv1, register SV *sv2)
5967 {
5968     dVAR;
5969     const char *pv1;
5970     STRLEN cur1;
5971     const char *pv2;
5972     STRLEN cur2;
5973     I32  eq     = 0;
5974     char *tpv   = NULL;
5975     SV* svrecode = NULL;
5976 
5977     if (!sv1) {
5978 	pv1 = "";
5979 	cur1 = 0;
5980     }
5981     else {
5982 	/* if pv1 and pv2 are the same, second SvPV_const call may
5983 	 * invalidate pv1, so we may need to make a copy */
5984 	if (sv1 == sv2 && (SvTHINKFIRST(sv1) || SvGMAGICAL(sv1))) {
5985 	    pv1 = SvPV_const(sv1, cur1);
5986 	    sv1 = sv_2mortal(newSVpvn(pv1, cur1));
5987 	    if (SvUTF8(sv2)) SvUTF8_on(sv1);
5988 	}
5989 	pv1 = SvPV_const(sv1, cur1);
5990     }
5991 
5992     if (!sv2){
5993 	pv2 = "";
5994 	cur2 = 0;
5995     }
5996     else
5997 	pv2 = SvPV_const(sv2, cur2);
5998 
5999     if (cur1 && cur2 && SvUTF8(sv1) != SvUTF8(sv2) && !IN_BYTES) {
6000         /* Differing utf8ness.
6001 	 * Do not UTF8size the comparands as a side-effect. */
6002 	 if (PL_encoding) {
6003 	      if (SvUTF8(sv1)) {
6004 		   svrecode = newSVpvn(pv2, cur2);
6005 		   sv_recode_to_utf8(svrecode, PL_encoding);
6006 		   pv2 = SvPV_const(svrecode, cur2);
6007 	      }
6008 	      else {
6009 		   svrecode = newSVpvn(pv1, cur1);
6010 		   sv_recode_to_utf8(svrecode, PL_encoding);
6011 		   pv1 = SvPV_const(svrecode, cur1);
6012 	      }
6013 	      /* Now both are in UTF-8. */
6014 	      if (cur1 != cur2) {
6015 		   SvREFCNT_dec(svrecode);
6016 		   return FALSE;
6017 	      }
6018 	 }
6019 	 else {
6020 	      bool is_utf8 = TRUE;
6021 
6022 	      if (SvUTF8(sv1)) {
6023 		   /* sv1 is the UTF-8 one,
6024 		    * if is equal it must be downgrade-able */
6025 		   char * const pv = (char*)bytes_from_utf8((const U8*)pv1,
6026 						     &cur1, &is_utf8);
6027 		   if (pv != pv1)
6028 			pv1 = tpv = pv;
6029 	      }
6030 	      else {
6031 		   /* sv2 is the UTF-8 one,
6032 		    * if is equal it must be downgrade-able */
6033 		   char * const pv = (char *)bytes_from_utf8((const U8*)pv2,
6034 						      &cur2, &is_utf8);
6035 		   if (pv != pv2)
6036 			pv2 = tpv = pv;
6037 	      }
6038 	      if (is_utf8) {
6039 		   /* Downgrade not possible - cannot be eq */
6040 		   assert (tpv == 0);
6041 		   return FALSE;
6042 	      }
6043 	 }
6044     }
6045 
6046     if (cur1 == cur2)
6047 	eq = (pv1 == pv2) || memEQ(pv1, pv2, cur1);
6048 
6049     SvREFCNT_dec(svrecode);
6050     if (tpv)
6051 	Safefree(tpv);
6052 
6053     return eq;
6054 }
6055 
6056 /*
6057 =for apidoc sv_cmp
6058 
6059 Compares the strings in two SVs.  Returns -1, 0, or 1 indicating whether the
6060 string in C<sv1> is less than, equal to, or greater than the string in
6061 C<sv2>. Is UTF-8 and 'use bytes' aware, handles get magic, and will
6062 coerce its args to strings if necessary.  See also C<sv_cmp_locale>.
6063 
6064 =cut
6065 */
6066 
6067 I32
6068 Perl_sv_cmp(pTHX_ register SV *sv1, register SV *sv2)
6069 {
6070     dVAR;
6071     STRLEN cur1, cur2;
6072     const char *pv1, *pv2;
6073     char *tpv = NULL;
6074     I32  cmp;
6075     SV *svrecode = NULL;
6076 
6077     if (!sv1) {
6078 	pv1 = "";
6079 	cur1 = 0;
6080     }
6081     else
6082 	pv1 = SvPV_const(sv1, cur1);
6083 
6084     if (!sv2) {
6085 	pv2 = "";
6086 	cur2 = 0;
6087     }
6088     else
6089 	pv2 = SvPV_const(sv2, cur2);
6090 
6091     if (cur1 && cur2 && SvUTF8(sv1) != SvUTF8(sv2) && !IN_BYTES) {
6092         /* Differing utf8ness.
6093 	 * Do not UTF8size the comparands as a side-effect. */
6094 	if (SvUTF8(sv1)) {
6095 	    if (PL_encoding) {
6096 		 svrecode = newSVpvn(pv2, cur2);
6097 		 sv_recode_to_utf8(svrecode, PL_encoding);
6098 		 pv2 = SvPV_const(svrecode, cur2);
6099 	    }
6100 	    else {
6101 		 pv2 = tpv = (char*)bytes_to_utf8((const U8*)pv2, &cur2);
6102 	    }
6103 	}
6104 	else {
6105 	    if (PL_encoding) {
6106 		 svrecode = newSVpvn(pv1, cur1);
6107 		 sv_recode_to_utf8(svrecode, PL_encoding);
6108 		 pv1 = SvPV_const(svrecode, cur1);
6109 	    }
6110 	    else {
6111 		 pv1 = tpv = (char*)bytes_to_utf8((const U8*)pv1, &cur1);
6112 	    }
6113 	}
6114     }
6115 
6116     if (!cur1) {
6117 	cmp = cur2 ? -1 : 0;
6118     } else if (!cur2) {
6119 	cmp = 1;
6120     } else {
6121         const I32 retval = memcmp((const void*)pv1, (const void*)pv2, cur1 < cur2 ? cur1 : cur2);
6122 
6123 	if (retval) {
6124 	    cmp = retval < 0 ? -1 : 1;
6125 	} else if (cur1 == cur2) {
6126 	    cmp = 0;
6127         } else {
6128 	    cmp = cur1 < cur2 ? -1 : 1;
6129 	}
6130     }
6131 
6132     SvREFCNT_dec(svrecode);
6133     if (tpv)
6134 	Safefree(tpv);
6135 
6136     return cmp;
6137 }
6138 
6139 /*
6140 =for apidoc sv_cmp_locale
6141 
6142 Compares the strings in two SVs in a locale-aware manner. Is UTF-8 and
6143 'use bytes' aware, handles get magic, and will coerce its args to strings
6144 if necessary.  See also C<sv_cmp_locale>.  See also C<sv_cmp>.
6145 
6146 =cut
6147 */
6148 
6149 I32
6150 Perl_sv_cmp_locale(pTHX_ register SV *sv1, register SV *sv2)
6151 {
6152     dVAR;
6153 #ifdef USE_LOCALE_COLLATE
6154 
6155     char *pv1, *pv2;
6156     STRLEN len1, len2;
6157     I32 retval;
6158 
6159     if (PL_collation_standard)
6160 	goto raw_compare;
6161 
6162     len1 = 0;
6163     pv1 = sv1 ? sv_collxfrm(sv1, &len1) : (char *) NULL;
6164     len2 = 0;
6165     pv2 = sv2 ? sv_collxfrm(sv2, &len2) : (char *) NULL;
6166 
6167     if (!pv1 || !len1) {
6168 	if (pv2 && len2)
6169 	    return -1;
6170 	else
6171 	    goto raw_compare;
6172     }
6173     else {
6174 	if (!pv2 || !len2)
6175 	    return 1;
6176     }
6177 
6178     retval = memcmp((void*)pv1, (void*)pv2, len1 < len2 ? len1 : len2);
6179 
6180     if (retval)
6181 	return retval < 0 ? -1 : 1;
6182 
6183     /*
6184      * When the result of collation is equality, that doesn't mean
6185      * that there are no differences -- some locales exclude some
6186      * characters from consideration.  So to avoid false equalities,
6187      * we use the raw string as a tiebreaker.
6188      */
6189 
6190   raw_compare:
6191     /*FALLTHROUGH*/
6192 
6193 #endif /* USE_LOCALE_COLLATE */
6194 
6195     return sv_cmp(sv1, sv2);
6196 }
6197 
6198 
6199 #ifdef USE_LOCALE_COLLATE
6200 
6201 /*
6202 =for apidoc sv_collxfrm
6203 
6204 Add Collate Transform magic to an SV if it doesn't already have it.
6205 
6206 Any scalar variable may carry PERL_MAGIC_collxfrm magic that contains the
6207 scalar data of the variable, but transformed to such a format that a normal
6208 memory comparison can be used to compare the data according to the locale
6209 settings.
6210 
6211 =cut
6212 */
6213 
6214 char *
6215 Perl_sv_collxfrm(pTHX_ SV *sv, STRLEN *nxp)
6216 {
6217     dVAR;
6218     MAGIC *mg;
6219 
6220     mg = SvMAGICAL(sv) ? mg_find(sv, PERL_MAGIC_collxfrm) : (MAGIC *) NULL;
6221     if (!mg || !mg->mg_ptr || *(U32*)mg->mg_ptr != PL_collation_ix) {
6222 	const char *s;
6223 	char *xf;
6224 	STRLEN len, xlen;
6225 
6226 	if (mg)
6227 	    Safefree(mg->mg_ptr);
6228 	s = SvPV_const(sv, len);
6229 	if ((xf = mem_collxfrm(s, len, &xlen))) {
6230 	    if (SvREADONLY(sv)) {
6231 		SAVEFREEPV(xf);
6232 		*nxp = xlen;
6233 		return xf + sizeof(PL_collation_ix);
6234 	    }
6235 	    if (! mg) {
6236 #ifdef PERL_OLD_COPY_ON_WRITE
6237 		if (SvIsCOW(sv))
6238 		    sv_force_normal_flags(sv, 0);
6239 #endif
6240 		mg = sv_magicext(sv, 0, PERL_MAGIC_collxfrm, &PL_vtbl_collxfrm,
6241 				 0, 0);
6242 		assert(mg);
6243 	    }
6244 	    mg->mg_ptr = xf;
6245 	    mg->mg_len = xlen;
6246 	}
6247 	else {
6248 	    if (mg) {
6249 		mg->mg_ptr = NULL;
6250 		mg->mg_len = -1;
6251 	    }
6252 	}
6253     }
6254     if (mg && mg->mg_ptr) {
6255 	*nxp = mg->mg_len;
6256 	return mg->mg_ptr + sizeof(PL_collation_ix);
6257     }
6258     else {
6259 	*nxp = 0;
6260 	return NULL;
6261     }
6262 }
6263 
6264 #endif /* USE_LOCALE_COLLATE */
6265 
6266 /*
6267 =for apidoc sv_gets
6268 
6269 Get a line from the filehandle and store it into the SV, optionally
6270 appending to the currently-stored string.
6271 
6272 =cut
6273 */
6274 
6275 char *
6276 Perl_sv_gets(pTHX_ register SV *sv, register PerlIO *fp, I32 append)
6277 {
6278     dVAR;
6279     const char *rsptr;
6280     STRLEN rslen;
6281     register STDCHAR rslast;
6282     register STDCHAR *bp;
6283     register I32 cnt;
6284     I32 i = 0;
6285     I32 rspara = 0;
6286 
6287     if (SvTHINKFIRST(sv))
6288 	sv_force_normal_flags(sv, append ? 0 : SV_COW_DROP_PV);
6289     /* XXX. If you make this PVIV, then copy on write can copy scalars read
6290        from <>.
6291        However, perlbench says it's slower, because the existing swipe code
6292        is faster than copy on write.
6293        Swings and roundabouts.  */
6294     SvUPGRADE(sv, SVt_PV);
6295 
6296     SvSCREAM_off(sv);
6297 
6298     if (append) {
6299 	if (PerlIO_isutf8(fp)) {
6300 	    if (!SvUTF8(sv)) {
6301 		sv_utf8_upgrade_nomg(sv);
6302 		sv_pos_u2b(sv,&append,0);
6303 	    }
6304 	} else if (SvUTF8(sv)) {
6305 	    SV * const tsv = newSV(0);
6306 	    sv_gets(tsv, fp, 0);
6307 	    sv_utf8_upgrade_nomg(tsv);
6308 	    SvCUR_set(sv,append);
6309 	    sv_catsv(sv,tsv);
6310 	    sv_free(tsv);
6311 	    goto return_string_or_null;
6312 	}
6313     }
6314 
6315     SvPOK_only(sv);
6316     if (PerlIO_isutf8(fp))
6317 	SvUTF8_on(sv);
6318 
6319     if (IN_PERL_COMPILETIME) {
6320 	/* we always read code in line mode */
6321 	rsptr = "\n";
6322 	rslen = 1;
6323     }
6324     else if (RsSNARF(PL_rs)) {
6325     	/* If it is a regular disk file use size from stat() as estimate
6326 	   of amount we are going to read -- may result in mallocing
6327 	   more memory than we really need if the layers below reduce
6328 	   the size we read (e.g. CRLF or a gzip layer).
6329 	 */
6330 	Stat_t st;
6331 	if (!PerlLIO_fstat(PerlIO_fileno(fp), &st) && S_ISREG(st.st_mode))  {
6332 	    const Off_t offset = PerlIO_tell(fp);
6333 	    if (offset != (Off_t) -1 && st.st_size + append > offset) {
6334 	     	(void) SvGROW(sv, (STRLEN)((st.st_size - offset) + append + 1));
6335 	    }
6336 	}
6337 	rsptr = NULL;
6338 	rslen = 0;
6339     }
6340     else if (RsRECORD(PL_rs)) {
6341       I32 bytesread;
6342       char *buffer;
6343       U32 recsize;
6344 
6345       /* Grab the size of the record we're getting */
6346       recsize = SvUV(SvRV(PL_rs)); /* RsRECORD() guarantees > 0. */
6347       buffer = SvGROW(sv, (STRLEN)(recsize + append + 1)) + append;
6348       /* Go yank in */
6349 #ifdef VMS
6350       /* VMS wants read instead of fread, because fread doesn't respect */
6351       /* RMS record boundaries. This is not necessarily a good thing to be */
6352       /* doing, but we've got no other real choice - except avoid stdio
6353          as implementation - perhaps write a :vms layer ?
6354        */
6355       bytesread = PerlLIO_read(PerlIO_fileno(fp), buffer, recsize);
6356 #else
6357       bytesread = PerlIO_read(fp, buffer, recsize);
6358 #endif
6359       if (bytesread < 0)
6360 	  bytesread = 0;
6361       SvCUR_set(sv, bytesread += append);
6362       buffer[bytesread] = '\0';
6363       goto return_string_or_null;
6364     }
6365     else if (RsPARA(PL_rs)) {
6366 	rsptr = "\n\n";
6367 	rslen = 2;
6368 	rspara = 1;
6369     }
6370     else {
6371 	/* Get $/ i.e. PL_rs into same encoding as stream wants */
6372 	if (PerlIO_isutf8(fp)) {
6373 	    rsptr = SvPVutf8(PL_rs, rslen);
6374 	}
6375 	else {
6376 	    if (SvUTF8(PL_rs)) {
6377 		if (!sv_utf8_downgrade(PL_rs, TRUE)) {
6378 		    Perl_croak(aTHX_ "Wide character in $/");
6379 		}
6380 	    }
6381 	    rsptr = SvPV_const(PL_rs, rslen);
6382 	}
6383     }
6384 
6385     rslast = rslen ? rsptr[rslen - 1] : '\0';
6386 
6387     if (rspara) {		/* have to do this both before and after */
6388 	do {			/* to make sure file boundaries work right */
6389 	    if (PerlIO_eof(fp))
6390 		return 0;
6391 	    i = PerlIO_getc(fp);
6392 	    if (i != '\n') {
6393 		if (i == -1)
6394 		    return 0;
6395 		PerlIO_ungetc(fp,i);
6396 		break;
6397 	    }
6398 	} while (i != EOF);
6399     }
6400 
6401     /* See if we know enough about I/O mechanism to cheat it ! */
6402 
6403     /* This used to be #ifdef test - it is made run-time test for ease
6404        of abstracting out stdio interface. One call should be cheap
6405        enough here - and may even be a macro allowing compile
6406        time optimization.
6407      */
6408 
6409     if (PerlIO_fast_gets(fp)) {
6410 
6411     /*
6412      * We're going to steal some values from the stdio struct
6413      * and put EVERYTHING in the innermost loop into registers.
6414      */
6415     register STDCHAR *ptr;
6416     STRLEN bpx;
6417     I32 shortbuffered;
6418 
6419 #if defined(VMS) && defined(PERLIO_IS_STDIO)
6420     /* An ungetc()d char is handled separately from the regular
6421      * buffer, so we getc() it back out and stuff it in the buffer.
6422      */
6423     i = PerlIO_getc(fp);
6424     if (i == EOF) return 0;
6425     *(--((*fp)->_ptr)) = (unsigned char) i;
6426     (*fp)->_cnt++;
6427 #endif
6428 
6429     /* Here is some breathtakingly efficient cheating */
6430 
6431     cnt = PerlIO_get_cnt(fp);			/* get count into register */
6432     /* make sure we have the room */
6433     if ((I32)(SvLEN(sv) - append) <= cnt + 1) {
6434     	/* Not room for all of it
6435 	   if we are looking for a separator and room for some
6436 	 */
6437 	if (rslen && cnt > 80 && (I32)SvLEN(sv) > append) {
6438 	    /* just process what we have room for */
6439 	    shortbuffered = cnt - SvLEN(sv) + append + 1;
6440 	    cnt -= shortbuffered;
6441 	}
6442 	else {
6443 	    shortbuffered = 0;
6444 	    /* remember that cnt can be negative */
6445 	    SvGROW(sv, (STRLEN)(append + (cnt <= 0 ? 2 : (cnt + 1))));
6446 	}
6447     }
6448     else
6449 	shortbuffered = 0;
6450     bp = (STDCHAR*)SvPVX_const(sv) + append;  /* move these two too to registers */
6451     ptr = (STDCHAR*)PerlIO_get_ptr(fp);
6452     DEBUG_P(PerlIO_printf(Perl_debug_log,
6453 	"Screamer: entering, ptr=%"UVuf", cnt=%ld\n",PTR2UV(ptr),(long)cnt));
6454     DEBUG_P(PerlIO_printf(Perl_debug_log,
6455 	"Screamer: entering: PerlIO * thinks ptr=%"UVuf", cnt=%ld, base=%"UVuf"\n",
6456 	       PTR2UV(PerlIO_get_ptr(fp)), (long)PerlIO_get_cnt(fp),
6457 	       PTR2UV(PerlIO_has_base(fp) ? PerlIO_get_base(fp) : 0)));
6458     for (;;) {
6459       screamer:
6460 	if (cnt > 0) {
6461 	    if (rslen) {
6462 		while (cnt > 0) {		     /* this     |  eat */
6463 		    cnt--;
6464 		    if ((*bp++ = *ptr++) == rslast)  /* really   |  dust */
6465 			goto thats_all_folks;	     /* screams  |  sed :-) */
6466 		}
6467 	    }
6468 	    else {
6469 	        Copy(ptr, bp, cnt, char);	     /* this     |  eat */
6470 		bp += cnt;			     /* screams  |  dust */
6471 		ptr += cnt;			     /* louder   |  sed :-) */
6472 		cnt = 0;
6473 	    }
6474 	}
6475 
6476 	if (shortbuffered) {		/* oh well, must extend */
6477 	    cnt = shortbuffered;
6478 	    shortbuffered = 0;
6479 	    bpx = bp - (STDCHAR*)SvPVX_const(sv); /* box up before relocation */
6480 	    SvCUR_set(sv, bpx);
6481 	    SvGROW(sv, SvLEN(sv) + append + cnt + 2);
6482 	    bp = (STDCHAR*)SvPVX_const(sv) + bpx; /* unbox after relocation */
6483 	    continue;
6484 	}
6485 
6486 	DEBUG_P(PerlIO_printf(Perl_debug_log,
6487 			      "Screamer: going to getc, ptr=%"UVuf", cnt=%ld\n",
6488 			      PTR2UV(ptr),(long)cnt));
6489 	PerlIO_set_ptrcnt(fp, (STDCHAR*)ptr, cnt); /* deregisterize cnt and ptr */
6490 #if 0
6491 	DEBUG_P(PerlIO_printf(Perl_debug_log,
6492 	    "Screamer: pre: FILE * thinks ptr=%"UVuf", cnt=%ld, base=%"UVuf"\n",
6493 	    PTR2UV(PerlIO_get_ptr(fp)), (long)PerlIO_get_cnt(fp),
6494 	    PTR2UV(PerlIO_has_base (fp) ? PerlIO_get_base(fp) : 0)));
6495 #endif
6496 	/* This used to call 'filbuf' in stdio form, but as that behaves like
6497 	   getc when cnt <= 0 we use PerlIO_getc here to avoid introducing
6498 	   another abstraction.  */
6499 	i   = PerlIO_getc(fp);		/* get more characters */
6500 #if 0
6501 	DEBUG_P(PerlIO_printf(Perl_debug_log,
6502 	    "Screamer: post: FILE * thinks ptr=%"UVuf", cnt=%ld, base=%"UVuf"\n",
6503 	    PTR2UV(PerlIO_get_ptr(fp)), (long)PerlIO_get_cnt(fp),
6504 	    PTR2UV(PerlIO_has_base (fp) ? PerlIO_get_base(fp) : 0)));
6505 #endif
6506 	cnt = PerlIO_get_cnt(fp);
6507 	ptr = (STDCHAR*)PerlIO_get_ptr(fp);	/* reregisterize cnt and ptr */
6508 	DEBUG_P(PerlIO_printf(Perl_debug_log,
6509 	    "Screamer: after getc, ptr=%"UVuf", cnt=%ld\n",PTR2UV(ptr),(long)cnt));
6510 
6511 	if (i == EOF)			/* all done for ever? */
6512 	    goto thats_really_all_folks;
6513 
6514 	bpx = bp - (STDCHAR*)SvPVX_const(sv);	/* box up before relocation */
6515 	SvCUR_set(sv, bpx);
6516 	SvGROW(sv, bpx + cnt + 2);
6517 	bp = (STDCHAR*)SvPVX_const(sv) + bpx;	/* unbox after relocation */
6518 
6519 	*bp++ = (STDCHAR)i;		/* store character from PerlIO_getc */
6520 
6521 	if (rslen && (STDCHAR)i == rslast)  /* all done for now? */
6522 	    goto thats_all_folks;
6523     }
6524 
6525 thats_all_folks:
6526     if ((rslen > 1 && (STRLEN)(bp - (STDCHAR*)SvPVX_const(sv)) < rslen) ||
6527 	  memNE((char*)bp - rslen, rsptr, rslen))
6528 	goto screamer;				/* go back to the fray */
6529 thats_really_all_folks:
6530     if (shortbuffered)
6531 	cnt += shortbuffered;
6532 	DEBUG_P(PerlIO_printf(Perl_debug_log,
6533 	    "Screamer: quitting, ptr=%"UVuf", cnt=%ld\n",PTR2UV(ptr),(long)cnt));
6534     PerlIO_set_ptrcnt(fp, (STDCHAR*)ptr, cnt);	/* put these back or we're in trouble */
6535     DEBUG_P(PerlIO_printf(Perl_debug_log,
6536 	"Screamer: end: FILE * thinks ptr=%"UVuf", cnt=%ld, base=%"UVuf"\n",
6537 	PTR2UV(PerlIO_get_ptr(fp)), (long)PerlIO_get_cnt(fp),
6538 	PTR2UV(PerlIO_has_base (fp) ? PerlIO_get_base(fp) : 0)));
6539     *bp = '\0';
6540     SvCUR_set(sv, bp - (STDCHAR*)SvPVX_const(sv));	/* set length */
6541     DEBUG_P(PerlIO_printf(Perl_debug_log,
6542 	"Screamer: done, len=%ld, string=|%.*s|\n",
6543 	(long)SvCUR(sv),(int)SvCUR(sv),SvPVX_const(sv)));
6544     }
6545    else
6546     {
6547        /*The big, slow, and stupid way. */
6548 #ifdef USE_HEAP_INSTEAD_OF_STACK	/* Even slower way. */
6549 	STDCHAR *buf = NULL;
6550 	Newx(buf, 8192, STDCHAR);
6551 	assert(buf);
6552 #else
6553 	STDCHAR buf[8192];
6554 #endif
6555 
6556 screamer2:
6557 	if (rslen) {
6558             register const STDCHAR * const bpe = buf + sizeof(buf);
6559 	    bp = buf;
6560 	    while ((i = PerlIO_getc(fp)) != EOF && (*bp++ = (STDCHAR)i) != rslast && bp < bpe)
6561 		; /* keep reading */
6562 	    cnt = bp - buf;
6563 	}
6564 	else {
6565 	    cnt = PerlIO_read(fp,(char*)buf, sizeof(buf));
6566 	    /* Accomodate broken VAXC compiler, which applies U8 cast to
6567 	     * both args of ?: operator, causing EOF to change into 255
6568 	     */
6569 	    if (cnt > 0)
6570 		 i = (U8)buf[cnt - 1];
6571 	    else
6572 		 i = EOF;
6573 	}
6574 
6575 	if (cnt < 0)
6576 	    cnt = 0;  /* we do need to re-set the sv even when cnt <= 0 */
6577 	if (append)
6578 	     sv_catpvn(sv, (char *) buf, cnt);
6579 	else
6580 	     sv_setpvn(sv, (char *) buf, cnt);
6581 
6582 	if (i != EOF &&			/* joy */
6583 	    (!rslen ||
6584 	     SvCUR(sv) < rslen ||
6585 	     memNE(SvPVX_const(sv) + SvCUR(sv) - rslen, rsptr, rslen)))
6586 	{
6587 	    append = -1;
6588 	    /*
6589 	     * If we're reading from a TTY and we get a short read,
6590 	     * indicating that the user hit his EOF character, we need
6591 	     * to notice it now, because if we try to read from the TTY
6592 	     * again, the EOF condition will disappear.
6593 	     *
6594 	     * The comparison of cnt to sizeof(buf) is an optimization
6595 	     * that prevents unnecessary calls to feof().
6596 	     *
6597 	     * - jik 9/25/96
6598 	     */
6599 	    if (!(cnt < (I32)sizeof(buf) && PerlIO_eof(fp)))
6600 		goto screamer2;
6601 	}
6602 
6603 #ifdef USE_HEAP_INSTEAD_OF_STACK
6604 	Safefree(buf);
6605 #endif
6606     }
6607 
6608     if (rspara) {		/* have to do this both before and after */
6609         while (i != EOF) {	/* to make sure file boundaries work right */
6610 	    i = PerlIO_getc(fp);
6611 	    if (i != '\n') {
6612 		PerlIO_ungetc(fp,i);
6613 		break;
6614 	    }
6615 	}
6616     }
6617 
6618 return_string_or_null:
6619     return (SvCUR(sv) - append) ? SvPVX(sv) : NULL;
6620 }
6621 
6622 /*
6623 =for apidoc sv_inc
6624 
6625 Auto-increment of the value in the SV, doing string to numeric conversion
6626 if necessary. Handles 'get' magic.
6627 
6628 =cut
6629 */
6630 
6631 void
6632 Perl_sv_inc(pTHX_ register SV *sv)
6633 {
6634     dVAR;
6635     register char *d;
6636     int flags;
6637 
6638     if (!sv)
6639 	return;
6640     SvGETMAGIC(sv);
6641     if (SvTHINKFIRST(sv)) {
6642 	if (SvIsCOW(sv))
6643 	    sv_force_normal_flags(sv, 0);
6644 	if (SvREADONLY(sv)) {
6645 	    if (IN_PERL_RUNTIME)
6646 		Perl_croak(aTHX_ PL_no_modify);
6647 	}
6648 	if (SvROK(sv)) {
6649 	    IV i;
6650 	    if (SvAMAGIC(sv) && AMG_CALLun(sv,inc))
6651 		return;
6652 	    i = PTR2IV(SvRV(sv));
6653 	    sv_unref(sv);
6654 	    sv_setiv(sv, i);
6655 	}
6656     }
6657     flags = SvFLAGS(sv);
6658     if ((flags & (SVp_NOK|SVp_IOK)) == SVp_NOK) {
6659 	/* It's (privately or publicly) a float, but not tested as an
6660 	   integer, so test it to see. */
6661 	(void) SvIV(sv);
6662 	flags = SvFLAGS(sv);
6663     }
6664     if ((flags & SVf_IOK) || ((flags & (SVp_IOK | SVp_NOK)) == SVp_IOK)) {
6665 	/* It's publicly an integer, or privately an integer-not-float */
6666 #ifdef PERL_PRESERVE_IVUV
6667       oops_its_int:
6668 #endif
6669 	if (SvIsUV(sv)) {
6670 	    if (SvUVX(sv) == UV_MAX)
6671 		sv_setnv(sv, UV_MAX_P1);
6672 	    else
6673 		(void)SvIOK_only_UV(sv);
6674 		SvUV_set(sv, SvUVX(sv) + 1);
6675 	} else {
6676 	    if (SvIVX(sv) == IV_MAX)
6677 		sv_setuv(sv, (UV)IV_MAX + 1);
6678 	    else {
6679 		(void)SvIOK_only(sv);
6680 		SvIV_set(sv, SvIVX(sv) + 1);
6681 	    }
6682 	}
6683 	return;
6684     }
6685     if (flags & SVp_NOK) {
6686 	(void)SvNOK_only(sv);
6687         SvNV_set(sv, SvNVX(sv) + 1.0);
6688 	return;
6689     }
6690 
6691     if (!(flags & SVp_POK) || !*SvPVX_const(sv)) {
6692 	if ((flags & SVTYPEMASK) < SVt_PVIV)
6693 	    sv_upgrade(sv, ((flags & SVTYPEMASK) > SVt_IV ? SVt_PVIV : SVt_IV));
6694 	(void)SvIOK_only(sv);
6695 	SvIV_set(sv, 1);
6696 	return;
6697     }
6698     d = SvPVX(sv);
6699     while (isALPHA(*d)) d++;
6700     while (isDIGIT(*d)) d++;
6701     if (*d) {
6702 #ifdef PERL_PRESERVE_IVUV
6703 	/* Got to punt this as an integer if needs be, but we don't issue
6704 	   warnings. Probably ought to make the sv_iv_please() that does
6705 	   the conversion if possible, and silently.  */
6706 	const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), NULL);
6707 	if (numtype && !(numtype & IS_NUMBER_INFINITY)) {
6708 	    /* Need to try really hard to see if it's an integer.
6709 	       9.22337203685478e+18 is an integer.
6710 	       but "9.22337203685478e+18" + 0 is UV=9223372036854779904
6711 	       so $a="9.22337203685478e+18"; $a+0; $a++
6712 	       needs to be the same as $a="9.22337203685478e+18"; $a++
6713 	       or we go insane. */
6714 
6715 	    (void) sv_2iv(sv);
6716 	    if (SvIOK(sv))
6717 		goto oops_its_int;
6718 
6719 	    /* sv_2iv *should* have made this an NV */
6720 	    if (flags & SVp_NOK) {
6721 		(void)SvNOK_only(sv);
6722                 SvNV_set(sv, SvNVX(sv) + 1.0);
6723 		return;
6724 	    }
6725 	    /* I don't think we can get here. Maybe I should assert this
6726 	       And if we do get here I suspect that sv_setnv will croak. NWC
6727 	       Fall through. */
6728 #if defined(USE_LONG_DOUBLE)
6729 	    DEBUG_c(PerlIO_printf(Perl_debug_log,"sv_inc punt failed to convert '%s' to IOK or NOKp, UV=0x%"UVxf" NV=%"PERL_PRIgldbl"\n",
6730 				  SvPVX_const(sv), SvIVX(sv), SvNVX(sv)));
6731 #else
6732 	    DEBUG_c(PerlIO_printf(Perl_debug_log,"sv_inc punt failed to convert '%s' to IOK or NOKp, UV=0x%"UVxf" NV=%"NVgf"\n",
6733 				  SvPVX_const(sv), SvIVX(sv), SvNVX(sv)));
6734 #endif
6735 	}
6736 #endif /* PERL_PRESERVE_IVUV */
6737 	sv_setnv(sv,Atof(SvPVX_const(sv)) + 1.0);
6738 	return;
6739     }
6740     d--;
6741     while (d >= SvPVX_const(sv)) {
6742 	if (isDIGIT(*d)) {
6743 	    if (++*d <= '9')
6744 		return;
6745 	    *(d--) = '0';
6746 	}
6747 	else {
6748 #ifdef EBCDIC
6749 	    /* MKS: The original code here died if letters weren't consecutive.
