1 /* pp_sort.c 2 * 3 * Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 4 * 2000, 2001, 2002, 2003, 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 */ 10 11 /* 12 * ...they shuffled back towards the rear of the line. 'No, not at the 13 * rear!' the slave-driver shouted. 'Three files up. And stay there... 14 */ 15 16 #include "EXTERN.h" 17 #define PERL_IN_PP_SORT_C 18 #include "perl.h" 19 20 #if defined(UNDER_CE) 21 /* looks like 'small' is reserved word for WINCE (or somesuch)*/ 22 #define small xsmall 23 #endif 24 25 static I32 sortcv(pTHX_ SV *a, SV *b); 26 static I32 sortcv_stacked(pTHX_ SV *a, SV *b); 27 static I32 sortcv_xsub(pTHX_ SV *a, SV *b); 28 static I32 sv_ncmp(pTHX_ SV *a, SV *b); 29 static I32 sv_i_ncmp(pTHX_ SV *a, SV *b); 30 static I32 amagic_ncmp(pTHX_ SV *a, SV *b); 31 static I32 amagic_i_ncmp(pTHX_ SV *a, SV *b); 32 static I32 amagic_cmp(pTHX_ SV *a, SV *b); 33 static I32 amagic_cmp_locale(pTHX_ SV *a, SV *b); 34 35 #define sv_cmp_static Perl_sv_cmp 36 #define sv_cmp_locale_static Perl_sv_cmp_locale 37 38 #define SORTHINTS(hintsv) \ 39 (((hintsv) = GvSV(gv_fetchpv("sort::hints", GV_ADDMULTI, SVt_IV))), \ 40 (SvIOK(hintsv) ? ((I32)SvIV(hintsv)) : 0)) 41 42 #ifndef SMALLSORT 43 #define SMALLSORT (200) 44 #endif 45 46 /* 47 * The mergesort implementation is by Peter M. Mcilroy <pmcilroy@lucent.com>. 48 * 49 * The original code was written in conjunction with BSD Computer Software 50 * Research Group at University of California, Berkeley. 51 * 52 * See also: "Optimistic Merge Sort" (SODA '92) 53 * 54 * The integration to Perl is by John P. Linderman <jpl@research.att.com>. 55 * 56 * The code can be distributed under the same terms as Perl itself. 57 * 58 */ 59 60 61 typedef char * aptr; /* pointer for arithmetic on sizes */ 62 typedef SV * gptr; /* pointers in our lists */ 63 64 /* Binary merge internal sort, with a few special mods 65 ** for the special perl environment it now finds itself in. 66 ** 67 ** Things that were once options have been hotwired 68 ** to values suitable for this use. In particular, we'll always 69 ** initialize looking for natural runs, we'll always produce stable 70 ** output, and we'll always do Peter McIlroy's binary merge. 71 */ 72 73 /* Pointer types for arithmetic and storage and convenience casts */ 74 75 #define APTR(P) ((aptr)(P)) 76 #define GPTP(P) ((gptr *)(P)) 77 #define GPPP(P) ((gptr **)(P)) 78 79 80 /* byte offset from pointer P to (larger) pointer Q */ 81 #define BYTEOFF(P, Q) (APTR(Q) - APTR(P)) 82 83 #define PSIZE sizeof(gptr) 84 85 /* If PSIZE is power of 2, make PSHIFT that power, if that helps */ 86 87 #ifdef PSHIFT 88 #define PNELEM(P, Q) (BYTEOFF(P,Q) >> (PSHIFT)) 89 #define PNBYTE(N) ((N) << (PSHIFT)) 90 #define PINDEX(P, N) (GPTP(APTR(P) + PNBYTE(N))) 91 #else 92 /* Leave optimization to compiler */ 93 #define PNELEM(P, Q) (GPTP(Q) - GPTP(P)) 94 #define PNBYTE(N) ((N) * (PSIZE)) 95 #define PINDEX(P, N) (GPTP(P) + (N)) 96 #endif 97 98 /* Pointer into other corresponding to pointer into this */ 99 #define POTHER(P, THIS, OTHER) GPTP(APTR(OTHER) + BYTEOFF(THIS,P)) 100 101 #define FROMTOUPTO(src, dst, lim) do *dst++ = *src++; while(src<lim) 102 103 104 /* Runs are identified by a pointer in the auxilliary list. 105 ** The pointer is at the start of the list, 106 ** and it points to the start of the next list. 107 ** NEXT is used as an lvalue, too. 108 */ 109 110 #define NEXT(P) (*GPPP(P)) 111 112 113 /* PTHRESH is the minimum number of pairs with the same sense to justify 114 ** checking for a run and extending it. Note that PTHRESH counts PAIRS, 115 ** not just elements, so PTHRESH == 8 means a run of 16. 116 */ 117 118 #define PTHRESH (8) 119 120 /* RTHRESH is the number of elements in a run that must compare low 121 ** to the low element from the opposing run before we justify 122 ** doing a binary rampup instead of single stepping. 123 ** In random input, N in a row low should only happen with 124 ** probability 2^(1-N), so we can risk that we are dealing 125 ** with orderly input without paying much when we aren't. 126 */ 127 128 #define RTHRESH (6) 129 130 131 /* 132 ** Overview of algorithm and variables. 133 ** The array of elements at list1 will be organized into runs of length 2, 134 ** or runs of length >= 2 * PTHRESH. We only try to form long runs when 135 ** PTHRESH adjacent pairs compare in the same way, suggesting overall order. 136 ** 137 ** Unless otherwise specified, pair pointers address the first of two elements. 138 ** 139 ** b and b+1 are a pair that compare with sense ``sense''. 140 ** b is the ``bottom'' of adjacent pairs that might form a longer run. 141 ** 142 ** p2 parallels b in the list2 array, where runs are defined by 143 ** a pointer chain. 144 ** 145 ** t represents the ``top'' of the adjacent pairs that might extend 146 ** the run beginning at b. Usually, t addresses a pair 147 ** that compares with opposite sense from (b,b+1). 148 ** However, it may also address a singleton element at the end of list1, 149 ** or it may be equal to ``last'', the first element beyond list1. 150 ** 151 ** r addresses the Nth pair following b. If this would be beyond t, 152 ** we back it off to t. Only when r is less than t do we consider the 153 ** run long enough to consider checking. 154 ** 155 ** q addresses a pair such that the pairs at b through q already form a run. 156 ** Often, q will equal b, indicating we only are sure of the pair itself. 157 ** However, a search on the previous cycle may have revealed a longer run, 158 ** so q may be greater than b. 159 ** 160 ** p is used to work back from a candidate r, trying to reach q, 161 ** which would mean b through r would be a run. If we discover such a run, 162 ** we start q at r and try to push it further towards t. 163 ** If b through r is NOT a run, we detect the wrong order at (p-1,p). 164 ** In any event, after the check (if any), we have two main cases. 165 ** 166 ** 1) Short run. b <= q < p <= r <= t. 167 ** b through q is a run (perhaps trivial) 168 ** q through p are uninteresting pairs 169 ** p through r is a run 170 ** 171 ** 2) Long run. b < r <= q < t. 172 ** b through q is a run (of length >= 2 * PTHRESH) 173 ** 174 ** Note that degenerate cases are not only possible, but likely. 175 ** For example, if the pair following b compares with opposite sense, 176 ** then b == q < p == r == t. 177 */ 178 179 180 static IV 181 dynprep(pTHX_ gptr *list1, gptr *list2, size_t nmemb, SVCOMPARE_t cmp) 182 { 183 I32 sense; 184 register gptr *b, *p, *q, *t, *p2; 185 register gptr c, *last, *r; 186 gptr *savep; 187 IV runs = 0; 188 189 b = list1; 190 last = PINDEX(b, nmemb); 191 sense = (cmp(aTHX_ *b, *(b+1)) > 0); 192 for (p2 = list2; b < last; ) { 193 /* We just started, or just reversed sense. 194 ** Set t at end of pairs with the prevailing sense. 195 */ 196 for (p = b+2, t = p; ++p < last; t = ++p) { 197 if ((cmp(aTHX_ *t, *p) > 0) != sense) break; 198 } 199 q = b; 200 /* Having laid out the playing field, look for long runs */ 201 do { 202 p = r = b + (2 * PTHRESH); 203 if (r >= t) p = r = t; /* too short to care about */ 204 else { 205 while (((cmp(aTHX_ *(p-1), *p) > 0) == sense) && 206 ((p -= 2) > q)); 207 if (p <= q) { 208 /* b through r is a (long) run. 209 ** Extend it as far as possible. 