1 /* $NetBSD: snprintf.c,v 1.1.1.1 2016/01/13 18:41:48 christos Exp $ */
2
3 /*
4 * snprintf.c - a portable implementation of snprintf
5 *
6 * AUTHOR
7 * Mark Martinec <mark.martinec@ijs.si>, April 1999.
8 *
9 * Copyright 1999-2002 Mark Martinec. All rights reserved.
10 *
11 * TERMS AND CONDITIONS
12 * This program is free software; it is dual licensed, the terms of the
13 * "Frontier Artistic License" or the "GNU General Public License"
14 * can be chosen at your discretion. The chosen license then applies
15 * solely and in its entirety. Both licenses come with this Kit.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty
19 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
20 * See the license for more details.
21 *
22 * You should have received a copy of the "Frontier Artistic License"
23 * with this Kit in the file named LICENSE.txt, and the copy of
24 * the "GNU General Public License" in the file named LICENSE-GPL.txt.
25 * If not, I'll be glad to provide one.
26 *
27 * FEATURES
28 * - careful adherence to specs regarding flags, field width and precision;
29 * - good performance for large string handling (large format, large
30 * argument or large paddings). Performance is similar to system's sprintf
31 * and in several cases significantly better (make sure you compile with
32 * optimizations turned on, tell the compiler the code is strict ANSI
33 * if necessary to give it more freedom for optimizations);
34 * - return value semantics per ISO/IEC 9899:1999 ("ISO C99");
35 * - written in standard ISO/ANSI C - requires an ANSI C compiler;
36 * - works also with non-ASCII 8-bit character sets (e.g. EBCDIC)
37 * provided strings are '\0'-terminated.
38 *
39 * SUPPORTED CONVERSION SPECIFIERS AND DATA TYPES
40 *
41 * This snprintf only supports the following conversion specifiers:
42 * s, c, d, u, o, x, X, p (and synonyms: i, D, U, O - see below)
43 * with flags: '-', '+', ' ', '0' and '#'.
44 * An asterisk is supported for field width and for the precision.
45 *
46 * Length modifiers 'h' (short int), 'l' (long int),
47 * and 'll' (long long int) are supported.
48 * NOTE:
49 * If macro SNPRINTF_LONGLONG_SUPPORT is not defined (default) the
50 * length modifier 'll' is recognized but treated the same as 'l',
51 * which may cause argument value truncation! Defining
52 * SNPRINTF_LONGLONG_SUPPORT requires that your system's sprintf also
53 * handles length modifier 'll'. long long int is a language extension
54 * which may not be portable.
55 *
56 * Conversion of numeric data (conversion specifiers d, u, o, x, X, p)
57 * with length modifiers (none or h, l, ll) is left to the system routine
58 * sprintf, but all handling of flags, field width and precision as well as
59 * c and s conversions is done very carefully by this portable routine.
60 * If a string precision (truncation) is specified (e.g. %.8s) it is
61 * guaranteed the string beyond the specified precision will not be referenced.
62 *
63 * Length modifiers h, l and ll are ignored for c and s conversions (data
64 * types wint_t and wchar_t are not supported).
65 *
66 * The following common synonyms for conversion characters are supported:
67 * - i is a synonym for d
68 * - D is a synonym for ld, explicit length modifiers are ignored
69 * - U is a synonym for lu, explicit length modifiers are ignored
70 * - O is a synonym for lo, explicit length modifiers are ignored
71 * The D, O and U conversion characters are nonstandard, they are supported
72 * for backward compatibility only, and should not be used for new code.
73 *
74 * The following is specifically NOT supported:
75 * - flag ' (thousands' grouping character) is recognized but ignored
76 * - numeric conversion specifiers: f, e, E, g, G and synonym F,
77 * as well as the new a and A conversion specifiers
78 * - length modifier 'L' (long double) and 'q' (quad - use 'll' instead)
79 * - wide character/string conversions: lc, ls, and nonstandard
80 * synonyms C and S
81 * - writeback of converted string length: conversion character n
82 * - the n$ specification for direct reference to n-th argument
83 * - locales
84 *
85 * It is permitted for str_m to be zero, and it is permitted to specify NULL
86 * pointer for resulting string argument if str_m is zero (as per ISO C99).
87 *
88 * The return value is the number of characters which would be generated
89 * for the given input, excluding the trailing null. If this value
90 * is greater or equal to str_m, not all characters from the result
91 * have been stored in str, output bytes beyond the (str_m-1) -th character
92 * are discarded. If str_m is greater than zero it is guaranteed
93 * the resulting string will be null-terminated.