6750 	     * at least it didn't have to worry about non-C locales.  The
6751 	     * new code assumes that ('z'-'a')==('Z'-'A'), letters are
6752 	     * arranged in order (although not consecutively) and that only
6753 	     * [A-Za-z] are accepted by isALPHA in the C locale.
6754 	     */
6755 	    if (*d != 'z' && *d != 'Z') {
6756 		do { ++*d; } while (!isALPHA(*d));
6757 		return;
6758 	    }
6759 	    *(d--) -= 'z' - 'a';
6760 #else
6761 	    ++*d;
6762 	    if (isALPHA(*d))
6763 		return;
6764 	    *(d--) -= 'z' - 'a' + 1;
6765 #endif
6766 	}
6767     }
6768     /* oh,oh, the number grew */
6769     SvGROW(sv, SvCUR(sv) + 2);
6770     SvCUR_set(sv, SvCUR(sv) + 1);
6771     for (d = SvPVX(sv) + SvCUR(sv); d > SvPVX_const(sv); d--)
6772 	*d = d[-1];
6773     if (isDIGIT(d[1]))
6774 	*d = '1';
6775     else
6776 	*d = d[1];
6777 }
6778 
6779 /*
6780 =for apidoc sv_dec
6781 
6782 Auto-decrement of the value in the SV, doing string to numeric conversion
6783 if necessary. Handles 'get' magic.
6784 
6785 =cut
6786 */
6787 
6788 void
6789 Perl_sv_dec(pTHX_ register SV *sv)
6790 {
6791     dVAR;
6792     int flags;
6793 
6794     if (!sv)
6795 	return;
6796     SvGETMAGIC(sv);
6797     if (SvTHINKFIRST(sv)) {
6798 	if (SvIsCOW(sv))
6799 	    sv_force_normal_flags(sv, 0);
6800 	if (SvREADONLY(sv)) {
6801 	    if (IN_PERL_RUNTIME)
6802 		Perl_croak(aTHX_ PL_no_modify);
6803 	}
6804 	if (SvROK(sv)) {
6805 	    IV i;
6806 	    if (SvAMAGIC(sv) && AMG_CALLun(sv,dec))
6807 		return;
6808 	    i = PTR2IV(SvRV(sv));
6809 	    sv_unref(sv);
6810 	    sv_setiv(sv, i);
6811 	}
6812     }
6813     /* Unlike sv_inc we don't have to worry about string-never-numbers
6814        and keeping them magic. But we mustn't warn on punting */
6815     flags = SvFLAGS(sv);
6816     if ((flags & SVf_IOK) || ((flags & (SVp_IOK | SVp_NOK)) == SVp_IOK)) {
6817 	/* It's publicly an integer, or privately an integer-not-float */
6818 #ifdef PERL_PRESERVE_IVUV
6819       oops_its_int:
6820 #endif
6821 	if (SvIsUV(sv)) {
6822 	    if (SvUVX(sv) == 0) {
6823 		(void)SvIOK_only(sv);
6824 		SvIV_set(sv, -1);
6825 	    }
6826 	    else {
6827 		(void)SvIOK_only_UV(sv);
6828 		SvUV_set(sv, SvUVX(sv) - 1);
6829 	    }
6830 	} else {
6831 	    if (SvIVX(sv) == IV_MIN)
6832 		sv_setnv(sv, (NV)IV_MIN - 1.0);
6833 	    else {
6834 		(void)SvIOK_only(sv);
6835 		SvIV_set(sv, SvIVX(sv) - 1);
6836 	    }
6837 	}
6838 	return;
6839     }
6840     if (flags & SVp_NOK) {
6841         SvNV_set(sv, SvNVX(sv) - 1.0);
6842 	(void)SvNOK_only(sv);
6843 	return;
6844     }
6845     if (!(flags & SVp_POK)) {
6846 	if ((flags & SVTYPEMASK) < SVt_PVIV)
6847 	    sv_upgrade(sv, ((flags & SVTYPEMASK) > SVt_IV) ? SVt_PVIV : SVt_IV);
6848 	SvIV_set(sv, -1);
6849 	(void)SvIOK_only(sv);
6850 	return;
6851     }
6852 #ifdef PERL_PRESERVE_IVUV
6853     {
6854 	const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), NULL);
6855 	if (numtype && !(numtype & IS_NUMBER_INFINITY)) {
6856 	    /* Need to try really hard to see if it's an integer.
6857 	       9.22337203685478e+18 is an integer.
6858 	       but "9.22337203685478e+18" + 0 is UV=9223372036854779904
6859 	       so $a="9.22337203685478e+18"; $a+0; $a--
6860 	       needs to be the same as $a="9.22337203685478e+18"; $a--
6861 	       or we go insane. */
6862 
6863 	    (void) sv_2iv(sv);
6864 	    if (SvIOK(sv))
6865 		goto oops_its_int;
6866 
6867 	    /* sv_2iv *should* have made this an NV */
6868 	    if (flags & SVp_NOK) {
6869 		(void)SvNOK_only(sv);
6870                 SvNV_set(sv, SvNVX(sv) - 1.0);
6871 		return;
6872 	    }
6873 	    /* I don't think we can get here. Maybe I should assert this
6874 	       And if we do get here I suspect that sv_setnv will croak. NWC
6875 	       Fall through. */
6876 #if defined(USE_LONG_DOUBLE)
6877 	    DEBUG_c(PerlIO_printf(Perl_debug_log,"sv_dec punt failed to convert '%s' to IOK or NOKp, UV=0x%"UVxf" NV=%"PERL_PRIgldbl"\n",
6878 				  SvPVX_const(sv), SvIVX(sv), SvNVX(sv)));
6879 #else
6880 	    DEBUG_c(PerlIO_printf(Perl_debug_log,"sv_dec punt failed to convert '%s' to IOK or NOKp, UV=0x%"UVxf" NV=%"NVgf"\n",
6881 				  SvPVX_const(sv), SvIVX(sv), SvNVX(sv)));
6882 #endif
6883 	}
6884     }
6885 #endif /* PERL_PRESERVE_IVUV */
6886     sv_setnv(sv,Atof(SvPVX_const(sv)) - 1.0);	/* punt */
6887 }
6888 
6889 /*
6890 =for apidoc sv_mortalcopy
6891 
6892 Creates a new SV which is a copy of the original SV (using C<sv_setsv>).
6893 The new SV is marked as mortal. It will be destroyed "soon", either by an
6894 explicit call to FREETMPS, or by an implicit call at places such as
6895 statement boundaries.  See also C<sv_newmortal> and C<sv_2mortal>.
6896 
6897 =cut
6898 */
6899 
6900 /* Make a string that will exist for the duration of the expression
6901  * evaluation.  Actually, it may have to last longer than that, but
6902  * hopefully we won't free it until it has been assigned to a
6903  * permanent location. */
6904 
6905 SV *
6906 Perl_sv_mortalcopy(pTHX_ SV *oldstr)
6907 {
6908     dVAR;
6909     register SV *sv;
6910 
6911     new_SV(sv);
6912     sv_setsv(sv,oldstr);
6913     EXTEND_MORTAL(1);
6914     PL_tmps_stack[++PL_tmps_ix] = sv;
6915     SvTEMP_on(sv);
6916     return sv;
6917 }
6918 
6919 /*
6920 =for apidoc sv_newmortal
6921 
6922 Creates a new null SV which is mortal.  The reference count of the SV is
6923 set to 1. It will be destroyed "soon", either by an explicit call to
6924 FREETMPS, or by an implicit call at places such as statement boundaries.
6925 See also C<sv_mortalcopy> and C<sv_2mortal>.
6926 
6927 =cut
6928 */
6929 
6930 SV *
6931 Perl_sv_newmortal(pTHX)
6932 {
6933     dVAR;
6934     register SV *sv;
6935 
6936     new_SV(sv);
6937     SvFLAGS(sv) = SVs_TEMP;
6938     EXTEND_MORTAL(1);
6939     PL_tmps_stack[++PL_tmps_ix] = sv;
6940     return sv;
6941 }
6942 
6943 /*
6944 =for apidoc sv_2mortal
6945 
6946 Marks an existing SV as mortal.  The SV will be destroyed "soon", either
6947 by an explicit call to FREETMPS, or by an implicit call at places such as
6948 statement boundaries.  SvTEMP() is turned on which means that the SV's
6949 string buffer can be "stolen" if this SV is copied. See also C<sv_newmortal>
6950 and C<sv_mortalcopy>.
6951 
6952 =cut
6953 */
6954 
6955 SV *
6956 Perl_sv_2mortal(pTHX_ register SV *sv)
6957 {
6958     dVAR;
6959     if (!sv)
6960 	return NULL;
6961     if (SvREADONLY(sv) && SvIMMORTAL(sv))
6962 	return sv;
6963     EXTEND_MORTAL(1);
6964     PL_tmps_stack[++PL_tmps_ix] = sv;
6965     SvTEMP_on(sv);
6966     return sv;
6967 }
6968 
6969 /*
6970 =for apidoc newSVpv
6971 
6972 Creates a new SV and copies a string into it.  The reference count for the
6973 SV is set to 1.  If C<len> is zero, Perl will compute the length using
6974 strlen().  For efficiency, consider using C<newSVpvn> instead.
6975 
6976 =cut
6977 */
6978 
6979 SV *
6980 Perl_newSVpv(pTHX_ const char *s, STRLEN len)
6981 {
6982     dVAR;
6983     register SV *sv;
6984 
6985     new_SV(sv);
6986     sv_setpvn(sv, s, len || s == NULL ? len : strlen(s));
6987     return sv;
6988 }
6989 
6990 /*
6991 =for apidoc newSVpvn
6992 
6993 Creates a new SV and copies a string into it.  The reference count for the
6994 SV is set to 1.  Note that if C<len> is zero, Perl will create a zero length
6995 string.  You are responsible for ensuring that the source string is at least
6996 C<len> bytes long.  If the C<s> argument is NULL the new SV will be undefined.
6997 
6998 =cut
6999 */
7000 
7001 SV *
7002 Perl_newSVpvn(pTHX_ const char *s, STRLEN len)
7003 {
7004     dVAR;
7005     register SV *sv;
7006 
7007     new_SV(sv);
7008     sv_setpvn(sv,s,len);
7009     return sv;
7010 }
7011 
7012 
7013 /*
7014 =for apidoc newSVhek
7015 
7016 Creates a new SV from the hash key structure.  It will generate scalars that
7017 point to the shared string table where possible. Returns a new (undefined)
7018 SV if the hek is NULL.
7019 
7020 =cut
7021 */
7022 
7023 SV *
7024 Perl_newSVhek(pTHX_ const HEK *hek)
7025 {
7026     dVAR;
7027     if (!hek) {
7028 	SV *sv;
7029 
7030 	new_SV(sv);
7031 	return sv;
7032     }
7033 
7034     if (HEK_LEN(hek) == HEf_SVKEY) {
7035 	return newSVsv(*(SV**)HEK_KEY(hek));
7036     } else {
7037 	const int flags = HEK_FLAGS(hek);
7038 	if (flags & HVhek_WASUTF8) {
7039 	    /* Trouble :-)
7040 	       Andreas would like keys he put in as utf8 to come back as utf8
7041 	    */
7042 	    STRLEN utf8_len = HEK_LEN(hek);
7043 	    const U8 *as_utf8 = bytes_to_utf8 ((U8*)HEK_KEY(hek), &utf8_len);
7044 	    SV * const sv = newSVpvn ((const char*)as_utf8, utf8_len);
7045 
7046 	    SvUTF8_on (sv);
7047 	    Safefree (as_utf8); /* bytes_to_utf8() allocates a new string */
7048 	    return sv;
7049 	} else if (flags & (HVhek_REHASH|HVhek_UNSHARED)) {
7050 	    /* We don't have a pointer to the hv, so we have to replicate the
7051 	       flag into every HEK. This hv is using custom a hasing
7052 	       algorithm. Hence we can't return a shared string scalar, as
7053 	       that would contain the (wrong) hash value, and might get passed
7054 	       into an hv routine with a regular hash.
7055 	       Similarly, a hash that isn't using shared hash keys has to have
7056 	       the flag in every key so that we know not to try to call
7057 	       share_hek_kek on it.  */
7058 
7059 	    SV * const sv = newSVpvn (HEK_KEY(hek), HEK_LEN(hek));
7060 	    if (HEK_UTF8(hek))
7061 		SvUTF8_on (sv);
7062 	    return sv;
7063 	}
7064 	/* This will be overwhelminly the most common case.  */
7065 	{
7066 	    /* Inline most of newSVpvn_share(), because share_hek_hek() is far
7067 	       more efficient than sharepvn().  */
7068 	    SV *sv;
7069 
7070 	    new_SV(sv);
7071 	    sv_upgrade(sv, SVt_PV);
7072 	    SvPV_set(sv, (char *)HEK_KEY(share_hek_hek(hek)));
7073 	    SvCUR_set(sv, HEK_LEN(hek));
7074 	    SvLEN_set(sv, 0);
7075 	    SvREADONLY_on(sv);
7076 	    SvFAKE_on(sv);
7077 	    SvPOK_on(sv);
7078 	    if (HEK_UTF8(hek))
7079 		SvUTF8_on(sv);
7080 	    return sv;
7081 	}
7082     }
7083 }
7084 
7085 /*
7086 =for apidoc newSVpvn_share
7087 
7088 Creates a new SV with its SvPVX_const pointing to a shared string in the string
7089 table. If the string does not already exist in the table, it is created
7090 first.  Turns on READONLY and FAKE. If the C<hash> parameter is non-zero, that
7091 value is used; otherwise the hash is computed. The string's hash can be later
7092 be retrieved from the SV with the C<SvSHARED_HASH()> macro. The idea here is
7093 that as the string table is used for shared hash keys these strings will have
7094 SvPVX_const == HeKEY and hash lookup will avoid string compare.
7095 
7096 =cut
7097 */
7098 
7099 SV *
7100 Perl_newSVpvn_share(pTHX_ const char *src, I32 len, U32 hash)
7101 {
7102     dVAR;
7103     register SV *sv;
7104     bool is_utf8 = FALSE;
7105     const char *const orig_src = src;
7106 
7107     if (len < 0) {
7108 	STRLEN tmplen = -len;
7109         is_utf8 = TRUE;
7110 	/* See the note in hv.c:hv_fetch() --jhi */
7111 	src = (char*)bytes_from_utf8((const U8*)src, &tmplen, &is_utf8);
7112 	len = tmplen;
7113     }
7114     if (!hash)
7115 	PERL_HASH(hash, src, len);
7116     new_SV(sv);
7117     sv_upgrade(sv, SVt_PV);
7118     SvPV_set(sv, sharepvn(src, is_utf8?-len:len, hash));
7119     SvCUR_set(sv, len);
7120     SvLEN_set(sv, 0);
7121     SvREADONLY_on(sv);
7122     SvFAKE_on(sv);
7123     SvPOK_on(sv);
7124     if (is_utf8)
7125         SvUTF8_on(sv);
7126     if (src != orig_src)
7127 	Safefree(src);
7128     return sv;
7129 }
7130 
7131 
7132 #if defined(PERL_IMPLICIT_CONTEXT)
7133 
7134 /* pTHX_ magic can't cope with varargs, so this is a no-context
7135  * version of the main function, (which may itself be aliased to us).
7136  * Don't access this version directly.
7137  */
7138 
7139 SV *
7140 Perl_newSVpvf_nocontext(const char* pat, ...)
7141 {
7142     dTHX;
7143     register SV *sv;
7144     va_list args;
7145     va_start(args, pat);
7146     sv = vnewSVpvf(pat, &args);
7147     va_end(args);
7148     return sv;
7149 }
7150 #endif
7151 
7152 /*
7153 =for apidoc newSVpvf
7154 
7155 Creates a new SV and initializes it with the string formatted like
7156 C<sprintf>.
7157 
7158 =cut
7159 */
7160 
7161 SV *
7162 Perl_newSVpvf(pTHX_ const char* pat, ...)
7163 {
7164     register SV *sv;
7165     va_list args;
7166     va_start(args, pat);
7167     sv = vnewSVpvf(pat, &args);
7168     va_end(args);
7169     return sv;
7170 }
7171 
7172 /* backend for newSVpvf() and newSVpvf_nocontext() */
7173 
7174 SV *
7175 Perl_vnewSVpvf(pTHX_ const char* pat, va_list* args)
7176 {
7177     dVAR;
7178     register SV *sv;
7179     new_SV(sv);
7180     sv_vsetpvfn(sv, pat, strlen(pat), args, NULL, 0, NULL);
7181     return sv;
7182 }
7183 
7184 /*
7185 =for apidoc newSVnv
7186 
7187 Creates a new SV and copies a floating point value into it.
7188 The reference count for the SV is set to 1.
7189 
7190 =cut
7191 */
7192 
7193 SV *
7194 Perl_newSVnv(pTHX_ NV n)
7195 {
7196     dVAR;
7197     register SV *sv;
7198 
7199     new_SV(sv);
7200     sv_setnv(sv,n);
7201     return sv;
7202 }
7203 
7204 /*
7205 =for apidoc newSViv
7206 
7207 Creates a new SV and copies an integer into it.  The reference count for the
7208 SV is set to 1.
7209 
7210 =cut
7211 */
7212 
7213 SV *
7214 Perl_newSViv(pTHX_ IV i)
7215 {
7216     dVAR;
7217     register SV *sv;
7218 
7219     new_SV(sv);
7220     sv_setiv(sv,i);
7221     return sv;
7222 }
7223 
7224 /*
7225 =for apidoc newSVuv
7226 
7227 Creates a new SV and copies an unsigned integer into it.
7228 The reference count for the SV is set to 1.
7229 
7230 =cut
7231 */
7232 
7233 SV *
7234 Perl_newSVuv(pTHX_ UV u)
7235 {
7236     dVAR;
7237     register SV *sv;
7238 
7239     new_SV(sv);
7240     sv_setuv(sv,u);
7241     return sv;
7242 }
7243 
7244 /*
7245 =for apidoc newSV_type
7246 
7247 Creates a new SV, of the type specified.  The reference count for the new SV
7248 is set to 1.
7249 
7250 =cut
7251 */
7252 
7253 SV *
7254 Perl_newSV_type(pTHX_ svtype type)
7255 {
7256     register SV *sv;
7257 
7258     new_SV(sv);
7259     sv_upgrade(sv, type);
7260     return sv;
7261 }
7262 
7263 /*
7264 =for apidoc newRV_noinc
7265 
7266 Creates an RV wrapper for an SV.  The reference count for the original
7267 SV is B<not> incremented.
7268 
7269 =cut
7270 */
7271 
7272 SV *
7273 Perl_newRV_noinc(pTHX_ SV *tmpRef)
7274 {
7275     dVAR;
7276     register SV *sv = newSV_type(SVt_RV);
7277     SvTEMP_off(tmpRef);
7278     SvRV_set(sv, tmpRef);
7279     SvROK_on(sv);
7280     return sv;
7281 }
7282 
7283 /* newRV_inc is the official function name to use now.
7284  * newRV_inc is in fact #defined to newRV in sv.h
7285  */
7286 
7287 SV *
7288 Perl_newRV(pTHX_ SV *sv)
7289 {
7290     dVAR;
7291     return newRV_noinc(SvREFCNT_inc_simple_NN(sv));
7292 }
7293 
7294 /*
7295 =for apidoc newSVsv
7296 
7297 Creates a new SV which is an exact duplicate of the original SV.
7298 (Uses C<sv_setsv>).
7299 
7300 =cut
7301 */
7302 
7303 SV *
7304 Perl_newSVsv(pTHX_ register SV *old)
7305 {
7306     dVAR;
7307     register SV *sv;
7308 
7309     if (!old)
7310 	return NULL;
7311     if (SvTYPE(old) == SVTYPEMASK) {
7312         if (ckWARN_d(WARN_INTERNAL))
7313 	    Perl_warner(aTHX_ packWARN(WARN_INTERNAL), "semi-panic: attempt to dup freed string");
7314 	return NULL;
7315     }
7316     new_SV(sv);
7317     /* SV_GMAGIC is the default for sv_setv()
7318        SV_NOSTEAL prevents TEMP buffers being, well, stolen, and saves games
7319        with SvTEMP_off and SvTEMP_on round a call to sv_setsv.  */
7320     sv_setsv_flags(sv, old, SV_GMAGIC | SV_NOSTEAL);
7321     return sv;
7322 }
7323 
7324 /*
7325 =for apidoc sv_reset
7326 
7327 Underlying implementation for the C<reset> Perl function.
7328 Note that the perl-level function is vaguely deprecated.
7329 
7330 =cut
7331 */
7332 
7333 void
7334 Perl_sv_reset(pTHX_ register const char *s, HV *stash)
7335 {
7336     dVAR;
7337     char todo[PERL_UCHAR_MAX+1];
7338 
7339     if (!stash)
7340 	return;
7341 
7342     if (!*s) {		/* reset ?? searches */
7343 	MAGIC * const mg = mg_find((SV *)stash, PERL_MAGIC_symtab);
7344 	if (mg) {
7345 	    const U32 count = mg->mg_len / sizeof(PMOP**);
7346 	    PMOP **pmp = (PMOP**) mg->mg_ptr;
7347 	    PMOP *const *const end = pmp + count;
7348 
7349 	    while (pmp < end) {
7350 #ifdef USE_ITHREADS
7351                 SvREADONLY_off(PL_regex_pad[(*pmp)->op_pmoffset]);
7352 #else
7353 		(*pmp)->op_pmflags &= ~PMf_USED;
7354 #endif
7355 		++pmp;
7356 	    }
7357 	}
7358 	return;
7359     }
7360 
7361     /* reset variables */
7362 
7363     if (!HvARRAY(stash))
7364 	return;
7365 
7366     Zero(todo, 256, char);
7367     while (*s) {
7368 	I32 max;
7369 	I32 i = (unsigned char)*s;
7370 	if (s[1] == '-') {
7371 	    s += 2;
7372 	}
7373 	max = (unsigned char)*s++;
7374 	for ( ; i <= max; i++) {
7375 	    todo[i] = 1;
7376 	}
7377 	for (i = 0; i <= (I32) HvMAX(stash); i++) {
7378 	    HE *entry;
7379 	    for (entry = HvARRAY(stash)[i];
7380 		 entry;
7381 		 entry = HeNEXT(entry))
7382 	    {
7383 		register GV *gv;
7384 		register SV *sv;
7385 
7386 		if (!todo[(U8)*HeKEY(entry)])
7387 		    continue;
7388 		gv = (GV*)HeVAL(entry);
7389 		sv = GvSV(gv);
7390 		if (sv) {
7391 		    if (SvTHINKFIRST(sv)) {
7392 			if (!SvREADONLY(sv) && SvROK(sv))
7393 			    sv_unref(sv);
7394 			/* XXX Is this continue a bug? Why should THINKFIRST
7395 			   exempt us from resetting arrays and hashes?  */
7396 			continue;
7397 		    }
7398 		    SvOK_off(sv);
7399 		    if (SvTYPE(sv) >= SVt_PV) {
7400 			SvCUR_set(sv, 0);
7401 			if (SvPVX_const(sv) != NULL)
7402 			    *SvPVX(sv) = '\0';
7403 			SvTAINT(sv);
7404 		    }
7405 		}
7406 		if (GvAV(gv)) {
7407 		    av_clear(GvAV(gv));
7408 		}
7409 		if (GvHV(gv) && !HvNAME_get(GvHV(gv))) {
7410 #if defined(VMS)
7411 		    Perl_die(aTHX_ "Can't reset %%ENV on this system");
7412 #else /* ! VMS */
7413 		    hv_clear(GvHV(gv));
7414 #  if defined(USE_ENVIRON_ARRAY)
7415 		    if (gv == PL_envgv)
7416 		        my_clearenv();
7417 #  endif /* USE_ENVIRON_ARRAY */
7418 #endif /* VMS */
7419 		}
7420 	    }
7421 	}
7422     }
7423 }
7424 
7425 /*
7426 =for apidoc sv_2io
7427 
7428 Using various gambits, try to get an IO from an SV: the IO slot if its a
7429 GV; or the recursive result if we're an RV; or the IO slot of the symbol
7430 named after the PV if we're a string.
7431 
7432 =cut
7433 */
7434 
7435 IO*
7436 Perl_sv_2io(pTHX_ SV *sv)
7437 {
7438     IO* io;
7439     GV* gv;
7440 
7441     switch (SvTYPE(sv)) {
7442     case SVt_PVIO:
7443 	io = (IO*)sv;
7444 	break;
7445     case SVt_PVGV:
7446 	gv = (GV*)sv;
7447 	io = GvIO(gv);
7448 	if (!io)
7449 	    Perl_croak(aTHX_ "Bad filehandle: %s", GvNAME(gv));
7450 	break;
7451     default:
7452 	if (!SvOK(sv))
7453 	    Perl_croak(aTHX_ PL_no_usym, "filehandle");
7454 	if (SvROK(sv))
7455 	    return sv_2io(SvRV(sv));
7456 	gv = gv_fetchsv(sv, 0, SVt_PVIO);
7457 	if (gv)
7458 	    io = GvIO(gv);
7459 	else
7460 	    io = 0;
7461 	if (!io)
7462 	    Perl_croak(aTHX_ "Bad filehandle: %"SVf, SVfARG(sv));
7463 	break;
7464     }
7465     return io;
7466 }
7467 
7468 /*
7469 =for apidoc sv_2cv
7470 
7471 Using various gambits, try to get a CV from an SV; in addition, try if
7472 possible to set C<*st> and C<*gvp> to the stash and GV associated with it.
7473 The flags in C<lref> are passed to sv_fetchsv.
7474 
7475 =cut
7476 */
7477 
7478 CV *
7479 Perl_sv_2cv(pTHX_ SV *sv, HV **st, GV **gvp, I32 lref)
7480 {
7481     dVAR;
7482     GV *gv = NULL;
7483     CV *cv = NULL;
7484 
7485     if (!sv) {
7486 	*st = NULL;
7487 	*gvp = NULL;
7488 	return NULL;
7489     }
7490     switch (SvTYPE(sv)) {
7491     case SVt_PVCV:
7492 	*st = CvSTASH(sv);
7493 	*gvp = NULL;
7494 	return (CV*)sv;
7495     case SVt_PVHV:
7496     case SVt_PVAV:
7497 	*st = NULL;
7498 	*gvp = NULL;
7499 	return NULL;
7500     case SVt_PVGV:
7501 	gv = (GV*)sv;
7502 	*gvp = gv;
7503 	*st = GvESTASH(gv);
7504 	goto fix_gv;
7505 
7506     default:
7507 	SvGETMAGIC(sv);
7508 	if (SvROK(sv)) {
7509 	    SV * const *sp = &sv;	/* Used in tryAMAGICunDEREF macro. */
7510 	    tryAMAGICunDEREF(to_cv);
7511 
7512 	    sv = SvRV(sv);
7513 	    if (SvTYPE(sv) == SVt_PVCV) {
7514 		cv = (CV*)sv;
7515 		*gvp = NULL;
7516 		*st = CvSTASH(cv);
7517 		return cv;
7518 	    }
7519 	    else if(isGV(sv))
7520 		gv = (GV*)sv;
7521 	    else
7522 		Perl_croak(aTHX_ "Not a subroutine reference");
7523 	}
7524 	else if (isGV(sv))
7525 	    gv = (GV*)sv;
7526 	else
7527 	    gv = gv_fetchsv(sv, lref, SVt_PVCV);
7528 	*gvp = gv;
7529 	if (!gv) {
7530 	    *st = NULL;
7531 	    return NULL;
7532 	}
7533 	/* Some flags to gv_fetchsv mean don't really create the GV  */
7534 	if (SvTYPE(gv) != SVt_PVGV) {
7535 	    *st = NULL;
7536 	    return NULL;
7537 	}
7538 	*st = GvESTASH(gv);
7539     fix_gv:
7540 	if (lref && !GvCVu(gv)) {
7541 	    SV *tmpsv;
7542 	    ENTER;
7543 	    tmpsv = newSV(0);
7544 	    gv_efullname3(tmpsv, gv, NULL);
7545 	    /* XXX this is probably not what they think they're getting.
7546 	     * It has the same effect as "sub name;", i.e. just a forward
7547 	     * declaration! */
7548 	    newSUB(start_subparse(FALSE, 0),
7549 		   newSVOP(OP_CONST, 0, tmpsv),
7550 		   NULL, NULL);
7551 	    LEAVE;
7552 	    if (!GvCVu(gv))
7553 		Perl_croak(aTHX_ "Unable to create sub named \"%"SVf"\"",
7554 			   SVfARG(sv));
7555 	}
7556 	return GvCVu(gv);
7557     }
7558 }
7559 
7560 /*
7561 =for apidoc sv_true
7562 
7563 Returns true if the SV has a true value by Perl's rules.
7564 Use the C<SvTRUE> macro instead, which may call C<sv_true()> or may
7565 instead use an in-line version.
7566 
7567 =cut
7568 */
7569 
7570 I32
7571 Perl_sv_true(pTHX_ register SV *sv)
7572 {
7573     if (!sv)
7574 	return 0;
7575     if (SvPOK(sv)) {
7576 	register const XPV* const tXpv = (XPV*)SvANY(sv);
7577 	if (tXpv &&
7578 		(tXpv->xpv_cur > 1 ||
7579 		(tXpv->xpv_cur && *sv->sv_u.svu_pv != '0')))
7580 	    return 1;
7581 	else
7582 	    return 0;
7583     }
7584     else {
7585 	if (SvIOK(sv))
7586 	    return SvIVX(sv) != 0;
7587 	else {
7588 	    if (SvNOK(sv))
7589 		return SvNVX(sv) != 0.0;
7590 	    else
7591 		return sv_2bool(sv);
7592 	}
7593     }
7594 }
7595 
7596 /*
7597 =for apidoc sv_pvn_force
7598 
7599 Get a sensible string out of the SV somehow.
7600 A private implementation of the C<SvPV_force> macro for compilers which
7601 can't cope with complex macro expressions. Always use the macro instead.
7602 
7603 =for apidoc sv_pvn_force_flags
7604 
7605 Get a sensible string out of the SV somehow.
7606 If C<flags> has C<SV_GMAGIC> bit set, will C<mg_get> on C<sv> if
7607 appropriate, else not. C<sv_pvn_force> and C<sv_pvn_force_nomg> are
7608 implemented in terms of this function.