210 */ 211 p = q = r; 212 while (((p += 2) < t) && 213 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) q = p; 214 r = p = q + 2; /* no simple pairs, no after-run */ 215 } 216 } 217 if (q > b) { /* run of greater than 2 at b */ 218 savep = p; 219 p = q += 2; 220 /* pick up singleton, if possible */ 221 if ((p == t) && 222 ((t + 1) == last) && 223 ((cmp(aTHX_ *(p-1), *p) > 0) == sense)) 224 savep = r = p = q = last; 225 p2 = NEXT(p2) = p2 + (p - b); ++runs; 226 if (sense) while (b < --p) { 227 c = *b; 228 *b++ = *p; 229 *p = c; 230 } 231 p = savep; 232 } 233 while (q < p) { /* simple pairs */ 234 p2 = NEXT(p2) = p2 + 2; ++runs; 235 if (sense) { 236 c = *q++; 237 *(q-1) = *q; 238 *q++ = c; 239 } else q += 2; 240 } 241 if (((b = p) == t) && ((t+1) == last)) { 242 NEXT(p2) = p2 + 1; ++runs; 243 b++; 244 } 245 q = r; 246 } while (b < t); 247 sense = !sense; 248 } 249 return runs; 250 } 251 252 253 /* The original merge sort, in use since 5.7, was as fast as, or faster than, 254 * qsort on many platforms, but slower than qsort, conspicuously so, 255 * on others. The most likely explanation was platform-specific 256 * differences in cache sizes and relative speeds. 257 * 258 * The quicksort divide-and-conquer algorithm guarantees that, as the 259 * problem is subdivided into smaller and smaller parts, the parts 260 * fit into smaller (and faster) caches. So it doesn't matter how 261 * many levels of cache exist, quicksort will "find" them, and, 262 * as long as smaller is faster, take advanatge of them. 263 * 264 * By contrast, consider how the original mergesort algorithm worked. 265 * Suppose we have five runs (each typically of length 2 after dynprep). 266 * 267 * pass base aux 268 * 0 1 2 3 4 5 269 * 1 12 34 5 270 * 2 1234 5 271 * 3 12345 272 * 4 12345 273 * 274 * Adjacent pairs are merged in "grand sweeps" through the input. 275 * This means, on pass 1, the records in runs 1 and 2 aren't revisited until 276 * runs 3 and 4 are merged and the runs from run 5 have been copied. 277 * The only cache that matters is one large enough to hold *all* the input. 278 * On some platforms, this may be many times slower than smaller caches. 279 * 280 * The following pseudo-code uses the same basic merge algorithm, 281 * but in a divide-and-conquer way. 282 * 283 * # merge $runs runs at offset $offset of list $list1 into $list2. 284 * # all unmerged runs ($runs == 1) originate in list $base. 285 * sub mgsort2 { 286 * my ($offset, $runs, $base, $list1, $list2) = @_; 287 * 288 * if ($runs == 1) { 289 * if ($list1 is $base) copy run to $list2 290 * return offset of end of list (or copy) 291 * } else { 292 * $off2 = mgsort2($offset, $runs-($runs/2), $base, $list2, $list1) 293 * mgsort2($off2, $runs/2, $base, $list2, $list1) 294 * merge the adjacent runs at $offset of $list1 into $list2 295 * return the offset of the end of the merged runs 296 * } 297 * } 298 * mgsort2(0, $runs, $base, $aux, $base); 299 * 300 * For our 5 runs, the tree of calls looks like 301 * 302 * 5 303 * 3 2 304 * 2 1 1 1 305 * 1 1 306 * 307 * 1 2 3 4 5 308 * 309 * and the corresponding activity looks like 310 * 311 * copy runs 1 and 2 from base to aux 312 * merge runs 1 and 2 from aux to base 313 * (run 3 is where it belongs, no copy needed) 314 * merge runs 12 and 3 from base to aux 315 * (runs 4 and 5 are where they belong, no copy needed) 316 * merge runs 4 and 5 from base to aux 317 * merge runs 123 and 45 from aux to base 318 * 319 * Note that we merge runs 1 and 2 immediately after copying them, 320 * while they are still likely to be in fast cache. Similarly, 321 * run 3 is merged with run 12 while it still may be lingering in cache. 322 * This implementation should therefore enjoy much of the cache-friendly 323 * behavior that quicksort does. In addition, it does less copying 324 * than the original mergesort implementation (only runs 1 and 2 are copied) 325 * and the "balancing" of merges is better (merged runs comprise more nearly 326 * equal numbers of original runs). 327 * 328 * The actual cache-friendly implementation will use a pseudo-stack 329 * to avoid recursion, and will unroll processing of runs of length 2, 330 * but it is otherwise similar to the recursive implementation. 331 */ 332 333 typedef struct { 334 IV offset; /* offset of 1st of 2 runs at this level */ 335 IV runs; /* how many runs must be combined into 1 */ 336 } off_runs; /* pseudo-stack element */ 337 338 STATIC void 339 S_mergesortsv(pTHX_ gptr *base, size_t nmemb, SVCOMPARE_t cmp) 340 { 341 IV i, run, runs, offset; 342 I32 sense, level; 343 int iwhich; 344 register gptr *f1, *f2, *t, *b, *p, *tp2, *l1, *l2, *q; 345 gptr *aux, *list1, *list2; 346 gptr *p1; 347 gptr small[SMALLSORT]; 348 gptr *which[3]; 349 off_runs stack[60], *stackp; 350 351 if (nmemb <= 1) return; /* sorted trivially */ 352 if (nmemb <= SMALLSORT) aux = small; /* use stack for aux array */ 353 else { New(799,aux,nmemb,gptr); } /* allocate auxilliary array */ 354 level = 0; 355 stackp = stack; 356 stackp->runs = dynprep(aTHX_ base, aux, nmemb, cmp); 357 stackp->offset = offset = 0; 358 which[0] = which[2] = base; 359 which[1] = aux; 360 for (;;) { 361 /* On levels where both runs have be constructed (stackp->runs == 0), 362 * merge them, and note the offset of their end, in case the offset 363 * is needed at the next level up. Hop up a level, and, 364 * as long as stackp->runs is 0, keep merging. 365 */ 366 if ((runs = stackp->runs) == 0) { 367 iwhich = level & 1; 368 list1 = which[iwhich]; /* area where runs are now */ 369 list2 = which[++iwhich]; /* area for merged runs */ 370 do { 371 offset = stackp->offset; 372 f1 = p1 = list1 + offset; /* start of first run */ 373 p = tp2 = list2 + offset; /* where merged run will go */ 374 t = NEXT(p); /* where first run ends */ 375 f2 = l1 = POTHER(t, list2, list1); /* ... on the other side */ 376 t = NEXT(t); /* where second runs ends */ 377 l2 = POTHER(t, list2, list1); /* ... on the other side */ 378 offset = PNELEM(list2, t); 379 while (f1 < l1 && f2 < l2) { 380 /* If head 1 is larger than head 2, find ALL the elements 381 ** in list 2 strictly less than head1, write them all, 382 ** then head 1. Then compare the new heads, and repeat, 383 ** until one or both lists are exhausted. 384 ** 385 ** In all comparisons (after establishing 386 ** which head to merge) the item to merge 387 ** (at pointer q) is the first operand of 388 ** the comparison. When we want to know 389 ** if ``q is strictly less than the other'', 390 ** we can't just do 391 ** cmp(q, other) < 0 392 ** because stability demands that we treat equality 393 ** as high when q comes from l2, and as low when 394 ** q was from l1. So we ask the question by doing 395 ** cmp(q, other) <= sense 396 ** and make sense == 0 when equality should look low, 397 ** and -1 when equality should look high. 398 */ 399 400 401 if (cmp(aTHX_ *f1, *f2) <= 0) { 402 q = f2; b = f1; t = l1; 403 sense = -1; 404 } else { 405 q = f1; b = f2; t = l2; 406 sense = 0; 407 } 408 409 410 /* ramp up 411 ** 412 ** Leave t at something strictly 413 ** greater than q (or at the end of the list), 414 ** and b at something strictly less than q. 415 */ 416 for (i = 1, run = 0 ;;) { 417 if ((p = PINDEX(b, i)) >= t) { 418 /* off the end */ 419 if (((p = PINDEX(t, -1)) > b) && 420 (cmp(aTHX_ *q, *p) <= sense)) 421 t = p; 422 else b = p; 423 break; 424 } else if (cmp(aTHX_ *q, *p) <= sense) { 425 t = p; 426 break; 427 } else b = p; 428 if (++run >= RTHRESH) i += i; 429 } 430 431 432 /* q is known to follow b and must be inserted before t. 433 ** Increment b, so the range of possibilities is [b,t). 