94 *
95 * NOTE that this matches the ISO C99, OpenBSD, and GNU C library 2.1,
96 * but is different from some older and vendor implementations,
97 * and is also different from XPG, XSH5, SUSv2 specifications.
98 * For historical discussion on changes in the semantics and standards
99 * of snprintf see printf(3) man page in the Linux programmers manual.
100 *
101 * Routines asprintf and vasprintf return a pointer (in the ptr argument)
102 * to a buffer sufficiently large to hold the resulting string. This pointer
103 * should be passed to free(3) to release the allocated storage when it is
104 * no longer needed. If sufficient space cannot be allocated, these functions
105 * will return -1 and set ptr to be a NULL pointer. These two routines are a
106 * GNU C library extensions (glibc).
107 *
108 * Routines asnprintf and vasnprintf are similar to asprintf and vasprintf,
109 * yet, like snprintf and vsnprintf counterparts, will write at most str_m-1
110 * characters into the allocated output string, the last character in the
111 * allocated buffer then gets the terminating null. If the formatted string
112 * length (the return value) is greater than or equal to the str_m argument,
113 * the resulting string was truncated and some of the formatted characters
114 * were discarded. These routines present a handy way to limit the amount
115 * of allocated memory to some sane value.
116 *
117 * AVAILABILITY
118 * http://www.ijs.si/software/snprintf/
119 *
120 * REVISION HISTORY
121 * 1999-04 V0.9 Mark Martinec
122 * - initial version, some modifications after comparing printf
123 * man pages for Digital Unix 4.0, Solaris 2.6 and HPUX 10,
124 * and checking how Perl handles sprintf (differently!);
125 * 1999-04-09 V1.0 Mark Martinec <mark.martinec@ijs.si>
126 * - added main test program, fixed remaining inconsistencies,
127 * added optional (long long int) support;
128 * 1999-04-12 V1.1 Mark Martinec <mark.martinec@ijs.si>
129 * - support the 'p' conversion (pointer to void);
130 * - if a string precision is specified
131 * make sure the string beyond the specified precision
132 * will not be referenced (e.g. by strlen);
133 * 1999-04-13 V1.2 Mark Martinec <mark.martinec@ijs.si>
134 * - support synonyms %D=%ld, %U=%lu, %O=%lo;
135 * - speed up the case of long format string with few conversions;
136 * 1999-06-30 V1.3 Mark Martinec <mark.martinec@ijs.si>
137 * - fixed runaway loop (eventually crashing when str_l wraps
138 * beyond 2^31) while copying format string without
139 * conversion specifiers to a buffer that is too short
140 * (thanks to Edwin Young <edwiny@autonomy.com> for
141 * spotting the problem);
142 * - added macros PORTABLE_SNPRINTF_VERSION_(MAJOR|MINOR)
143 * to snprintf.h
144 * 2000-02-14 V2.0 (never released) Mark Martinec <mark.martinec@ijs.si>
145 * - relaxed license terms: The Artistic License now applies.
146 * You may still apply the GNU GENERAL PUBLIC LICENSE
147 * as was distributed with previous versions, if you prefer;
148 * - changed REVISION HISTORY dates to use ISO 8601 date format;
149 * - added vsnprintf (patch also independently proposed by
150 * Caolan McNamara 2000-05-04, and Keith M Willenson 2000-06-01)
151 * 2000-06-27 V2.1 Mark Martinec <mark.martinec@ijs.si>
152 * - removed POSIX check for str_m<1; value 0 for str_m is
153 * allowed by ISO C99 (and GNU C library 2.1) - (pointed out
154 * on 2000-05-04 by Caolan McNamara, caolan@ csn dot ul dot ie).