7609 You normally want to use the various wrapper macros instead: see
7610 C<SvPV_force> and C<SvPV_force_nomg>
7611 
7612 =cut
7613 */
7614 
7615 char *
7616 Perl_sv_pvn_force_flags(pTHX_ SV *sv, STRLEN *lp, I32 flags)
7617 {
7618     dVAR;
7619     if (SvTHINKFIRST(sv) && !SvROK(sv))
7620         sv_force_normal_flags(sv, 0);
7621 
7622     if (SvPOK(sv)) {
7623 	if (lp)
7624 	    *lp = SvCUR(sv);
7625     }
7626     else {
7627 	char *s;
7628 	STRLEN len;
7629 
7630 	if (SvREADONLY(sv) && !(flags & SV_MUTABLE_RETURN)) {
7631 	    const char * const ref = sv_reftype(sv,0);
7632 	    if (PL_op)
7633 		Perl_croak(aTHX_ "Can't coerce readonly %s to string in %s",
7634 			   ref, OP_NAME(PL_op));
7635 	    else
7636 		Perl_croak(aTHX_ "Can't coerce readonly %s to string", ref);
7637 	}
7638 	if (SvTYPE(sv) > SVt_PVLV && SvTYPE(sv) != SVt_PVFM)
7639 	    Perl_croak(aTHX_ "Can't coerce %s to string in %s", sv_reftype(sv,0),
7640 		OP_NAME(PL_op));
7641 	s = sv_2pv_flags(sv, &len, flags);
7642 	if (lp)
7643 	    *lp = len;
7644 
7645 	if (s != SvPVX_const(sv)) {	/* Almost, but not quite, sv_setpvn() */
7646 	    if (SvROK(sv))
7647 		sv_unref(sv);
7648 	    SvUPGRADE(sv, SVt_PV);		/* Never FALSE */
7649 	    SvGROW(sv, len + 1);
7650 	    Move(s,SvPVX(sv),len,char);
7651 	    SvCUR_set(sv, len);
7652 	    SvPVX(sv)[len] = '\0';
7653 	}
7654 	if (!SvPOK(sv)) {
7655 	    SvPOK_on(sv);		/* validate pointer */
7656 	    SvTAINT(sv);
7657 	    DEBUG_c(PerlIO_printf(Perl_debug_log, "0x%"UVxf" 2pv(%s)\n",
7658 				  PTR2UV(sv),SvPVX_const(sv)));
7659 	}
7660     }
7661     return SvPVX_mutable(sv);
7662 }
7663 
7664 /*
7665 =for apidoc sv_pvbyten_force
7666 
7667 The backend for the C<SvPVbytex_force> macro. Always use the macro instead.
7668 
7669 =cut
7670 */
7671 
7672 char *
7673 Perl_sv_pvbyten_force(pTHX_ SV *sv, STRLEN *lp)
7674 {
7675     sv_pvn_force(sv,lp);
7676     sv_utf8_downgrade(sv,0);
7677     *lp = SvCUR(sv);
7678     return SvPVX(sv);
7679 }
7680 
7681 /*
7682 =for apidoc sv_pvutf8n_force
7683 
7684 The backend for the C<SvPVutf8x_force> macro. Always use the macro instead.
7685 
7686 =cut
7687 */
7688 
7689 char *
7690 Perl_sv_pvutf8n_force(pTHX_ SV *sv, STRLEN *lp)
7691 {
7692     sv_pvn_force(sv,lp);
7693     sv_utf8_upgrade(sv);
7694     *lp = SvCUR(sv);
7695     return SvPVX(sv);
7696 }
7697 
7698 /*
7699 =for apidoc sv_reftype
7700 
7701 Returns a string describing what the SV is a reference to.
7702 
7703 =cut
7704 */
7705 
7706 const char *
7707 Perl_sv_reftype(pTHX_ const SV *sv, int ob)
7708 {
7709     /* The fact that I don't need to downcast to char * everywhere, only in ?:
7710        inside return suggests a const propagation bug in g++.  */
7711     if (ob && SvOBJECT(sv)) {
7712 	char * const name = HvNAME_get(SvSTASH(sv));
7713 	return name ? name : (char *) "__ANON__";
7714     }
7715     else {
7716 	switch (SvTYPE(sv)) {
7717 	case SVt_NULL:
7718 	case SVt_IV:
7719 	case SVt_NV:
7720 	case SVt_RV:
7721 	case SVt_PV:
7722 	case SVt_PVIV:
7723 	case SVt_PVNV:
7724 	case SVt_PVMG:
7725 				if (SvVOK(sv))
7726 				    return "VSTRING";
7727 				if (SvROK(sv))
7728 				    return "REF";
7729 				else
7730 				    return "SCALAR";
7731 
7732 	case SVt_PVLV:		return (char *)  (SvROK(sv) ? "REF"
7733 				/* tied lvalues should appear to be
7734 				 * scalars for backwards compatitbility */
7735 				: (LvTYPE(sv) == 't' || LvTYPE(sv) == 'T')
7736 				    ? "SCALAR" : "LVALUE");
7737 	case SVt_PVAV:		return "ARRAY";
7738 	case SVt_PVHV:		return "HASH";
7739 	case SVt_PVCV:		return "CODE";
7740 	case SVt_PVGV:		return "GLOB";
7741 	case SVt_PVFM:		return "FORMAT";
7742 	case SVt_PVIO:		return "IO";
7743 	case SVt_BIND:		return "BIND";
7744 	default:		return "UNKNOWN";
7745 	}
7746     }
7747 }
7748 
7749 /*
7750 =for apidoc sv_isobject
7751 
7752 Returns a boolean indicating whether the SV is an RV pointing to a blessed
7753 object.  If the SV is not an RV, or if the object is not blessed, then this
7754 will return false.
7755 
7756 =cut
7757 */
7758 
7759 int
7760 Perl_sv_isobject(pTHX_ SV *sv)
7761 {
7762     if (!sv)
7763 	return 0;
7764     SvGETMAGIC(sv);
7765     if (!SvROK(sv))
7766 	return 0;
7767     sv = (SV*)SvRV(sv);
7768     if (!SvOBJECT(sv))
7769 	return 0;
7770     return 1;
7771 }
7772 
7773 /*
7774 =for apidoc sv_isa
7775 
7776 Returns a boolean indicating whether the SV is blessed into the specified
7777 class.  This does not check for subtypes; use C<sv_derived_from> to verify
7778 an inheritance relationship.
7779 
7780 =cut
7781 */
7782 
7783 int
7784 Perl_sv_isa(pTHX_ SV *sv, const char *name)
7785 {
7786     const char *hvname;
7787     if (!sv)
7788 	return 0;
7789     SvGETMAGIC(sv);
7790     if (!SvROK(sv))
7791 	return 0;
7792     sv = (SV*)SvRV(sv);
7793     if (!SvOBJECT(sv))
7794 	return 0;
7795     hvname = HvNAME_get(SvSTASH(sv));
7796     if (!hvname)
7797 	return 0;
7798 
7799     return strEQ(hvname, name);
7800 }
7801 
7802 /*
7803 =for apidoc newSVrv
7804 
7805 Creates a new SV for the RV, C<rv>, to point to.  If C<rv> is not an RV then
7806 it will be upgraded to one.  If C<classname> is non-null then the new SV will
7807 be blessed in the specified package.  The new SV is returned and its
7808 reference count is 1.
7809 
7810 =cut
7811 */
7812 
7813 SV*
7814 Perl_newSVrv(pTHX_ SV *rv, const char *classname)
7815 {
7816     dVAR;
7817     SV *sv;
7818 
7819     new_SV(sv);
7820 
7821     SV_CHECK_THINKFIRST_COW_DROP(rv);
7822     (void)SvAMAGIC_off(rv);
7823 
7824     if (SvTYPE(rv) >= SVt_PVMG) {
7825 	const U32 refcnt = SvREFCNT(rv);
7826 	SvREFCNT(rv) = 0;
7827 	sv_clear(rv);
7828 	SvFLAGS(rv) = 0;
7829 	SvREFCNT(rv) = refcnt;
7830 
7831 	sv_upgrade(rv, SVt_RV);
7832     } else if (SvROK(rv)) {
7833 	SvREFCNT_dec(SvRV(rv));
7834     } else if (SvTYPE(rv) < SVt_RV)
7835 	sv_upgrade(rv, SVt_RV);
7836     else if (SvTYPE(rv) > SVt_RV) {
7837 	SvPV_free(rv);
7838 	SvCUR_set(rv, 0);
7839 	SvLEN_set(rv, 0);
7840     }
7841 
7842     SvOK_off(rv);
7843     SvRV_set(rv, sv);
7844     SvROK_on(rv);
7845 
7846     if (classname) {
7847 	HV* const stash = gv_stashpv(classname, GV_ADD);
7848 	(void)sv_bless(rv, stash);
7849     }
7850     return sv;
7851 }
7852 
7853 /*
7854 =for apidoc sv_setref_pv
7855 
7856 Copies a pointer into a new SV, optionally blessing the SV.  The C<rv>
7857 argument will be upgraded to an RV.  That RV will be modified to point to
7858 the new SV.  If the C<pv> argument is NULL then C<PL_sv_undef> will be placed
7859 into the SV.  The C<classname> argument indicates the package for the
7860 blessing.  Set C<classname> to C<NULL> to avoid the blessing.  The new SV
7861 will have a reference count of 1, and the RV will be returned.
7862 
7863 Do not use with other Perl types such as HV, AV, SV, CV, because those
7864 objects will become corrupted by the pointer copy process.
7865 
7866 Note that C<sv_setref_pvn> copies the string while this copies the pointer.
7867 
7868 =cut
7869 */
7870 
7871 SV*
7872 Perl_sv_setref_pv(pTHX_ SV *rv, const char *classname, void *pv)
7873 {
7874     dVAR;
7875     if (!pv) {
7876 	sv_setsv(rv, &PL_sv_undef);
7877 	SvSETMAGIC(rv);
7878     }
7879     else
7880 	sv_setiv(newSVrv(rv,classname), PTR2IV(pv));
7881     return rv;
7882 }
7883 
7884 /*
7885 =for apidoc sv_setref_iv
7886 
7887 Copies an integer into a new SV, optionally blessing the SV.  The C<rv>
7888 argument will be upgraded to an RV.  That RV will be modified to point to
7889 the new SV.  The C<classname> argument indicates the package for the
7890 blessing.  Set C<classname> to C<NULL> to avoid the blessing.  The new SV
7891 will have a reference count of 1, and the RV will be returned.
7892 
7893 =cut
7894 */
7895 
7896 SV*
7897 Perl_sv_setref_iv(pTHX_ SV *rv, const char *classname, IV iv)
7898 {
7899     sv_setiv(newSVrv(rv,classname), iv);
7900     return rv;
7901 }
7902 
7903 /*
7904 =for apidoc sv_setref_uv
7905 
7906 Copies an unsigned integer into a new SV, optionally blessing the SV.  The C<rv>
7907 argument will be upgraded to an RV.  That RV will be modified to point to
7908 the new SV.  The C<classname> argument indicates the package for the
7909 blessing.  Set C<classname> to C<NULL> to avoid the blessing.  The new SV
7910 will have a reference count of 1, and the RV will be returned.
7911 
7912 =cut
7913 */
7914 
7915 SV*
7916 Perl_sv_setref_uv(pTHX_ SV *rv, const char *classname, UV uv)
7917 {
7918     sv_setuv(newSVrv(rv,classname), uv);
7919     return rv;
7920 }
7921 
7922 /*
7923 =for apidoc sv_setref_nv
7924 
7925 Copies a double into a new SV, optionally blessing the SV.  The C<rv>
7926 argument will be upgraded to an RV.  That RV will be modified to point to
7927 the new SV.  The C<classname> argument indicates the package for the
7928 blessing.  Set C<classname> to C<NULL> to avoid the blessing.  The new SV
7929 will have a reference count of 1, and the RV will be returned.
7930 
7931 =cut
7932 */
7933 
7934 SV*
7935 Perl_sv_setref_nv(pTHX_ SV *rv, const char *classname, NV nv)
7936 {
7937     sv_setnv(newSVrv(rv,classname), nv);
7938     return rv;
7939 }
7940 
7941 /*
7942 =for apidoc sv_setref_pvn
7943 
7944 Copies a string into a new SV, optionally blessing the SV.  The length of the
7945 string must be specified with C<n>.  The C<rv> argument will be upgraded to
7946 an RV.  That RV will be modified to point to the new SV.  The C<classname>
7947 argument indicates the package for the blessing.  Set C<classname> to
7948 C<NULL> to avoid the blessing.  The new SV will have a reference count
7949 of 1, and the RV will be returned.
7950 
7951 Note that C<sv_setref_pv> copies the pointer while this copies the string.
7952 
7953 =cut
7954 */
7955 
7956 SV*
7957 Perl_sv_setref_pvn(pTHX_ SV *rv, const char *classname, const char *pv, STRLEN n)
7958 {
7959     sv_setpvn(newSVrv(rv,classname), pv, n);
7960     return rv;
7961 }
7962 
7963 /*
7964 =for apidoc sv_bless
7965 
7966 Blesses an SV into a specified package.  The SV must be an RV.  The package
7967 must be designated by its stash (see C<gv_stashpv()>).  The reference count
7968 of the SV is unaffected.
7969 
7970 =cut
7971 */
7972 
7973 SV*
7974 Perl_sv_bless(pTHX_ SV *sv, HV *stash)
7975 {
7976     dVAR;
7977     SV *tmpRef;
7978     if (!SvROK(sv))
7979         Perl_croak(aTHX_ "Can't bless non-reference value");
7980     tmpRef = SvRV(sv);
7981     if (SvFLAGS(tmpRef) & (SVs_OBJECT|SVf_READONLY)) {
7982 	if (SvIsCOW(tmpRef))
7983 	    sv_force_normal_flags(tmpRef, 0);
7984 	if (SvREADONLY(tmpRef))
7985 	    Perl_croak(aTHX_ PL_no_modify);
7986 	if (SvOBJECT(tmpRef)) {
7987 	    if (SvTYPE(tmpRef) != SVt_PVIO)
7988 		--PL_sv_objcount;
7989 	    SvREFCNT_dec(SvSTASH(tmpRef));
7990 	}
7991     }
7992     SvOBJECT_on(tmpRef);
7993     if (SvTYPE(tmpRef) != SVt_PVIO)
7994 	++PL_sv_objcount;
7995     SvUPGRADE(tmpRef, SVt_PVMG);
7996     SvSTASH_set(tmpRef, (HV*)SvREFCNT_inc_simple(stash));
7997 
7998     if (Gv_AMG(stash))
7999 	SvAMAGIC_on(sv);
8000     else
8001 	(void)SvAMAGIC_off(sv);
8002 
8003     if(SvSMAGICAL(tmpRef))
8004         if(mg_find(tmpRef, PERL_MAGIC_ext) || mg_find(tmpRef, PERL_MAGIC_uvar))
8005             mg_set(tmpRef);
8006 
8007 
8008 
8009     return sv;
8010 }
8011 
8012 /* Downgrades a PVGV to a PVMG.
8013  */
8014 
8015 STATIC void
8016 S_sv_unglob(pTHX_ SV *sv)
8017 {
8018     dVAR;
8019     void *xpvmg;
8020     HV *stash;
8021     SV * const temp = sv_newmortal();
8022 
8023     assert(SvTYPE(sv) == SVt_PVGV);
8024     SvFAKE_off(sv);
8025     gv_efullname3(temp, (GV *) sv, "*");
8026 
8027     if (GvGP(sv)) {
8028         if(GvCVu((GV*)sv) && (stash = GvSTASH((GV*)sv)) && HvNAME_get(stash))
8029             mro_method_changed_in(stash);
8030 	gp_free((GV*)sv);
8031     }
8032     if (GvSTASH(sv)) {
8033 	sv_del_backref((SV*)GvSTASH(sv), sv);
8034 	GvSTASH(sv) = NULL;
8035     }
8036     GvMULTI_off(sv);
8037     if (GvNAME_HEK(sv)) {
8038 	unshare_hek(GvNAME_HEK(sv));
8039     }
8040     isGV_with_GP_off(sv);
8041 
8042     /* need to keep SvANY(sv) in the right arena */
8043     xpvmg = new_XPVMG();
8044     StructCopy(SvANY(sv), xpvmg, XPVMG);
8045     del_XPVGV(SvANY(sv));
8046     SvANY(sv) = xpvmg;
8047 
8048     SvFLAGS(sv) &= ~SVTYPEMASK;
8049     SvFLAGS(sv) |= SVt_PVMG;
8050 
8051     /* Intentionally not calling any local SET magic, as this isn't so much a
8052        set operation as merely an internal storage change.  */
8053     sv_setsv_flags(sv, temp, 0);
8054 }
8055 
8056 /*
8057 =for apidoc sv_unref_flags
8058 
8059 Unsets the RV status of the SV, and decrements the reference count of
8060 whatever was being referenced by the RV.  This can almost be thought of
8061 as a reversal of C<newSVrv>.  The C<cflags> argument can contain
8062 C<SV_IMMEDIATE_UNREF> to force the reference count to be decremented
8063 (otherwise the decrementing is conditional on the reference count being
8064 different from one or the reference being a readonly SV).
8065 See C<SvROK_off>.
8066 
8067 =cut
8068 */
8069 
8070 void
8071 Perl_sv_unref_flags(pTHX_ SV *ref, U32 flags)
8072 {
8073     SV* const target = SvRV(ref);
8074 
8075     if (SvWEAKREF(ref)) {
8076     	sv_del_backref(target, ref);
8077 	SvWEAKREF_off(ref);
8078 	SvRV_set(ref, NULL);
8079 	return;
8080     }
8081     SvRV_set(ref, NULL);
8082     SvROK_off(ref);
8083     /* You can't have a || SvREADONLY(target) here, as $a = $$a, where $a was
8084        assigned to as BEGIN {$a = \"Foo"} will fail.  */
8085     if (SvREFCNT(target) != 1 || (flags & SV_IMMEDIATE_UNREF))
8086 	SvREFCNT_dec(target);
8087     else /* XXX Hack, but hard to make $a=$a->[1] work otherwise */
8088 	sv_2mortal(target);	/* Schedule for freeing later */
8089 }
8090 
8091 /*
8092 =for apidoc sv_untaint
8093 
8094 Untaint an SV. Use C<SvTAINTED_off> instead.
8095 =cut
8096 */
8097 
8098 void
8099 Perl_sv_untaint(pTHX_ SV *sv)
8100 {
8101     if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv)) {
8102 	MAGIC * const mg = mg_find(sv, PERL_MAGIC_taint);
8103 	if (mg)
8104 	    mg->mg_len &= ~1;
8105     }
8106 }
8107 
8108 /*
8109 =for apidoc sv_tainted
8110 
8111 Test an SV for taintedness. Use C<SvTAINTED> instead.
8112 =cut
8113 */
8114 
8115 bool
8116 Perl_sv_tainted(pTHX_ SV *sv)
8117 {
8118     if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv)) {
8119 	const MAGIC * const mg = mg_find(sv, PERL_MAGIC_taint);
8120 	if (mg && (mg->mg_len & 1) )
8121 	    return TRUE;
8122     }
8123     return FALSE;
8124 }
8125 
8126 /*
8127 =for apidoc sv_setpviv
8128 
8129 Copies an integer into the given SV, also updating its string value.
8130 Does not handle 'set' magic.  See C<sv_setpviv_mg>.
8131 
8132 =cut
8133 */
8134 
8135 void
8136 Perl_sv_setpviv(pTHX_ SV *sv, IV iv)
8137 {
8138     char buf[TYPE_CHARS(UV)];
8139     char *ebuf;
8140     char * const ptr = uiv_2buf(buf, iv, 0, 0, &ebuf);
8141 
8142     sv_setpvn(sv, ptr, ebuf - ptr);
8143 }
8144 
8145 /*
8146 =for apidoc sv_setpviv_mg
8147 
8148 Like C<sv_setpviv>, but also handles 'set' magic.
8149 
8150 =cut
8151 */
8152 
8153 void
8154 Perl_sv_setpviv_mg(pTHX_ SV *sv, IV iv)
8155 {
8156     sv_setpviv(sv, iv);
8157     SvSETMAGIC(sv);
8158 }
8159 
8160 #if defined(PERL_IMPLICIT_CONTEXT)
8161 
8162 /* pTHX_ magic can't cope with varargs, so this is a no-context
8163  * version of the main function, (which may itself be aliased to us).
8164  * Don't access this version directly.
8165  */
8166 
8167 void
8168 Perl_sv_setpvf_nocontext(SV *sv, const char* pat, ...)
8169 {
8170     dTHX;
8171     va_list args;
8172     va_start(args, pat);
8173     sv_vsetpvf(sv, pat, &args);
8174     va_end(args);
8175 }
8176 
8177 /* pTHX_ magic can't cope with varargs, so this is a no-context
8178  * version of the main function, (which may itself be aliased to us).
8179  * Don't access this version directly.
8180  */
8181 
8182 void
8183 Perl_sv_setpvf_mg_nocontext(SV *sv, const char* pat, ...)
8184 {
8185     dTHX;
8186     va_list args;
8187     va_start(args, pat);
8188     sv_vsetpvf_mg(sv, pat, &args);
8189     va_end(args);
8190 }
8191 #endif
8192 
8193 /*
8194 =for apidoc sv_setpvf
8195 
8196 Works like C<sv_catpvf> but copies the text into the SV instead of
8197 appending it.  Does not handle 'set' magic.  See C<sv_setpvf_mg>.
8198 
8199 =cut
8200 */
8201 
8202 void
8203 Perl_sv_setpvf(pTHX_ SV *sv, const char* pat, ...)
8204 {
8205     va_list args;
8206     va_start(args, pat);
8207     sv_vsetpvf(sv, pat, &args);
8208     va_end(args);
8209 }
8210 
8211 /*
8212 =for apidoc sv_vsetpvf
8213 
8214 Works like C<sv_vcatpvf> but copies the text into the SV instead of
8215 appending it.  Does not handle 'set' magic.  See C<sv_vsetpvf_mg>.
8216 
8217 Usually used via its frontend C<sv_setpvf>.
8218 
8219 =cut
8220 */
8221 
8222 void
8223 Perl_sv_vsetpvf(pTHX_ SV *sv, const char* pat, va_list* args)
8224 {
8225     sv_vsetpvfn(sv, pat, strlen(pat), args, NULL, 0, NULL);
8226 }
8227 
8228 /*
8229 =for apidoc sv_setpvf_mg
8230 
8231 Like C<sv_setpvf>, but also handles 'set' magic.
8232 
8233 =cut
8234 */
8235 
8236 void
8237 Perl_sv_setpvf_mg(pTHX_ SV *sv, const char* pat, ...)
8238 {
8239     va_list args;
8240     va_start(args, pat);
8241     sv_vsetpvf_mg(sv, pat, &args);
8242     va_end(args);
8243 }
8244 
8245 /*
8246 =for apidoc sv_vsetpvf_mg
8247 
8248 Like C<sv_vsetpvf>, but also handles 'set' magic.
8249 
8250 Usually used via its frontend C<sv_setpvf_mg>.
8251 
8252 =cut
8253 */
8254 
8255 void
8256 Perl_sv_vsetpvf_mg(pTHX_ SV *sv, const char* pat, va_list* args)
8257 {
8258     sv_vsetpvfn(sv, pat, strlen(pat), args, NULL, 0, NULL);
8259     SvSETMAGIC(sv);
8260 }
8261 
8262 #if defined(PERL_IMPLICIT_CONTEXT)
8263 
8264 /* pTHX_ magic can't cope with varargs, so this is a no-context
8265  * version of the main function, (which may itself be aliased to us).
8266  * Don't access this version directly.
8267  */
8268 
8269 void
8270 Perl_sv_catpvf_nocontext(SV *sv, const char* pat, ...)
8271 {
8272     dTHX;
8273     va_list args;
8274     va_start(args, pat);
8275     sv_vcatpvf(sv, pat, &args);
8276     va_end(args);
8277 }
8278 
8279 /* pTHX_ magic can't cope with varargs, so this is a no-context
8280  * version of the main function, (which may itself be aliased to us).
8281  * Don't access this version directly.
8282  */
8283 
8284 void
8285 Perl_sv_catpvf_mg_nocontext(SV *sv, const char* pat, ...)
8286 {
8287     dTHX;
8288     va_list args;
8289     va_start(args, pat);
8290     sv_vcatpvf_mg(sv, pat, &args);
8291     va_end(args);
8292 }
8293 #endif
8294 
8295 /*
8296 =for apidoc sv_catpvf
8297 
8298 Processes its arguments like C<sprintf> and appends the formatted
8299 output to an SV.  If the appended data contains "wide" characters
8300 (including, but not limited to, SVs with a UTF-8 PV formatted with %s,
8301 and characters >255 formatted with %c), the original SV might get
8302 upgraded to UTF-8.  Handles 'get' magic, but not 'set' magic.  See
8303 C<sv_catpvf_mg>. If the original SV was UTF-8, the pattern should be
8304 valid UTF-8; if the original SV was bytes, the pattern should be too.
8305 
8306 =cut */
8307 
8308 void
8309 Perl_sv_catpvf(pTHX_ SV *sv, const char* pat, ...)
8310 {
8311     va_list args;
8312     va_start(args, pat);
8313     sv_vcatpvf(sv, pat, &args);
8314     va_end(args);
8315 }
8316 
8317 /*
8318 =for apidoc sv_vcatpvf
8319 
8320 Processes its arguments like C<vsprintf> and appends the formatted output
8321 to an SV.  Does not handle 'set' magic.  See C<sv_vcatpvf_mg>.
8322 
8323 Usually used via its frontend C<sv_catpvf>.
8324 
8325 =cut
8326 */
8327 
8328 void
8329 Perl_sv_vcatpvf(pTHX_ SV *sv, const char* pat, va_list* args)
8330 {
8331     sv_vcatpvfn(sv, pat, strlen(pat), args, NULL, 0, NULL);
8332 }
8333 
8334 /*
8335 =for apidoc sv_catpvf_mg
8336 
8337 Like C<sv_catpvf>, but also handles 'set' magic.
8338 
8339 =cut
8340 */
8341 
8342 void
8343 Perl_sv_catpvf_mg(pTHX_ SV *sv, const char* pat, ...)
8344 {
8345     va_list args;
8346     va_start(args, pat);
8347     sv_vcatpvf_mg(sv, pat, &args);
8348     va_end(args);
8349 }
8350 
8351 /*
8352 =for apidoc sv_vcatpvf_mg
8353 
8354 Like C<sv_vcatpvf>, but also handles 'set' magic.
8355 
8356 Usually used via its frontend C<sv_catpvf_mg>.
8357 
8358 =cut
8359 */
8360 
8361 void
8362 Perl_sv_vcatpvf_mg(pTHX_ SV *sv, const char* pat, va_list* args)
8363 {
8364     sv_vcatpvfn(sv, pat, strlen(pat), args, NULL, 0, NULL);
8365     SvSETMAGIC(sv);
8366 }
8367 
8368 /*
8369 =for apidoc sv_vsetpvfn
8370 
8371 Works like C<sv_vcatpvfn> but copies the text into the SV instead of
8372 appending it.
8373 
8374 Usually used via one of its frontends C<sv_vsetpvf> and C<sv_vsetpvf_mg>.
8375 
8376 =cut
8377 */
8378 
8379 void
8380 Perl_sv_vsetpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV **svargs, I32 svmax, bool *maybe_tainted)
8381 {
8382     sv_setpvn(sv, "", 0);
8383     sv_vcatpvfn(sv, pat, patlen, args, svargs, svmax, maybe_tainted);
8384 }
8385 
8386 STATIC I32
8387 S_expect_number(pTHX_ char** pattern)
8388 {
8389     dVAR;
8390     I32 var = 0;
8391     switch (**pattern) {
8392     case '1': case '2': case '3':
8393     case '4': case '5': case '6':
8394     case '7': case '8': case '9':
8395 	var = *(*pattern)++ - '0';
8396 	while (isDIGIT(**pattern)) {
8397 	    const I32 tmp = var * 10 + (*(*pattern)++ - '0');
8398 	    if (tmp < var)
8399 		Perl_croak(aTHX_ "Integer overflow in format string for %s", (PL_op ? OP_NAME(PL_op) : "sv_vcatpvfn"));
8400 	    var = tmp;
8401 	}
8402     }
8403     return var;
8404 }
8405 
8406 STATIC char *
8407 S_F0convert(NV nv, char *endbuf, STRLEN *len)
8408 {
8409     const int neg = nv < 0;
8410     UV uv;
8411 
8412     if (neg)
8413 	nv = -nv;
8414     if (nv < UV_MAX) {
8415 	char *p = endbuf;
8416 	nv += 0.5;
8417 	uv = (UV)nv;
8418 	if (uv & 1 && uv == nv)
8419 	    uv--;			/* Round to even */
8420 	do {
8421 	    const unsigned dig = uv % 10;
8422 	    *--p = '0' + dig;
8423 	} while (uv /= 10);
8424 	if (neg)
8425 	    *--p = '-';
8426 	*len = endbuf - p;
8427 	return p;
8428     }
8429     return NULL;
8430 }
8431 
8432 
8433 /*
8434 =for apidoc sv_vcatpvfn
8435 
8436 Processes its arguments like C<vsprintf> and appends the formatted output
8437 to an SV.  Uses an array of SVs if the C style variable argument list is
8438 missing (NULL).  When running with taint checks enabled, indicates via
8439 C<maybe_tainted> if results are untrustworthy (often due to the use of
8440 locales).
8441 
8442 Usually used via one of its frontends C<sv_vcatpvf> and C<sv_vcatpvf_mg>.
8443 
8444 =cut
8445 */
8446 
8447 
8448 #define VECTORIZE_ARGS	vecsv = va_arg(*args, SV*);\
8449 			vecstr = (U8*)SvPV_const(vecsv,veclen);\
8450 			vec_utf8 = DO_UTF8(vecsv);
8451 
8452 /* XXX maybe_tainted is never assigned to, so the doc above is lying. */
8453 
8454 void
8455 Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV **svargs, I32 svmax, bool *maybe_tainted)
8456 {
8457     dVAR;
8458     char *p;
8459     char *q;
8460     const char *patend;
8461     STRLEN origlen;
8462     I32 svix = 0;
8463     static const char nullstr[] = "(null)";
8464     SV *argsv = NULL;
8465     bool has_utf8 = DO_UTF8(sv);    /* has the result utf8? */
8466     const bool pat_utf8 = has_utf8; /* the pattern is in utf8? */
8467     SV *nsv = NULL;
8468     /* Times 4: a decimal digit takes more than 3 binary digits.
8469      * NV_DIG: mantissa takes than many decimal digits.
8470      * Plus 32: Playing safe. */
8471     char ebuf[IV_DIG * 4 + NV_DIG + 32];
8472     /* large enough for "%#.#f" --chip */
8473     /* what about long double NVs? --jhi */
8474 
8475     PERL_UNUSED_ARG(maybe_tainted);
8476 
8477     /* no matter what, this is a string now */
8478     (void)SvPV_force(sv, origlen);
8479 
8480     /* special-case "", "%s", and "%-p" (SVf - see below) */
8481     if (patlen == 0)
8482 	return;
8483     if (patlen == 2 && pat[0] == '%' && pat[1] == 's') {
8484 	if (args) {
8485 	    const char * const s = va_arg(*args, char*);
8486 	    sv_catpv(sv, s ? s : nullstr);
8487 	}
8488 	else if (svix < svmax) {
8489 	    sv_catsv(sv, *svargs);
8490 	}
8491 	return;
8492     }
8493     if (args && patlen == 3 && pat[0] == '%' &&
8494 		pat[1] == '-' && pat[2] == 'p') {
8495 	argsv = (SV*)va_arg(*args, void*);
8496 	sv_catsv(sv, argsv);
8497 	return;
8498     }
8499 
8500 #ifndef USE_LONG_DOUBLE
8501     /* special-case "%.<number>[gf]" */
8502     if ( !args && patlen <= 5 && pat[0] == '%' && pat[1] == '.'