434 ** Round binary split down, to favor early appearance. 435 ** Adjust b and t until q belongs just before t. 436 */ 437 438 b++; 439 while (b < t) { 440 p = PINDEX(b, (PNELEM(b, t) - 1) / 2); 441 if (cmp(aTHX_ *q, *p) <= sense) { 442 t = p; 443 } else b = p + 1; 444 } 445 446 447 /* Copy all the strictly low elements */ 448 449 if (q == f1) { 450 FROMTOUPTO(f2, tp2, t); 451 *tp2++ = *f1++; 452 } else { 453 FROMTOUPTO(f1, tp2, t); 454 *tp2++ = *f2++; 455 } 456 } 457 458 459 /* Run out remaining list */ 460 if (f1 == l1) { 461 if (f2 < l2) FROMTOUPTO(f2, tp2, l2); 462 } else FROMTOUPTO(f1, tp2, l1); 463 p1 = NEXT(p1) = POTHER(tp2, list2, list1); 464 465 if (--level == 0) goto done; 466 --stackp; 467 t = list1; list1 = list2; list2 = t; /* swap lists */ 468 } while ((runs = stackp->runs) == 0); 469 } 470 471 472 stackp->runs = 0; /* current run will finish level */ 473 /* While there are more than 2 runs remaining, 474 * turn them into exactly 2 runs (at the "other" level), 475 * each made up of approximately half the runs. 476 * Stack the second half for later processing, 477 * and set about producing the first half now. 478 */ 479 while (runs > 2) { 480 ++level; 481 ++stackp; 482 stackp->offset = offset; 483 runs -= stackp->runs = runs / 2; 484 } 485 /* We must construct a single run from 1 or 2 runs. 486 * All the original runs are in which[0] == base. 487 * The run we construct must end up in which[level&1]. 488 */ 489 iwhich = level & 1; 490 if (runs == 1) { 491 /* Constructing a single run from a single run. 492 * If it's where it belongs already, there's nothing to do. 493 * Otherwise, copy it to where it belongs. 494 * A run of 1 is either a singleton at level 0, 495 * or the second half of a split 3. In neither event 496 * is it necessary to set offset. It will be set by the merge 497 * that immediately follows. 498 */ 499 if (iwhich) { /* Belongs in aux, currently in base */ 500 f1 = b = PINDEX(base, offset); /* where list starts */ 501 f2 = PINDEX(aux, offset); /* where list goes */ 502 t = NEXT(f2); /* where list will end */ 503 offset = PNELEM(aux, t); /* offset thereof */ 504 t = PINDEX(base, offset); /* where it currently ends */ 505 FROMTOUPTO(f1, f2, t); /* copy */ 506 NEXT(b) = t; /* set up parallel pointer */ 507 } else if (level == 0) goto done; /* single run at level 0 */ 508 } else { 509 /* Constructing a single run from two runs. 510 * The merge code at the top will do that. 511 * We need only make sure the two runs are in the "other" array, 512 * so they'll end up in the correct array after the merge. 513 */ 514 ++level; 515 ++stackp; 516 stackp->offset = offset; 517 stackp->runs = 0; /* take care of both runs, trigger merge */ 518 if (!iwhich) { /* Merged runs belong in aux, copy 1st */ 519 f1 = b = PINDEX(base, offset); /* where first run starts */ 520 f2 = PINDEX(aux, offset); /* where it will be copied */ 521 t = NEXT(f2); /* where first run will end */ 522 offset = PNELEM(aux, t); /* offset thereof */ 523 p = PINDEX(base, offset); /* end of first run */ 524 t = NEXT(t); /* where second run will end */ 525 t = PINDEX(base, PNELEM(aux, t)); /* where it now ends */ 526 FROMTOUPTO(f1, f2, t); /* copy both runs */ 527 NEXT(b) = p; /* paralled pointer for 1st */ 528 NEXT(p) = t; /* ... and for second */ 529 } 530 } 531 } 532 done: 533 if (aux != small) Safefree(aux); /* free iff allocated */ 534 return; 535 } 536 537 /* 538 * The quicksort implementation was derived from source code contributed 539 * by Tom Horsley. 540 * 541 * NOTE: this code was derived from Tom Horsley's qsort replacement 542 * and should not be confused with the original code. 543 */ 544 545 /* Copyright (C) Tom Horsley, 1997. All rights reserved. 546 547 Permission granted to distribute under the same terms as perl which are 548 (briefly): 549 550 This program is free software; you can redistribute it and/or modify 551 it under the terms of either: 552 553 a) the GNU General Public License as published by the Free 554 Software Foundation; either version 1, or (at your option) any 555 later version, or 556 557 b) the "Artistic License" which comes with this Kit. 558 559 Details on the perl license can be found in the perl source code which 560 may be located via the www.perl.com web page. 561 562 This is the most wonderfulest possible qsort I can come up with (and 563 still be mostly portable) My (limited) tests indicate it consistently 564 does about 20% fewer calls to compare than does the qsort in the Visual 565 C++ library, other vendors may vary. 566 567 Some of the ideas in here can be found in "Algorithms" by Sedgewick, 568 others I invented myself (or more likely re-invented since they seemed 569 pretty obvious once I watched the algorithm operate for a while). 570 571 Most of this code was written while watching the Marlins sweep the Giants 572 in the 1997 National League Playoffs - no Braves fans allowed to use this 573 code (just kidding :-). 574 575 I realize that if I wanted to be true to the perl tradition, the only 576 comment in this file would be something like: 577 578 ...they shuffled back towards the rear of the line. 'No, not at the 579 rear!' the slave-driver shouted. 'Three files up. And stay there... 580 581 However, I really needed to violate that tradition just so I could keep 582 track of what happens myself, not to mention some poor fool trying to 583 understand this years from now :-). 584 */ 585 586 /* ********************************************************** Configuration */ 587 588 #ifndef QSORT_ORDER_GUESS 589 #define QSORT_ORDER_GUESS 2 /* Select doubling version of the netBSD trick */ 590 #endif 591 592 /* QSORT_MAX_STACK is the largest number of partitions that can be stacked up for 593 future processing - a good max upper bound is log base 2 of memory size 594 (32 on 32 bit machines, 64 on 64 bit machines, etc). In reality can 595 safely be smaller than that since the program is taking up some space and 596 most operating systems only let you grab some subset of contiguous 597 memory (not to mention that you are normally sorting data larger than 598 1 byte element size :-). 599 */ 600 #ifndef QSORT_MAX_STACK 601 #define QSORT_MAX_STACK 32 602 #endif 603 604 /* QSORT_BREAK_EVEN is the size of the largest partition we should insertion sort. 605 Anything bigger and we use qsort. If you make this too small, the qsort 606 will probably break (or become less efficient), because it doesn't expect 607 the middle element of a partition to be the same as the right or left - 608 you have been warned). 609 */ 610 #ifndef QSORT_BREAK_EVEN 611 #define QSORT_BREAK_EVEN 6 612 #endif 613 614 /* QSORT_PLAY_SAFE is the size of the largest partition we're willing 615 to go quadratic on. We innoculate larger partitions against 616 quadratic behavior by shuffling them before sorting. This is not 617 an absolute guarantee of non-quadratic behavior, but it would take 618 staggeringly bad luck to pick extreme elements as the pivot 619 from randomized data. 620 */ 621 #ifndef QSORT_PLAY_SAFE 622 #define QSORT_PLAY_SAFE 255 623 #endif 624 625 /* ************************************************************* Data Types */ 626 627 /* hold left and right index values of a partition waiting to be sorted (the 628 partition includes both left and right - right is NOT one past the end or 629 anything like that). 