155 * Besides relaxed license this change in standards adherence
156 * is the main reason to bump up the major version number;
157 * - added nonstandard routines asnprintf, vasnprintf, asprintf,
158 * vasprintf that dynamically allocate storage for the
159 * resulting string; these routines are not compiled by default,
160 * see comments where NEED_V?ASN?PRINTF macros are defined;
161 * - autoconf contributed by Caolan McNamara
162 * 2000-10-06 V2.2 Mark Martinec <mark.martinec@ijs.si>
163 * - BUG FIX: the %c conversion used a temporary variable
164 * that was no longer in scope when referenced,
165 * possibly causing incorrect resulting character;
166 * - BUG FIX: make precision and minimal field width unsigned
167 * to handle huge values (2^31 <= n < 2^32) correctly;
168 * also be more careful in the use of signed/unsigned/size_t
169 * internal variables - probably more careful than many
170 * vendor implementations, but there may still be a case
171 * where huge values of str_m, precision or minimal field
172 * could cause incorrect behaviour;
173 * - use separate variables for signed/unsigned arguments,
174 * and for short/int, long, and long long argument lengths
175 * to avoid possible incompatibilities on certain
176 * computer architectures. Also use separate variable
177 * arg_sign to hold sign of a numeric argument,
178 * to make code more transparent;
179 * - some fiddling with zero padding and "0x" to make it
180 * Linux compatible;
181 * - systematically use macros fast_memcpy and fast_memset
182 * instead of case-by-case hand optimization; determine some
183 * breakeven string lengths for different architectures;
184 * - terminology change: 'format' -> 'conversion specifier',
185 * 'C9x' -> 'ISO/IEC 9899:1999 ("ISO C99")',
186 * 'alternative form' -> 'alternate form',
187 * 'data type modifier' -> 'length modifier';
188 * - several comments rephrased and new ones added;
189 * - make compiler not complain about 'credits' defined but
190 * not used;
191 * 2001-08 V2.3 Mark Martinec <mark.martinec@ijs.si>
192 * .. 2002-02 - writeback conversion specifier 'n' is now supported;
193 * - bump the size of a temporary buffer for simple
194 * numeric->string conversion from 32 to 48 characters
195 * in anticipation of 128-bit machines;
196 * - added #include <stddef.h> and <stdarg.h> to snprintf.h;
197 * - fixed one assert in test.c
198 * (thanks to Tuomo A Turunen for reporting this problem);
199 * - portability fix: use isdigit() provided with <ctype.h>
200 * and do not assume character set is ASCII - call strtoul()
201 * if needed to convert field width and precision;
202 * - check for broken or non-ANSI native sprintf (e.g. SunOS)
203 * which does not return string lenth, and work around it;
204 * - shouldn't happen, but just in case (applies to numeric
205 * conversions only): added assertion after a call to
206 * system's sprintf to make sure we detect a problem
207 * as it happens (or very shortly - but still - after a
208 * buffer overflow occured for some strange reason
209 * in system's sprintf);
210 * - cleanup: avoid comparing signed and unsigned values
211 * (ANSI c++ complaint); added a couple of 'const' qualifiers;
212 * - changed few comments, new references to some other
213 * implementations added to the README file;
214 * - it appears the Artistic License and its variant the Frontier
215 * Artistic License are incompatible with GPL and precludes
216 * this work to be included with GPL-licensed work. This was
217 * not my intention. The fact that this package is dual licensed
218 * comes to the rescue. Changed the credits[] string, and
219 * TERMS AND CONDITIONS to explicitly say so, stressing
220 * the fact that this work is dual licensed.
221 */
222
223
224 /* Define HAVE_SNPRINTF if your system already has snprintf and vsnprintf.
225 *
226 * If HAVE_SNPRINTF is defined this module will not produce code for
227 * snprintf and vsnprintf, unless PREFER_PORTABLE_SNPRINTF is defined as well,
228 * causing this portable version of snprintf to be called portable_snprintf
229 * (and portable_vsnprintf).
230 */
231 /* #define HAVE_SNPRINTF */
232
233 /* Define PREFER_PORTABLE_SNPRINTF if your system does have snprintf and
234 * vsnprintf but you would prefer to use the portable routine(s) instead.
235 * In this case the portable routine is declared as portable_snprintf
236 * (and portable_vsnprintf) and a macro 'snprintf' (and 'vsnprintf')
237 * is defined to expand to 'portable_v?snprintf' - see file snprintf.h .
238 * Defining this macro is only useful if HAVE_SNPRINTF is also defined,
239 * but does no harm if defined nevertheless.
240 */
241 /* #define PREFER_PORTABLE_SNPRINTF */
242
243 /* Define SNPRINTF_LONGLONG_SUPPORT if you want to support
244 * data type (long long int) and length modifier 'll' (e.g. %lld).
245 * If undefined, 'll' is recognized but treated as a single 'l'.
246 *
247 * If the system's sprintf does not handle 'll'
248 * the SNPRINTF_LONGLONG_SUPPORT must not be defined!
249 *
250 * This is off by default as (long long int) is a language extension.
251 */
252 /* #define SNPRINTF_LONGLONG_SUPPORT */
253
254 /* Define NEED_SNPRINTF_ONLY if you only need snprintf, and not vsnprintf.