8503 	 && (pat[patlen-1] == 'g' || pat[patlen-1] == 'f') ) {
8504 	unsigned digits = 0;
8505 	const char *pp;
8506 
8507 	pp = pat + 2;
8508 	while (*pp >= '0' && *pp <= '9')
8509 	    digits = 10 * digits + (*pp++ - '0');
8510 	if (pp - pat == (int)patlen - 1) {
8511 	    NV nv;
8512 
8513 	    if (svix < svmax)
8514 		nv = SvNV(*svargs);
8515 	    else
8516 		return;
8517 	    if (*pp == 'g') {
8518 		/* Add check for digits != 0 because it seems that some
8519 		   gconverts are buggy in this case, and we don't yet have
8520 		   a Configure test for this.  */
8521 		if (digits && digits < sizeof(ebuf) - NV_DIG - 10) {
8522 		     /* 0, point, slack */
8523 		    Gconvert(nv, (int)digits, 0, ebuf);
8524 		    sv_catpv(sv, ebuf);
8525 		    if (*ebuf)	/* May return an empty string for digits==0 */
8526 			return;
8527 		}
8528 	    } else if (!digits) {
8529 		STRLEN l;
8530 
8531 		if ((p = F0convert(nv, ebuf + sizeof ebuf, &l))) {
8532 		    sv_catpvn(sv, p, l);
8533 		    return;
8534 		}
8535 	    }
8536 	}
8537     }
8538 #endif /* !USE_LONG_DOUBLE */
8539 
8540     if (!args && svix < svmax && DO_UTF8(*svargs))
8541 	has_utf8 = TRUE;
8542 
8543     patend = (char*)pat + patlen;
8544     for (p = (char*)pat; p < patend; p = q) {
8545 	bool alt = FALSE;
8546 	bool left = FALSE;
8547 	bool vectorize = FALSE;
8548 	bool vectorarg = FALSE;
8549 	bool vec_utf8 = FALSE;
8550 	char fill = ' ';
8551 	char plus = 0;
8552 	char intsize = 0;
8553 	STRLEN width = 0;
8554 	STRLEN zeros = 0;
8555 	bool has_precis = FALSE;
8556 	STRLEN precis = 0;
8557 	const I32 osvix = svix;
8558 	bool is_utf8 = FALSE;  /* is this item utf8?   */
8559 #ifdef HAS_LDBL_SPRINTF_BUG
8560 	/* This is to try to fix a bug with irix/nonstop-ux/powerux and
8561 	   with sfio - Allen <allens@cpan.org> */
8562 	bool fix_ldbl_sprintf_bug = FALSE;
8563 #endif
8564 
8565 	char esignbuf[4];
8566 	U8 utf8buf[UTF8_MAXBYTES+1];
8567 	STRLEN esignlen = 0;
8568 
8569 	const char *eptr = NULL;
8570 	STRLEN elen = 0;
8571 	SV *vecsv = NULL;
8572 	const U8 *vecstr = NULL;
8573 	STRLEN veclen = 0;
8574 	char c = 0;
8575 	int i;
8576 	unsigned base = 0;
8577 	IV iv = 0;
8578 	UV uv = 0;
8579 	/* we need a long double target in case HAS_LONG_DOUBLE but
8580 	   not USE_LONG_DOUBLE
8581 	*/
8582 #if defined(HAS_LONG_DOUBLE) && LONG_DOUBLESIZE > DOUBLESIZE
8583 	long double nv;
8584 #else
8585 	NV nv;
8586 #endif
8587 	STRLEN have;
8588 	STRLEN need;
8589 	STRLEN gap;
8590 	const char *dotstr = ".";
8591 	STRLEN dotstrlen = 1;
8592 	I32 efix = 0; /* explicit format parameter index */
8593 	I32 ewix = 0; /* explicit width index */
8594 	I32 epix = 0; /* explicit precision index */
8595 	I32 evix = 0; /* explicit vector index */
8596 	bool asterisk = FALSE;
8597 
8598 	/* echo everything up to the next format specification */
8599 	for (q = p; q < patend && *q != '%'; ++q) ;
8600 	if (q > p) {
8601 	    if (has_utf8 && !pat_utf8)
8602 		sv_catpvn_utf8_upgrade(sv, p, q - p, nsv);
8603 	    else
8604 		sv_catpvn(sv, p, q - p);
8605 	    p = q;
8606 	}
8607 	if (q++ >= patend)
8608 	    break;
8609 
8610 /*
8611     We allow format specification elements in this order:
8612 	\d+\$              explicit format parameter index
8613 	[-+ 0#]+           flags
8614 	v|\*(\d+\$)?v      vector with optional (optionally specified) arg
8615 	0		   flag (as above): repeated to allow "v02"
8616 	\d+|\*(\d+\$)?     width using optional (optionally specified) arg
8617 	\.(\d*|\*(\d+\$)?) precision using optional (optionally specified) arg
8618 	[hlqLV]            size
8619     [%bcdefginopsuxDFOUX] format (mandatory)
8620 */
8621 
8622 	if (args) {
8623 /*
8624 	As of perl5.9.3, printf format checking is on by default.
8625 	Internally, perl uses %p formats to provide an escape to
8626 	some extended formatting.  This block deals with those
8627 	extensions: if it does not match, (char*)q is reset and
8628 	the normal format processing code is used.
8629 
8630 	Currently defined extensions are:
8631 		%p		include pointer address (standard)
8632 		%-p	(SVf)	include an SV (previously %_)
8633 		%-<num>p	include an SV with precision <num>
8634 		%<num>p		reserved for future extensions
8635 
8636 	Robin Barker 2005-07-14
8637 
8638 		%1p	(VDf)	removed.  RMB 2007-10-19
8639 */
8640  	    char* r = q;
8641 	    bool sv = FALSE;
8642 	    STRLEN n = 0;
8643 	    if (*q == '-')
8644 		sv = *q++;
8645 	    n = expect_number(&q);
8646 	    if (*q++ == 'p') {
8647 		if (sv) {			/* SVf */
8648 		    if (n) {
8649 			precis = n;
8650 			has_precis = TRUE;
8651 		    }
8652 		    argsv = (SV*)va_arg(*args, void*);
8653 		    eptr = SvPV_const(argsv, elen);
8654 		    if (DO_UTF8(argsv))
8655 			is_utf8 = TRUE;
8656 		    goto string;
8657 		}
8658 		else if (n) {
8659 		    if (ckWARN_d(WARN_INTERNAL))
8660 			Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
8661 			"internal %%<num>p might conflict with future printf extensions");
8662 		}
8663 	    }
8664 	    q = r;
8665 	}
8666 
8667 	if ( (width = expect_number(&q)) ) {
8668 	    if (*q == '$') {
8669 		++q;
8670 		efix = width;
8671 	    } else {
8672 		goto gotwidth;
8673 	    }
8674 	}
8675 
8676 	/* FLAGS */
8677 
8678 	while (*q) {
8679 	    switch (*q) {
8680 	    case ' ':
8681 	    case '+':
8682 		if (plus == '+' && *q == ' ') /* '+' over ' ' */
8683 		    q++;
8684 		else
8685 		    plus = *q++;
8686 		continue;
8687 
8688 	    case '-':
8689 		left = TRUE;
8690 		q++;
8691 		continue;
8692 
8693 	    case '0':
8694 		fill = *q++;
8695 		continue;
8696 
8697 	    case '#':
8698 		alt = TRUE;
8699 		q++;
8700 		continue;
8701 
8702 	    default:
8703 		break;
8704 	    }
8705 	    break;
8706 	}
8707 
8708       tryasterisk:
8709 	if (*q == '*') {
8710 	    q++;
8711 	    if ( (ewix = expect_number(&q)) )
8712 		if (*q++ != '$')
8713 		    goto unknown;
8714 	    asterisk = TRUE;
8715 	}
8716 	if (*q == 'v') {
8717 	    q++;
8718 	    if (vectorize)
8719 		goto unknown;
8720 	    if ((vectorarg = asterisk)) {
8721 		evix = ewix;
8722 		ewix = 0;
8723 		asterisk = FALSE;
8724 	    }
8725 	    vectorize = TRUE;
8726 	    goto tryasterisk;
8727 	}
8728 
8729 	if (!asterisk)
8730 	{
8731 	    if( *q == '0' )
8732 		fill = *q++;
8733 	    width = expect_number(&q);
8734 	}
8735 
8736 	if (vectorize) {
8737 	    if (vectorarg) {
8738 		if (args)
8739 		    vecsv = va_arg(*args, SV*);
8740 		else if (evix) {
8741 		    vecsv = (evix > 0 && evix <= svmax)
8742 			? svargs[evix-1] : &PL_sv_undef;
8743 		} else {
8744 		    vecsv = svix < svmax ? svargs[svix++] : &PL_sv_undef;
8745 		}
8746 		dotstr = SvPV_const(vecsv, dotstrlen);
8747 		/* Keep the DO_UTF8 test *after* the SvPV call, else things go
8748 		   bad with tied or overloaded values that return UTF8.  */
8749 		if (DO_UTF8(vecsv))
8750 		    is_utf8 = TRUE;
8751 		else if (has_utf8) {
8752 		    vecsv = sv_mortalcopy(vecsv);
8753 		    sv_utf8_upgrade(vecsv);
8754 		    dotstr = SvPV_const(vecsv, dotstrlen);
8755 		    is_utf8 = TRUE;
8756 		}
8757 	    }
8758 	    if (args) {
8759 		VECTORIZE_ARGS
8760 	    }
8761 	    else if (efix ? (efix > 0 && efix <= svmax) : svix < svmax) {
8762 		vecsv = svargs[efix ? efix-1 : svix++];
8763 		vecstr = (U8*)SvPV_const(vecsv,veclen);
8764 		vec_utf8 = DO_UTF8(vecsv);
8765 
8766 		/* if this is a version object, we need to convert
8767 		 * back into v-string notation and then let the
8768 		 * vectorize happen normally
8769 		 */
8770 		if (sv_derived_from(vecsv, "version")) {
8771 		    char *version = savesvpv(vecsv);
8772 		    if ( hv_exists((HV*)SvRV(vecsv), "alpha", 5 ) ) {
8773 			Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
8774 			"vector argument not supported with alpha versions");
8775 			goto unknown;
8776 		    }
8777 		    vecsv = sv_newmortal();
8778 		    scan_vstring(version, version + veclen, vecsv);
8779 		    vecstr = (U8*)SvPV_const(vecsv, veclen);
8780 		    vec_utf8 = DO_UTF8(vecsv);
8781 		    Safefree(version);
8782 		}
8783 	    }
8784 	    else {
8785 		vecstr = (U8*)"";
8786 		veclen = 0;
8787 	    }
8788 	}
8789 
8790 	if (asterisk) {
8791 	    if (args)
8792 		i = va_arg(*args, int);
8793 	    else
8794 		i = (ewix ? ewix <= svmax : svix < svmax) ?
8795 		    SvIVx(svargs[ewix ? ewix-1 : svix++]) : 0;
8796 	    left |= (i < 0);
8797 	    width = (i < 0) ? -i : i;
8798 	}
8799       gotwidth:
8800 
8801 	/* PRECISION */
8802 
8803 	if (*q == '.') {
8804 	    q++;
8805 	    if (*q == '*') {
8806 		q++;
8807 		if ( ((epix = expect_number(&q))) && (*q++ != '$') )
8808 		    goto unknown;
8809 		/* XXX: todo, support specified precision parameter */
8810 		if (epix)
8811 		    goto unknown;
8812 		if (args)
8813 		    i = va_arg(*args, int);
8814 		else
8815 		    i = (ewix ? ewix <= svmax : svix < svmax)
8816 			? SvIVx(svargs[ewix ? ewix-1 : svix++]) : 0;
8817 		precis = i;
8818 		has_precis = !(i < 0);
8819 	    }
8820 	    else {
8821 		precis = 0;
8822 		while (isDIGIT(*q))
8823 		    precis = precis * 10 + (*q++ - '0');
8824 		has_precis = TRUE;
8825 	    }
8826 	}
8827 
8828 	/* SIZE */
8829 
8830 	switch (*q) {
8831 #ifdef WIN32
8832 	case 'I':			/* Ix, I32x, and I64x */
8833 #  ifdef WIN64
8834 	    if (q[1] == '6' && q[2] == '4') {
8835 		q += 3;
8836 		intsize = 'q';
8837 		break;
8838 	    }
8839 #  endif
8840 	    if (q[1] == '3' && q[2] == '2') {
8841 		q += 3;
8842 		break;
8843 	    }
8844 #  ifdef WIN64
8845 	    intsize = 'q';
8846 #  endif
8847 	    q++;
8848 	    break;
8849 #endif
8850 #if defined(HAS_QUAD) || defined(HAS_LONG_DOUBLE)
8851 	case 'L':			/* Ld */
8852 	    /*FALLTHROUGH*/
8853 #ifdef HAS_QUAD
8854 	case 'q':			/* qd */
8855 #endif
8856 	    intsize = 'q';
8857 	    q++;
8858 	    break;
8859 #endif
8860 	case 'l':
8861 #if defined(HAS_QUAD) || defined(HAS_LONG_DOUBLE)
8862 	    if (*(q + 1) == 'l') {	/* lld, llf */
8863 		intsize = 'q';
8864 		q += 2;
8865 		break;
8866 	     }
8867 #endif
8868 	    /*FALLTHROUGH*/
8869 	case 'h':
8870 	    /*FALLTHROUGH*/
8871 	case 'V':
8872 	    intsize = *q++;
8873 	    break;
8874 	}
8875 
8876 	/* CONVERSION */
8877 
8878 	if (*q == '%') {
8879 	    eptr = q++;
8880 	    elen = 1;
8881 	    if (vectorize) {
8882 		c = '%';
8883 		goto unknown;
8884 	    }
8885 	    goto string;
8886 	}
8887 
8888 	if (!vectorize && !args) {
8889 	    if (efix) {
8890 		const I32 i = efix-1;
8891 		argsv = (i >= 0 && i < svmax) ? svargs[i] : &PL_sv_undef;
8892 	    } else {
8893 		argsv = (svix >= 0 && svix < svmax)
8894 		    ? svargs[svix++] : &PL_sv_undef;
8895 	    }
8896 	}
8897 
8898 	switch (c = *q++) {
8899 
8900 	    /* STRINGS */
8901 
8902 	case 'c':
8903 	    if (vectorize)
8904 		goto unknown;
8905 	    uv = (args) ? va_arg(*args, int) : SvIV(argsv);
8906 	    if ((uv > 255 ||
8907 		 (!UNI_IS_INVARIANT(uv) && SvUTF8(sv)))
8908 		&& !IN_BYTES) {
8909 		eptr = (char*)utf8buf;
8910 		elen = uvchr_to_utf8((U8*)eptr, uv) - utf8buf;
8911 		is_utf8 = TRUE;
8912 	    }
8913 	    else {
8914 		c = (char)uv;
8915 		eptr = &c;
8916 		elen = 1;
8917 	    }
8918 	    goto string;
8919 
8920 	case 's':
8921 	    if (vectorize)
8922 		goto unknown;
8923 	    if (args) {
8924 		eptr = va_arg(*args, char*);
8925 		if (eptr)
8926 #ifdef MACOS_TRADITIONAL
8927 		  /* On MacOS, %#s format is used for Pascal strings */
8928 		  if (alt)
8929 		    elen = *eptr++;
8930 		  else
8931 #endif
8932 		    elen = strlen(eptr);
8933 		else {
8934 		    eptr = (char *)nullstr;
8935 		    elen = sizeof nullstr - 1;
8936 		}
8937 	    }
8938 	    else {
8939 		eptr = SvPV_const(argsv, elen);
8940 		if (DO_UTF8(argsv)) {
8941 		    I32 old_precis = precis;
8942 		    if (has_precis && precis < elen) {
8943 			I32 p = precis;
8944 			sv_pos_u2b(argsv, &p, 0); /* sticks at end */
8945 			precis = p;
8946 		    }
8947 		    if (width) { /* fudge width (can't fudge elen) */
8948 			if (has_precis && precis < elen)
8949 			    width += precis - old_precis;
8950 			else
8951 			    width += elen - sv_len_utf8(argsv);
8952 		    }
8953 		    is_utf8 = TRUE;
8954 		}
8955 	    }
8956 
8957 	string:
8958 	    if (has_precis && elen > precis)
8959 		elen = precis;
8960 	    break;
8961 
8962 	    /* INTEGERS */
8963 
8964 	case 'p':
8965 	    if (alt || vectorize)
8966 		goto unknown;
8967 	    uv = PTR2UV(args ? va_arg(*args, void*) : argsv);
8968 	    base = 16;
8969 	    goto integer;
8970 
8971 	case 'D':
8972 #ifdef IV_IS_QUAD
8973 	    intsize = 'q';
8974 #else
8975 	    intsize = 'l';
8976 #endif
8977 	    /*FALLTHROUGH*/
8978 	case 'd':
8979 	case 'i':
8980 #if vdNUMBER
8981 	format_vd:
8982 #endif
8983 	    if (vectorize) {
8984 		STRLEN ulen;
8985 		if (!veclen)
8986 		    continue;
8987 		if (vec_utf8)
8988 		    uv = utf8n_to_uvchr(vecstr, veclen, &ulen,
8989 					UTF8_ALLOW_ANYUV);
8990 		else {
8991 		    uv = *vecstr;
8992 		    ulen = 1;
8993 		}
8994 		vecstr += ulen;
8995 		veclen -= ulen;
8996 		if (plus)
8997 		     esignbuf[esignlen++] = plus;
8998 	    }
8999 	    else if (args) {
9000 		switch (intsize) {
9001 		case 'h':	iv = (short)va_arg(*args, int); break;
9002 		case 'l':	iv = va_arg(*args, long); break;
9003 		case 'V':	iv = va_arg(*args, IV); break;
9004 		default:	iv = va_arg(*args, int); break;
9005 #ifdef HAS_QUAD
9006 		case 'q':	iv = va_arg(*args, Quad_t); break;
9007 #endif
9008 		}
9009 	    }
9010 	    else {
9011 		IV tiv = SvIV(argsv); /* work around GCC bug #13488 */
9012 		switch (intsize) {
9013 		case 'h':	iv = (short)tiv; break;
9014 		case 'l':	iv = (long)tiv; break;
9015 		case 'V':
9016 		default:	iv = tiv; break;
9017 #ifdef HAS_QUAD
9018 		case 'q':	iv = (Quad_t)tiv; break;
9019 #endif
9020 		}
9021 	    }
9022 	    if ( !vectorize )	/* we already set uv above */
9023 	    {
9024 		if (iv >= 0) {
9025 		    uv = iv;
9026 		    if (plus)
9027 			esignbuf[esignlen++] = plus;
9028 		}
9029 		else {
9030 		    uv = -iv;
9031 		    esignbuf[esignlen++] = '-';
9032 		}
9033 	    }
9034 	    base = 10;
9035 	    goto integer;
9036 
9037 	case 'U':
9038 #ifdef IV_IS_QUAD
9039 	    intsize = 'q';
9040 #else
9041 	    intsize = 'l';
9042 #endif
9043 	    /*FALLTHROUGH*/
9044 	case 'u':
9045 	    base = 10;
9046 	    goto uns_integer;
9047 
9048 	case 'B':
9049 	case 'b':
9050 	    base = 2;
9051 	    goto uns_integer;
9052 
9053 	case 'O':
9054 #ifdef IV_IS_QUAD
9055 	    intsize = 'q';
9056 #else
9057 	    intsize = 'l';
9058 #endif
9059 	    /*FALLTHROUGH*/
9060 	case 'o':
9061 	    base = 8;
9062 	    goto uns_integer;
9063 
9064 	case 'X':
9065 	case 'x':
9066 	    base = 16;
9067 
9068 	uns_integer:
9069 	    if (vectorize) {
9070 		STRLEN ulen;
9071 	vector:
9072 		if (!veclen)
9073 		    continue;
9074 		if (vec_utf8)
9075 		    uv = utf8n_to_uvchr(vecstr, veclen, &ulen,
9076 					UTF8_ALLOW_ANYUV);
9077 		else {
9078 		    uv = *vecstr;
9079 		    ulen = 1;
9080 		}
9081 		vecstr += ulen;
9082 		veclen -= ulen;
9083 	    }
9084 	    else if (args) {
9085 		switch (intsize) {
9086 		case 'h':  uv = (unsigned short)va_arg(*args, unsigned); break;
9087 		case 'l':  uv = va_arg(*args, unsigned long); break;
9088 		case 'V':  uv = va_arg(*args, UV); break;
9089 		default:   uv = va_arg(*args, unsigned); break;
9090 #ifdef HAS_QUAD
9091 		case 'q':  uv = va_arg(*args, Uquad_t); break;
9092 #endif
9093 		}
9094 	    }
9095 	    else {
9096 		UV tuv = SvUV(argsv); /* work around GCC bug #13488 */
9097 		switch (intsize) {
9098 		case 'h':	uv = (unsigned short)tuv; break;
9099 		case 'l':	uv = (unsigned long)tuv; break;
9100 		case 'V':
9101 		default:	uv = tuv; break;
9102 #ifdef HAS_QUAD
9103 		case 'q':	uv = (Uquad_t)tuv; break;
9104 #endif
9105 		}
9106 	    }
9107 
9108 	integer:
9109 	    {
9110 		char *ptr = ebuf + sizeof ebuf;
9111 		bool tempalt = uv ? alt : FALSE; /* Vectors can't change alt */
9112 		zeros = 0;
9113 
9114 		switch (base) {
9115 		    unsigned dig;
9116 		case 16:
9117 		    p = (char *)((c == 'X') ? PL_hexdigit + 16 : PL_hexdigit);
9118 		    do {
9119 			dig = uv & 15;
9120 			*--ptr = p[dig];
9121 		    } while (uv >>= 4);
9122 		    if (tempalt) {
9123 			esignbuf[esignlen++] = '0';
9124 			esignbuf[esignlen++] = c;  /* 'x' or 'X' */
9125 		    }
9126 		    break;
9127 		case 8:
9128 		    do {
9129 			dig = uv & 7;
9130 			*--ptr = '0' + dig;
9131 		    } while (uv >>= 3);
9132 		    if (alt && *ptr != '0')
9133 			*--ptr = '0';
9134 		    break;
9135 		case 2:
9136 		    do {
9137 			dig = uv & 1;
9138 			*--ptr = '0' + dig;
9139 		    } while (uv >>= 1);
9140 		    if (tempalt) {
9141 			esignbuf[esignlen++] = '0';
9142 			esignbuf[esignlen++] = c;
9143 		    }
9144 		    break;
9145 		default:		/* it had better be ten or less */
9146 		    do {
9147 			dig = uv % base;
9148 			*--ptr = '0' + dig;
9149 		    } while (uv /= base);
9150 		    break;
9151 		}
9152 		elen = (ebuf + sizeof ebuf) - ptr;
9153 		eptr = ptr;
9154 		if (has_precis) {
9155 		    if (precis > elen)
9156 			zeros = precis - elen;
9157 		    else if (precis == 0 && elen == 1 && *eptr == '0'
9158 			     && !(base == 8 && alt)) /* "%#.0o" prints "0" */
9159 			elen = 0;
9160 
9161 		/* a precision nullifies the 0 flag. */
9162 		    if (fill == '0')
9163 			fill = ' ';
9164 		}
9165 	    }
9166 	    break;
9167 
9168 	    /* FLOATING POINT */
9169 
9170 	case 'F':
9171 	    c = 'f';		/* maybe %F isn't supported here */
9172 	    /*FALLTHROUGH*/
9173 	case 'e': case 'E':
9174 	case 'f':
9175 	case 'g': case 'G':
9176 	    if (vectorize)
9177 		goto unknown;
9178 
9179 	    /* This is evil, but floating point is even more evil */
9180 
9181 	    /* for SV-style calling, we can only get NV
9182 	       for C-style calling, we assume %f is double;
9183 	       for simplicity we allow any of %Lf, %llf, %qf for long double
9184 	    */
9185 	    switch (intsize) {
9186 	    case 'V':
9187 #if defined(USE_LONG_DOUBLE)
9188 		intsize = 'q';
9189 #endif
9190 		break;
9191 /* [perl #20339] - we should accept and ignore %lf rather than die */
9192 	    case 'l':
9193 		/*FALLTHROUGH*/
9194 	    default:
9195 #if defined(USE_LONG_DOUBLE)
9196 		intsize = args ? 0 : 'q';
9197 #endif
9198 		break;
9199 	    case 'q':
9200 #if defined(HAS_LONG_DOUBLE)
9201 		break;
9202 #else
9203 		/*FALLTHROUGH*/
9204 #endif
9205 	    case 'h':
9206 		goto unknown;
9207 	    }
9208 
9209 	    /* now we need (long double) if intsize == 'q', else (double) */
9210 	    nv = (args) ?
9211 #if LONG_DOUBLESIZE > DOUBLESIZE
9212 		intsize == 'q' ?
9213 		    va_arg(*args, long double) :
9214 		    va_arg(*args, double)
9215 #else
9216 		    va_arg(*args, double)
9217 #endif
9218 		: SvNV(argsv);
9219 
9220 	    need = 0;
9221 	    /* nv * 0 will be NaN for NaN, +Inf and -Inf, and 0 for anything
9222 	       else. frexp() has some unspecified behaviour for those three */
9223 	    if (c != 'e' && c != 'E' && (nv * 0) == 0) {
9224 		i = PERL_INT_MIN;
9225 		/* FIXME: if HAS_LONG_DOUBLE but not USE_LONG_DOUBLE this
9226 		   will cast our (long double) to (double) */
9227 		(void)Perl_frexp(nv, &i);
9228 		if (i == PERL_INT_MIN)
9229 		    Perl_die(aTHX_ "panic: frexp");
9230 		if (i > 0)
9231 		    need = BIT_DIGITS(i);
9232 	    }
9233 	    need += has_precis ? precis : 6; /* known default */
9234 
9235 	    if (need < width)
9236 		need = width;
9237 
9238 #ifdef HAS_LDBL_SPRINTF_BUG
9239 	    /* This is to try to fix a bug with irix/nonstop-ux/powerux and
9240 	       with sfio - Allen <allens@cpan.org> */
9241 
9242 #  ifdef DBL_MAX
9243 #    define MY_DBL_MAX DBL_MAX
9244 #  else /* XXX guessing! HUGE_VAL may be defined as infinity, so not using */
9245 #    if DOUBLESIZE >= 8
9246 #      define MY_DBL_MAX 1.7976931348623157E+308L
9247 #    else
9248 #      define MY_DBL_MAX 3.40282347E+38L
9249 #    endif
9250 #  endif
9251 
9252 #  ifdef HAS_LDBL_SPRINTF_BUG_LESS1 /* only between -1L & 1L - Allen */
9253 #    define MY_DBL_MAX_BUG 1L
9254 #  else
9255 #    define MY_DBL_MAX_BUG MY_DBL_MAX
9256 #  endif
9257 
9258 #  ifdef DBL_MIN
9259 #    define MY_DBL_MIN DBL_MIN
9260 #  else  /* XXX guessing! -Allen */
9261 #    if DOUBLESIZE >= 8
9262 #      define MY_DBL_MIN 2.2250738585072014E-308L
9263 #    else
9264 #      define MY_DBL_MIN 1.17549435E-38L
9265 #    endif
9266 #  endif
9267 
9268 	    if ((intsize == 'q') && (c == 'f') &&
9269 		((nv < MY_DBL_MAX_BUG) && (nv > -MY_DBL_MAX_BUG)) &&
9270 		(need < DBL_DIG)) {
9271 		/* it's going to be short enough that
9272 		 * long double precision is not needed */
9273 
9274 		if ((nv <= 0L) && (nv >= -0L))
9275 		    fix_ldbl_sprintf_bug = TRUE; /* 0 is 0 - easiest */
9276 		else {
9277 		    /* would use Perl_fp_class as a double-check but not
9278 		     * functional on IRIX - see perl.h comments */
9279 
9280 		    if ((nv >= MY_DBL_MIN) || (nv <= -MY_DBL_MIN)) {
9281 			/* It's within the range that a double can represent */
9282 #if defined(DBL_MAX) && !defined(DBL_MIN)
9283 			if ((nv >= ((long double)1/DBL_MAX)) ||
9284 			    (nv <= (-(long double)1/DBL_MAX)))
9285 #endif
9286 			fix_ldbl_sprintf_bug = TRUE;
9287 		    }
9288 		}
9289 		if (fix_ldbl_sprintf_bug == TRUE) {
9290 		    double temp;
9291 
9292 		    intsize = 0;
9293 		    temp = (double)nv;
9294 		    nv = (NV)temp;
9295 		}
9296 	    }
9297 
9298 #  undef MY_DBL_MAX
9299 #  undef MY_DBL_MAX_BUG
9300 #  undef MY_DBL_MIN
9301 
9302 #endif /* HAS_LDBL_SPRINTF_BUG */
9303 
9304 	    need += 20; /* fudge factor */
9305 	    if (PL_efloatsize < need) {
9306 		Safefree(PL_efloatbuf);
9307 		PL_efloatsize = need + 20; /* more fudge */
9308 		Newx(PL_efloatbuf, PL_efloatsize, char);
9309 		PL_efloatbuf[0] = '\0';
9310 	    }
9311 
9312 	    if ( !(width || left || plus || alt) && fill != '0'
9313 		 && has_precis && intsize != 'q' ) {	/* Shortcuts */
9314 		/* See earlier comment about buggy Gconvert when digits,
9315 		   aka precis is 0  */
9316 		if ( c == 'g' && precis) {
9317 		    Gconvert((NV)nv, (int)precis, 0, PL_efloatbuf);
9318 		    /* May return an empty string for digits==0 */
9319 		    if (*PL_efloatbuf) {
9320 			elen = strlen(PL_efloatbuf);
9321 			goto float_converted;
9322 		    }
9323 		} else if ( c == 'f' && !precis) {
9324 		    if ((eptr = F0convert(nv, ebuf + sizeof ebuf, &elen)))
9325 			break;
9326 		}
9327 	    }
9328 	    {
9329 		char *ptr = ebuf + sizeof ebuf;
9330 		*--ptr = '\0';
9331 		*--ptr = c;
9332 		/* FIXME: what to do if HAS_LONG_DOUBLE but not PERL_PRIfldbl? */
9333 #if defined(HAS_LONG_DOUBLE) && defined(PERL_PRIfldbl)
9334 		if (intsize == 'q') {
9335 		    /* Copy the one or more characters in a long double
9336 		     * format before the 'base' ([efgEFG]) character to
9337 		     * the format string. */
9338 		    static char const prifldbl[] = PERL_PRIfldbl;
9339 		    char const *p = prifldbl + sizeof(prifldbl) - 3;
9340 		    while (p >= prifldbl) { *--ptr = *p--; }
9341 		}
9342 #endif
9343 		if (has_precis) {
9344 		    base = precis;
9345 		    do { *--ptr = '0' + (base % 10); } while (base /= 10);
9346 		    *--ptr = '.';
9347 		}
9348 		if (width) {
9349 		    base = width;
9350 		    do { *--ptr = '0' + (base % 10); } while (base /= 10);
9351 		}
9352 		if (fill == '0')
9353 		    *--ptr = fill;
9354 		if (left)
9355 		    *--ptr = '-';
9356 		if (plus)
9357 		    *--ptr = plus;
9358 		if (alt)
9359 		    *--ptr = '#';
9360 		*--ptr = '%';
9361 
9362 		/* No taint.  Otherwise we are in the strange situation
9363 		 * where printf() taints but print($float) doesn't.
9364 		 * --jhi */
9365 #if defined(HAS_LONG_DOUBLE)
9366 		elen = ((intsize == 'q')
9367 			? my_snprintf(PL_efloatbuf, PL_efloatsize, ptr, nv)
9368 			: my_snprintf(PL_efloatbuf, PL_efloatsize, ptr, (double)nv));
9369 #else
9370 		elen = my_sprintf(PL_efloatbuf, ptr, nv);
9371 #endif
9372 	    }
9373 	float_converted:
9374 	    eptr = PL_efloatbuf;
9375 	    break;
9376 
9377 	    /* SPECIAL */
9378 
9379 	case 'n':
9380 	    if (vectorize)
9381 		goto unknown;
9382 	    i = SvCUR(sv) - origlen;
9383 	    if (args) {
9384 		switch (intsize) {
9385 		case 'h':	*(va_arg(*args, short*)) = i; break;
9386 		default:	*(va_arg(*args, int*)) = i; break;
9387 		case 'l':	*(va_arg(*args, long*)) = i; break;
9388 		case 'V':	*(va_arg(*args, IV*)) = i; break;
9389 #ifdef HAS_QUAD
9390 		case 'q':	*(va_arg(*args, Quad_t*)) = i; break;
9391 #endif
9392 		}
9393 	    }
9394 	    else
9395 		sv_setuv_mg(argsv, (UV)i);
9396 	    continue;	/* not "break" */
9397 
9398 	    /* UNKNOWN */
9399 
9400 	default:
9401       unknown:
9402 	    if (!args
9403 		&& (PL_op->op_type == OP_PRTF || PL_op->op_type == OP_SPRINTF)
9404 		&& ckWARN(WARN_PRINTF))
9405 	    {
9406 		SV * const msg = sv_newmortal();
9407 		Perl_sv_setpvf(aTHX_ msg, "Invalid conversion in %sprintf: ",
9408 			  (PL_op->op_type == OP_PRTF) ? "" : "s");
9409 		if (c) {
9410 		    if (isPRINT(c))
9411 			Perl_sv_catpvf(aTHX_ msg,
9412 				       "\"%%%c\"", c & 0xFF);
9413 		    else
9414 			Perl_sv_catpvf(aTHX_ msg,
9415 				       "\"%%\\%03"UVof"\"",
9416 				       (UV)c & 0xFF);
9417 		} else
9418 		    sv_catpvs(msg, "end of string");
9419 		Perl_warner(aTHX_ packWARN(WARN_PRINTF), "%"SVf, SVfARG(msg)); /* yes, this is reentrant */
9420 	    }
9421 
9422 	    /* output mangled stuff ... */
9423 	    if (c == '\0')
9424 		--q;
9425 	    eptr = p;
9426 	    elen = q - p;
9427 
9428 	    /* ... right here, because formatting flags should not apply */
9429 	    SvGROW(sv, SvCUR(sv) + elen + 1);
9430 	    p = SvEND(sv);
9431 	    Copy(eptr, p, elen, char);
9432 	    p += elen;
9433 	    *p = '\0';
9434 	    SvCUR_set(sv, p - SvPVX_const(sv));
9435 	    svix = osvix;
9436 	    continue;	/* not "break" */
9437 	}
9438 
9439 	if (is_utf8 != has_utf8) {
9440 	    if (is_utf8) {
9441 		if (SvCUR(sv))
9442 		    sv_utf8_upgrade(sv);
9443 	    }
9444 	    else {
9445 		const STRLEN old_elen = elen;
9446 		SV * const nsv = sv_2mortal(newSVpvn(eptr, elen));
9447 		sv_utf8_upgrade(nsv);
9448 		eptr = SvPVX_const(nsv);
9449 		elen = SvCUR(nsv);
9450 
9451 		if (width) { /* fudge width (can't fudge elen) */
9452 		    width += elen - old_elen;
9453 		}
9454 		is_utf8 = TRUE;
9455 	    }
9456 	}
9457 
9458 	have = esignlen + zeros + elen;
9459 	if (have < zeros)
9460 	    Perl_croak_nocontext(PL_memory_wrap);
9461 
9462 	need = (have > width ? have : width);
9463 	gap = need - have;
9464 
9465 	if (need >= (((STRLEN)~0) - SvCUR(sv) - dotstrlen - 1))
9466 	    Perl_croak_nocontext(PL_memory_wrap);
9467 	SvGROW(sv, SvCUR(sv) + need + dotstrlen + 1);
9468 	p = SvEND(sv);
9469 	if (esignlen && fill == '0') {
9470 	    int i;
9471 	    for (i = 0; i < (int)esignlen; i++)
9472 		*p++ = esignbuf[i];
9473 	}
9474 	if (gap && !left) {
9475 	    memset(p, fill, gap);
9476 	    p += gap;
9477 	}
9478 	if (esignlen && fill != '0') {
9479 	    int i;
9480 	    for (i = 0; i < (int)esignlen; i++)
9481 		*p++ = esignbuf[i];
9482 	}
9483 	if (zeros) {
9484 	    int i;
9485 	    for (i = zeros; i; i--)
9486 		*p++ = '0';
9487 	}
9488 	if (elen) {
9489 	    Copy(eptr, p, elen, char);
9490 	    p += elen;
9491 	}
9492 	if (gap && left) {
9493 	    memset(p, ' ', gap);
9494 	    p += gap;
9495 	}
9496 	if (vectorize) {
9497 	    if (veclen) {
9498 		Copy(dotstr, p, dotstrlen, char);
9499 		p += dotstrlen;
9500 	    }
9501 	    else
9502 		vectorize = FALSE;		/* done iterating over vecstr */
9503 	}
9504 	if (is_utf8)
9505 	    has_utf8 = TRUE;
9506 	if (has_utf8)
9507 	    SvUTF8_on(sv);
9508 	*p = '\0';
9509 	SvCUR_set(sv, p - SvPVX_const(sv));
9510 	if (vectorize) {
9511 	    esignlen = 0;
9512 	    goto vector;
9513 	}
9514     }
9515 }
9516 
9517 /* =========================================================================
9518 
9519 =head1 Cloning an interpreter
9520 
9521 All the macros and functions in this section are for the private use of
9522 the main function, perl_clone().