630 */ 631 struct partition_stack_entry { 632 int left; 633 int right; 634 #ifdef QSORT_ORDER_GUESS 635 int qsort_break_even; 636 #endif 637 }; 638 639 /* ******************************************************* Shorthand Macros */ 640 641 /* Note that these macros will be used from inside the qsort function where 642 we happen to know that the variable 'elt_size' contains the size of an 643 array element and the variable 'temp' points to enough space to hold a 644 temp element and the variable 'array' points to the array being sorted 645 and 'compare' is the pointer to the compare routine. 646 647 Also note that there are very many highly architecture specific ways 648 these might be sped up, but this is simply the most generally portable 649 code I could think of. 650 */ 651 652 /* Return < 0 == 0 or > 0 as the value of elt1 is < elt2, == elt2, > elt2 653 */ 654 #define qsort_cmp(elt1, elt2) \ 655 ((*compare)(aTHX_ array[elt1], array[elt2])) 656 657 #ifdef QSORT_ORDER_GUESS 658 #define QSORT_NOTICE_SWAP swapped++; 659 #else 660 #define QSORT_NOTICE_SWAP 661 #endif 662 663 /* swaps contents of array elements elt1, elt2. 664 */ 665 #define qsort_swap(elt1, elt2) \ 666 STMT_START { \ 667 QSORT_NOTICE_SWAP \ 668 temp = array[elt1]; \ 669 array[elt1] = array[elt2]; \ 670 array[elt2] = temp; \ 671 } STMT_END 672 673 /* rotate contents of elt1, elt2, elt3 such that elt1 gets elt2, elt2 gets 674 elt3 and elt3 gets elt1. 675 */ 676 #define qsort_rotate(elt1, elt2, elt3) \ 677 STMT_START { \ 678 QSORT_NOTICE_SWAP \ 679 temp = array[elt1]; \ 680 array[elt1] = array[elt2]; \ 681 array[elt2] = array[elt3]; \ 682 array[elt3] = temp; \ 683 } STMT_END 684 685 /* ************************************************************ Debug stuff */ 686 687 #ifdef QSORT_DEBUG 688 689 static void 690 break_here() 691 { 692 return; /* good place to set a breakpoint */ 693 } 694 695 #define qsort_assert(t) (void)( (t) || (break_here(), 0) ) 696 697 static void 698 doqsort_all_asserts( 699 void * array, 700 size_t num_elts, 701 size_t elt_size, 702 int (*compare)(const void * elt1, const void * elt2), 703 int pc_left, int pc_right, int u_left, int u_right) 704 { 705 int i; 706 707 qsort_assert(pc_left <= pc_right); 708 qsort_assert(u_right < pc_left); 709 qsort_assert(pc_right < u_left); 710 for (i = u_right + 1; i < pc_left; ++i) { 711 qsort_assert(qsort_cmp(i, pc_left) < 0); 712 } 713 for (i = pc_left; i < pc_right; ++i) { 714 qsort_assert(qsort_cmp(i, pc_right) == 0); 715 } 716 for (i = pc_right + 1; i < u_left; ++i) { 717 qsort_assert(qsort_cmp(pc_right, i) < 0); 718 } 719 } 720 721 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) \ 722 doqsort_all_asserts(array, num_elts, elt_size, compare, \ 723 PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) 724 725 #else 726 727 #define qsort_assert(t) ((void)0) 728 729 #define qsort_all_asserts(PC_LEFT, PC_RIGHT, U_LEFT, U_RIGHT) ((void)0) 730 731 #endif 732 733 /* ****************************************************************** qsort */ 734 735 STATIC void /* the standard unstable (u) quicksort (qsort) */ 736 S_qsortsvu(pTHX_ SV ** array, size_t num_elts, SVCOMPARE_t compare) 737 { 738 register SV * temp; 739 740 struct partition_stack_entry partition_stack[QSORT_MAX_STACK]; 741 int next_stack_entry = 0; 742 743 int part_left; 744 int part_right; 745 #ifdef QSORT_ORDER_GUESS 746 int qsort_break_even; 747 int swapped; 748 #endif 749 750 /* Make sure we actually have work to do. 751 */ 752 if (num_elts <= 1) { 753 return; 754 } 755 756 /* Innoculate large partitions against quadratic behavior */ 757 if (num_elts > QSORT_PLAY_SAFE) { 758 register size_t n, j; 759 register SV **q; 760 for (n = num_elts, q = array; n > 1; ) { 761 j = (size_t)(n-- * Drand01()); 762 temp = q[j]; 763 q[j] = q[n]; 764 q[n] = temp; 765 } 766 } 767 768 /* Setup the initial partition definition and fall into the sorting loop 769 */ 770 part_left = 0; 771 part_right = (int)(num_elts - 1); 772 #ifdef QSORT_ORDER_GUESS 773 qsort_break_even = QSORT_BREAK_EVEN; 774 #else 775 #define qsort_break_even QSORT_BREAK_EVEN 776 #endif 777 for ( ; ; ) { 778 if ((part_right - part_left) >= qsort_break_even) { 779 /* OK, this is gonna get hairy, so lets try to document all the 780 concepts and abbreviations and variables and what they keep 781 track of: 782 783 pc: pivot chunk - the set of array elements we accumulate in the 784 middle of the partition, all equal in value to the original 785 pivot element selected. The pc is defined by: 786 787 pc_left - the leftmost array index of the pc 788 pc_right - the rightmost array index of the pc 789 790 we start with pc_left == pc_right and only one element 791 in the pivot chunk (but it can grow during the scan). 792 793 u: uncompared elements - the set of elements in the partition 794 we have not yet compared to the pivot value. There are two 795 uncompared sets during the scan - one to the left of the pc 796 and one to the right. 797 798 u_right - the rightmost index of the left side's uncompared set 799 u_left - the leftmost index of the right side's uncompared set 800 801 The leftmost index of the left sides's uncompared set 802 doesn't need its own variable because it is always defined 803 by the leftmost edge of the whole partition (part_left). The 804 same goes for the rightmost edge of the right partition 805 (part_right). 806 807 We know there are no uncompared elements on the left once we 808 get u_right < part_left and no uncompared elements on the 809 right once u_left > part_right. When both these conditions 810 are met, we have completed the scan of the partition. 811 812 Any elements which are between the pivot chunk and the 813 uncompared elements should be less than the pivot value on 814 the left side and greater than the pivot value on the right 815 side (in fact, the goal of the whole algorithm is to arrange 816 for that to be true and make the groups of less-than and 817 greater-then elements into new partitions to sort again). 818 819 As you marvel at the complexity of the code and wonder why it 820 has to be so confusing. Consider some of the things this level 821 of confusion brings: 822 823 Once I do a compare, I squeeze every ounce of juice out of it. I 824 never do compare calls I don't have to do, and I certainly never 825 do redundant calls. 826 827 I also never swap any elements unless I can prove there is a 828 good reason. Many sort algorithms will swap a known value with 829 an uncompared value just to get things in the right place (or 830 avoid complexity :-), but that uncompared value, once it gets 831 compared, may then have to be swapped again. A lot of the 832 complexity of this code is due to the fact that it never swaps 833 anything except compared values, and it only swaps them when the 834 compare shows they are out of position. 