255 * If NEED_SNPRINTF_ONLY is defined, the snprintf will be defined directly,
256 * otherwise both snprintf and vsnprintf routines will be defined
257 * and snprintf will be a simple wrapper around vsnprintf, at the expense
258 * of an extra procedure call.
259 */
260 /* #define NEED_SNPRINTF_ONLY */
261
262 /* Define NEED_V?ASN?PRINTF macros if you need library extension
263 * routines asprintf, vasprintf, asnprintf, vasnprintf respectively,
264 * and your system library does not provide them. They are all small
265 * wrapper routines around portable_vsnprintf. Defining any of the four
266 * NEED_V?ASN?PRINTF macros automatically turns off NEED_SNPRINTF_ONLY
267 * and turns on PREFER_PORTABLE_SNPRINTF.
268 *
269 * Watch for name conflicts with the system library if these routines
270 * are already present there.
271 *
272 * NOTE: vasprintf and vasnprintf routines need va_copy() from stdarg.h, as
273 * specified by C99, to be able to traverse the same list of arguments twice.
274 * I don't know of any other standard and portable way of achieving the same.
275 * With some versions of gcc you may use __va_copy(). You might even get away
276 * with "ap2 = ap", in this case you must not call va_end(ap2) !
277 * #define va_copy(ap2,ap) __va_copy((ap2),(ap))
278 * #define va_copy(ap2,ap) (ap2) = (ap)
279 */
280 /* #define NEED_ASPRINTF */
281 /* #define NEED_ASNPRINTF */
282 /* #define NEED_VASPRINTF */
283 /* #define NEED_VASNPRINTF */
284
285 /* Define the following macros if desired:
286 * SOLARIS_COMPATIBLE, SOLARIS_BUG_COMPATIBLE,
287 * HPUX_COMPATIBLE, HPUX_BUG_COMPATIBLE, LINUX_COMPATIBLE,
288 * DIGITAL_UNIX_COMPATIBLE, DIGITAL_UNIX_BUG_COMPATIBLE,
289 * PERL_COMPATIBLE, PERL_BUG_COMPATIBLE,
290 *
291 * - For portable applications it is best not to rely on peculiarities
292 * of a given implementation so it may be best not to define any
293 * of the macros that select compatibility and to avoid features
294 * that vary among the systems.
295 *
296 * - Selecting compatibility with more than one operating system
297 * is not strictly forbidden but is not recommended.
298 *
299 * - 'x'_BUG_COMPATIBLE implies 'x'_COMPATIBLE .
300 *
301 * - 'x'_COMPATIBLE refers to (and enables) a behaviour that is
302 * documented in a sprintf man page on a given operating system
303 * and actually adhered to by the system's sprintf (but not on
304 * most other operating systems). It may also refer to and enable
305 * a behaviour that is declared 'undefined' or 'implementation specific'
306 * in the man page but a given implementation behaves predictably
307 * in a certain way.
308 *
309 * - 'x'_BUG_COMPATIBLE refers to (and enables) a behaviour of system's sprintf
310 * that contradicts the sprintf man page on the same operating system.
311 *
312 * - I do not claim that the 'x'_COMPATIBLE and 'x'_BUG_COMPATIBLE
313 * conditionals take into account all idiosyncrasies of a particular
314 * implementation, there may be other incompatibilities.
315 */
316
317
318
319 /* ============================================= */
320 /* NO USER SERVICABLE PARTS FOLLOWING THIS POINT */
321 /* ============================================= */
322
323 #define PORTABLE_SNPRINTF_VERSION_MAJOR 2
324 #define PORTABLE_SNPRINTF_VERSION_MINOR 3
325
326 #if defined(NEED_ASPRINTF) || defined(NEED_ASNPRINTF) || defined(NEED_VASPRINTF) || defined(NEED_VASNPRINTF)
327 # if defined(NEED_SNPRINTF_ONLY)
328 # undef NEED_SNPRINTF_ONLY
329 # endif
330 # if !defined(PREFER_PORTABLE_SNPRINTF)
331 # define PREFER_PORTABLE_SNPRINTF
332 # endif
333 #endif
334
335 #if defined(SOLARIS_BUG_COMPATIBLE) && !defined(SOLARIS_COMPATIBLE)
336 #define SOLARIS_COMPATIBLE
337 #endif
338
339 #if defined(HPUX_BUG_COMPATIBLE) && !defined(HPUX_COMPATIBLE)
340 #define HPUX_COMPATIBLE
341 #endif
342
343 #if defined(DIGITAL_UNIX_BUG_COMPATIBLE) && !defined(DIGITAL_UNIX_COMPATIBLE)
344 #define DIGITAL_UNIX_COMPATIBLE
345 #endif
346
347 #if defined(PERL_BUG_COMPATIBLE) && !defined(PERL_COMPATIBLE)
348 #define PERL_COMPATIBLE
349 #endif
350
351 #if defined(LINUX_BUG_COMPATIBLE) && !defined(LINUX_COMPATIBLE)
352 #define LINUX_COMPATIBLE
353 #endif
354
355 #include <sys/types.h>
356 #include <ctype.h>
357 #include <string.h>
358 #include <stdlib.h>
359 #include <stdio.h>
360 #include <stdarg.h>
361 #include <assert.h>
362 #include <errno.h>
363
364 /* For copying strings longer or equal to 'breakeven_point'
365 * it is more efficient to call memcpy() than to do it inline.