9523 
9524 The foo_dup() functions make an exact copy of an existing foo thingy.
9525 During the course of a cloning, a hash table is used to map old addresses
9526 to new addresses. The table is created and manipulated with the
9527 ptr_table_* functions.
9528 
9529 =cut
9530 
9531 ============================================================================*/
9532 
9533 
9534 #if defined(USE_ITHREADS)
9535 
9536 /* XXX Remove this so it doesn't have to go thru the macro and return for nothing */
9537 #ifndef GpREFCNT_inc
9538 #  define GpREFCNT_inc(gp)	((gp) ? (++(gp)->gp_refcnt, (gp)) : (GP*)NULL)
9539 #endif
9540 
9541 
9542 /* Certain cases in Perl_ss_dup have been merged, by relying on the fact
9543    that currently av_dup, gv_dup and hv_dup are the same as sv_dup.
9544    If this changes, please unmerge ss_dup.  */
9545 #define sv_dup_inc(s,t)	SvREFCNT_inc(sv_dup(s,t))
9546 #define sv_dup_inc_NN(s,t)	SvREFCNT_inc_NN(sv_dup(s,t))
9547 #define av_dup(s,t)	(AV*)sv_dup((SV*)s,t)
9548 #define av_dup_inc(s,t)	(AV*)SvREFCNT_inc(sv_dup((SV*)s,t))
9549 #define hv_dup(s,t)	(HV*)sv_dup((SV*)s,t)
9550 #define hv_dup_inc(s,t)	(HV*)SvREFCNT_inc(sv_dup((SV*)s,t))
9551 #define cv_dup(s,t)	(CV*)sv_dup((SV*)s,t)
9552 #define cv_dup_inc(s,t)	(CV*)SvREFCNT_inc(sv_dup((SV*)s,t))
9553 #define io_dup(s,t)	(IO*)sv_dup((SV*)s,t)
9554 #define io_dup_inc(s,t)	(IO*)SvREFCNT_inc(sv_dup((SV*)s,t))
9555 #define gv_dup(s,t)	(GV*)sv_dup((SV*)s,t)
9556 #define gv_dup_inc(s,t)	(GV*)SvREFCNT_inc(sv_dup((SV*)s,t))
9557 #define SAVEPV(p)	((p) ? savepv(p) : NULL)
9558 #define SAVEPVN(p,n)	((p) ? savepvn(p,n) : NULL)
9559 
9560 /* clone a parser */
9561 
9562 yy_parser *
9563 Perl_parser_dup(pTHX_ const yy_parser *proto, CLONE_PARAMS* param)
9564 {
9565     yy_parser *parser;
9566 
9567     if (!proto)
9568 	return NULL;
9569 
9570     /* look for it in the table first */
9571     parser = (yy_parser *)ptr_table_fetch(PL_ptr_table, proto);
9572     if (parser)
9573 	return parser;
9574 
9575     /* create anew and remember what it is */
9576     Newxz(parser, 1, yy_parser);
9577     ptr_table_store(PL_ptr_table, proto, parser);
9578 
9579     parser->yyerrstatus = 0;
9580     parser->yychar = YYEMPTY;		/* Cause a token to be read.  */
9581 
9582     /* XXX these not yet duped */
9583     parser->old_parser = NULL;
9584     parser->stack = NULL;
9585     parser->ps = NULL;
9586     parser->stack_size = 0;
9587     /* XXX parser->stack->state = 0; */
9588 
9589     /* XXX eventually, just Copy() most of the parser struct ? */
9590 
9591     parser->lex_brackets = proto->lex_brackets;
9592     parser->lex_casemods = proto->lex_casemods;
9593     parser->lex_brackstack = savepvn(proto->lex_brackstack,
9594 		    (proto->lex_brackets < 120 ? 120 : proto->lex_brackets));
9595     parser->lex_casestack = savepvn(proto->lex_casestack,
9596 		    (proto->lex_casemods < 12 ? 12 : proto->lex_casemods));
9597     parser->lex_defer	= proto->lex_defer;
9598     parser->lex_dojoin	= proto->lex_dojoin;
9599     parser->lex_expect	= proto->lex_expect;
9600     parser->lex_formbrack = proto->lex_formbrack;
9601     parser->lex_inpat	= proto->lex_inpat;
9602     parser->lex_inwhat	= proto->lex_inwhat;
9603     parser->lex_op	= proto->lex_op;
9604     parser->lex_repl	= sv_dup_inc(proto->lex_repl, param);
9605     parser->lex_starts	= proto->lex_starts;
9606     parser->lex_stuff	= sv_dup_inc(proto->lex_stuff, param);
9607     parser->multi_close	= proto->multi_close;
9608     parser->multi_open	= proto->multi_open;
9609     parser->multi_start	= proto->multi_start;
9610     parser->multi_end	= proto->multi_end;
9611     parser->pending_ident = proto->pending_ident;
9612     parser->preambled	= proto->preambled;
9613     parser->sublex_info	= proto->sublex_info; /* XXX not quite right */
9614     parser->linestr	= sv_dup_inc(proto->linestr, param);
9615     parser->expect	= proto->expect;
9616     parser->copline	= proto->copline;
9617     parser->last_lop_op	= proto->last_lop_op;
9618     parser->lex_state	= proto->lex_state;
9619     parser->rsfp	= fp_dup(proto->rsfp, '<', param);
9620     /* rsfp_filters entries have fake IoDIRP() */
9621     parser->rsfp_filters= av_dup_inc(proto->rsfp_filters, param);
9622     parser->in_my	= proto->in_my;
9623     parser->in_my_stash	= hv_dup(proto->in_my_stash, param);
9624     parser->error_count	= proto->error_count;
9625 
9626 
9627     parser->linestr	= sv_dup_inc(proto->linestr, param);
9628 
9629     {
9630 	char * const ols = SvPVX(proto->linestr);
9631 	char * const ls  = SvPVX(parser->linestr);
9632 
9633 	parser->bufptr	    = ls + (proto->bufptr >= ols ?
9634 				    proto->bufptr -  ols : 0);
9635 	parser->oldbufptr   = ls + (proto->oldbufptr >= ols ?
9636 				    proto->oldbufptr -  ols : 0);
9637 	parser->oldoldbufptr= ls + (proto->oldoldbufptr >= ols ?
9638 				    proto->oldoldbufptr -  ols : 0);
9639 	parser->linestart   = ls + (proto->linestart >= ols ?
9640 				    proto->linestart -  ols : 0);
9641 	parser->last_uni    = ls + (proto->last_uni >= ols ?
9642 				    proto->last_uni -  ols : 0);
9643 	parser->last_lop    = ls + (proto->last_lop >= ols ?
9644 				    proto->last_lop -  ols : 0);
9645 
9646 	parser->bufend	    = ls + SvCUR(parser->linestr);
9647     }
9648 
9649     Copy(proto->tokenbuf, parser->tokenbuf, 256, char);
9650 
9651 
9652 #ifdef PERL_MAD
9653     parser->endwhite	= proto->endwhite;
9654     parser->faketokens	= proto->faketokens;
9655     parser->lasttoke	= proto->lasttoke;
9656     parser->nextwhite	= proto->nextwhite;
9657     parser->realtokenstart = proto->realtokenstart;
9658     parser->skipwhite	= proto->skipwhite;
9659     parser->thisclose	= proto->thisclose;
9660     parser->thismad	= proto->thismad;
9661     parser->thisopen	= proto->thisopen;
9662     parser->thisstuff	= proto->thisstuff;
9663     parser->thistoken	= proto->thistoken;
9664     parser->thiswhite	= proto->thiswhite;
9665 
9666     Copy(proto->nexttoke, parser->nexttoke, 5, NEXTTOKE);
9667     parser->curforce	= proto->curforce;
9668 #else
9669     Copy(proto->nextval, parser->nextval, 5, YYSTYPE);
9670     Copy(proto->nexttype, parser->nexttype, 5,	I32);
9671     parser->nexttoke	= proto->nexttoke;
9672 #endif
9673     return parser;
9674 }
9675 
9676 
9677 /* duplicate a file handle */
9678 
9679 PerlIO *
9680 Perl_fp_dup(pTHX_ PerlIO *fp, char type, CLONE_PARAMS *param)
9681 {
9682     PerlIO *ret;
9683 
9684     PERL_UNUSED_ARG(type);
9685 
9686     if (!fp)
9687 	return (PerlIO*)NULL;
9688 
9689     /* look for it in the table first */
9690     ret = (PerlIO*)ptr_table_fetch(PL_ptr_table, fp);
9691     if (ret)
9692 	return ret;
9693 
9694     /* create anew and remember what it is */
9695     ret = PerlIO_fdupopen(aTHX_ fp, param, PERLIO_DUP_CLONE);
9696     ptr_table_store(PL_ptr_table, fp, ret);
9697     return ret;
9698 }
9699 
9700 /* duplicate a directory handle */
9701 
9702 DIR *
9703 Perl_dirp_dup(pTHX_ DIR *dp)
9704 {
9705     PERL_UNUSED_CONTEXT;
9706     if (!dp)
9707 	return (DIR*)NULL;
9708     /* XXX TODO */
9709     return dp;
9710 }
9711 
9712 /* duplicate a typeglob */
9713 
9714 GP *
9715 Perl_gp_dup(pTHX_ GP *gp, CLONE_PARAMS* param)
9716 {
9717     GP *ret;
9718 
9719     if (!gp)
9720 	return (GP*)NULL;
9721     /* look for it in the table first */
9722     ret = (GP*)ptr_table_fetch(PL_ptr_table, gp);
9723     if (ret)
9724 	return ret;
9725 
9726     /* create anew and remember what it is */
9727     Newxz(ret, 1, GP);
9728     ptr_table_store(PL_ptr_table, gp, ret);
9729 
9730     /* clone */
9731     ret->gp_refcnt	= 0;			/* must be before any other dups! */
9732     ret->gp_sv		= sv_dup_inc(gp->gp_sv, param);
9733     ret->gp_io		= io_dup_inc(gp->gp_io, param);
9734     ret->gp_form	= cv_dup_inc(gp->gp_form, param);
9735     ret->gp_av		= av_dup_inc(gp->gp_av, param);
9736     ret->gp_hv		= hv_dup_inc(gp->gp_hv, param);
9737     ret->gp_egv	= gv_dup(gp->gp_egv, param);/* GvEGV is not refcounted */
9738     ret->gp_cv		= cv_dup_inc(gp->gp_cv, param);
9739     ret->gp_cvgen	= gp->gp_cvgen;
9740     ret->gp_line	= gp->gp_line;
9741     ret->gp_file_hek	= hek_dup(gp->gp_file_hek, param);
9742     return ret;
9743 }
9744 
9745 /* duplicate a chain of magic */
9746 
9747 MAGIC *
9748 Perl_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS* param)
9749 {
9750     MAGIC *mgprev = (MAGIC*)NULL;
9751     MAGIC *mgret;
9752     if (!mg)
9753 	return (MAGIC*)NULL;
9754     /* look for it in the table first */
9755     mgret = (MAGIC*)ptr_table_fetch(PL_ptr_table, mg);
9756     if (mgret)
9757 	return mgret;
9758 
9759     for (; mg; mg = mg->mg_moremagic) {
9760 	MAGIC *nmg;
9761 	Newxz(nmg, 1, MAGIC);
9762 	if (mgprev)
9763 	    mgprev->mg_moremagic = nmg;
9764 	else
9765 	    mgret = nmg;
9766 	nmg->mg_virtual	= mg->mg_virtual;	/* XXX copy dynamic vtable? */
9767 	nmg->mg_private	= mg->mg_private;
9768 	nmg->mg_type	= mg->mg_type;
9769 	nmg->mg_flags	= mg->mg_flags;
9770 	if (mg->mg_type == PERL_MAGIC_qr) {
9771 	    nmg->mg_obj	= (SV*)CALLREGDUPE((REGEXP*)mg->mg_obj, param);
9772 	}
9773 	else if(mg->mg_type == PERL_MAGIC_backref) {
9774 	    /* The backref AV has its reference count deliberately bumped by
9775 	       1.  */
9776 	    nmg->mg_obj = SvREFCNT_inc(av_dup_inc((AV*) mg->mg_obj, param));
9777 	}
9778 	else {
9779 	    nmg->mg_obj	= (mg->mg_flags & MGf_REFCOUNTED)
9780 			      ? sv_dup_inc(mg->mg_obj, param)
9781 			      : sv_dup(mg->mg_obj, param);
9782 	}
9783 	nmg->mg_len	= mg->mg_len;
9784 	nmg->mg_ptr	= mg->mg_ptr;	/* XXX random ptr? */
9785 	if (mg->mg_ptr && mg->mg_type != PERL_MAGIC_regex_global) {
9786 	    if (mg->mg_len > 0) {
9787 		nmg->mg_ptr	= SAVEPVN(mg->mg_ptr, mg->mg_len);
9788 		if (mg->mg_type == PERL_MAGIC_overload_table &&
9789 			AMT_AMAGIC((AMT*)mg->mg_ptr))
9790 		{
9791 		    const AMT * const amtp = (AMT*)mg->mg_ptr;
9792 		    AMT * const namtp = (AMT*)nmg->mg_ptr;
9793 		    I32 i;
9794 		    for (i = 1; i < NofAMmeth; i++) {
9795 			namtp->table[i] = cv_dup_inc(amtp->table[i], param);
9796 		    }
9797 		}
9798 	    }
9799 	    else if (mg->mg_len == HEf_SVKEY)
9800 		nmg->mg_ptr	= (char*)sv_dup_inc((SV*)mg->mg_ptr, param);
9801 	}
9802 	if ((mg->mg_flags & MGf_DUP) && mg->mg_virtual && mg->mg_virtual->svt_dup) {
9803 	    CALL_FPTR(nmg->mg_virtual->svt_dup)(aTHX_ nmg, param);
9804 	}
9805 	mgprev = nmg;
9806     }
9807     return mgret;
9808 }
9809 
9810 #endif /* USE_ITHREADS */
9811 
9812 /* create a new pointer-mapping table */
9813 
9814 PTR_TBL_t *
9815 Perl_ptr_table_new(pTHX)
9816 {
9817     PTR_TBL_t *tbl;
9818     PERL_UNUSED_CONTEXT;
9819 
9820     Newxz(tbl, 1, PTR_TBL_t);
9821     tbl->tbl_max	= 511;
9822     tbl->tbl_items	= 0;
9823     Newxz(tbl->tbl_ary, tbl->tbl_max + 1, PTR_TBL_ENT_t*);
9824     return tbl;
9825 }
9826 
9827 #define PTR_TABLE_HASH(ptr) \
9828   ((PTR2UV(ptr) >> 3) ^ (PTR2UV(ptr) >> (3 + 7)) ^ (PTR2UV(ptr) >> (3 + 17)))
9829 
9830 /*
9831    we use the PTE_SVSLOT 'reservation' made above, both here (in the
9832    following define) and at call to new_body_inline made below in
9833    Perl_ptr_table_store()
9834  */
9835 
9836 #define del_pte(p)     del_body_type(p, PTE_SVSLOT)
9837 
9838 /* map an existing pointer using a table */
9839 
9840 STATIC PTR_TBL_ENT_t *
9841 S_ptr_table_find(PTR_TBL_t *tbl, const void *sv) {
9842     PTR_TBL_ENT_t *tblent;
9843     const UV hash = PTR_TABLE_HASH(sv);
9844     assert(tbl);
9845     tblent = tbl->tbl_ary[hash & tbl->tbl_max];
9846     for (; tblent; tblent = tblent->next) {
9847 	if (tblent->oldval == sv)
9848 	    return tblent;
9849     }
9850     return NULL;
9851 }
9852 
9853 void *
9854 Perl_ptr_table_fetch(pTHX_ PTR_TBL_t *tbl, const void *sv)
9855 {
9856     PTR_TBL_ENT_t const *const tblent = ptr_table_find(tbl, sv);
9857     PERL_UNUSED_CONTEXT;
9858     return tblent ? tblent->newval : NULL;
9859 }
9860 
9861 /* add a new entry to a pointer-mapping table */
9862 
9863 void
9864 Perl_ptr_table_store(pTHX_ PTR_TBL_t *tbl, const void *oldsv, void *newsv)
9865 {
9866     PTR_TBL_ENT_t *tblent = ptr_table_find(tbl, oldsv);
9867     PERL_UNUSED_CONTEXT;
9868 
9869     if (tblent) {
9870 	tblent->newval = newsv;
9871     } else {
9872 	const UV entry = PTR_TABLE_HASH(oldsv) & tbl->tbl_max;
9873 
9874 	new_body_inline(tblent, PTE_SVSLOT);
9875 
9876 	tblent->oldval = oldsv;
9877 	tblent->newval = newsv;
9878 	tblent->next = tbl->tbl_ary[entry];
9879 	tbl->tbl_ary[entry] = tblent;
9880 	tbl->tbl_items++;
9881 	if (tblent->next && tbl->tbl_items > tbl->tbl_max)
9882 	    ptr_table_split(tbl);
9883     }
9884 }
9885 
9886 /* double the hash bucket size of an existing ptr table */
9887 
9888 void
9889 Perl_ptr_table_split(pTHX_ PTR_TBL_t *tbl)
9890 {
9891     PTR_TBL_ENT_t **ary = tbl->tbl_ary;
9892     const UV oldsize = tbl->tbl_max + 1;
9893     UV newsize = oldsize * 2;
9894     UV i;
9895     PERL_UNUSED_CONTEXT;
9896 
9897     Renew(ary, newsize, PTR_TBL_ENT_t*);
9898     Zero(&ary[oldsize], newsize-oldsize, PTR_TBL_ENT_t*);
9899     tbl->tbl_max = --newsize;
9900     tbl->tbl_ary = ary;
9901     for (i=0; i < oldsize; i++, ary++) {
9902 	PTR_TBL_ENT_t **curentp, **entp, *ent;
9903 	if (!*ary)
9904 	    continue;
9905 	curentp = ary + oldsize;
9906 	for (entp = ary, ent = *ary; ent; ent = *entp) {
9907 	    if ((newsize & PTR_TABLE_HASH(ent->oldval)) != i) {
9908 		*entp = ent->next;
9909 		ent->next = *curentp;
9910 		*curentp = ent;
9911 		continue;
9912 	    }
9913 	    else
9914 		entp = &ent->next;
9915 	}
9916     }
9917 }
9918 
9919 /* remove all the entries from a ptr table */
9920 
9921 void
9922 Perl_ptr_table_clear(pTHX_ PTR_TBL_t *tbl)
9923 {
9924     if (tbl && tbl->tbl_items) {
9925 	register PTR_TBL_ENT_t * const * const array = tbl->tbl_ary;
9926 	UV riter = tbl->tbl_max;
9927 
9928 	do {
9929 	    PTR_TBL_ENT_t *entry = array[riter];
9930 
9931 	    while (entry) {
9932 		PTR_TBL_ENT_t * const oentry = entry;
9933 		entry = entry->next;
9934 		del_pte(oentry);
9935 	    }
9936 	} while (riter--);
9937 
9938 	tbl->tbl_items = 0;
9939     }
9940 }
9941 
9942 /* clear and free a ptr table */
9943 
9944 void
9945 Perl_ptr_table_free(pTHX_ PTR_TBL_t *tbl)
9946 {
9947     if (!tbl) {
9948         return;
9949     }
9950     ptr_table_clear(tbl);
9951     Safefree(tbl->tbl_ary);
9952     Safefree(tbl);
9953 }
9954 
9955 #if defined(USE_ITHREADS)
9956 
9957 void
9958 Perl_rvpv_dup(pTHX_ SV *dstr, const SV *sstr, CLONE_PARAMS* param)
9959 {
9960     if (SvROK(sstr)) {
9961 	SvRV_set(dstr, SvWEAKREF(sstr)
9962 		       ? sv_dup(SvRV(sstr), param)
9963 		       : sv_dup_inc(SvRV(sstr), param));
9964 
9965     }
9966     else if (SvPVX_const(sstr)) {
9967 	/* Has something there */
9968 	if (SvLEN(sstr)) {
9969 	    /* Normal PV - clone whole allocated space */
9970 	    SvPV_set(dstr, SAVEPVN(SvPVX_const(sstr), SvLEN(sstr)-1));
9971 	    if (SvREADONLY(sstr) && SvFAKE(sstr)) {
9972 		/* Not that normal - actually sstr is copy on write.
9973 		   But we are a true, independant SV, so:  */
9974 		SvREADONLY_off(dstr);
9975 		SvFAKE_off(dstr);
9976 	    }
9977 	}
9978 	else {
9979 	    /* Special case - not normally malloced for some reason */
9980 	    if (isGV_with_GP(sstr)) {
9981 		/* Don't need to do anything here.  */
9982 	    }
9983 	    else if ((SvREADONLY(sstr) && SvFAKE(sstr))) {
9984 		/* A "shared" PV - clone it as "shared" PV */
9985 		SvPV_set(dstr,
9986 			 HEK_KEY(hek_dup(SvSHARED_HEK_FROM_PV(SvPVX_const(sstr)),
9987 					 param)));
9988 	    }
9989 	    else {
9990 		/* Some other special case - random pointer */
9991 		SvPV_set(dstr, SvPVX(sstr));
9992 	    }
9993 	}
9994     }
9995     else {
9996 	/* Copy the NULL */
9997 	if (SvTYPE(dstr) == SVt_RV)
9998 	    SvRV_set(dstr, NULL);
9999 	else
10000 	    SvPV_set(dstr, NULL);
10001     }
10002 }
10003 
10004 /* duplicate an SV of any type (including AV, HV etc) */
10005 
10006 SV *
10007 Perl_sv_dup(pTHX_ const SV *sstr, CLONE_PARAMS* param)
10008 {
10009     dVAR;
10010     SV *dstr;
10011 
10012     if (!sstr || SvTYPE(sstr) == SVTYPEMASK)
10013 	return NULL;
10014     /* look for it in the table first */
10015     dstr = (SV*)ptr_table_fetch(PL_ptr_table, sstr);
10016     if (dstr)
10017 	return dstr;
10018 
10019     if(param->flags & CLONEf_JOIN_IN) {
10020         /** We are joining here so we don't want do clone
10021 	    something that is bad **/
10022 	if (SvTYPE(sstr) == SVt_PVHV) {
10023 	    const HEK * const hvname = HvNAME_HEK(sstr);
10024 	    if (hvname)
10025 		/** don't clone stashes if they already exist **/
10026 		return (SV*)gv_stashpvn(HEK_KEY(hvname), HEK_LEN(hvname), 0);
10027         }
10028     }
10029 
10030     /* create anew and remember what it is */
10031     new_SV(dstr);
10032 
10033 #ifdef DEBUG_LEAKING_SCALARS
10034     dstr->sv_debug_optype = sstr->sv_debug_optype;
10035     dstr->sv_debug_line = sstr->sv_debug_line;
10036     dstr->sv_debug_inpad = sstr->sv_debug_inpad;
10037     dstr->sv_debug_cloned = 1;
10038     dstr->sv_debug_file = savepv(sstr->sv_debug_file);
10039 #endif
10040 
10041     ptr_table_store(PL_ptr_table, sstr, dstr);
10042 
10043     /* clone */
10044     SvFLAGS(dstr)	= SvFLAGS(sstr);
10045     SvFLAGS(dstr)	&= ~SVf_OOK;		/* don't propagate OOK hack */
10046     SvREFCNT(dstr)	= 0;			/* must be before any other dups! */
10047 
10048 #ifdef DEBUGGING
10049     if (SvANY(sstr) && PL_watch_pvx && SvPVX_const(sstr) == PL_watch_pvx)
10050 	PerlIO_printf(Perl_debug_log, "watch at %p hit, found string \"%s\"\n",
10051 		      (void*)PL_watch_pvx, SvPVX_const(sstr));
10052 #endif
10053 
10054     /* don't clone objects whose class has asked us not to */
10055     if (SvOBJECT(sstr) && ! (SvFLAGS(SvSTASH(sstr)) & SVphv_CLONEABLE)) {
10056 	SvFLAGS(dstr) = 0;
10057 	return dstr;
10058     }
10059 
10060     switch (SvTYPE(sstr)) {
10061     case SVt_NULL:
10062 	SvANY(dstr)	= NULL;
10063 	break;
10064     case SVt_IV:
10065 	SvANY(dstr)	= (XPVIV*)((char*)&(dstr->sv_u.svu_iv) - STRUCT_OFFSET(XPVIV, xiv_iv));
10066 	SvIV_set(dstr, SvIVX(sstr));
10067 	break;
10068     case SVt_NV:
10069 	SvANY(dstr)	= new_XNV();
10070 	SvNV_set(dstr, SvNVX(sstr));
10071 	break;
10072     case SVt_RV:
10073 	SvANY(dstr)	= &(dstr->sv_u.svu_rv);
10074 	Perl_rvpv_dup(aTHX_ dstr, sstr, param);
10075 	break;
10076 	/* case SVt_BIND: */
10077     default:
10078 	{
10079 	    /* These are all the types that need complex bodies allocating.  */
10080 	    void *new_body;
10081 	    const svtype sv_type = SvTYPE(sstr);
10082 	    const struct body_details *const sv_type_details
10083 		= bodies_by_type + sv_type;
10084 
10085 	    switch (sv_type) {
10086 	    default:
10087 		Perl_croak(aTHX_ "Bizarre SvTYPE [%" IVdf "]", (IV)SvTYPE(sstr));
10088 		break;
10089 
10090 	    case SVt_PVGV:
10091 		if (GvUNIQUE((GV*)sstr)) {
10092 		    NOOP;   /* Do sharing here, and fall through */
10093 		}
10094 	    case SVt_PVIO:
10095 	    case SVt_PVFM:
10096 	    case SVt_PVHV:
10097 	    case SVt_PVAV:
10098 	    case SVt_PVCV:
10099 	    case SVt_PVLV:
10100 	    case SVt_PVMG:
10101 	    case SVt_PVNV:
10102 	    case SVt_PVIV:
10103 	    case SVt_PV:
10104 		assert(sv_type_details->body_size);
10105 		if (sv_type_details->arena) {
10106 		    new_body_inline(new_body, sv_type);
10107 		    new_body
10108 			= (void*)((char*)new_body - sv_type_details->offset);
10109 		} else {
10110 		    new_body = new_NOARENA(sv_type_details);
10111 		}
10112 	    }
10113 	    assert(new_body);
10114 	    SvANY(dstr) = new_body;
10115 
10116 #ifndef PURIFY
10117 	    Copy(((char*)SvANY(sstr)) + sv_type_details->offset,
10118 		 ((char*)SvANY(dstr)) + sv_type_details->offset,
10119 		 sv_type_details->copy, char);
10120 #else
10121 	    Copy(((char*)SvANY(sstr)),
10122 		 ((char*)SvANY(dstr)),
10123 		 sv_type_details->body_size + sv_type_details->offset, char);
10124 #endif
10125 
10126 	    if (sv_type != SVt_PVAV && sv_type != SVt_PVHV
10127 		&& !isGV_with_GP(dstr))
10128 		Perl_rvpv_dup(aTHX_ dstr, sstr, param);
10129 
10130 	    /* The Copy above means that all the source (unduplicated) pointers
10131 	       are now in the destination.  We can check the flags and the
10132 	       pointers in either, but it's possible that there's less cache
10133 	       missing by always going for the destination.