835 */ 836 int pc_left, pc_right; 837 int u_right, u_left; 838 839 int s; 840 841 pc_left = ((part_left + part_right) / 2); 842 pc_right = pc_left; 843 u_right = pc_left - 1; 844 u_left = pc_right + 1; 845 846 /* Qsort works best when the pivot value is also the median value 847 in the partition (unfortunately you can't find the median value 848 without first sorting :-), so to give the algorithm a helping 849 hand, we pick 3 elements and sort them and use the median value 850 of that tiny set as the pivot value. 851 852 Some versions of qsort like to use the left middle and right as 853 the 3 elements to sort so they can insure the ends of the 854 partition will contain values which will stop the scan in the 855 compare loop, but when you have to call an arbitrarily complex 856 routine to do a compare, its really better to just keep track of 857 array index values to know when you hit the edge of the 858 partition and avoid the extra compare. An even better reason to 859 avoid using a compare call is the fact that you can drop off the 860 edge of the array if someone foolishly provides you with an 861 unstable compare function that doesn't always provide consistent 862 results. 863 864 So, since it is simpler for us to compare the three adjacent 865 elements in the middle of the partition, those are the ones we 866 pick here (conveniently pointed at by u_right, pc_left, and 867 u_left). The values of the left, center, and right elements 868 are refered to as l c and r in the following comments. 869 */ 870 871 #ifdef QSORT_ORDER_GUESS 872 swapped = 0; 873 #endif 874 s = qsort_cmp(u_right, pc_left); 875 if (s < 0) { 876 /* l < c */ 877 s = qsort_cmp(pc_left, u_left); 878 /* if l < c, c < r - already in order - nothing to do */ 879 if (s == 0) { 880 /* l < c, c == r - already in order, pc grows */ 881 ++pc_right; 882 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 883 } else if (s > 0) { 884 /* l < c, c > r - need to know more */ 885 s = qsort_cmp(u_right, u_left); 886 if (s < 0) { 887 /* l < c, c > r, l < r - swap c & r to get ordered */ 888 qsort_swap(pc_left, u_left); 889 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 890 } else if (s == 0) { 891 /* l < c, c > r, l == r - swap c&r, grow pc */ 892 qsort_swap(pc_left, u_left); 893 --pc_left; 894 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 895 } else { 896 /* l < c, c > r, l > r - make lcr into rlc to get ordered */ 897 qsort_rotate(pc_left, u_right, u_left); 898 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 899 } 900 } 901 } else if (s == 0) { 902 /* l == c */ 903 s = qsort_cmp(pc_left, u_left); 904 if (s < 0) { 905 /* l == c, c < r - already in order, grow pc */ 906 --pc_left; 907 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 908 } else if (s == 0) { 909 /* l == c, c == r - already in order, grow pc both ways */ 910 --pc_left; 911 ++pc_right; 912 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 913 } else { 914 /* l == c, c > r - swap l & r, grow pc */ 915 qsort_swap(u_right, u_left); 916 ++pc_right; 917 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 918 } 919 } else { 920 /* l > c */ 921 s = qsort_cmp(pc_left, u_left); 922 if (s < 0) { 923 /* l > c, c < r - need to know more */ 924 s = qsort_cmp(u_right, u_left); 925 if (s < 0) { 926 /* l > c, c < r, l < r - swap l & c to get ordered */ 927 qsort_swap(u_right, pc_left); 928 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 929 } else if (s == 0) { 930 /* l > c, c < r, l == r - swap l & c, grow pc */ 931 qsort_swap(u_right, pc_left); 932 ++pc_right; 933 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 934 } else { 935 /* l > c, c < r, l > r - rotate lcr into crl to order */ 936 qsort_rotate(u_right, pc_left, u_left); 937 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 938 } 939 } else if (s == 0) { 940 /* l > c, c == r - swap ends, grow pc */ 941 qsort_swap(u_right, u_left); 942 --pc_left; 943 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 944 } else { 945 /* l > c, c > r - swap ends to get in order */ 946 qsort_swap(u_right, u_left); 947 qsort_all_asserts(pc_left, pc_right, u_left + 1, u_right - 1); 948 } 949 } 950 /* We now know the 3 middle elements have been compared and 951 arranged in the desired order, so we can shrink the uncompared 952 sets on both sides 953 */ 954 --u_right; 955 ++u_left; 956 qsort_all_asserts(pc_left, pc_right, u_left, u_right); 957 958 /* The above massive nested if was the simple part :-). We now have 959 the middle 3 elements ordered and we need to scan through the 960 uncompared sets on either side, swapping elements that are on 961 the wrong side or simply shuffling equal elements around to get 962 all equal elements into the pivot chunk. 963 */ 964 965 for ( ; ; ) { 966 int still_work_on_left; 967 int still_work_on_right; 968 969 /* Scan the uncompared values on the left. If I find a value 970 equal to the pivot value, move it over so it is adjacent to 971 the pivot chunk and expand the pivot chunk. If I find a value 972 less than the pivot value, then just leave it - its already 973 on the correct side of the partition. If I find a greater 974 value, then stop the scan. 975 */ 976 while ((still_work_on_left = (u_right >= part_left))) { 977 s = qsort_cmp(u_right, pc_left); 978 if (s < 0) { 979 --u_right; 980 } else if (s == 0) { 981 --pc_left; 982 if (pc_left != u_right) { 983 qsort_swap(u_right, pc_left); 984 } 985 --u_right; 986 } else { 987 break; 988 } 989 qsort_assert(u_right < pc_left); 990 qsort_assert(pc_left <= pc_right); 991 qsort_assert(qsort_cmp(u_right + 1, pc_left) <= 0); 992 qsort_assert(qsort_cmp(pc_left, pc_right) == 0); 993 } 994 995 /* Do a mirror image scan of uncompared values on the right 996 */ 997 while ((still_work_on_right = (u_left <= part_right))) { 998 s = qsort_cmp(pc_right, u_left); 999 if (s < 0) { 1000 ++u_left; 1001 } else if (s == 0) { 1002 ++pc_right; 1003 if (pc_right != u_left) { 1004 qsort_swap(pc_right, u_left); 1005 } 1006 ++u_left; 1007 } else { 1008 break; 1009 } 1010 qsort_assert(u_left > pc_right); 1011 qsort_assert(pc_left <= pc_right); 1012 qsort_assert(qsort_cmp(pc_right, u_left - 1) <= 0); 1013 qsort_assert(qsort_cmp(pc_left, pc_right) == 0); 1014 } 1015 1016 if (still_work_on_left) { 1017 /* I know I have a value on the left side which needs to be 1018 on the right side, but I need to know more to decide 1019 exactly the best thing to do with it. 1020 */ 1021 if (still_work_on_right) { 1022 /* I know I have values on both side which are out of 1023 position. This is a big win because I kill two birds 1024 with one swap (so to speak). I can advance the 1025 uncompared pointers on both sides after swapping both 1026 of them into the right place. 1027 */ 1028 qsort_swap(u_right, u_left); 1029 --u_right; 1030 ++u_left; 1031 qsort_all_asserts(pc_left, pc_right, u_left, u_right); 1032 } else { 1033 /* I have an out of position value on the left, but the 1034 right is fully scanned, so I "slide" the pivot chunk 1035 and any less-than values left one to make room for the 1036 greater value over on the right. If the out of position 1037 value is immediately adjacent to the pivot chunk (there 1038 are no less-than values), I can do that with a swap, 1039 otherwise, I have to rotate one of the less than values 1040 into the former position of the out of position value 1041 and the right end of the pivot chunk into the left end 1042 (got all that?). 