366 * The value depends mostly on the processor architecture,
367 * but also on the compiler and its optimization capabilities.
368 * The value is not critical, some small value greater than zero
369 * will be just fine if you don't care to squeeze every drop
370 * of performance out of the code.
371 *
372 * Small values favour memcpy & memset (extra procedure call, less code),
373 * large values favour inline code (saves procedure call, more code).
374 */
375 #if defined(__alpha__) || defined(__alpha)
376 # define breakeven_point 2 /* AXP (DEC Alpha) - gcc or cc */
377 #endif
378 #if defined(__i386__) || defined(__i386)
379 # define breakeven_point 15 /* Intel Pentium/Linux - gcc 2.96 (12..30) */
380 #endif
381 #if defined(__hppa)
382 # define breakeven_point 10 /* HP-PA - gcc */
383 #endif
384 #if defined(__sparc__) || defined(__sparc)
385 # define breakeven_point 33 /* Sun Sparc 5 - gcc 2.8.1 */
386 #endif
387
388 /* some other values of possible interest: */
389 /* #define breakeven_point 8 */ /* VAX 4000 - vaxc */
390 /* #define breakeven_point 19 */ /* VAX 4000 - gcc 2.7.0 */
391
392 #ifndef breakeven_point
393 # define breakeven_point 6 /* some reasonable one-size-fits-all value */
394 #endif
395
396 #define fast_memcpy(d,s,n) \
397 { register size_t nn = (size_t)(n); \
398 if (nn >= breakeven_point) memcpy((d), (s), nn); \
399 else if (nn > 0) { /* call overhead is worth only for large strings*/ \
400 register char *dd; register const char *ss; \
401 for (ss=(s), dd=(d); nn>0; nn--) *dd++ = *ss++; } }
402
403 #define fast_memset(d,c,n) \
404 { register size_t nn = (size_t)(n); \
405 if (nn >= breakeven_point) memset((d), (int)(c), nn); \
406 else if (nn > 0) { /* call overhead is worth only for large strings*/ \
407 register char *dd; register const int cc=(int)(c); \
408 for (dd=(d); nn>0; nn--) *dd++ = cc; } }
409
410 /* The following isdigit() is not portable (e.g. may not work
411 * with non-ASCII character sets). Use the system-provided isdigit()
412 * if available, otherwise uncomment:
413 * #define isdigit(c) ((c) >= '0' && (c) <= '9')
414 */
415
416 /* atosizet converts a span of decimal digits to a number of type size_t.
417 * It is a macro, similar to: (but not quite, p will be modified!)
418 * void atosizet(const char *p, const char **endp, size_t *result);
419 * endp will point to just beyond the digits substring.
420 * This is _not_ a general-purpose macro:
421 * - the first argument will be modified;
422 * - the first character must already be checked to be a digit!
423 * NOTE: size_t could be wider than unsigned int;
424 * but we treat numeric string like common implementations do!
425 * If character set is ASCII (checking with a quick and simple-minded test)
426 * we convert string to a number inline for speed, otherwise we call strtoul.