10134 	       FIXME - instrument and check that assumption  */
10135 	    if (sv_type >= SVt_PVMG) {
10136 		if ((sv_type == SVt_PVMG) && SvPAD_OUR(dstr)) {
10137 		    SvOURSTASH_set(dstr, hv_dup_inc(SvOURSTASH(dstr), param));
10138 		} else if (SvMAGIC(dstr))
10139 		    SvMAGIC_set(dstr, mg_dup(SvMAGIC(dstr), param));
10140 		if (SvSTASH(dstr))
10141 		    SvSTASH_set(dstr, hv_dup_inc(SvSTASH(dstr), param));
10142 	    }
10143 
10144 	    /* The cast silences a GCC warning about unhandled types.  */
10145 	    switch ((int)sv_type) {
10146 	    case SVt_PV:
10147 		break;
10148 	    case SVt_PVIV:
10149 		break;
10150 	    case SVt_PVNV:
10151 		break;
10152 	    case SVt_PVMG:
10153 		break;
10154 	    case SVt_PVLV:
10155 		/* XXX LvTARGOFF sometimes holds PMOP* when DEBUGGING */
10156 		if (LvTYPE(dstr) == 't') /* for tie: unrefcnted fake (SV**) */
10157 		    LvTARG(dstr) = dstr;
10158 		else if (LvTYPE(dstr) == 'T') /* for tie: fake HE */
10159 		    LvTARG(dstr) = (SV*)he_dup((HE*)LvTARG(dstr), 0, param);
10160 		else
10161 		    LvTARG(dstr) = sv_dup_inc(LvTARG(dstr), param);
10162 	    case SVt_PVGV:
10163 		if(isGV_with_GP(sstr)) {
10164 		    if (GvNAME_HEK(dstr))
10165 			GvNAME_HEK(dstr) = hek_dup(GvNAME_HEK(dstr), param);
10166 		    /* Don't call sv_add_backref here as it's going to be
10167 		       created as part of the magic cloning of the symbol
10168 		       table.  */
10169 		    /* Danger Will Robinson - GvGP(dstr) isn't initialised
10170 		       at the point of this comment.  */
10171 		    GvSTASH(dstr) = hv_dup(GvSTASH(dstr), param);
10172 		    GvGP(dstr)	= gp_dup(GvGP(sstr), param);
10173 		    (void)GpREFCNT_inc(GvGP(dstr));
10174 		} else
10175 		    Perl_rvpv_dup(aTHX_ dstr, sstr, param);
10176 		break;
10177 	    case SVt_PVIO:
10178 		IoIFP(dstr)	= fp_dup(IoIFP(dstr), IoTYPE(dstr), param);
10179 		if (IoOFP(dstr) == IoIFP(sstr))
10180 		    IoOFP(dstr) = IoIFP(dstr);
10181 		else
10182 		    IoOFP(dstr)	= fp_dup(IoOFP(dstr), IoTYPE(dstr), param);
10183 		/* PL_parser->rsfp_filters entries have fake IoDIRP() */
10184 		if(IoFLAGS(dstr) & IOf_FAKE_DIRP) {
10185 		    /* I have no idea why fake dirp (rsfps)
10186 		       should be treated differently but otherwise
10187 		       we end up with leaks -- sky*/
10188 		    IoTOP_GV(dstr)      = gv_dup_inc(IoTOP_GV(dstr), param);
10189 		    IoFMT_GV(dstr)      = gv_dup_inc(IoFMT_GV(dstr), param);
10190 		    IoBOTTOM_GV(dstr)   = gv_dup_inc(IoBOTTOM_GV(dstr), param);
10191 		} else {
10192 		    IoTOP_GV(dstr)      = gv_dup(IoTOP_GV(dstr), param);
10193 		    IoFMT_GV(dstr)      = gv_dup(IoFMT_GV(dstr), param);
10194 		    IoBOTTOM_GV(dstr)   = gv_dup(IoBOTTOM_GV(dstr), param);
10195 		    if (IoDIRP(dstr)) {
10196 			IoDIRP(dstr)	= dirp_dup(IoDIRP(dstr));
10197 		    } else {
10198 			NOOP;
10199 			/* IoDIRP(dstr) is already a copy of IoDIRP(sstr)  */
10200 		    }
10201 		}
10202 		IoTOP_NAME(dstr)	= SAVEPV(IoTOP_NAME(dstr));
10203 		IoFMT_NAME(dstr)	= SAVEPV(IoFMT_NAME(dstr));
10204 		IoBOTTOM_NAME(dstr)	= SAVEPV(IoBOTTOM_NAME(dstr));
10205 		break;
10206 	    case SVt_PVAV:
10207 		if (AvARRAY((AV*)sstr)) {
10208 		    SV **dst_ary, **src_ary;
10209 		    SSize_t items = AvFILLp((AV*)sstr) + 1;
10210 
10211 		    src_ary = AvARRAY((AV*)sstr);
10212 		    Newxz(dst_ary, AvMAX((AV*)sstr)+1, SV*);
10213 		    ptr_table_store(PL_ptr_table, src_ary, dst_ary);
10214 		    AvARRAY((AV*)dstr) = dst_ary;
10215 		    AvALLOC((AV*)dstr) = dst_ary;
10216 		    if (AvREAL((AV*)sstr)) {
10217 			while (items-- > 0)
10218 			    *dst_ary++ = sv_dup_inc(*src_ary++, param);
10219 		    }
10220 		    else {
10221 			while (items-- > 0)
10222 			    *dst_ary++ = sv_dup(*src_ary++, param);
10223 		    }
10224 		    items = AvMAX((AV*)sstr) - AvFILLp((AV*)sstr);
10225 		    while (items-- > 0) {
10226 			*dst_ary++ = &PL_sv_undef;
10227 		    }
10228 		}
10229 		else {
10230 		    AvARRAY((AV*)dstr)	= NULL;
10231 		    AvALLOC((AV*)dstr)	= (SV**)NULL;
10232 		}
10233 		break;
10234 	    case SVt_PVHV:
10235 		if (HvARRAY((HV*)sstr)) {
10236 		    STRLEN i = 0;
10237 		    const bool sharekeys = !!HvSHAREKEYS(sstr);
10238 		    XPVHV * const dxhv = (XPVHV*)SvANY(dstr);
10239 		    XPVHV * const sxhv = (XPVHV*)SvANY(sstr);
10240 		    char *darray;
10241 		    Newx(darray, PERL_HV_ARRAY_ALLOC_BYTES(dxhv->xhv_max+1)
10242 			+ (SvOOK(sstr) ? sizeof(struct xpvhv_aux) : 0),
10243 			char);
10244 		    HvARRAY(dstr) = (HE**)darray;
10245 		    while (i <= sxhv->xhv_max) {
10246 			const HE * const source = HvARRAY(sstr)[i];
10247 			HvARRAY(dstr)[i] = source
10248 			    ? he_dup(source, sharekeys, param) : 0;
10249 			++i;
10250 		    }
10251 		    if (SvOOK(sstr)) {
10252 			HEK *hvname;
10253 			const struct xpvhv_aux * const saux = HvAUX(sstr);
10254 			struct xpvhv_aux * const daux = HvAUX(dstr);
10255 			/* This flag isn't copied.  */
10256 			/* SvOOK_on(hv) attacks the IV flags.  */
10257 			SvFLAGS(dstr) |= SVf_OOK;
10258 
10259 			hvname = saux->xhv_name;
10260 			daux->xhv_name = hvname ? hek_dup(hvname, param) : hvname;
10261 
10262 			daux->xhv_riter = saux->xhv_riter;
10263 			daux->xhv_eiter = saux->xhv_eiter
10264 			    ? he_dup(saux->xhv_eiter,
10265 					(bool)!!HvSHAREKEYS(sstr), param) : 0;
10266 			daux->xhv_backreferences =
10267 			    saux->xhv_backreferences
10268 				? (AV*) SvREFCNT_inc(
10269 					sv_dup((SV*)saux->xhv_backreferences, param))
10270 				: 0;
10271 
10272                         daux->xhv_mro_meta = saux->xhv_mro_meta
10273                             ? mro_meta_dup(saux->xhv_mro_meta, param)
10274                             : 0;
10275 
10276 			/* Record stashes for possible cloning in Perl_clone(). */
10277 			if (hvname)
10278 			    av_push(param->stashes, dstr);
10279 		    }
10280 		}
10281 		else
10282 		    HvARRAY((HV*)dstr) = NULL;
10283 		break;
10284 	    case SVt_PVCV:
10285 		if (!(param->flags & CLONEf_COPY_STACKS)) {
10286 		    CvDEPTH(dstr) = 0;
10287 		}
10288 	    case SVt_PVFM:
10289 		/* NOTE: not refcounted */
10290 		CvSTASH(dstr)	= hv_dup(CvSTASH(dstr), param);
10291 		OP_REFCNT_LOCK;
10292 		if (!CvISXSUB(dstr))
10293 		    CvROOT(dstr) = OpREFCNT_inc(CvROOT(dstr));
10294 		OP_REFCNT_UNLOCK;
10295 		if (CvCONST(dstr) && CvISXSUB(dstr)) {
10296 		    CvXSUBANY(dstr).any_ptr = GvUNIQUE(CvGV(dstr)) ?
10297 			SvREFCNT_inc(CvXSUBANY(dstr).any_ptr) :
10298 			sv_dup_inc((SV *)CvXSUBANY(dstr).any_ptr, param);
10299 		}
10300 		/* don't dup if copying back - CvGV isn't refcounted, so the
10301 		 * duped GV may never be freed. A bit of a hack! DAPM */
10302 		CvGV(dstr)	= (param->flags & CLONEf_JOIN_IN) ?
10303 		    NULL : gv_dup(CvGV(dstr), param) ;
10304 		PAD_DUP(CvPADLIST(dstr), CvPADLIST(sstr), param);
10305 		CvOUTSIDE(dstr)	=
10306 		    CvWEAKOUTSIDE(sstr)
10307 		    ? cv_dup(    CvOUTSIDE(dstr), param)
10308 		    : cv_dup_inc(CvOUTSIDE(dstr), param);
10309 		if (!CvISXSUB(dstr))
10310 		    CvFILE(dstr) = SAVEPV(CvFILE(dstr));
10311 		break;
10312 	    }
10313 	}
10314     }
10315 
10316     if (SvOBJECT(dstr) && SvTYPE(dstr) != SVt_PVIO)
10317 	++PL_sv_objcount;
10318 
10319     return dstr;
10320  }
10321 
10322 /* duplicate a context */
10323 
10324 PERL_CONTEXT *
10325 Perl_cx_dup(pTHX_ PERL_CONTEXT *cxs, I32 ix, I32 max, CLONE_PARAMS* param)
10326 {
10327     PERL_CONTEXT *ncxs;
10328 
10329     if (!cxs)
10330 	return (PERL_CONTEXT*)NULL;
10331 
10332     /* look for it in the table first */
10333     ncxs = (PERL_CONTEXT*)ptr_table_fetch(PL_ptr_table, cxs);
10334     if (ncxs)
10335 	return ncxs;
10336 
10337     /* create anew and remember what it is */
10338     Newxz(ncxs, max + 1, PERL_CONTEXT);
10339     ptr_table_store(PL_ptr_table, cxs, ncxs);
10340 
10341     while (ix >= 0) {
10342 	PERL_CONTEXT * const cx = &cxs[ix];
10343 	PERL_CONTEXT * const ncx = &ncxs[ix];
10344 	ncx->cx_type	= cx->cx_type;
10345 	if (CxTYPE(cx) == CXt_SUBST) {
10346 	    Perl_croak(aTHX_ "Cloning substitution context is unimplemented");
10347 	}
10348 	else {
10349 	    ncx->blk_oldsp	= cx->blk_oldsp;
10350 	    ncx->blk_oldcop	= cx->blk_oldcop;
10351 	    ncx->blk_oldmarksp	= cx->blk_oldmarksp;
10352 	    ncx->blk_oldscopesp	= cx->blk_oldscopesp;
10353 	    ncx->blk_oldpm	= cx->blk_oldpm;
10354 	    ncx->blk_gimme	= cx->blk_gimme;
10355 	    switch (CxTYPE(cx)) {
10356 	    case CXt_SUB:
10357 		ncx->blk_sub.cv		= (cx->blk_sub.olddepth == 0
10358 					   ? cv_dup_inc(cx->blk_sub.cv, param)
10359 					   : cv_dup(cx->blk_sub.cv,param));
10360 		ncx->blk_sub.argarray	= (cx->blk_sub.hasargs
10361 					   ? av_dup_inc(cx->blk_sub.argarray, param)
10362 					   : NULL);
10363 		ncx->blk_sub.savearray	= av_dup_inc(cx->blk_sub.savearray, param);
10364 		ncx->blk_sub.olddepth	= cx->blk_sub.olddepth;
10365 		ncx->blk_sub.hasargs	= cx->blk_sub.hasargs;
10366 		ncx->blk_sub.lval	= cx->blk_sub.lval;
10367 		ncx->blk_sub.retop	= cx->blk_sub.retop;
10368 		ncx->blk_sub.oldcomppad = (PAD*)ptr_table_fetch(PL_ptr_table,
10369 					   cx->blk_sub.oldcomppad);
10370 		break;
10371 	    case CXt_EVAL:
10372 		ncx->blk_eval.old_in_eval = cx->blk_eval.old_in_eval;
10373 		ncx->blk_eval.old_op_type = cx->blk_eval.old_op_type;
10374 		ncx->blk_eval.old_namesv = sv_dup_inc(cx->blk_eval.old_namesv, param);
10375 		ncx->blk_eval.old_eval_root = cx->blk_eval.old_eval_root;
10376 		ncx->blk_eval.cur_text	= sv_dup(cx->blk_eval.cur_text, param);
10377 		ncx->blk_eval.retop = cx->blk_eval.retop;
10378 		break;
10379 	    case CXt_LOOP:
10380 		ncx->blk_loop.label	= cx->blk_loop.label;
10381 		ncx->blk_loop.resetsp	= cx->blk_loop.resetsp;
10382 		ncx->blk_loop.my_op	= cx->blk_loop.my_op;
10383 		ncx->blk_loop.iterdata	= (CxPADLOOP(cx)
10384 					   ? cx->blk_loop.iterdata
10385 					   : gv_dup((GV*)cx->blk_loop.iterdata, param));
10386 		ncx->blk_loop.oldcomppad
10387 		    = (PAD*)ptr_table_fetch(PL_ptr_table,
10388 					    cx->blk_loop.oldcomppad);
10389 		ncx->blk_loop.itersave	= sv_dup_inc(cx->blk_loop.itersave, param);
10390 		ncx->blk_loop.iterlval	= sv_dup_inc(cx->blk_loop.iterlval, param);
10391 		ncx->blk_loop.iterary	= av_dup_inc(cx->blk_loop.iterary, param);
10392 		ncx->blk_loop.iterix	= cx->blk_loop.iterix;
10393 		ncx->blk_loop.itermax	= cx->blk_loop.itermax;
10394 		break;
10395 	    case CXt_FORMAT:
10396 		ncx->blk_sub.cv		= cv_dup(cx->blk_sub.cv, param);
10397 		ncx->blk_sub.gv		= gv_dup(cx->blk_sub.gv, param);
10398 		ncx->blk_sub.dfoutgv	= gv_dup_inc(cx->blk_sub.dfoutgv, param);
10399 		ncx->blk_sub.hasargs	= cx->blk_sub.hasargs;
10400 		ncx->blk_sub.retop	= cx->blk_sub.retop;
10401 		break;
10402 	    case CXt_BLOCK:
10403 	    case CXt_NULL:
10404 		break;
10405 	    }
10406 	}
10407 	--ix;
10408     }
10409     return ncxs;
10410 }
10411 
10412 /* duplicate a stack info structure */
10413 
10414 PERL_SI *
10415 Perl_si_dup(pTHX_ PERL_SI *si, CLONE_PARAMS* param)
10416 {
10417     PERL_SI *nsi;
10418 
10419     if (!si)
10420 	return (PERL_SI*)NULL;
10421 
10422     /* look for it in the table first */
10423     nsi = (PERL_SI*)ptr_table_fetch(PL_ptr_table, si);
10424     if (nsi)
10425 	return nsi;
10426 
10427     /* create anew and remember what it is */
10428     Newxz(nsi, 1, PERL_SI);
10429     ptr_table_store(PL_ptr_table, si, nsi);
10430 
10431     nsi->si_stack	= av_dup_inc(si->si_stack, param);
10432     nsi->si_cxix	= si->si_cxix;
10433     nsi->si_cxmax	= si->si_cxmax;
10434     nsi->si_cxstack	= cx_dup(si->si_cxstack, si->si_cxix, si->si_cxmax, param);
10435     nsi->si_type	= si->si_type;
10436     nsi->si_prev	= si_dup(si->si_prev, param);
10437     nsi->si_next	= si_dup(si->si_next, param);
10438     nsi->si_markoff	= si->si_markoff;
10439 
10440     return nsi;
10441 }
10442 
10443 #define POPINT(ss,ix)	((ss)[--(ix)].any_i32)
10444 #define TOPINT(ss,ix)	((ss)[ix].any_i32)
10445 #define POPLONG(ss,ix)	((ss)[--(ix)].any_long)
10446 #define TOPLONG(ss,ix)	((ss)[ix].any_long)
10447 #define POPIV(ss,ix)	((ss)[--(ix)].any_iv)
10448 #define TOPIV(ss,ix)	((ss)[ix].any_iv)
10449 #define POPBOOL(ss,ix)	((ss)[--(ix)].any_bool)
10450 #define TOPBOOL(ss,ix)	((ss)[ix].any_bool)
10451 #define POPPTR(ss,ix)	((ss)[--(ix)].any_ptr)
10452 #define TOPPTR(ss,ix)	((ss)[ix].any_ptr)
10453 #define POPDPTR(ss,ix)	((ss)[--(ix)].any_dptr)
10454 #define TOPDPTR(ss,ix)	((ss)[ix].any_dptr)
10455 #define POPDXPTR(ss,ix)	((ss)[--(ix)].any_dxptr)
10456 #define TOPDXPTR(ss,ix)	((ss)[ix].any_dxptr)
10457 
10458 /* XXXXX todo */
10459 #define pv_dup_inc(p)	SAVEPV(p)
10460 #define pv_dup(p)	SAVEPV(p)
10461 #define svp_dup_inc(p,pp)	any_dup(p,pp)
10462 
10463 /* map any object to the new equivent - either something in the
10464  * ptr table, or something in the interpreter structure
10465  */
10466 
10467 void *
10468 Perl_any_dup(pTHX_ void *v, const PerlInterpreter *proto_perl)
10469 {
10470     void *ret;
10471 
10472     if (!v)
10473 	return (void*)NULL;
10474 
10475     /* look for it in the table first */
10476     ret = ptr_table_fetch(PL_ptr_table, v);
10477     if (ret)
10478 	return ret;
10479 
10480     /* see if it is part of the interpreter structure */
10481     if (v >= (void*)proto_perl && v < (void*)(proto_perl+1))
10482 	ret = (void*)(((char*)aTHX) + (((char*)v) - (char*)proto_perl));
10483     else {
10484 	ret = v;
10485     }
10486 
10487     return ret;
10488 }
10489 
10490 /* duplicate the save stack */
10491 
10492 ANY *
10493 Perl_ss_dup(pTHX_ PerlInterpreter *proto_perl, CLONE_PARAMS* param)
10494 {
10495     dVAR;
10496     ANY * const ss	= proto_perl->Isavestack;
10497     const I32 max	= proto_perl->Isavestack_max;
10498     I32 ix		= proto_perl->Isavestack_ix;
10499     ANY *nss;
10500     SV *sv;
10501     GV *gv;
10502     AV *av;
10503     HV *hv;
10504     void* ptr;
10505     int intval;
10506     long longval;
10507     GP *gp;
10508     IV iv;
10509     I32 i;
10510     char *c = NULL;
10511     void (*dptr) (void*);
10512     void (*dxptr) (pTHX_ void*);
10513 
10514     Newxz(nss, max, ANY);
10515 
10516     while (ix > 0) {
10517 	const I32 type = POPINT(ss,ix);
10518 	TOPINT(nss,ix) = type;
10519 	switch (type) {
10520 	case SAVEt_HELEM:		/* hash element */
10521 	    sv = (SV*)POPPTR(ss,ix);
10522 	    TOPPTR(nss,ix) = sv_dup_inc(sv, param);
10523 	    /* fall through */
10524 	case SAVEt_ITEM:			/* normal string */
10525         case SAVEt_SV:				/* scalar reference */
10526 	    sv = (SV*)POPPTR(ss,ix);
10527 	    TOPPTR(nss,ix) = sv_dup_inc(sv, param);
10528 	    /* fall through */
10529 	case SAVEt_FREESV:
10530 	case SAVEt_MORTALIZESV:
10531 	    sv = (SV*)POPPTR(ss,ix);
10532 	    TOPPTR(nss,ix) = sv_dup_inc(sv, param);
10533 	    break;
10534 	case SAVEt_SHARED_PVREF:		/* char* in shared space */
10535 	    c = (char*)POPPTR(ss,ix);
10536 	    TOPPTR(nss,ix) = savesharedpv(c);
10537 	    ptr = POPPTR(ss,ix);
10538 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10539 	    break;
10540         case SAVEt_GENERIC_SVREF:		/* generic sv */
10541         case SAVEt_SVREF:			/* scalar reference */
10542 	    sv = (SV*)POPPTR(ss,ix);
10543 	    TOPPTR(nss,ix) = sv_dup_inc(sv, param);
10544 	    ptr = POPPTR(ss,ix);
10545 	    TOPPTR(nss,ix) = svp_dup_inc((SV**)ptr, proto_perl);/* XXXXX */
10546 	    break;
10547         case SAVEt_HV:				/* hash reference */
10548         case SAVEt_AV:				/* array reference */
10549 	    sv = (SV*) POPPTR(ss,ix);
10550 	    TOPPTR(nss,ix) = sv_dup_inc(sv, param);
10551 	    /* fall through */
10552 	case SAVEt_COMPPAD:
10553 	case SAVEt_NSTAB:
10554 	    sv = (SV*) POPPTR(ss,ix);
10555 	    TOPPTR(nss,ix) = sv_dup(sv, param);
10556 	    break;
10557 	case SAVEt_INT:				/* int reference */
10558 	    ptr = POPPTR(ss,ix);
10559 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10560 	    intval = (int)POPINT(ss,ix);
10561 	    TOPINT(nss,ix) = intval;
10562 	    break;
10563 	case SAVEt_LONG:			/* long reference */
10564 	    ptr = POPPTR(ss,ix);
10565 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10566 	    /* fall through */
10567 	case SAVEt_CLEARSV:
10568 	    longval = (long)POPLONG(ss,ix);
10569 	    TOPLONG(nss,ix) = longval;
10570 	    break;
10571 	case SAVEt_I32:				/* I32 reference */
10572 	case SAVEt_I16:				/* I16 reference */
10573 	case SAVEt_I8:				/* I8 reference */
10574 	case SAVEt_COP_ARYBASE:			/* call CopARYBASE_set */
10575 	    ptr = POPPTR(ss,ix);
10576 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10577 	    i = POPINT(ss,ix);
10578 	    TOPINT(nss,ix) = i;
10579 	    break;
10580 	case SAVEt_IV:				/* IV reference */
10581 	    ptr = POPPTR(ss,ix);
10582 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10583 	    iv = POPIV(ss,ix);
10584 	    TOPIV(nss,ix) = iv;
10585 	    break;
10586 	case SAVEt_HPTR:			/* HV* reference */
10587 	case SAVEt_APTR:			/* AV* reference */
10588 	case SAVEt_SPTR:			/* SV* reference */
10589 	    ptr = POPPTR(ss,ix);
10590 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10591 	    sv = (SV*)POPPTR(ss,ix);
10592 	    TOPPTR(nss,ix) = sv_dup(sv, param);
10593 	    break;
10594 	case SAVEt_VPTR:			/* random* reference */
10595 	    ptr = POPPTR(ss,ix);
10596 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10597 	    ptr = POPPTR(ss,ix);
10598 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10599 	    break;
10600 	case SAVEt_GENERIC_PVREF:		/* generic char* */
10601 	case SAVEt_PPTR:			/* char* reference */
10602 	    ptr = POPPTR(ss,ix);
10603 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10604 	    c = (char*)POPPTR(ss,ix);
10605 	    TOPPTR(nss,ix) = pv_dup(c);
10606 	    break;
10607 	case SAVEt_GP:				/* scalar reference */
10608 	    gp = (GP*)POPPTR(ss,ix);
10609 	    TOPPTR(nss,ix) = gp = gp_dup(gp, param);
10610 	    (void)GpREFCNT_inc(gp);
10611 	    gv = (GV*)POPPTR(ss,ix);
10612 	    TOPPTR(nss,ix) = gv_dup_inc(gv, param);
10613             break;
10614 	case SAVEt_FREEOP:
10615 	    ptr = POPPTR(ss,ix);
10616 	    if (ptr && (((OP*)ptr)->op_private & OPpREFCOUNTED)) {
10617 		/* these are assumed to be refcounted properly */
10618 		OP *o;
10619 		switch (((OP*)ptr)->op_type) {
10620 		case OP_LEAVESUB:
10621 		case OP_LEAVESUBLV:
10622 		case OP_LEAVEEVAL:
10623 		case OP_LEAVE:
10624 		case OP_SCOPE:
10625 		case OP_LEAVEWRITE:
10626 		    TOPPTR(nss,ix) = ptr;
10627 		    o = (OP*)ptr;
10628 		    OP_REFCNT_LOCK;
10629 		    (void) OpREFCNT_inc(o);
10630 		    OP_REFCNT_UNLOCK;
10631 		    break;
10632 		default:
10633 		    TOPPTR(nss,ix) = NULL;
10634 		    break;
10635 		}
10636 	    }
10637 	    else
10638 		TOPPTR(nss,ix) = NULL;
10639 	    break;
10640 	case SAVEt_FREEPV:
10641 	    c = (char*)POPPTR(ss,ix);
10642 	    TOPPTR(nss,ix) = pv_dup_inc(c);
10643 	    break;
10644 	case SAVEt_DELETE:
10645 	    hv = (HV*)POPPTR(ss,ix);
10646 	    TOPPTR(nss,ix) = hv_dup_inc(hv, param);
10647 	    c = (char*)POPPTR(ss,ix);
10648 	    TOPPTR(nss,ix) = pv_dup_inc(c);
10649 	    /* fall through */
10650 	case SAVEt_STACK_POS:		/* Position on Perl stack */
10651 	    i = POPINT(ss,ix);
10652 	    TOPINT(nss,ix) = i;
10653 	    break;
10654 	case SAVEt_DESTRUCTOR:
10655 	    ptr = POPPTR(ss,ix);
10656 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);	/* XXX quite arbitrary */
10657 	    dptr = POPDPTR(ss,ix);
10658 	    TOPDPTR(nss,ix) = DPTR2FPTR(void (*)(void*),
10659 					any_dup(FPTR2DPTR(void *, dptr),
10660 						proto_perl));
10661 	    break;
10662 	case SAVEt_DESTRUCTOR_X:
10663 	    ptr = POPPTR(ss,ix);
10664 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);	/* XXX quite arbitrary */
10665 	    dxptr = POPDXPTR(ss,ix);
10666 	    TOPDXPTR(nss,ix) = DPTR2FPTR(void (*)(pTHX_ void*),
10667 					 any_dup(FPTR2DPTR(void *, dxptr),
10668 						 proto_perl));
10669 	    break;
10670 	case SAVEt_REGCONTEXT:
10671 	case SAVEt_ALLOC:
10672 	    i = POPINT(ss,ix);
10673 	    TOPINT(nss,ix) = i;
10674 	    ix -= i;
10675 	    break;
10676 	case SAVEt_AELEM:		/* array element */
10677 	    sv = (SV*)POPPTR(ss,ix);
10678 	    TOPPTR(nss,ix) = sv_dup_inc(sv, param);
10679 	    i = POPINT(ss,ix);
10680 	    TOPINT(nss,ix) = i;
10681 	    av = (AV*)POPPTR(ss,ix);
10682 	    TOPPTR(nss,ix) = av_dup_inc(av, param);
10683 	    break;
10684 	case SAVEt_OP:
10685 	    ptr = POPPTR(ss,ix);
10686 	    TOPPTR(nss,ix) = ptr;
10687 	    break;
10688 	case SAVEt_HINTS:
10689 	    i = POPINT(ss,ix);
10690 	    TOPINT(nss,ix) = i;
10691 	    ptr = POPPTR(ss,ix);
10692 	    if (ptr) {
10693 		HINTS_REFCNT_LOCK;
10694 		((struct refcounted_he *)ptr)->refcounted_he_refcnt++;
10695 		HINTS_REFCNT_UNLOCK;
10696 	    }
10697 	    TOPPTR(nss,ix) = ptr;
10698 	    if (i & HINT_LOCALIZE_HH) {
10699 		hv = (HV*)POPPTR(ss,ix);
10700 		TOPPTR(nss,ix) = hv_dup_inc(hv, param);
10701 	    }
10702 	    break;
10703 	case SAVEt_PADSV:
10704 	    longval = (long)POPLONG(ss,ix);
10705 	    TOPLONG(nss,ix) = longval;
10706 	    ptr = POPPTR(ss,ix);
10707 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10708 	    sv = (SV*)POPPTR(ss,ix);
10709 	    TOPPTR(nss,ix) = sv_dup(sv, param);
10710 	    break;
10711 	case SAVEt_BOOL:
10712 	    ptr = POPPTR(ss,ix);
10713 	    TOPPTR(nss,ix) = any_dup(ptr, proto_perl);
10714 	    longval = (long)POPBOOL(ss,ix);
10715 	    TOPBOOL(nss,ix) = (bool)longval;
10716 	    break;
10717 	case SAVEt_SET_SVFLAGS:
10718 	    i = POPINT(ss,ix);
10719 	    TOPINT(nss,ix) = i;
10720 	    i = POPINT(ss,ix);
10721 	    TOPINT(nss,ix) = i;
10722 	    sv = (SV*)POPPTR(ss,ix);
10723 	    TOPPTR(nss,ix) = sv_dup(sv, param);
10724 	    break;
10725 	case SAVEt_RE_STATE:
10726 	    {
10727 		const struct re_save_state *const old_state
10728 		    = (struct re_save_state *)
10729 		    (ss + ix - SAVESTACK_ALLOC_FOR_RE_SAVE_STATE);
10730 		struct re_save_state *const new_state
10731 		    = (struct re_save_state *)
10732 		    (nss + ix - SAVESTACK_ALLOC_FOR_RE_SAVE_STATE);
10733 
10734 		Copy(old_state, new_state, 1, struct re_save_state);
10735 		ix -= SAVESTACK_ALLOC_FOR_RE_SAVE_STATE;
10736 
10737 		new_state->re_state_bostr
10738 		    = pv_dup(old_state->re_state_bostr);
10739 		new_state->re_state_reginput
10740 		    = pv_dup(old_state->re_state_reginput);
10741 		new_state->re_state_regeol
10742 		    = pv_dup(old_state->re_state_regeol);
10743 		new_state->re_state_regoffs
10744 		    = (regexp_paren_pair*)
10745 			any_dup(old_state->re_state_regoffs, proto_perl);
10746 		new_state->re_state_reglastparen
10747 		    = (U32*) any_dup(old_state->re_state_reglastparen,
10748 			      proto_perl);
10749 		new_state->re_state_reglastcloseparen
10750 		    = (U32*)any_dup(old_state->re_state_reglastcloseparen,
10751 			      proto_perl);
10752 		/* XXX This just has to be broken. The old save_re_context
10753 		   code did SAVEGENERICPV(PL_reg_start_tmp);
10754 		   PL_reg_start_tmp is char **.
10755 		   Look above to what the dup code does for
10756 		   SAVEt_GENERIC_PVREF
10757 		   It can never have worked.
10758 		   So this is merely a faithful copy of the exiting bug:  */
10759 		new_state->re_state_reg_start_tmp
10760 		    = (char **) pv_dup((char *)
10761 				      old_state->re_state_reg_start_tmp);
10762 		/* I assume that it only ever "worked" because no-one called
10763 		   (pseudo)fork while the regexp engine had re-entered itself.
10764 		*/
10765 #ifdef PERL_OLD_COPY_ON_WRITE
10766 		new_state->re_state_nrs
10767 		    = sv_dup(old_state->re_state_nrs, param);
10768 #endif
10769 		new_state->re_state_reg_magic
10770 		    = (MAGIC*) any_dup(old_state->re_state_reg_magic,
10771 			       proto_perl);
10772 		new_state->re_state_reg_oldcurpm
10773 		    = (PMOP*) any_dup(old_state->re_state_reg_oldcurpm,
10774 			      proto_perl);
10775 		new_state->re_state_reg_curpm
10776 		    = (PMOP*)  any_dup(old_state->re_state_reg_curpm,
10777 			       proto_perl);
10778 		new_state->re_state_reg_oldsaved
10779 		    = pv_dup(old_state->re_state_reg_oldsaved);
10780 		new_state->re_state_reg_poscache
10781 		    = pv_dup(old_state->re_state_reg_poscache);
10782 		new_state->re_state_reg_starttry
10783 		    = pv_dup(old_state->re_state_reg_starttry);
10784 		break;
10785 	    }
10786 	case SAVEt_COMPILE_WARNINGS:
10787 	    ptr = POPPTR(ss,ix);
10788 	    TOPPTR(nss,ix) = DUP_WARNINGS((STRLEN*)ptr);
10789 	    break;
10790 	case SAVEt_PARSER:
10791 	    ptr = POPPTR(ss,ix);
10792 	    TOPPTR(nss,ix) = parser_dup((const yy_parser*)ptr, param);
10793 	    break;
10794 	default:
10795 	    Perl_croak(aTHX_
10796 		       "panic: ss_dup inconsistency (%"IVdf")", (IV) type);
10797 	}
10798     }
10799 
10800     return nss;
10801 }
10802 
10803 
10804 /* if sv is a stash, call $class->CLONE_SKIP(), and set the SVphv_CLONEABLE
10805  * flag to the result. This is done for each stash before cloning starts,
10806  * so we know which stashes want their objects cloned */
10807 
10808 static void
10809 do_mark_cloneable_stash(pTHX_ SV *sv)
10810 {
10811     const HEK * const hvname = HvNAME_HEK((HV*)sv);
10812     if (hvname) {
10813 	GV* const cloner = gv_fetchmethod_autoload((HV*)sv, "CLONE_SKIP", 0);
10814 	SvFLAGS(sv) |= SVphv_CLONEABLE; /* clone objects by default */
10815 	if (cloner && GvCV(cloner)) {
10816 	    dSP;
10817 	    UV status;
10818 
10819 	    ENTER;
10820 	    SAVETMPS;
10821 	    PUSHMARK(SP);
10822 	    XPUSHs(sv_2mortal(newSVhek(hvname)));
10823 	    PUTBACK;
10824 	    call_sv((SV*)GvCV(cloner), G_SCALAR);
10825 	    SPAGAIN;
10826 	    status = POPu;
10827 	    PUTBACK;
10828 	    FREETMPS;
10829 	    LEAVE;
10830 	    if (status)
10831 		SvFLAGS(sv) &= ~SVphv_CLONEABLE;
10832 	}
10833     }
10834 }
10835 
10836 
10837 
10838 /*
10839 =for apidoc perl_clone
10840 
10841 Create and return a new interpreter by cloning the current one.
10842 
10843 perl_clone takes these flags as parameters:
10844 
10845 CLONEf_COPY_STACKS - is used to, well, copy the stacks also,
10846 without it we only clone the data and zero the stacks,
10847 with it we copy the stacks and the new perl interpreter is
10848 ready to run at the exact same point as the previous one.