1043 */ 1044 --pc_left; 1045 if (pc_left == u_right) { 1046 qsort_swap(u_right, pc_right); 1047 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); 1048 } else { 1049 qsort_rotate(u_right, pc_left, pc_right); 1050 qsort_all_asserts(pc_left, pc_right-1, u_left, u_right-1); 1051 } 1052 --pc_right; 1053 --u_right; 1054 } 1055 } else if (still_work_on_right) { 1056 /* Mirror image of complex case above: I have an out of 1057 position value on the right, but the left is fully 1058 scanned, so I need to shuffle things around to make room 1059 for the right value on the left. 1060 */ 1061 ++pc_right; 1062 if (pc_right == u_left) { 1063 qsort_swap(u_left, pc_left); 1064 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); 1065 } else { 1066 qsort_rotate(pc_right, pc_left, u_left); 1067 qsort_all_asserts(pc_left+1, pc_right, u_left+1, u_right); 1068 } 1069 ++pc_left; 1070 ++u_left; 1071 } else { 1072 /* No more scanning required on either side of partition, 1073 break out of loop and figure out next set of partitions 1074 */ 1075 break; 1076 } 1077 } 1078 1079 /* The elements in the pivot chunk are now in the right place. They 1080 will never move or be compared again. All I have to do is decide 1081 what to do with the stuff to the left and right of the pivot 1082 chunk. 1083 1084 Notes on the QSORT_ORDER_GUESS ifdef code: 1085 1086 1. If I just built these partitions without swapping any (or 1087 very many) elements, there is a chance that the elements are 1088 already ordered properly (being properly ordered will 1089 certainly result in no swapping, but the converse can't be 1090 proved :-). 1091 1092 2. A (properly written) insertion sort will run faster on 1093 already ordered data than qsort will. 1094 1095 3. Perhaps there is some way to make a good guess about 1096 switching to an insertion sort earlier than partition size 6 1097 (for instance - we could save the partition size on the stack 1098 and increase the size each time we find we didn't swap, thus 1099 switching to insertion sort earlier for partitions with a 1100 history of not swapping). 1101 1102 4. Naturally, if I just switch right away, it will make 1103 artificial benchmarks with pure ascending (or descending) 1104 data look really good, but is that a good reason in general? 1105 Hard to say... 1106 */ 1107 1108 #ifdef QSORT_ORDER_GUESS 1109 if (swapped < 3) { 1110 #if QSORT_ORDER_GUESS == 1 1111 qsort_break_even = (part_right - part_left) + 1; 1112 #endif 1113 #if QSORT_ORDER_GUESS == 2 1114 qsort_break_even *= 2; 1115 #endif 1116 #if QSORT_ORDER_GUESS == 3 1117 int prev_break = qsort_break_even; 1118 qsort_break_even *= qsort_break_even; 1119 if (qsort_break_even < prev_break) { 1120 qsort_break_even = (part_right - part_left) + 1; 1121 } 1122 #endif 1123 } else { 1124 qsort_break_even = QSORT_BREAK_EVEN; 1125 } 1126 #endif 1127 1128 if (part_left < pc_left) { 1129 /* There are elements on the left which need more processing. 1130 Check the right as well before deciding what to do. 1131 */ 1132 if (pc_right < part_right) { 1133 /* We have two partitions to be sorted. Stack the biggest one 1134 and process the smallest one on the next iteration. This 1135 minimizes the stack height by insuring that any additional 1136 stack entries must come from the smallest partition which 1137 (because it is smallest) will have the fewest 1138 opportunities to generate additional stack entries. 1139 */ 1140 if ((part_right - pc_right) > (pc_left - part_left)) { 1141 /* stack the right partition, process the left */ 1142 partition_stack[next_stack_entry].left = pc_right + 1; 1143 partition_stack[next_stack_entry].right = part_right; 1144 #ifdef QSORT_ORDER_GUESS 1145 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; 1146 #endif 1147 part_right = pc_left - 1; 1148 } else { 1149 /* stack the left partition, process the right */ 1150 partition_stack[next_stack_entry].left = part_left; 1151 partition_stack[next_stack_entry].right = pc_left - 1; 1152 #ifdef QSORT_ORDER_GUESS 1153 partition_stack[next_stack_entry].qsort_break_even = qsort_break_even; 1154 #endif 1155 part_left = pc_right + 1; 1156 } 1157 qsort_assert(next_stack_entry < QSORT_MAX_STACK); 1158 ++next_stack_entry; 1159 } else { 1160 /* The elements on the left are the only remaining elements 1161 that need sorting, arrange for them to be processed as the 1162 next partition. 1163 */ 1164 part_right = pc_left - 1; 1165 } 1166 } else if (pc_right < part_right) { 1167 /* There is only one chunk on the right to be sorted, make it 1168 the new partition and loop back around. 1169 */ 1170 part_left = pc_right + 1; 1171 } else { 1172 /* This whole partition wound up in the pivot chunk, so 1173 we need to get a new partition off the stack. 1174 */ 1175 if (next_stack_entry == 0) { 1176 /* the stack is empty - we are done */ 1177 break; 1178 } 1179 --next_stack_entry; 1180 part_left = partition_stack[next_stack_entry].left; 1181 part_right = partition_stack[next_stack_entry].right; 1182 #ifdef QSORT_ORDER_GUESS 1183 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; 1184 #endif 1185 } 1186 } else { 1187 /* This partition is too small to fool with qsort complexity, just 1188 do an ordinary insertion sort to minimize overhead. 1189 */ 1190 int i; 1191 /* Assume 1st element is in right place already, and start checking 1192 at 2nd element to see where it should be inserted. 1193 */ 1194 for (i = part_left + 1; i <= part_right; ++i) { 1195 int j; 1196 /* Scan (backwards - just in case 'i' is already in right place) 1197 through the elements already sorted to see if the ith element 1198 belongs ahead of one of them. 1199 */ 1200 for (j = i - 1; j >= part_left; --j) { 1201 if (qsort_cmp(i, j) >= 0) { 1202 /* i belongs right after j 1203 */ 1204 break; 1205 } 1206 } 1207 ++j; 1208 if (j != i) { 1209 /* Looks like we really need to move some things 1210 */ 1211 int k; 1212 temp = array[i]; 1213 for (k = i - 1; k >= j; --k) 1214 array[k + 1] = array[k]; 1215 array[j] = temp; 1216 } 1217 } 1218 1219 /* That partition is now sorted, grab the next one, or get out 1220 of the loop if there aren't any more. 1221 */ 1222 1223 if (next_stack_entry == 0) { 1224 /* the stack is empty - we are done */ 1225 break; 1226 } 1227 --next_stack_entry; 1228 part_left = partition_stack[next_stack_entry].left; 1229 part_right = partition_stack[next_stack_entry].right; 1230 #ifdef QSORT_ORDER_GUESS 1231 qsort_break_even = partition_stack[next_stack_entry].qsort_break_even; 1232 #endif 1233 } 1234 } 1235 1236 /* Believe it or not, the array is sorted at this point! */ 1237 } 1238 1239 /* Stabilize what is, presumably, an otherwise unstable sort method. 1240 * We do that by allocating (or having on hand) an array of pointers 1241 * that is the same size as the original array of elements to be sorted. 1242 * We initialize this parallel array with the addresses of the original 1243 * array elements. This indirection can make you crazy. 1244 * Some pictures can help. After initializing, we have 1245 * 1246 * indir list1 1247 * +----+ +----+ 1248 * | | --------------> | | ------> first element to be sorted 1249 * +----+ +----+ 1250 * | | --------------> | | ------> second element to be sorted 1251 * +----+ +----+ 1252 * | | --------------> | | ------> third element to be sorted 1253 * +----+ +----+ 1254 * ... 