427 */
428 #define atosizet(p, endp, result) \
429 if ((int)'0' == 48) { /* a compile-time constant expression, */ \
430 /* hoping the code from one branch */ \
431 /* will be optimized away */ \
432 /* looks like ASCII character set, let's hope it really is */ \
433 register unsigned int uj = (unsigned int)(*(p)++ - '0'); \
434 while (isdigit((int)(*(p)))) \
435 uj = 10*uj + (unsigned int)(*(p)++ - '0'); \
436 if ((endp) != NULL) *(endp) = (p); \
437 *(result) = (size_t) uj; \
438 } else { \
439 /* non-ASCII character set, play by the rules */ \
440 char *ep; /* NOTE: no 'const' to make strtoul happy! */ \
441 /* NOTE: clip (unsigned long) to (unsigned int) as is common !!! */ \
442 const unsigned int uj = (unsigned int) strtoul((p), &ep, 10); \
443 /* The following assignment is legal: the address of a non-const */ \
444 /* object can be assigned to a pointer to a const object, but */ \
445 /* that pointer cannot be used to alter the value of the object. */ \
446 if ((endp) != NULL) *(endp) = ep; \
447 /* if num too large the result will be ULONG_MAX and errno=ERANGE */ \
448 *(result) = (size_t) uj; \
449 } \
450
451 /* prototypes */
452
453 #if defined(NEED_ASPRINTF)
454 int asprintf (char **ptr, const char *fmt, /*args*/ ...);
455 #endif
456 #if defined(NEED_VASPRINTF)
457 int vasprintf (char **ptr, const char *fmt, va_list ap);
458 #endif
459 #if defined(NEED_ASNPRINTF)
460 int asnprintf (char **ptr, size_t str_m, const char *fmt, /*args*/ ...);
461 #endif
462 #if defined(NEED_VASNPRINTF)
463 int vasnprintf (char **ptr, size_t str_m, const char *fmt, va_list ap);
464 #endif
465
466 #if defined(HAVE_SNPRINTF)
467 /* declare our portable snprintf routine under name portable_snprintf */
468 /* declare our portable vsnprintf routine under name portable_vsnprintf */
469 #else
470 /* declare our portable routines under names snprintf and vsnprintf */
471 #define portable_snprintf snprintf
472 #if !defined(NEED_SNPRINTF_ONLY)
473 #define portable_vsnprintf vsnprintf
474 #endif
475 #endif
476
477 #if !defined(HAVE_SNPRINTF) || defined(PREFER_PORTABLE_SNPRINTF)
478 int portable_snprintf(char *str, size_t str_m, const char *fmt, /*args*/ ...);
479 #if !defined(NEED_SNPRINTF_ONLY)
480 int portable_vsnprintf(char *str, size_t str_m, const char *fmt, va_list ap);
481 #endif
482 #endif
483
484 /* declarations */
485
486 static const char credits[] = "\n\
487 @(#)snprintf.c, v2.3: Mark Martinec, <mark.martinec@ijs.si>\n\
488 @(#)snprintf.c, v2.3: Copyright 1999-2002 Mark Martinec. Dual licensed: Frontier Artistic License or GNU General Public License applies.\n\
489 @(#)snprintf.c, v2.3: http://www.ijs.si/software/snprintf/\n";
490
491 #if defined(NEED_ASPRINTF)
asprintf(char ** ptr,const char * fmt,...)492 int asprintf(char **ptr, const char *fmt, /*args*/ ...) {
493 va_list ap;
494 size_t str_m;
495 int str_l;
496
497 *ptr = NULL;
498 va_start(ap, fmt); /* measure the required size */
499 str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap);
500 va_end(ap);
501 assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */
502 *ptr = (char *) malloc(str_m = (size_t)str_l + 1);
503 if (*ptr == NULL) { errno = ENOMEM; str_l = -1; }
504 else {
505 int str_l2;
506 va_start(ap, fmt);
507 str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap);
508 va_end(ap);
509 assert(str_l2 == str_l);
510 }
511 return str_l;
512 }
513 #endif
514
515 #if defined(NEED_VASPRINTF)
vasprintf(char ** ptr,const char * fmt,va_list ap)516 int vasprintf(char **ptr, const char *fmt, va_list ap) {
517 size_t str_m;
518 int str_l;
519
520 *ptr = NULL;
521 { va_list ap2;
522 va_copy(ap2, ap); /* don't consume the original ap, we'll need it again */
523 str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap2);/*get required size*/
524 va_end(ap2);
525 }
526 assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */
527 *ptr = (char *) malloc(str_m = (size_t)str_l + 1);
528 if (*ptr == NULL) { errno = ENOMEM; str_l = -1; }
529 else {
530 const int str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap);
531 assert(str_l2 == str_l);
532 }
533 return str_l;
534 }
535 #endif
536
537 #if defined(NEED_ASNPRINTF)
asnprintf(char ** ptr,size_t str_m,const char * fmt,...)538 int asnprintf(char **ptr, size_t str_m, const char *fmt, /*args*/ ...) {
539 va_list ap;