10849 The pseudo-fork code uses COPY_STACKS while the
10850 threads->create doesn't.
10851 
10852 CLONEf_KEEP_PTR_TABLE
10853 perl_clone keeps a ptr_table with the pointer of the old
10854 variable as a key and the new variable as a value,
10855 this allows it to check if something has been cloned and not
10856 clone it again but rather just use the value and increase the
10857 refcount. If KEEP_PTR_TABLE is not set then perl_clone will kill
10858 the ptr_table using the function
10859 C<ptr_table_free(PL_ptr_table); PL_ptr_table = NULL;>,
10860 reason to keep it around is if you want to dup some of your own
10861 variable who are outside the graph perl scans, example of this
10862 code is in threads.xs create
10863 
10864 CLONEf_CLONE_HOST
10865 This is a win32 thing, it is ignored on unix, it tells perls
10866 win32host code (which is c++) to clone itself, this is needed on
10867 win32 if you want to run two threads at the same time,
10868 if you just want to do some stuff in a separate perl interpreter
10869 and then throw it away and return to the original one,
10870 you don't need to do anything.
10871 
10872 =cut
10873 */
10874 
10875 /* XXX the above needs expanding by someone who actually understands it ! */
10876 EXTERN_C PerlInterpreter *
10877 perl_clone_host(PerlInterpreter* proto_perl, UV flags);
10878 
10879 PerlInterpreter *
10880 perl_clone(PerlInterpreter *proto_perl, UV flags)
10881 {
10882    dVAR;
10883 #ifdef PERL_IMPLICIT_SYS
10884 
10885    /* perlhost.h so we need to call into it
10886    to clone the host, CPerlHost should have a c interface, sky */
10887 
10888    if (flags & CLONEf_CLONE_HOST) {
10889        return perl_clone_host(proto_perl,flags);
10890    }
10891    return perl_clone_using(proto_perl, flags,
10892 			    proto_perl->IMem,
10893 			    proto_perl->IMemShared,
10894 			    proto_perl->IMemParse,
10895 			    proto_perl->IEnv,
10896 			    proto_perl->IStdIO,
10897 			    proto_perl->ILIO,
10898 			    proto_perl->IDir,
10899 			    proto_perl->ISock,
10900 			    proto_perl->IProc);
10901 }
10902 
10903 PerlInterpreter *
10904 perl_clone_using(PerlInterpreter *proto_perl, UV flags,
10905 		 struct IPerlMem* ipM, struct IPerlMem* ipMS,
10906 		 struct IPerlMem* ipMP, struct IPerlEnv* ipE,
10907 		 struct IPerlStdIO* ipStd, struct IPerlLIO* ipLIO,
10908 		 struct IPerlDir* ipD, struct IPerlSock* ipS,
10909 		 struct IPerlProc* ipP)
10910 {
10911     /* XXX many of the string copies here can be optimized if they're
10912      * constants; they need to be allocated as common memory and just
10913      * their pointers copied. */
10914 
10915     IV i;
10916     CLONE_PARAMS clone_params;
10917     CLONE_PARAMS* const param = &clone_params;
10918 
10919     PerlInterpreter * const my_perl = (PerlInterpreter*)(*ipM->pMalloc)(ipM, sizeof(PerlInterpreter));
10920     /* for each stash, determine whether its objects should be cloned */
10921     S_visit(proto_perl, do_mark_cloneable_stash, SVt_PVHV, SVTYPEMASK);
10922     PERL_SET_THX(my_perl);
10923 
10924 #  ifdef DEBUGGING
10925     PoisonNew(my_perl, 1, PerlInterpreter);
10926     PL_op = NULL;
10927     PL_curcop = NULL;
10928     PL_markstack = 0;
10929     PL_scopestack = 0;
10930     PL_savestack = 0;
10931     PL_savestack_ix = 0;
10932     PL_savestack_max = -1;
10933     PL_sig_pending = 0;
10934     PL_parser = NULL;
10935     Zero(&PL_debug_pad, 1, struct perl_debug_pad);
10936 #  else	/* !DEBUGGING */
10937     Zero(my_perl, 1, PerlInterpreter);
10938 #  endif	/* DEBUGGING */
10939 
10940     /* host pointers */
10941     PL_Mem		= ipM;
10942     PL_MemShared	= ipMS;
10943     PL_MemParse		= ipMP;
10944     PL_Env		= ipE;
10945     PL_StdIO		= ipStd;
10946     PL_LIO		= ipLIO;
10947     PL_Dir		= ipD;
10948     PL_Sock		= ipS;
10949     PL_Proc		= ipP;
10950 #else		/* !PERL_IMPLICIT_SYS */
10951     IV i;
10952     CLONE_PARAMS clone_params;
10953     CLONE_PARAMS* param = &clone_params;
10954     PerlInterpreter * const my_perl = (PerlInterpreter*)PerlMem_malloc(sizeof(PerlInterpreter));
10955     /* for each stash, determine whether its objects should be cloned */
10956     S_visit(proto_perl, do_mark_cloneable_stash, SVt_PVHV, SVTYPEMASK);
10957     PERL_SET_THX(my_perl);
10958 
10959 #    ifdef DEBUGGING
10960     PoisonNew(my_perl, 1, PerlInterpreter);
10961     PL_op = NULL;
10962     PL_curcop = NULL;
10963     PL_markstack = 0;
10964     PL_scopestack = 0;
10965     PL_savestack = 0;
10966     PL_savestack_ix = 0;
10967     PL_savestack_max = -1;
10968     PL_sig_pending = 0;
10969     PL_parser = NULL;
10970     Zero(&PL_debug_pad, 1, struct perl_debug_pad);
10971 #    else	/* !DEBUGGING */
10972     Zero(my_perl, 1, PerlInterpreter);
10973 #    endif	/* DEBUGGING */
10974 #endif		/* PERL_IMPLICIT_SYS */
10975     param->flags = flags;
10976     param->proto_perl = proto_perl;
10977 
10978     INIT_TRACK_MEMPOOL(my_perl->Imemory_debug_header, my_perl);
10979 
10980     PL_body_arenas = NULL;
10981     Zero(&PL_body_roots, 1, PL_body_roots);
10982 
10983     PL_nice_chunk	= NULL;
10984     PL_nice_chunk_size	= 0;
10985     PL_sv_count		= 0;
10986     PL_sv_objcount	= 0;
10987     PL_sv_root		= NULL;
10988     PL_sv_arenaroot	= NULL;
10989 
10990     PL_debug		= proto_perl->Idebug;
10991 
10992     PL_hash_seed	= proto_perl->Ihash_seed;
10993     PL_rehash_seed	= proto_perl->Irehash_seed;
10994 
10995 #ifdef USE_REENTRANT_API
10996     /* XXX: things like -Dm will segfault here in perlio, but doing
10997      *  PERL_SET_CONTEXT(proto_perl);
10998      * breaks too many other things
10999      */
11000     Perl_reentrant_init(aTHX);
11001 #endif
11002 
11003     /* create SV map for pointer relocation */
11004     PL_ptr_table = ptr_table_new();
11005 
11006     /* initialize these special pointers as early as possible */
11007     SvANY(&PL_sv_undef)		= NULL;
11008     SvREFCNT(&PL_sv_undef)	= (~(U32)0)/2;
11009     SvFLAGS(&PL_sv_undef)	= SVf_READONLY|SVt_NULL;
11010     ptr_table_store(PL_ptr_table, &proto_perl->Isv_undef, &PL_sv_undef);
11011 
11012     SvANY(&PL_sv_no)		= new_XPVNV();
11013     SvREFCNT(&PL_sv_no)		= (~(U32)0)/2;
11014     SvFLAGS(&PL_sv_no)		= SVp_IOK|SVf_IOK|SVp_NOK|SVf_NOK
11015 				  |SVp_POK|SVf_POK|SVf_READONLY|SVt_PVNV;
11016     SvPV_set(&PL_sv_no, savepvn(PL_No, 0));
11017     SvCUR_set(&PL_sv_no, 0);
11018     SvLEN_set(&PL_sv_no, 1);
11019     SvIV_set(&PL_sv_no, 0);
11020     SvNV_set(&PL_sv_no, 0);
11021     ptr_table_store(PL_ptr_table, &proto_perl->Isv_no, &PL_sv_no);
11022 
11023     SvANY(&PL_sv_yes)		= new_XPVNV();
11024     SvREFCNT(&PL_sv_yes)	= (~(U32)0)/2;
11025     SvFLAGS(&PL_sv_yes)		= SVp_IOK|SVf_IOK|SVp_NOK|SVf_NOK
11026 				  |SVp_POK|SVf_POK|SVf_READONLY|SVt_PVNV;
11027     SvPV_set(&PL_sv_yes, savepvn(PL_Yes, 1));
11028     SvCUR_set(&PL_sv_yes, 1);
11029     SvLEN_set(&PL_sv_yes, 2);
11030     SvIV_set(&PL_sv_yes, 1);
11031     SvNV_set(&PL_sv_yes, 1);
11032     ptr_table_store(PL_ptr_table, &proto_perl->Isv_yes, &PL_sv_yes);
11033 
11034     /* create (a non-shared!) shared string table */
11035     PL_strtab		= newHV();
11036     HvSHAREKEYS_off(PL_strtab);
11037     hv_ksplit(PL_strtab, HvTOTALKEYS(proto_perl->Istrtab));
11038     ptr_table_store(PL_ptr_table, proto_perl->Istrtab, PL_strtab);
11039 
11040     PL_compiling = proto_perl->Icompiling;
11041 
11042     /* These two PVs will be free'd special way so must set them same way op.c does */
11043     PL_compiling.cop_stashpv = savesharedpv(PL_compiling.cop_stashpv);
11044     ptr_table_store(PL_ptr_table, proto_perl->Icompiling.cop_stashpv, PL_compiling.cop_stashpv);
11045 
11046     PL_compiling.cop_file    = savesharedpv(PL_compiling.cop_file);
11047     ptr_table_store(PL_ptr_table, proto_perl->Icompiling.cop_file, PL_compiling.cop_file);
11048 
11049     ptr_table_store(PL_ptr_table, &proto_perl->Icompiling, &PL_compiling);
11050     PL_compiling.cop_warnings = DUP_WARNINGS(PL_compiling.cop_warnings);
11051     if (PL_compiling.cop_hints_hash) {
11052 	HINTS_REFCNT_LOCK;
11053 	PL_compiling.cop_hints_hash->refcounted_he_refcnt++;
11054 	HINTS_REFCNT_UNLOCK;
11055     }
11056     PL_curcop		= (COP*)any_dup(proto_perl->Icurcop, proto_perl);
11057 #ifdef PERL_DEBUG_READONLY_OPS
11058     PL_slabs = NULL;
11059     PL_slab_count = 0;
11060 #endif
11061 
11062     /* pseudo environmental stuff */
11063     PL_origargc		= proto_perl->Iorigargc;
11064     PL_origargv		= proto_perl->Iorigargv;
11065 
11066     param->stashes      = newAV();  /* Setup array of objects to call clone on */
11067 
11068     /* Set tainting stuff before PerlIO_debug can possibly get called */
11069     PL_tainting		= proto_perl->Itainting;
11070     PL_taint_warn	= proto_perl->Itaint_warn;
11071 
11072 #ifdef PERLIO_LAYERS
11073     /* Clone PerlIO tables as soon as we can handle general xx_dup() */
11074     PerlIO_clone(aTHX_ proto_perl, param);
11075 #endif
11076 
11077     PL_envgv		= gv_dup(proto_perl->Ienvgv, param);
11078     PL_incgv		= gv_dup(proto_perl->Iincgv, param);
11079     PL_hintgv		= gv_dup(proto_perl->Ihintgv, param);
11080     PL_origfilename	= SAVEPV(proto_perl->Iorigfilename);
11081     PL_diehook		= sv_dup_inc(proto_perl->Idiehook, param);
11082     PL_warnhook		= sv_dup_inc(proto_perl->Iwarnhook, param);
11083 
11084     /* switches */
11085     PL_minus_c		= proto_perl->Iminus_c;
11086     PL_patchlevel	= sv_dup_inc(proto_perl->Ipatchlevel, param);
11087     PL_localpatches	= proto_perl->Ilocalpatches;
11088     PL_splitstr		= proto_perl->Isplitstr;
11089     PL_preprocess	= proto_perl->Ipreprocess;
11090     PL_minus_n		= proto_perl->Iminus_n;
11091     PL_minus_p		= proto_perl->Iminus_p;
11092     PL_minus_l		= proto_perl->Iminus_l;
11093     PL_minus_a		= proto_perl->Iminus_a;
11094     PL_minus_E		= proto_perl->Iminus_E;
11095     PL_minus_F		= proto_perl->Iminus_F;
11096     PL_doswitches	= proto_perl->Idoswitches;
11097     PL_dowarn		= proto_perl->Idowarn;
11098     PL_doextract	= proto_perl->Idoextract;
11099     PL_sawampersand	= proto_perl->Isawampersand;
11100     PL_unsafe		= proto_perl->Iunsafe;
11101     PL_inplace		= SAVEPV(proto_perl->Iinplace);
11102     PL_e_script		= sv_dup_inc(proto_perl->Ie_script, param);
11103     PL_perldb		= proto_perl->Iperldb;
11104     PL_perl_destruct_level = proto_perl->Iperl_destruct_level;
11105     PL_exit_flags       = proto_perl->Iexit_flags;
11106 
11107     /* magical thingies */
11108     /* XXX time(&PL_basetime) when asked for? */
11109     PL_basetime		= proto_perl->Ibasetime;
11110     PL_formfeed		= sv_dup(proto_perl->Iformfeed, param);
11111 
11112     PL_maxsysfd		= proto_perl->Imaxsysfd;
11113     PL_statusvalue	= proto_perl->Istatusvalue;
11114 #ifdef VMS
11115     PL_statusvalue_vms	= proto_perl->Istatusvalue_vms;
11116 #else
11117     PL_statusvalue_posix = proto_perl->Istatusvalue_posix;
11118 #endif
11119     PL_encoding		= sv_dup(proto_perl->Iencoding, param);
11120 
11121     sv_setpvn(PERL_DEBUG_PAD(0), "", 0);	/* For regex debugging. */
11122     sv_setpvn(PERL_DEBUG_PAD(1), "", 0);	/* ext/re needs these */
11123     sv_setpvn(PERL_DEBUG_PAD(2), "", 0);	/* even without DEBUGGING. */
11124 
11125 
11126     /* RE engine related */
11127     Zero(&PL_reg_state, 1, struct re_save_state);
11128     PL_reginterp_cnt	= 0;
11129     PL_regmatch_slab	= NULL;
11130 
11131     /* Clone the regex array */
11132     PL_regex_padav = newAV();
11133     {
11134 	const I32 len = av_len((AV*)proto_perl->Iregex_padav);
11135 	SV* const * const regexen = AvARRAY((AV*)proto_perl->Iregex_padav);
11136 	IV i;
11137 	av_push(PL_regex_padav, sv_dup_inc_NN(regexen[0],param));
11138 	for(i = 1; i <= len; i++) {
11139 	    const SV * const regex = regexen[i];
11140 	    SV * const sv =
11141 		SvREPADTMP(regex)
11142 		    ? sv_dup_inc(regex, param)
11143 		    : SvREFCNT_inc(
11144 			newSViv(PTR2IV(CALLREGDUPE(
11145 				INT2PTR(REGEXP *, SvIVX(regex)), param))))
11146 		;
11147 	    if (SvFLAGS(regex) & SVf_BREAK)
11148 		SvFLAGS(sv) |= SVf_BREAK; /* unrefcnted PL_curpm */
11149 	    av_push(PL_regex_padav, sv);
11150 	}
11151     }
11152     PL_regex_pad = AvARRAY(PL_regex_padav);
11153 
11154     /* shortcuts to various I/O objects */
11155     PL_stdingv		= gv_dup(proto_perl->Istdingv, param);
11156     PL_stderrgv		= gv_dup(proto_perl->Istderrgv, param);
11157     PL_defgv		= gv_dup(proto_perl->Idefgv, param);
11158     PL_argvgv		= gv_dup(proto_perl->Iargvgv, param);
11159     PL_argvoutgv	= gv_dup(proto_perl->Iargvoutgv, param);
11160     PL_argvout_stack	= av_dup_inc(proto_perl->Iargvout_stack, param);
11161 
11162     /* shortcuts to regexp stuff */
11163     PL_replgv		= gv_dup(proto_perl->Ireplgv, param);
11164 
11165     /* shortcuts to misc objects */
11166     PL_errgv		= gv_dup(proto_perl->Ierrgv, param);
11167 
11168     /* shortcuts to debugging objects */
11169     PL_DBgv		= gv_dup(proto_perl->IDBgv, param);
11170     PL_DBline		= gv_dup(proto_perl->IDBline, param);
11171     PL_DBsub		= gv_dup(proto_perl->IDBsub, param);
11172     PL_DBsingle		= sv_dup(proto_perl->IDBsingle, param);
11173     PL_DBtrace		= sv_dup(proto_perl->IDBtrace, param);
11174     PL_DBsignal		= sv_dup(proto_perl->IDBsignal, param);
11175     PL_dbargs		= av_dup(proto_perl->Idbargs, param);
11176 
11177     /* symbol tables */
11178     PL_defstash		= hv_dup_inc(proto_perl->Idefstash, param);
11179     PL_curstash		= hv_dup(proto_perl->Icurstash, param);
11180     PL_debstash		= hv_dup(proto_perl->Idebstash, param);
11181     PL_globalstash	= hv_dup(proto_perl->Iglobalstash, param);
11182     PL_curstname	= sv_dup_inc(proto_perl->Icurstname, param);
11183 
11184     PL_beginav		= av_dup_inc(proto_perl->Ibeginav, param);
11185     PL_beginav_save	= av_dup_inc(proto_perl->Ibeginav_save, param);
11186     PL_checkav_save	= av_dup_inc(proto_perl->Icheckav_save, param);
11187     PL_unitcheckav      = av_dup_inc(proto_perl->Iunitcheckav, param);
11188     PL_unitcheckav_save = av_dup_inc(proto_perl->Iunitcheckav_save, param);
11189     PL_endav		= av_dup_inc(proto_perl->Iendav, param);
11190     PL_checkav		= av_dup_inc(proto_perl->Icheckav, param);
11191     PL_initav		= av_dup_inc(proto_perl->Iinitav, param);
11192 
11193     PL_sub_generation	= proto_perl->Isub_generation;
11194     PL_isarev		= hv_dup_inc(proto_perl->Iisarev, param);
11195 
11196     /* funky return mechanisms */
11197     PL_forkprocess	= proto_perl->Iforkprocess;
11198 
11199     /* subprocess state */
11200     PL_fdpid		= av_dup_inc(proto_perl->Ifdpid, param);
11201 
11202     /* internal state */
11203     PL_maxo		= proto_perl->Imaxo;
11204     if (proto_perl->Iop_mask)
11205 	PL_op_mask	= SAVEPVN(proto_perl->Iop_mask, PL_maxo);
11206     else
11207 	PL_op_mask 	= NULL;
11208     /* PL_asserting        = proto_perl->Iasserting; */
11209 
11210     /* current interpreter roots */
11211     PL_main_cv		= cv_dup_inc(proto_perl->Imain_cv, param);
11212     OP_REFCNT_LOCK;
11213     PL_main_root	= OpREFCNT_inc(proto_perl->Imain_root);
11214     OP_REFCNT_UNLOCK;
11215     PL_main_start	= proto_perl->Imain_start;
11216     PL_eval_root	= proto_perl->Ieval_root;
11217     PL_eval_start	= proto_perl->Ieval_start;
11218 
11219     /* runtime control stuff */
11220     PL_curcopdb		= (COP*)any_dup(proto_perl->Icurcopdb, proto_perl);
11221 
11222     PL_filemode		= proto_perl->Ifilemode;
11223     PL_lastfd		= proto_perl->Ilastfd;
11224     PL_oldname		= proto_perl->Ioldname;		/* XXX not quite right */
11225     PL_Argv		= NULL;
11226     PL_Cmd		= NULL;
11227     PL_gensym		= proto_perl->Igensym;
11228     PL_preambleav	= av_dup_inc(proto_perl->Ipreambleav, param);
11229     PL_laststatval	= proto_perl->Ilaststatval;
11230     PL_laststype	= proto_perl->Ilaststype;
11231     PL_mess_sv		= NULL;
11232 
11233     PL_ors_sv		= sv_dup_inc(proto_perl->Iors_sv, param);
11234 
11235     /* interpreter atexit processing */
11236     PL_exitlistlen	= proto_perl->Iexitlistlen;
11237     if (PL_exitlistlen) {
11238 	Newx(PL_exitlist, PL_exitlistlen, PerlExitListEntry);
11239 	Copy(proto_perl->Iexitlist, PL_exitlist, PL_exitlistlen, PerlExitListEntry);
11240     }
11241     else
11242 	PL_exitlist	= (PerlExitListEntry*)NULL;
11243 
11244     PL_my_cxt_size = proto_perl->Imy_cxt_size;
11245     if (PL_my_cxt_size) {
11246 	Newx(PL_my_cxt_list, PL_my_cxt_size, void *);
11247 	Copy(proto_perl->Imy_cxt_list, PL_my_cxt_list, PL_my_cxt_size, void *);
11248 #ifdef PERL_GLOBAL_STRUCT_PRIVATE
11249 	Newx(PL_my_cxt_keys, PL_my_cxt_size, const char *);
11250 	Copy(proto_perl->Imy_cxt_keys, PL_my_cxt_keys, PL_my_cxt_size, char *);
11251 #endif
11252     }
11253     else {
11254 	PL_my_cxt_list	= (void**)NULL;
11255 #ifdef PERL_GLOBAL_STRUCT_PRIVATE
11256 	PL_my_cxt_keys	= (const char**)NULL;
11257 #endif
11258     }
11259     PL_modglobal	= hv_dup_inc(proto_perl->Imodglobal, param);
11260     PL_custom_op_names  = hv_dup_inc(proto_perl->Icustom_op_names,param);
11261     PL_custom_op_descs  = hv_dup_inc(proto_perl->Icustom_op_descs,param);
11262 
11263     PL_profiledata	= NULL;
11264 
11265     PL_compcv			= cv_dup(proto_perl->Icompcv, param);
11266 
11267     PAD_CLONE_VARS(proto_perl, param);
11268 
11269 #ifdef HAVE_INTERP_INTERN
11270     sys_intern_dup(&proto_perl->Isys_intern, &PL_sys_intern);
11271 #endif
11272 
11273     /* more statics moved here */
11274     PL_generation	= proto_perl->Igeneration;
11275     PL_DBcv		= cv_dup(proto_perl->IDBcv, param);
11276 
11277     PL_in_clean_objs	= proto_perl->Iin_clean_objs;
11278     PL_in_clean_all	= proto_perl->Iin_clean_all;
11279 
11280     PL_uid		= proto_perl->Iuid;
11281     PL_euid		= proto_perl->Ieuid;
11282     PL_gid		= proto_perl->Igid;
11283     PL_egid		= proto_perl->Iegid;
11284     PL_nomemok		= proto_perl->Inomemok;
11285     PL_an		= proto_perl->Ian;
11286     PL_evalseq		= proto_perl->Ievalseq;
11287     PL_origenviron	= proto_perl->Iorigenviron;	/* XXX not quite right */
11288     PL_origalen		= proto_perl->Iorigalen;
11289 #ifdef PERL_USES_PL_PIDSTATUS
11290     PL_pidstatus	= newHV();			/* XXX flag for cloning? */
11291 #endif
11292     PL_osname		= SAVEPV(proto_perl->Iosname);
11293     PL_sighandlerp	= proto_perl->Isighandlerp;
11294 
11295     PL_runops		= proto_perl->Irunops;
11296 
11297     PL_parser		= parser_dup(proto_perl->Iparser, param);
11298 
11299     PL_subline		= proto_perl->Isubline;
11300     PL_subname		= sv_dup_inc(proto_perl->Isubname, param);
11301 
11302 #ifdef FCRYPT
11303     PL_cryptseen	= proto_perl->Icryptseen;
11304 #endif
11305 
11306     PL_hints		= proto_perl->Ihints;
11307 
11308     PL_amagic_generation	= proto_perl->Iamagic_generation;
11309 
11310 #ifdef USE_LOCALE_COLLATE
11311     PL_collation_ix	= proto_perl->Icollation_ix;
11312     PL_collation_name	= SAVEPV(proto_perl->Icollation_name);
11313     PL_collation_standard	= proto_perl->Icollation_standard;
11314     PL_collxfrm_base	= proto_perl->Icollxfrm_base;
11315     PL_collxfrm_mult	= proto_perl->Icollxfrm_mult;
11316 #endif /* USE_LOCALE_COLLATE */
11317 
11318 #ifdef USE_LOCALE_NUMERIC
11319     PL_numeric_name	= SAVEPV(proto_perl->Inumeric_name);
11320     PL_numeric_standard	= proto_perl->Inumeric_standard;
11321     PL_numeric_local	= proto_perl->Inumeric_local;
11322     PL_numeric_radix_sv	= sv_dup_inc(proto_perl->Inumeric_radix_sv, param);
11323 #endif /* !USE_LOCALE_NUMERIC */
11324 
11325     /* utf8 character classes */
11326     PL_utf8_alnum	= sv_dup_inc(proto_perl->Iutf8_alnum, param);
11327     PL_utf8_alnumc	= sv_dup_inc(proto_perl->Iutf8_alnumc, param);
11328     PL_utf8_ascii	= sv_dup_inc(proto_perl->Iutf8_ascii, param);
11329     PL_utf8_alpha	= sv_dup_inc(proto_perl->Iutf8_alpha, param);
11330     PL_utf8_space	= sv_dup_inc(proto_perl->Iutf8_space, param);
11331     PL_utf8_cntrl	= sv_dup_inc(proto_perl->Iutf8_cntrl, param);
11332     PL_utf8_graph	= sv_dup_inc(proto_perl->Iutf8_graph, param);
11333     PL_utf8_digit	= sv_dup_inc(proto_perl->Iutf8_digit, param);
11334     PL_utf8_upper	= sv_dup_inc(proto_perl->Iutf8_upper, param);
11335     PL_utf8_lower	= sv_dup_inc(proto_perl->Iutf8_lower, param);
11336     PL_utf8_print	= sv_dup_inc(proto_perl->Iutf8_print, param);
11337     PL_utf8_punct	= sv_dup_inc(proto_perl->Iutf8_punct, param);
11338     PL_utf8_xdigit	= sv_dup_inc(proto_perl->Iutf8_xdigit, param);
11339     PL_utf8_mark	= sv_dup_inc(proto_perl->Iutf8_mark, param);
11340     PL_utf8_toupper	= sv_dup_inc(proto_perl->Iutf8_toupper, param);
11341     PL_utf8_totitle	= sv_dup_inc(proto_perl->Iutf8_totitle, param);
11342     PL_utf8_tolower	= sv_dup_inc(proto_perl->Iutf8_tolower, param);
11343     PL_utf8_tofold	= sv_dup_inc(proto_perl->Iutf8_tofold, param);
11344     PL_utf8_idstart	= sv_dup_inc(proto_perl->Iutf8_idstart, param);
11345     PL_utf8_idcont	= sv_dup_inc(proto_perl->Iutf8_idcont, param);
11346 
11347     /* Did the locale setup indicate UTF-8? */
11348     PL_utf8locale	= proto_perl->Iutf8locale;
11349     /* Unicode features (see perlrun/-C) */
11350     PL_unicode		= proto_perl->Iunicode;
11351 
11352     /* Pre-5.8 signals control */
11353     PL_signals		= proto_perl->Isignals;
11354 
11355     /* times() ticks per second */
11356     PL_clocktick	= proto_perl->Iclocktick;
11357 
11358     /* Recursion stopper for PerlIO_find_layer */
11359     PL_in_load_module	= proto_perl->Iin_load_module;
11360 
11361     /* sort() routine */
11362     PL_sort_RealCmp	= proto_perl->Isort_RealCmp;
11363 
11364     /* Not really needed/useful since the reenrant_retint is "volatile",
11365      * but do it for consistency's sake. */
11366     PL_reentrant_retint	= proto_perl->Ireentrant_retint;
11367 
11368     /* Hooks to shared SVs and locks. */
11369     PL_sharehook	= proto_perl->Isharehook;
11370     PL_lockhook		= proto_perl->Ilockhook;
11371     PL_unlockhook	= proto_perl->Iunlockhook;
11372     PL_threadhook	= proto_perl->Ithreadhook;
11373     PL_destroyhook	= proto_perl->Idestroyhook;
11374 
11375 #ifdef THREADS_HAVE_PIDS
11376     PL_ppid		= proto_perl->Ippid;
11377 #endif
11378 
11379     /* swatch cache */
11380     PL_last_swash_hv	= NULL;	/* reinits on demand */
11381     PL_last_swash_klen	= 0;
11382     PL_last_swash_key[0]= '\0';
11383     PL_last_swash_tmps	= (U8*)NULL;
11384     PL_last_swash_slen	= 0;
11385 
11386     PL_glob_index	= proto_perl->Iglob_index;
11387     PL_srand_called	= proto_perl->Isrand_called;
11388     PL_bitcount		= NULL;	/* reinits on demand */
11389 
11390     if (proto_perl->Ipsig_pend) {
11391 	Newxz(PL_psig_pend, SIG_SIZE, int);
11392     }
11393     else {
11394 	PL_psig_pend	= (int*)NULL;
11395     }
11396 
11397     if (proto_perl->Ipsig_ptr) {
11398 	Newxz(PL_psig_ptr,  SIG_SIZE, SV*);
11399 	Newxz(PL_psig_name, SIG_SIZE, SV*);
11400 	for (i = 1; i < SIG_SIZE; i++) {
11401 	    PL_psig_ptr[i]  = sv_dup_inc(proto_perl->Ipsig_ptr[i], param);
11402 	    PL_psig_name[i] = sv_dup_inc(proto_perl->Ipsig_name[i], param);
11403 	}
11404     }
11405     else {
11406 	PL_psig_ptr	= (SV**)NULL;
11407 	PL_psig_name	= (SV**)NULL;
11408     }
11409 
11410     /* intrpvar.h stuff */
11411 
11412     if (flags & CLONEf_COPY_STACKS) {
11413 	/* next allocation will be PL_tmps_stack[PL_tmps_ix+1] */
11414 	PL_tmps_ix		= proto_perl->Itmps_ix;
11415 	PL_tmps_max		= proto_perl->Itmps_max;
11416 	PL_tmps_floor		= proto_perl->Itmps_floor;
11417 	Newxz(PL_tmps_stack, PL_tmps_max, SV*);
11418 	i = 0;
11419 	while (i <= PL_tmps_ix) {
11420 	    PL_tmps_stack[i]	= sv_dup_inc(proto_perl->Itmps_stack[i], param);
11421 	    ++i;
11422 	}
11423 
11424 	/* next PUSHMARK() sets *(PL_markstack_ptr+1) */
11425 	i = proto_perl->Imarkstack_max - proto_perl->Imarkstack;
11426 	Newxz(PL_markstack, i, I32);
11427 	PL_markstack_max	= PL_markstack + (proto_perl->Imarkstack_max
11428 						  - proto_perl->Imarkstack);
11429 	PL_markstack_ptr	= PL_markstack + (proto_perl->Imarkstack_ptr
11430 						  - proto_perl->Imarkstack);
11431 	Copy(proto_perl->Imarkstack, PL_markstack,
11432 	     PL_markstack_ptr - PL_markstack + 1, I32);
11433 
11434 	/* next push_scope()/ENTER sets PL_scopestack[PL_scopestack_ix]
11435 	 * NOTE: unlike the others! */
11436 	PL_scopestack_ix	= proto_perl->Iscopestack_ix;
11437 	PL_scopestack_max	= proto_perl->Iscopestack_max;
11438 	Newxz(PL_scopestack, PL_scopestack_max, I32);
11439 	Copy(proto_perl->Iscopestack, PL_scopestack, PL_scopestack_ix, I32);
11440 
11441 	/* NOTE: si_dup() looks at PL_markstack */
11442 	PL_curstackinfo		= si_dup(proto_perl->Icurstackinfo, param);
11443 
11444 	/* PL_curstack		= PL_curstackinfo->si_stack; */
11445 	PL_curstack		= av_dup(proto_perl->Icurstack, param);
11446 	PL_mainstack		= av_dup(proto_perl->Imainstack, param);
11447 
11448 	/* next PUSHs() etc. set *(PL_stack_sp+1) */
11449 	PL_stack_base		= AvARRAY(PL_curstack);
11450 	PL_stack_sp		= PL_stack_base + (proto_perl->Istack_sp
11451 						   - proto_perl->Istack_base);
11452 	PL_stack_max		= PL_stack_base + AvMAX(PL_curstack);
11453 
11454 	/* next SSPUSHFOO() sets PL_savestack[PL_savestack_ix]
11455 	 * NOTE: unlike the others! */
11456 	PL_savestack_ix		= proto_perl->Isavestack_ix;
11457 	PL_savestack_max	= proto_perl->Isavestack_max;
11458 	/*Newxz(PL_savestack, PL_savestack_max, ANY);*/
11459 	PL_savestack		= ss_dup(proto_perl, param);
11460     }
11461     else {
11462 	init_stacks();
11463 	ENTER;			/* perl_destruct() wants to LEAVE; */
11464 
11465 	/* although we're not duplicating the tmps stack, we should still
11466 	 * add entries for any SVs on the tmps stack that got cloned by a
11467 	 * non-refcount means (eg a temp in @_); otherwise they will be
11468 	 * orphaned
11469 	 */
11470 	for (i = 0; i<= proto_perl->Itmps_ix; i++) {
11471 	    SV * const nsv = (SV*)ptr_table_fetch(PL_ptr_table,
11472 		    proto_perl->Itmps_stack[i]);
11473 	    if (nsv && !SvREFCNT(nsv)) {
11474 		EXTEND_MORTAL(1);
11475 		PL_tmps_stack[++PL_tmps_ix] = SvREFCNT_inc_simple(nsv);
11476 	    }
11477 	}
11478     }
11479 
11480     PL_start_env	= proto_perl->Istart_env;	/* XXXXXX */
11481     PL_top_env		= &PL_start_env;
11482 
11483     PL_op		= proto_perl->Iop;
11484 
11485     PL_Sv		= NULL;
11486     PL_Xpv		= (XPV*)NULL;
11487     PL_na		= proto_perl->Ina;
11488 
11489     PL_statbuf		= proto_perl->Istatbuf;
11490     PL_statcache	= proto_perl->Istatcache;
11491     PL_statgv		= gv_dup(proto_perl->Istatgv, param);
11492     PL_statname		= sv_dup_inc(proto_perl->Istatname, param);
11493 #ifdef HAS_TIMES
11494     PL_timesbuf		= proto_perl->Itimesbuf;
11495 #endif
11496 
11497     PL_tainted		= proto_perl->Itainted;
11498     PL_curpm		= proto_perl->Icurpm;	/* XXX No PMOP ref count */
11499     PL_rs		= sv_dup_inc(proto_perl->Irs, param);
11500     PL_last_in_gv	= gv_dup(proto_perl->Ilast_in_gv, param);
11501     PL_ofs_sv		= sv_dup_inc(proto_perl->Iofs_sv, param);
11502     PL_defoutgv		= gv_dup_inc(proto_perl->Idefoutgv, param);
11503     PL_chopset		= proto_perl->Ichopset;	/* XXX never deallocated */
11504     PL_toptarget	= sv_dup_inc(proto_perl->Itoptarget, param);
11505     PL_bodytarget	= sv_dup_inc(proto_perl->Ibodytarget, param);
11506     PL_formtarget	= sv_dup(proto_perl->Iformtarget, param);
11507 
11508     PL_restartop	= proto_perl->Irestartop;
11509     PL_in_eval		= proto_perl->Iin_eval;
11510     PL_delaymagic	= proto_perl->Idelaymagic;
11511     PL_dirty		= proto_perl->Idirty;
11512     PL_localizing	= proto_perl->Ilocalizing;
11513 
11514     PL_errors		= sv_dup_inc(proto_perl->Ierrors, param);
11515     PL_hv_fetch_ent_mh	= NULL;
11516     PL_modcount		= proto_perl->Imodcount;
11517     PL_lastgotoprobe	= NULL;
11518     PL_dumpindent	= proto_perl->Idumpindent;
11519 
11520     PL_sortcop		= (OP*)any_dup(proto_perl->Isortcop, proto_perl);
11521     PL_sortstash	= hv_dup(proto_perl->Isortstash, param);
11522     PL_firstgv		= gv_dup(proto_perl->Ifirstgv, param);
11523     PL_secondgv		= gv_dup(proto_perl->Isecondgv, param);
11524     PL_efloatbuf	= NULL;		/* reinits on demand */
11525     PL_efloatsize	= 0;			/* reinits on demand */
11526 
11527     /* regex stuff */
11528 
11529     PL_screamfirst	= NULL;
11530     PL_screamnext	= NULL;
11531     PL_maxscream	= -1;			/* reinits on demand */
11532     PL_lastscream	= NULL;
11533 
11534 
11535     PL_regdummy		= proto_perl->Iregdummy;
11536     PL_colorset		= 0;		/* reinits PL_colors[] */
11537     /*PL_colors[6]	= {0,0,0,0,0,0};*/
11538 
11539 
11540 
11541     /* Pluggable optimizer */
11542     PL_peepp		= proto_perl->Ipeepp;
11543 
11544     PL_stashcache       = newHV();
11545 
11546     PL_watchaddr	= (char **) ptr_table_fetch(PL_ptr_table,
11547 					    proto_perl->Iwatchaddr);
11548     PL_watchok		= PL_watchaddr ? * PL_watchaddr : NULL;
11549     if (PL_debug && PL_watchaddr) {
11550 	PerlIO_printf(Perl_debug_log,
11551 	  "WATCHING: %"UVxf" cloned as %"UVxf" with value %"UVxf"\n",
11552 	  PTR2UV(proto_perl->Iwatchaddr), PTR2UV(PL_watchaddr),
11553 	  PTR2UV(PL_watchok));
11554     }
11555 
11556     if (!(flags & CLONEf_KEEP_PTR_TABLE)) {
11557         ptr_table_free(PL_ptr_table);
11558         PL_ptr_table = NULL;
11559     }
11560 
11561     /* Call the ->CLONE method, if it exists, for each of the stashes
11562        identified by sv_dup() above.