1255 * +----+ +----+ 1256 * | | --------------> | | ------> n-1st element to be sorted 1257 * +----+ +----+ 1258 * | | --------------> | | ------> n-th element to be sorted 1259 * +----+ +----+ 1260 * 1261 * During the sort phase, we leave the elements of list1 where they are, 1262 * and sort the pointers in the indirect array in the same order determined 1263 * by the original comparison routine on the elements pointed to. 1264 * Because we don't move the elements of list1 around through 1265 * this phase, we can break ties on elements that compare equal 1266 * using their address in the list1 array, ensuring stabilty. 1267 * This leaves us with something looking like 1268 * 1269 * indir list1 1270 * +----+ +----+ 1271 * | | --+ +---> | | ------> first element to be sorted 1272 * +----+ | | +----+ 1273 * | | --|-------|---> | | ------> second element to be sorted 1274 * +----+ | | +----+ 1275 * | | --|-------+ +-> | | ------> third element to be sorted 1276 * +----+ | | +----+ 1277 * ... 1278 * +----+ | | | | +----+ 1279 * | | ---|-+ | +--> | | ------> n-1st element to be sorted 1280 * +----+ | | +----+ 1281 * | | ---+ +----> | | ------> n-th element to be sorted 1282 * +----+ +----+ 1283 * 1284 * where the i-th element of the indirect array points to the element 1285 * that should be i-th in the sorted array. After the sort phase, 1286 * we have to put the elements of list1 into the places 1287 * dictated by the indirect array. 1288 */ 1289 1290 1291 static I32 1292 cmpindir(pTHX_ gptr a, gptr b) 1293 { 1294 I32 sense; 1295 gptr *ap = (gptr *)a; 1296 gptr *bp = (gptr *)b; 1297 1298 if ((sense = PL_sort_RealCmp(aTHX_ *ap, *bp)) == 0) 1299 sense = (ap > bp) ? 1 : ((ap < bp) ? -1 : 0); 1300 return sense; 1301 } 1302 1303 STATIC void 1304 S_qsortsv(pTHX_ gptr *list1, size_t nmemb, SVCOMPARE_t cmp) 1305 { 1306 SV *hintsv; 1307 1308 if (SORTHINTS(hintsv) & HINT_SORT_STABLE) { 1309 register gptr **pp, *q; 1310 register size_t n, j, i; 1311 gptr *small[SMALLSORT], **indir, tmp; 1312 SVCOMPARE_t savecmp; 1313 if (nmemb <= 1) return; /* sorted trivially */ 1314 1315 /* Small arrays can use the stack, big ones must be allocated */ 1316 if (nmemb <= SMALLSORT) indir = small; 1317 else { New(1799, indir, nmemb, gptr *); } 1318 1319 /* Copy pointers to original array elements into indirect array */ 1320 for (n = nmemb, pp = indir, q = list1; n--; ) *pp++ = q++; 1321 1322 savecmp = PL_sort_RealCmp; /* Save current comparison routine, if any */ 1323 PL_sort_RealCmp = cmp; /* Put comparison routine where cmpindir can find it */ 1324 1325 /* sort, with indirection */ 1326 S_qsortsvu(aTHX_ (gptr *)indir, nmemb, cmpindir); 1327 1328 pp = indir; 1329 q = list1; 1330 for (n = nmemb; n--; ) { 1331 /* Assert A: all elements of q with index > n are already 1332 * in place. This is vacuosly true at the start, and we 1333 * put element n where it belongs below (if it wasn't 1334 * already where it belonged). Assert B: we only move 1335 * elements that aren't where they belong, 1336 * so, by A, we never tamper with elements above n. 1337 */ 1338 j = pp[n] - q; /* This sets j so that q[j] is 1339 * at pp[n]. *pp[j] belongs in 1340 * q[j], by construction. 1341 */ 1342 if (n != j) { /* all's well if n == j */ 1343 tmp = q[j]; /* save what's in q[j] */ 1344 do { 1345 q[j] = *pp[j]; /* put *pp[j] where it belongs */ 1346 i = pp[j] - q; /* the index in q of the element 1347 * just moved */ 1348 pp[j] = q + j; /* this is ok now */ 1349 } while ((j = i) != n); 1350 /* There are only finitely many (nmemb) addresses 1351 * in the pp array. 1352 * So we must eventually revisit an index we saw before. 1353 * Suppose the first revisited index is k != n. 1354 * An index is visited because something else belongs there. 1355 * If we visit k twice, then two different elements must 1356 * belong in the same place, which cannot be. 1357 * So j must get back to n, the loop terminates, 1358 * and we put the saved element where it belongs. 1359 */ 1360 q[n] = tmp; /* put what belongs into 1361 * the n-th element */ 1362 } 1363 } 1364 1365 /* free iff allocated */ 1366 if (indir != small) { Safefree(indir); } 1367 /* restore prevailing comparison routine */ 1368 PL_sort_RealCmp = savecmp; 1369 } else { 1370 S_qsortsvu(aTHX_ list1, nmemb, cmp); 1371 } 1372 } 1373 1374 /* 1375 =head1 Array Manipulation Functions 1376 1377 =for apidoc sortsv 1378 1379 Sort an array. Here is an example: 1380 1381 sortsv(AvARRAY(av), av_len(av)+1, Perl_sv_cmp_locale); 1382 1383 See lib/sort.pm for details about controlling the sorting algorithm. 1384 1385 =cut 1386 */ 1387 1388 void 1389 Perl_sortsv(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) 1390 { 1391 void (*sortsvp)(pTHX_ SV **array, size_t nmemb, SVCOMPARE_t cmp) = 1392 S_mergesortsv; 1393 SV *hintsv; 1394 I32 hints; 1395 1396 /* Sun's Compiler (cc: WorkShop Compilers 4.2 30 Oct 1996 C 4.2) used 1397 to miscompile this function under optimization -O. If you get test 1398 errors related to picking the correct sort() function, try recompiling 1399 this file without optimiziation. -- A.D. 4/2002. 1400 */ 1401 hints = SORTHINTS(hintsv); 1402 if (hints & HINT_SORT_QUICKSORT) { 1403 sortsvp = S_qsortsv; 1404 } 1405 else { 1406 /* The default as of 5.8.0 is mergesort */ 1407 sortsvp = S_mergesortsv; 1408 } 1409 1410 sortsvp(aTHX_ array, nmemb, cmp); 1411 } 1412 1413 PP(pp_sort) 1414 { 1415 dSP; dMARK; dORIGMARK; 1416 register SV **up; 1417 SV **myorigmark = ORIGMARK; 1418 register I32 max; 1419 HV *stash; 1420 GV *gv; 1421 CV *cv = 0; 1422 I32 gimme = GIMME; 1423 OP* nextop = PL_op->op_next; 1424 I32 overloading = 0; 1425 bool hasargs = FALSE; 1426 I32 is_xsub = 0; 1427 1428 if (gimme != G_ARRAY) { 1429 SP = MARK; 1430 RETPUSHUNDEF; 1431 } 1432 1433 ENTER; 1434 SAVEVPTR(PL_sortcop); 1435 if (PL_op->op_flags & OPf_STACKED) { 1436 if (PL_op->op_flags & OPf_SPECIAL) { 1437 OP *kid = cLISTOP->op_first->op_sibling; /* pass pushmark */ 1438 kid = kUNOP->op_first; /* pass rv2gv */ 1439 kid = kUNOP->op_first; /* pass leave */ 1440 PL_sortcop = kid->op_next; 1441 stash = CopSTASH(PL_curcop); 1442 } 1443 else { 1444 cv = sv_2cv(*++MARK, &stash, &gv, 0); 1445 if (cv && SvPOK(cv)) { 1446 STRLEN n_a; 1447 char *proto = SvPV((SV*)cv, n_a); 1448 if (proto && strEQ(proto, "$$")) { 1449 hasargs = TRUE; 1450 } 1451 } 1452 if (!