540 int str_l;
541
542 *ptr = NULL;
543 va_start(ap, fmt); /* measure the required size */
544 str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap);
545 va_end(ap);
546 assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */
547 if ((size_t)str_l + 1 < str_m) str_m = (size_t)str_l + 1; /* truncate */
548 /* if str_m is 0, no buffer is allocated, just set *ptr to NULL */
549 if (str_m == 0) { /* not interested in resulting string, just return size */
550 } else {
551 *ptr = (char *) malloc(str_m);
552 if (*ptr == NULL) { errno = ENOMEM; str_l = -1; }
553 else {
554 int str_l2;
555 va_start(ap, fmt);
556 str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap);
557 va_end(ap);
558 assert(str_l2 == str_l);
559 }
560 }
561 return str_l;
562 }
563 #endif
564
565 #if defined(NEED_VASNPRINTF)
vasnprintf(char ** ptr,size_t str_m,const char * fmt,va_list ap)566 int vasnprintf(char **ptr, size_t str_m, const char *fmt, va_list ap) {
567 int str_l;
568
569 *ptr = NULL;
570 { va_list ap2;
571 va_copy(ap2, ap); /* don't consume the original ap, we'll need it again */
572 str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap2);/*get required size*/
573 va_end(ap2);
574 }
575 assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */
576 if ((size_t)str_l + 1 < str_m) str_m = (size_t)str_l + 1; /* truncate */
577 /* if str_m is 0, no buffer is allocated, just set *ptr to NULL */
578 if (str_m == 0) { /* not interested in resulting string, just return size */
579 } else {
580 *ptr = (char *) malloc(str_m);
581 if (*ptr == NULL) { errno = ENOMEM; str_l = -1; }
582 else {
583 const int str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap);
584 assert(str_l2 == str_l);
585 }
586 }
587 return str_l;
588 }
589 #endif
590
591 /*
592 * If the system does have snprintf and the portable routine is not
593 * specifically required, this module produces no code for snprintf/vsnprintf.
594 */
595 #if !defined(HAVE_SNPRINTF) || defined(PREFER_PORTABLE_SNPRINTF)
596
597 #if !defined(NEED_SNPRINTF_ONLY)
portable_snprintf(char * str,size_t str_m,const char * fmt,...)598 int portable_snprintf(char *str, size_t str_m, const char *fmt, /*args*/ ...) {
599 va_list ap;
600 int str_l;
601
602 va_start(ap, fmt);
603 str_l = portable_vsnprintf(str, str_m, fmt, ap);
604 va_end(ap);
605 return str_l;
606 }
607 #endif
608
609 #if defined(NEED_SNPRINTF_ONLY)
portable_snprintf(char * str,size_t str_m,const char * fmt,...)610 int portable_snprintf(char *str, size_t str_m, const char *fmt, /*args*/ ...) {
611 #else
612 int portable_vsnprintf(char *str, size_t str_m, const char *fmt, va_list ap) {
613 #endif
614
615 #if defined(NEED_SNPRINTF_ONLY)
616 va_list ap;
617 #endif
618 size_t str_l = 0;
619 const char *p = fmt;
620
621 /* In contrast to POSIX, the ISO C99 now says
622 * that str can be NULL and str_m can be 0.
623 * This is more useful than the old: if (str_m < 1) return -1; */
624
625 #if defined(NEED_SNPRINTF_ONLY)
626 va_start(ap, fmt);
627 #endif
628 if (!p) p = "";
629 while (*p) {
630 if (*p != '%') {
631 if (0) { /* compile time decision between two equivalent alternatives */
632 /* this is simple but slow */
633 if (str_l < str_m) str[str_l] = *p;
634 p++; str_l++;
635 } else {
636 /* this usually achieves much better performance for cases
637 * where format string is long and contains few conversions */
638 const char *const q = strchr(p+1,'%');
639 const size_t n = !q ? strlen(p) : (q-p);
640 if (str_l < str_m) {
641 const size_t avail = str_m-str_l;
642 fast_memcpy(str+str_l, p, (n>avail?avail:n));
643 }
644 p += n; str_l += n;
645 }
646 } else {
647 const char *starting_p;
648 size_t min_field_width = 0, precision = 0;
649 int zero_padding = 0, precision_specified = 0, justify_left = 0;
650 int alternate_form = 0, force_sign = 0;
651 int space_for_positive = 1; /* If both the ' ' and '+' flags appear,
652 the ' ' flag should be ignored. */
653 char length_modifier = '\0'; /* allowed values: \0, h, l, L */
654 char tmp[48];/* temporary buffer for simple numeric->string conversion */
655
656 const char *str_arg; /* string address in case of string argument */
657 size_t str_arg_l; /* natural field width of arg without padding
658 and sign */
659 unsigned char uchar_arg;
660 /* unsigned char argument value - only defined for c conversion.