11563     */
11564     while(av_len(param->stashes) != -1) {
11565 	HV* const stash = (HV*) av_shift(param->stashes);
11566 	GV* const cloner = gv_fetchmethod_autoload(stash, "CLONE", 0);
11567 	if (cloner && GvCV(cloner)) {
11568 	    dSP;
11569 	    ENTER;
11570 	    SAVETMPS;
11571 	    PUSHMARK(SP);
11572 	    XPUSHs(sv_2mortal(newSVhek(HvNAME_HEK(stash))));
11573 	    PUTBACK;
11574 	    call_sv((SV*)GvCV(cloner), G_DISCARD);
11575 	    FREETMPS;
11576 	    LEAVE;
11577 	}
11578     }
11579 
11580     SvREFCNT_dec(param->stashes);
11581 
11582     /* orphaned? eg threads->new inside BEGIN or use */
11583     if (PL_compcv && ! SvREFCNT(PL_compcv)) {
11584 	SvREFCNT_inc_simple_void(PL_compcv);
11585 	SAVEFREESV(PL_compcv);
11586     }
11587 
11588     return my_perl;
11589 }
11590 
11591 #endif /* USE_ITHREADS */
11592 
11593 /*
11594 =head1 Unicode Support
11595 
11596 =for apidoc sv_recode_to_utf8
11597 
11598 The encoding is assumed to be an Encode object, on entry the PV
11599 of the sv is assumed to be octets in that encoding, and the sv
11600 will be converted into Unicode (and UTF-8).
11601 
11602 If the sv already is UTF-8 (or if it is not POK), or if the encoding
11603 is not a reference, nothing is done to the sv.  If the encoding is not
11604 an C<Encode::XS> Encoding object, bad things will happen.
11605 (See F<lib/encoding.pm> and L<Encode>).
11606 
11607 The PV of the sv is returned.
11608 
11609 =cut */
11610 
11611 char *
11612 Perl_sv_recode_to_utf8(pTHX_ SV *sv, SV *encoding)
11613 {
11614     dVAR;
11615     if (SvPOK(sv) && !SvUTF8(sv) && !IN_BYTES && SvROK(encoding)) {
11616 	SV *uni;
11617 	STRLEN len;
11618 	const char *s;
11619 	dSP;
11620 	ENTER;
11621 	SAVETMPS;
11622 	save_re_context();
11623 	PUSHMARK(sp);
11624 	EXTEND(SP, 3);
11625 	XPUSHs(encoding);
11626 	XPUSHs(sv);
11627 /*
11628   NI-S 2002/07/09
11629   Passing sv_yes is wrong - it needs to be or'ed set of constants
11630   for Encode::XS, while UTf-8 decode (currently) assumes a true value means
11631   remove converted chars from source.
11632 
11633   Both will default the value - let them.
11634 
11635 	XPUSHs(&PL_sv_yes);
11636 */
11637 	PUTBACK;
11638 	call_method("decode", G_SCALAR);
11639 	SPAGAIN;
11640 	uni = POPs;
11641 	PUTBACK;
11642 	s = SvPV_const(uni, len);
11643 	if (s != SvPVX_const(sv)) {
11644 	    SvGROW(sv, len + 1);
11645 	    Move(s, SvPVX(sv), len + 1, char);
11646 	    SvCUR_set(sv, len);
11647 	}
11648 	FREETMPS;
11649 	LEAVE;
11650 	SvUTF8_on(sv);
11651 	return SvPVX(sv);
11652     }
11653     return SvPOKp(sv) ? SvPVX(sv) : NULL;
11654 }
11655 
11656 /*
11657 =for apidoc sv_cat_decode
11658 
11659 The encoding is assumed to be an Encode object, the PV of the ssv is
11660 assumed to be octets in that encoding and decoding the input starts
11661 from the position which (PV + *offset) pointed to.  The dsv will be
11662 concatenated the decoded UTF-8 string from ssv.  Decoding will terminate
11663 when the string tstr appears in decoding output or the input ends on
11664 the PV of the ssv. The value which the offset points will be modified
11665 to the last input position on the ssv.
11666 
11667 Returns TRUE if the terminator was found, else returns FALSE.
11668 
11669 =cut */
11670 
11671 bool
11672 Perl_sv_cat_decode(pTHX_ SV *dsv, SV *encoding,
11673 		   SV *ssv, int *offset, char *tstr, int tlen)
11674 {
11675     dVAR;
11676     bool ret = FALSE;
11677     if (SvPOK(ssv) && SvPOK(dsv) && SvROK(encoding) && offset) {
11678 	SV *offsv;
11679 	dSP;
11680 	ENTER;
11681 	SAVETMPS;
11682 	save_re_context();
11683 	PUSHMARK(sp);
11684 	EXTEND(SP, 6);
11685 	XPUSHs(encoding);
11686 	XPUSHs(dsv);
11687 	XPUSHs(ssv);
11688 	XPUSHs(offsv = sv_2mortal(newSViv(*offset)));
11689 	XPUSHs(sv_2mortal(newSVpvn(tstr, tlen)));
11690 	PUTBACK;
11691 	call_method("cat_decode", G_SCALAR);
11692 	SPAGAIN;
11693 	ret = SvTRUE(TOPs);
11694 	*offset = SvIV(offsv);
11695 	PUTBACK;
11696 	FREETMPS;
11697 	LEAVE;
11698     }
11699     else
11700         Perl_croak(aTHX_ "Invalid argument to sv_cat_decode");
11701     return ret;
11702 
11703 }
11704 
11705 /* ---------------------------------------------------------------------
11706  *
11707  * support functions for report_uninit()
11708  */
11709 
11710 /* the maxiumum size of array or hash where we will scan looking
11711  * for the undefined element that triggered the warning */
11712 
11713 #define FUV_MAX_SEARCH_SIZE 1000
11714 
11715 /* Look for an entry in the hash whose value has the same SV as val;
11716  * If so, return a mortal copy of the key. */
11717 
11718 STATIC SV*
11719 S_find_hash_subscript(pTHX_ HV *hv, SV* val)
11720 {
11721     dVAR;
11722     register HE **array;
11723     I32 i;
11724 
11725     if (!hv || SvMAGICAL(hv) || !HvARRAY(hv) ||
11726 			(HvTOTALKEYS(hv) > FUV_MAX_SEARCH_SIZE))
11727 	return NULL;
11728 
11729     array = HvARRAY(hv);
11730 
11731     for (i=HvMAX(hv); i>0; i--) {
11732 	register HE *entry;
11733 	for (entry = array[i]; entry; entry = HeNEXT(entry)) {
11734 	    if (HeVAL(entry) != val)
11735 		continue;
11736 	    if (    HeVAL(entry) == &PL_sv_undef ||
11737 		    HeVAL(entry) == &PL_sv_placeholder)
11738 		continue;
11739 	    if (!HeKEY(entry))
11740 		return NULL;
11741 	    if (HeKLEN(entry) == HEf_SVKEY)
11742 		return sv_mortalcopy(HeKEY_sv(entry));
11743 	    return sv_2mortal(newSVpvn(HeKEY(entry), HeKLEN(entry)));
11744 	}
11745     }
11746     return NULL;
11747 }
11748 
11749 /* Look for an entry in the array whose value has the same SV as val;
11750  * If so, return the index, otherwise return -1. */
11751 
11752 STATIC I32
11753 S_find_array_subscript(pTHX_ AV *av, SV* val)
11754 {
11755     dVAR;
11756     if (!av || SvMAGICAL(av) || !AvARRAY(av) ||
11757 			(AvFILLp(av) > FUV_MAX_SEARCH_SIZE))
11758 	return -1;
11759 
11760     if (val != &PL_sv_undef) {
11761 	SV ** const svp = AvARRAY(av);
11762 	I32 i;
11763 
11764 	for (i=AvFILLp(av); i>=0; i--)
11765 	    if (svp[i] == val)
11766 		return i;
11767     }
11768     return -1;
11769 }
11770 
11771 /* S_varname(): return the name of a variable, optionally with a subscript.
11772  * If gv is non-zero, use the name of that global, along with gvtype (one
11773  * of "$", "@", "%"); otherwise use the name of the lexical at pad offset
11774  * targ.  Depending on the value of the subscript_type flag, return:
11775  */
11776 
11777 #define FUV_SUBSCRIPT_NONE	1	/* "@foo"          */
11778 #define FUV_SUBSCRIPT_ARRAY	2	/* "$foo[aindex]"  */
11779 #define FUV_SUBSCRIPT_HASH	3	/* "$foo{keyname}" */
11780 #define FUV_SUBSCRIPT_WITHIN	4	/* "within @foo"   */
11781 
11782 STATIC SV*
11783 S_varname(pTHX_ GV *gv, const char gvtype, PADOFFSET targ,
11784 	SV* keyname, I32 aindex, int subscript_type)
11785 {
11786 
11787     SV * const name = sv_newmortal();
11788     if (gv) {
11789 	char buffer[2];
11790 	buffer[0] = gvtype;
11791 	buffer[1] = 0;
11792 
11793 	/* as gv_fullname4(), but add literal '^' for $^FOO names  */
11794 
11795 	gv_fullname4(name, gv, buffer, 0);
11796 
11797 	if ((unsigned int)SvPVX(name)[1] <= 26) {
11798 	    buffer[0] = '^';
11799 	    buffer[1] = SvPVX(name)[1] + 'A' - 1;
11800 
11801 	    /* Swap the 1 unprintable control character for the 2 byte pretty
11802 	       version - ie substr($name, 1, 1) = $buffer; */
11803 	    sv_insert(name, 1, 1, buffer, 2);
11804 	}
11805     }
11806     else {
11807 	CV * const cv = find_runcv(NULL);
11808 	SV *sv;
11809 	AV *av;
11810 
11811 	if (!cv || !CvPADLIST(cv))
11812 	    return NULL;
11813 	av = (AV*)(*av_fetch(CvPADLIST(cv), 0, FALSE));
11814 	sv = *av_fetch(av, targ, FALSE);
11815 	sv_setpvn(name, SvPV_nolen_const(sv), SvCUR(sv));
11816     }
11817 
11818     if (subscript_type == FUV_SUBSCRIPT_HASH) {
11819 	SV * const sv = newSV(0);
11820 	*SvPVX(name) = '$';
11821 	Perl_sv_catpvf(aTHX_ name, "{%s}",
11822 	    pv_display(sv,SvPVX_const(keyname), SvCUR(keyname), 0, 32));
11823 	SvREFCNT_dec(sv);
11824     }
11825     else if (subscript_type == FUV_SUBSCRIPT_ARRAY) {
11826 	*SvPVX(name) = '$';
11827 	Perl_sv_catpvf(aTHX_ name, "[%"IVdf"]", (IV)aindex);
11828     }
11829     else if (subscript_type == FUV_SUBSCRIPT_WITHIN)
11830 	Perl_sv_insert(aTHX_ name, 0, 0,  STR_WITH_LEN("within "));
11831 
11832     return name;
11833 }
11834 
11835 
11836 /*
11837 =for apidoc find_uninit_var
11838 
11839 Find the name of the undefined variable (if any) that caused the operator o
11840 to issue a "Use of uninitialized value" warning.
11841 If match is true, only return a name if it's value matches uninit_sv.
11842 So roughly speaking, if a unary operator (such as OP_COS) generates a
11843 warning, then following the direct child of the op may yield an
11844 OP_PADSV or OP_GV that gives the name of the undefined variable. On the
11845 other hand, with OP_ADD there are two branches to follow, so we only print
11846 the variable name if we get an exact match.
11847 
11848 The name is returned as a mortal SV.
11849 
11850 Assumes that PL_op is the op that originally triggered the error, and that
11851 PL_comppad/PL_curpad points to the currently executing pad.
11852 
11853 =cut
11854 */
11855 
11856 STATIC SV *
11857 S_find_uninit_var(pTHX_ OP* obase, SV* uninit_sv, bool match)
11858 {
11859     dVAR;
11860     SV *sv;
11861     AV *av;
11862     GV *gv;
11863     OP *o, *o2, *kid;
11864 
11865     if (!obase || (match && (!uninit_sv || uninit_sv == &PL_sv_undef ||
11866 			    uninit_sv == &PL_sv_placeholder)))
11867 	return NULL;
11868 
11869     switch (obase->op_type) {
11870 
11871     case OP_RV2AV:
11872     case OP_RV2HV:
11873     case OP_PADAV:
11874     case OP_PADHV:
11875       {
11876 	const bool pad  = (obase->op_type == OP_PADAV || obase->op_type == OP_PADHV);
11877 	const bool hash = (obase->op_type == OP_PADHV || obase->op_type == OP_RV2HV);
11878 	I32 index = 0;
11879 	SV *keysv = NULL;
11880 	int subscript_type = FUV_SUBSCRIPT_WITHIN;
11881 
11882 	if (pad) { /* @lex, %lex */
11883 	    sv = PAD_SVl(obase->op_targ);
11884 	    gv = NULL;
11885 	}
11886 	else {
11887 	    if (cUNOPx(obase)->op_first->op_type == OP_GV) {
11888 	    /* @global, %global */
11889 		gv = cGVOPx_gv(cUNOPx(obase)->op_first);
11890 		if (!gv)
11891 		    break;
11892 		sv = hash ? (SV*)GvHV(gv): (SV*)GvAV(gv);
11893 	    }
11894 	    else /* @{expr}, %{expr} */
11895 		return find_uninit_var(cUNOPx(obase)->op_first,
11896 						    uninit_sv, match);
11897 	}
11898 
11899 	/* attempt to find a match within the aggregate */
11900 	if (hash) {
11901 	    keysv = find_hash_subscript((HV*)sv, uninit_sv);
11902 	    if (keysv)
11903 		subscript_type = FUV_SUBSCRIPT_HASH;
11904 	}
11905 	else {
11906 	    index = find_array_subscript((AV*)sv, uninit_sv);
11907 	    if (index >= 0)
11908 		subscript_type = FUV_SUBSCRIPT_ARRAY;
11909 	}
11910 
11911 	if (match && subscript_type == FUV_SUBSCRIPT_WITHIN)
11912 	    break;
11913 
11914 	return varname(gv, hash ? '%' : '@', obase->op_targ,
11915 				    keysv, index, subscript_type);
11916       }
11917 
11918     case OP_PADSV:
11919 	if (match && PAD_SVl(obase->op_targ) != uninit_sv)
11920 	    break;
11921 	return varname(NULL, '$', obase->op_targ,
11922 				    NULL, 0, FUV_SUBSCRIPT_NONE);
11923 
11924     case OP_GVSV:
11925 	gv = cGVOPx_gv(obase);
11926 	if (!gv || (match && GvSV(gv) != uninit_sv))
11927 	    break;
11928 	return varname(gv, '$', 0, NULL, 0, FUV_SUBSCRIPT_NONE);
11929 
11930     case OP_AELEMFAST:
11931 	if (obase->op_flags & OPf_SPECIAL) { /* lexical array */
11932 	    if (match) {
11933 		SV **svp;
11934 		av = (AV*)PAD_SV(obase->op_targ);
11935 		if (!av || SvRMAGICAL(av))
11936 		    break;
11937 		svp = av_fetch(av, (I32)obase->op_private, FALSE);
11938 		if (!svp || *svp != uninit_sv)
11939 		    break;
11940 	    }
11941 	    return varname(NULL, '$', obase->op_targ,
11942 		    NULL, (I32)obase->op_private, FUV_SUBSCRIPT_ARRAY);
11943 	}
11944 	else {
11945 	    gv = cGVOPx_gv(obase);
11946 	    if (!gv)
11947 		break;
11948 	    if (match) {
11949 		SV **svp;
11950 		av = GvAV(gv);
11951 		if (!av || SvRMAGICAL(av))
11952 		    break;
11953 		svp = av_fetch(av, (I32)obase->op_private, FALSE);
11954 		if (!svp || *svp != uninit_sv)
11955 		    break;
11956 	    }
11957 	    return varname(gv, '$', 0,
11958 		    NULL, (I32)obase->op_private, FUV_SUBSCRIPT_ARRAY);
11959 	}
11960 	break;
11961 
11962     case OP_EXISTS:
11963 	o = cUNOPx(obase)->op_first;
11964 	if (!o || o->op_type != OP_NULL ||
11965 		! (o->op_targ == OP_AELEM || o->op_targ == OP_HELEM))
11966 	    break;
11967 	return find_uninit_var(cBINOPo->op_last, uninit_sv, match);
11968 
11969     case OP_AELEM:
11970     case OP_HELEM:
11971 	if (PL_op == obase)
11972 	    /* $a[uninit_expr] or $h{uninit_expr} */
11973 	    return find_uninit_var(cBINOPx(obase)->op_last, uninit_sv, match);
11974 
11975 	gv = NULL;
11976 	o = cBINOPx(obase)->op_first;
11977 	kid = cBINOPx(obase)->op_last;
11978 
11979 	/* get the av or hv, and optionally the gv */
11980 	sv = NULL;
11981 	if  (o->op_type == OP_PADAV || o->op_type == OP_PADHV) {
11982 	    sv = PAD_SV(o->op_targ);
11983 	}
11984 	else if ((o->op_type == OP_RV2AV || o->op_type == OP_RV2HV)
11985 		&& cUNOPo->op_first->op_type == OP_GV)
11986 	{
11987 	    gv = cGVOPx_gv(cUNOPo->op_first);
11988 	    if (!gv)
11989 		break;
11990 	    sv = o->op_type == OP_RV2HV ? (SV*)GvHV(gv) : (SV*)GvAV(gv);
11991 	}
11992 	if (!sv)
11993 	    break;
11994 
11995 	if (kid && kid->op_type == OP_CONST && SvOK(cSVOPx_sv(kid))) {
11996 	    /* index is constant */
11997 	    if (match) {
11998 		if (SvMAGICAL(sv))
11999 		    break;
12000 		if (obase->op_type == OP_HELEM) {
12001 		    HE* he = hv_fetch_ent((HV*)sv, cSVOPx_sv(kid), 0, 0);
12002 		    if (!he || HeVAL(he) != uninit_sv)
12003 			break;
12004 		}
12005 		else {
12006 		    SV * const * const svp = av_fetch((AV*)sv, SvIV(cSVOPx_sv(kid)), FALSE);
12007 		    if (!svp || *svp != uninit_sv)
12008 			break;
12009 		}
12010 	    }
12011 	    if (obase->op_type == OP_HELEM)
12012 		return varname(gv, '%', o->op_targ,
12013 			    cSVOPx_sv(kid), 0, FUV_SUBSCRIPT_HASH);
12014 	    else
12015 		return varname(gv, '@', o->op_targ, NULL,
12016 			    SvIV(cSVOPx_sv(kid)), FUV_SUBSCRIPT_ARRAY);
12017 	}
12018 	else  {
12019 	    /* index is an expression;
12020 	     * attempt to find a match within the aggregate */
12021 	    if (obase->op_type == OP_HELEM) {
12022 		SV * const keysv = find_hash_subscript((HV*)sv, uninit_sv);
12023 		if (keysv)
12024 		    return varname(gv, '%', o->op_targ,
12025 						keysv, 0, FUV_SUBSCRIPT_HASH);
12026 	    }
12027 	    else {
12028 		const I32 index = find_array_subscript((AV*)sv, uninit_sv);
12029 		if (index >= 0)
12030 		    return varname(gv, '@', o->op_targ,
12031 					NULL, index, FUV_SUBSCRIPT_ARRAY);
12032 	    }
12033 	    if (match)
12034 		break;
12035 	    return varname(gv,
12036 		(o->op_type == OP_PADAV || o->op_type == OP_RV2AV)
12037 		? '@' : '%',
12038 		o->op_targ, NULL, 0, FUV_SUBSCRIPT_WITHIN);
12039 	}
12040 	break;
12041 
12042     case OP_AASSIGN:
12043 	/* only examine RHS */
12044 	return find_uninit_var(cBINOPx(obase)->op_first, uninit_sv, match);
12045 
12046     case OP_OPEN:
12047 	o = cUNOPx(obase)->op_first;
12048 	if (o->op_type == OP_PUSHMARK)
12049 	    o = o->op_sibling;
12050 
12051 	if (!o->op_sibling) {
12052 	    /* one-arg version of open is highly magical */
12053 
12054 	    if (o->op_type == OP_GV) { /* open FOO; */
12055 		gv = cGVOPx_gv(o);
12056 		if (match && GvSV(gv) != uninit_sv)
12057 		    break;
12058 		return varname(gv, '$', 0,
12059 			    NULL, 0, FUV_SUBSCRIPT_NONE);
12060 	    }
12061 	    /* other possibilities not handled are:
12062 	     * open $x; or open my $x;	should return '${*$x}'
12063 	     * open expr;		should return '$'.expr ideally
12064 	     */
12065 	     break;
12066 	}
12067 	goto do_op;
12068 
12069     /* ops where $_ may be an implicit arg */
12070     case OP_TRANS:
12071     case OP_SUBST:
12072     case OP_MATCH:
12073 	if ( !(obase->op_flags & OPf_STACKED)) {
12074 	    if (uninit_sv == ((obase->op_private & OPpTARGET_MY)
12075 				 ? PAD_SVl(obase->op_targ)
12076 				 : DEFSV))
12077 	    {
12078 		sv = sv_newmortal();
12079 		sv_setpvn(sv, "$_", 2);
12080 		return sv;
12081 	    }
12082 	}
12083 	goto do_op;
12084 
12085     case OP_PRTF:
12086     case OP_PRINT:
12087     case OP_SAY:
12088 	/* skip filehandle as it can't produce 'undef' warning  */
12089 	o = cUNOPx(obase)->op_first;
12090 	if ((obase->op_flags & OPf_STACKED) && o->op_type == OP_PUSHMARK)
12091 	    o = o->op_sibling->op_sibling;
12092 	goto do_op2;
12093 
12094 
12095     case OP_RV2SV:
12096     case OP_CUSTOM:
12097 	match = 1; /* XS or custom code could trigger random warnings */
12098 	goto do_op;
12099 
12100     case OP_ENTERSUB:
12101     case OP_GOTO:
12102 	/* XXX tmp hack: these two may call an XS sub, and currently
12103 	  XS subs don't have a SUB entry on the context stack, so CV and
12104 	  pad determination goes wrong, and BAD things happen. So, just
12105 	  don't try to determine the value under those circumstances.
12106 	  Need a better fix at dome point. DAPM 11/2007 */
12107 	break;
12108 
12109     case OP_POS:
12110 	/* def-ness of rval pos() is independent of the def-ness of its arg */
12111 	if ( !(obase->op_flags & OPf_MOD))
12112 	    break;
12113 
12114     case OP_SCHOMP:
12115     case OP_CHOMP:
12116 	if (SvROK(PL_rs) && uninit_sv == SvRV(PL_rs))
12117 	    return sv_2mortal(newSVpvs("${$/}"));
12118 	/*FALLTHROUGH*/
12119 
12120     default:
12121     do_op:
12122 	if (!(obase->op_flags & OPf_KIDS))
12123 	    break;
12124 	o = cUNOPx(obase)->op_first;
12125 
12126     do_op2:
12127 	if (!o)
12128 	    break;
12129 
12130 	/* if all except one arg are constant, or have no side-effects,
12131 	 * or are optimized away, then it's unambiguous */
12132 	o2 = NULL;
12133 	for (kid=o; kid; kid = kid->op_sibling) {
12134 	    if (kid) {
12135 		const OPCODE type = kid->op_type;
12136 		if ( (type == OP_CONST && SvOK(cSVOPx_sv(kid)))
12137 		  || (type == OP_NULL  && ! (kid->op_flags & OPf_KIDS))
12138 		  || (type == OP_PUSHMARK)
12139 		)
12140 		continue;
12141 	    }
12142 	    if (o2) { /* more than one found */
12143 		o2 = NULL;
12144 		break;
12145 	    }
12146 	    o2 = kid;
12147 	}
12148 	if (o2)
12149 	    return find_uninit_var(o2, uninit_sv, match);
12150 
12151 	/* scan all args */
12152 	while (o) {
12153 	    sv = find_uninit_var(o, uninit_sv, 1);
12154 	    if (sv)
12155 		return sv;
12156 	    o = o->op_sibling;
12157 	}
12158 	break;
12159     }
12160     return NULL;
12161 }
12162 
12163 
12164 /*
12165 =for apidoc report_uninit
12166 
12167 Print appropriate "Use of uninitialized variable" warning
12168 
12169 =cut
12170 */
12171 
12172 void
12173 Perl_report_uninit(pTHX_ SV* uninit_sv)
12174 {
12175     dVAR;
12176     if (PL_op) {
12177 	SV* varname = NULL;
12178 	if (uninit_sv) {
12179 	    varname = find_uninit_var(PL_op, uninit_sv,0);
12180 	    if (varname)
12181 		sv_insert(varname, 0, 0, " ", 1);
12182 	}
12183 	Perl_warner(aTHX_ packWARN(WARN_UNINITIALIZED), PL_warn_uninit,
12184 		varname ? SvPV_nolen_const(varname) : "",
12185 		" in ", OP_DESC(PL_op));
12186     }
12187     else
12188 	Perl_warner(aTHX_ packWARN(WARN_UNINITIALIZED), PL_warn_uninit,
12189 		    "", "", "");
12190 }
12191 
12192 /*
12193  * Local variables:
12194  * c-indentation-style: bsd
12195  * c-basic-offset: 4
12196  * indent-tabs-mode: t
12197  * End:
12198  *
12199  * ex: set ts=8 sts=4 sw=4 noet:
12200  */
12201