(cv && CvROOT(cv))) { 1453 if (cv && CvXSUB(cv)) { 1454 is_xsub = 1; 1455 } 1456 else if (gv) { 1457 SV *tmpstr = sv_newmortal(); 1458 gv_efullname3(tmpstr, gv, Nullch); 1459 DIE(aTHX_ "Undefined sort subroutine \"%"SVf"\" called", 1460 tmpstr); 1461 } 1462 else { 1463 DIE(aTHX_ "Undefined subroutine in sort"); 1464 } 1465 } 1466 1467 if (is_xsub) 1468 PL_sortcop = (OP*)cv; 1469 else { 1470 PL_sortcop = CvSTART(cv); 1471 SAVEVPTR(CvROOT(cv)->op_ppaddr); 1472 CvROOT(cv)->op_ppaddr = PL_ppaddr[OP_NULL]; 1473 1474 PAD_SET_CUR(CvPADLIST(cv), 1); 1475 } 1476 } 1477 } 1478 else { 1479 PL_sortcop = Nullop; 1480 stash = CopSTASH(PL_curcop); 1481 } 1482 1483 up = myorigmark + 1; 1484 while (MARK < SP) { /* This may or may not shift down one here. */ 1485 /*SUPPRESS 560*/ 1486 if ((*up = *++MARK)) { /* Weed out nulls. */ 1487 SvTEMP_off(*up); 1488 if (!PL_sortcop && !SvPOK(*up)) { 1489 STRLEN n_a; 1490 if (SvAMAGIC(*up)) 1491 overloading = 1; 1492 else 1493 (void)sv_2pv(*up, &n_a); 1494 } 1495 up++; 1496 } 1497 } 1498 max = --up - myorigmark; 1499 if (PL_sortcop) { 1500 if (max > 1) { 1501 PERL_CONTEXT *cx; 1502 SV** newsp; 1503 bool oldcatch = CATCH_GET; 1504 1505 SAVETMPS; 1506 SAVEOP(); 1507 1508 CATCH_SET(TRUE); 1509 PUSHSTACKi(PERLSI_SORT); 1510 if (!hasargs && !is_xsub) { 1511 if (PL_sortstash != stash || !PL_firstgv || !PL_secondgv) { 1512 SAVESPTR(PL_firstgv); 1513 SAVESPTR(PL_secondgv); 1514 PL_firstgv = gv_fetchpv("a", TRUE, SVt_PV); 1515 PL_secondgv = gv_fetchpv("b", TRUE, SVt_PV); 1516 PL_sortstash = stash; 1517 } 1518 #ifdef USE_5005THREADS 1519 sv_lock((SV *)PL_firstgv); 1520 sv_lock((SV *)PL_secondgv); 1521 #endif 1522 SAVESPTR(GvSV(PL_firstgv)); 1523 SAVESPTR(GvSV(PL_secondgv)); 1524 } 1525 1526 PUSHBLOCK(cx, CXt_NULL, PL_stack_base); 1527 if (!(PL_op->op_flags & OPf_SPECIAL)) { 1528 cx->cx_type = CXt_SUB; 1529 cx->blk_gimme = G_SCALAR; 1530 PUSHSUB(cx); 1531 if (!CvDEPTH(cv)) 1532 (void)SvREFCNT_inc(cv); /* in preparation for POPSUB */ 1533 } 1534 PL_sortcxix = cxstack_ix; 1535 1536 if (hasargs && !is_xsub) { 1537 /* This is mostly copied from pp_entersub */ 1538 AV *av = (AV*)PAD_SVl(0); 1539 1540 #ifndef USE_5005THREADS 1541 cx->blk_sub.savearray = GvAV(PL_defgv); 1542 GvAV(PL_defgv) = (AV*)SvREFCNT_inc(av); 1543 #endif /* USE_5005THREADS */ 1544 CX_CURPAD_SAVE(cx->blk_sub); 1545 cx->blk_sub.argarray = av; 1546 } 1547 sortsv((myorigmark+1), max, 1548 is_xsub ? sortcv_xsub : hasargs ? sortcv_stacked : sortcv); 1549 1550 POPBLOCK(cx,PL_curpm); 1551 PL_stack_sp = newsp; 1552 POPSTACK; 1553 CATCH_SET(oldcatch); 1554 } 1555 } 1556 else { 1557 if (max > 1) { 1558 MEXTEND(SP, 20); /* Can't afford stack realloc on signal. */ 1559 sortsv(ORIGMARK+1, max, 1560 (PL_op->op_private & OPpSORT_NUMERIC) 1561 ? ( (PL_op->op_private & OPpSORT_INTEGER) 1562 ? ( overloading ? amagic_i_ncmp : sv_i_ncmp) 1563 : ( overloading ? amagic_ncmp : sv_ncmp)) 1564 : ( IN_LOCALE_RUNTIME 1565 ? ( overloading 1566 ? amagic_cmp_locale 1567 : sv_cmp_locale_static) 1568 : ( overloading ? amagic_cmp : sv_cmp_static))); 1569 if (PL_op->op_private & OPpSORT_REVERSE) { 1570 SV **p = ORIGMARK+1; 1571 SV **q = ORIGMARK+max; 1572 while (p < q) { 1573 SV *tmp = *p; 1574 *p++ = *q; 1575 *q-- = tmp; 1576 } 1577 } 1578 } 1579 } 1580 LEAVE; 1581 PL_stack_sp = ORIGMARK + max; 1582 return nextop; 1583 } 1584 1585 static I32 1586 sortcv(pTHX_ SV *a, SV *b) 1587 { 1588 I32 oldsaveix = PL_savestack_ix; 1589 I32 oldscopeix = PL_scopestack_ix; 1590 I32 result; 1591 GvSV(PL_firstgv) = a; 1592 GvSV(PL_secondgv) = b; 1593 PL_stack_sp = PL_stack_base; 1594 PL_op = PL_sortcop; 1595 CALLRUNOPS(aTHX); 1596 if (PL_stack_sp != PL_stack_base + 1) 1597 Perl_croak(aTHX_ "Sort subroutine didn't return single value"); 1598 if (!SvNIOKp(*PL_stack_sp)) 1599 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value"); 1600 result = SvIV(*PL_stack_sp); 1601 while (PL_scopestack_ix > oldscopeix) { 1602 LEAVE; 1603 } 1604 leave_scope(oldsaveix); 1605 return result; 1606 } 1607 1608 static I32 1609 sortcv_stacked(pTHX_ SV *a, SV *b) 1610 { 1611 I32 oldsaveix = PL_savestack_ix; 1612 I32 oldscopeix = PL_scopestack_ix; 1613 I32 result; 1614 AV *av; 1615 1616 #ifdef USE_5005THREADS 1617 av = (AV*)PAD_SVl(0); 1618 #else 1619 av = GvAV(PL_defgv); 1620 #endif 1621 1622 if (AvMAX(av) < 1) { 1623 SV** ary = AvALLOC(av); 1624 if (AvARRAY(av) != ary) { 1625 AvMAX(av) += AvARRAY(av) - AvALLOC(av); 1626 SvPVX(av) = (char*)ary; 1627 } 1628 if (AvMAX(av) < 1) { 1629 AvMAX(av) = 1; 1630 Renew(ary,2,SV*); 1631 SvPVX(av) = (char*)ary; 1632 } 1633 } 1634 AvFILLp(av) = 1; 1635 1636 AvARRAY(av)[0] = a; 1637 AvARRAY(av)[1] = b; 1638 PL_stack_sp = PL_stack_base; 1639 PL_op = PL_sortcop; 1640 CALLRUNOPS(aTHX); 1641 if (PL_stack_sp != PL_stack_base + 1) 1642 Perl_croak(aTHX_ "Sort subroutine didn't return single value"); 1643 if (!SvNIOKp(*PL_stack_sp)) 1644 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value"); 1645 result = SvIV(*PL_stack_sp); 1646 while (PL_scopestack_ix > oldscopeix) { 1647 LEAVE; 1648 } 1649 leave_scope(oldsaveix); 1650 return result; 1651 } 1652 1653 static I32 1654 sortcv_xsub(pTHX_ SV *a, SV *b) 1655 { 1656 dSP; 1657 I32 oldsaveix = PL_savestack_ix; 1658 I32 oldscopeix = PL_scopestack_ix; 1659 I32 result; 1660 CV *cv=(CV*)PL_sortcop; 1661 1662 SP = PL_stack_base; 1663 PUSHMARK(SP); 1664 EXTEND(SP, 2); 1665 *++SP = a; 1666 *++SP = b; 1667 PUTBACK; 1668 (void)(*CvXSUB(cv))(aTHX_ cv); 1669 if (PL_stack_sp != PL_stack_base + 1) 1670 Perl_croak(aTHX_ "Sort subroutine didn't return single value"); 1671 if (!SvNIOKp(*PL_stack_sp)) 1672 Perl_croak(aTHX_ "Sort subroutine didn't return a numeric value"); 1673 result = SvIV(*PL_stack_sp); 1674 while (PL_scopestack_ix > oldscopeix) { 1675 LEAVE; 1676 } 1677 leave_scope(oldsaveix); 1678 return result; 1679 } 1680 1681 1682 static I32 1683 sv_ncmp(pTHX_ SV *a, SV *b) 1684 { 1685 NV nv1 = SvNV(a); 1686 NV nv2 = SvNV(b); 1687 return nv1 < nv2 ? -1 : nv1 > nv2 ? 1 : 0; 1688 } 1689 1690 static I32 1691 sv_i_ncmp(pTHX_ SV *a, SV *b) 1692 { 1693 IV iv1 = SvIV(a); 1694 IV iv2 = SvIV(b); 1695 return iv1 < iv2 ? -1 : iv1 > iv2 ? 1 : 0; 1696 } 1697 #define tryCALL_AMAGICbin(left,right,meth,svp) STMT_START { \ 1698 *svp = Nullsv; \ 1699 if (PL_amagic_generation) { \ 1700 if (SvAMAGIC(left)||SvAMAGIC(right))\ 1701 *svp = amagic_call(left, \ 1702 right, \ 1703 CAT2(meth,_amg), \ 1704 0); \ 1705 } \ 1706 } STMT_END 1707 1708 static I32 1709 amagic_ncmp(pTHX_ register SV *a, register SV *b) 1710 { 1711 SV *tmpsv; 1712 tryCALL_AMAGICbin(a,b,ncmp,&tmpsv); 1713 if (tmpsv) { 1714 NV d; 1715 1716 if (SvIOK(tmpsv)) { 1717 I32 i = SvIVX(tmpsv); 1718 if (i > 0) 1719 return 1; 1720 return i? -1 : 0; 1721 } 1722 d = SvNV(tmpsv); 1723 if (d > 0) 1724 return 1; 1725 return d? -1 : 0; 1726 } 1727 return sv_ncmp(aTHX_ a, b); 1728 } 1729 1730 static I32 1731 amagic_i_ncmp(pTHX_ register SV *a, register SV *b) 1732 { 1733 SV *tmpsv; 1734 tryCALL_AMAGICbin(a,b,ncmp,&tmpsv); 1735 if (tmpsv) { 1736 NV d; 1737 1738 if (SvIOK(tmpsv)) { 1739 I32 i = SvIVX(tmpsv); 1740 if (i > 0) 1741 return 1; 1742 return i? -1 : 0; 1743 } 1744 d = SvNV(tmpsv); 1745 if (d > 0) 1746 return 1; 1747 return d? -1 : 0; 1748 } 1749 return sv_i_ncmp(aTHX_ a, b); 1750 } 1751 1752 static I32 1753 amagic_cmp(pTHX_ register SV *str1, register SV *str2) 1754 { 1755 SV *tmpsv; 1756 tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv); 1757 if (tmpsv) { 1758 NV d; 1759 1760 if (SvIOK(tmpsv)) { 1761 I32 i = SvIVX(tmpsv); 1762 if (i > 0) 1763 return 1; 1764 return i? -1 : 0; 1765 } 1766 d = SvNV(tmpsv); 1767 if (d > 0) 1768 return 1; 1769 return d? -1 : 0; 1770 } 1771 return sv_cmp(str1, str2); 1772 } 1773 1774 static I32 1775 amagic_cmp_locale(pTHX_ register SV *str1, register SV *str2) 1776 { 1777 SV *tmpsv; 1778 tryCALL_AMAGICbin(str1,str2,scmp,&tmpsv); 1779 if (tmpsv) { 1780 NV d; 1781 1782 if (SvIOK(tmpsv)) { 1783 I32 i = SvIVX(tmpsv); 1784 if (i > 0) 1785 return 1; 1786 return i? -1 : 0; 1787 } 1788 d = SvNV(tmpsv); 1789 if (d > 0) 1790 return 1; 1791 return d? -1 : 0; 1792 } 1793 return sv_cmp_locale(str1, str2); 1794 } 1795