661 N.B. standard explicitly states the char argument for
662 the c conversion is unsigned */
663
664 size_t number_of_zeros_to_pad = 0;
665 /* number of zeros to be inserted for numeric conversions
666 as required by the precision or minimal field width */
667
668 size_t zero_padding_insertion_ind = 0;
669 /* index into tmp where zero padding is to be inserted */
670
671 char fmt_spec = '\0';
672 /* current conversion specifier character */
673
674 str_arg = credits;/* just to make compiler happy (defined but not used)*/
675 str_arg = NULL;
676 starting_p = p; p++; /* skip '%' */
677 /* parse flags */
678 while (*p == '0' || *p == '-' || *p == '+' ||
679 *p == ' ' || *p == '#' || *p == '\'') {
680 switch (*p) {
681 case '0': zero_padding = 1; break;
682 case '-': justify_left = 1; break;
683 case '+': force_sign = 1; space_for_positive = 0; break;
684 case ' ': force_sign = 1;
685 /* If both the ' ' and '+' flags appear, the ' ' flag should be ignored */
686 #ifdef PERL_COMPATIBLE
687 /* ... but in Perl the last of ' ' and '+' applies */
688 space_for_positive = 1;
689 #endif
690 break;
691 case '#': alternate_form = 1; break;
692 case '\'': break;
693 }
694 p++;
695 }
696 /* If flags '0' and '-' both appear, the '0' flag should be ignored. */
697
698 /* parse field width */
699 if (*p == '*') {
700 const int j = va_arg(ap, int);
701 p++;
702 if (j >= 0) min_field_width = j;
703 else { min_field_width = -j; justify_left = 1; }
704 } else if (isdigit((int)(*p))) {
705 atosizet(p, &p, &min_field_width);
706 }
707 /* parse precision */
708 if (*p == '.') {
709 p++; precision_specified = 1;
710 if (*p == '*') {
711 const int j = va_arg(ap, int);
712 p++;
713 if (j >= 0) precision = j;
714 else {
715 precision_specified = 0; precision = 0;
716 /* NOTE:
717 * Solaris 2.6 man page claims that in this case the precision
718 * should be set to 0. Digital Unix 4.0, HPUX 10 and BSD man page
719 * claim that this case should be treated as unspecified precision,
720 * which is what we do here.
721 */
722 }
723 } else if (isdigit((int)(*p))) {
724 atosizet(p, &p, &precision);
725 }
726 }
727 /* parse 'h', 'l' and 'll' length modifiers */
728 if (*p == 'h' || *p == 'l') {
729 length_modifier = *p; p++;
730 if (length_modifier == 'l' && *p == 'l') { /* double el = long long */
731 #ifdef SNPRINTF_LONGLONG_SUPPORT
732 length_modifier = '2'; /* double letter el encoded as '2' */
733 #else
734 length_modifier = 'l'; /* treat it as a single 'l' (letter el) */
735 #endif
736 p++;
737 }
738 }
739 fmt_spec = *p;
740 /* common synonyms: */
741 switch (fmt_spec) {
742 case 'i': fmt_spec = 'd'; break;
743 case 'D': fmt_spec = 'd'; length_modifier = 'l'; break;
744 case 'U': fmt_spec = 'u'; length_modifier = 'l'; break;
745 case 'O': fmt_spec = 'o'; length_modifier = 'l'; break;
746 default: break;
747 }
748 /* get parameter value, do initial processing */
749 switch (fmt_spec) {
750 case '%': /* % behaves similar to 's' regarding flags and field widths */
751 case 'c': /* c behaves similar to 's' regarding flags and field widths */
752 case 's':
753 length_modifier = '\0'; /* wint_t and wchar_t not supported */
754 /* the result of zero padding flag with non-numeric conversion specifier*/
755 /* is undefined. Solaris and HPUX 10 does zero padding in this case, */
756 /* Digital Unix and Linux does not. */
757 #if !defined(SOLARIS_COMPATIBLE) && !defined(HPUX_COMPATIBLE)
758 zero_padding = 0; /* turn zero padding off for string conversions */
759 #endif
760 str_arg_l = 1;
761 switch (fmt_spec) {
762 case '%':
763 str_arg = p; break;
764 case 'c': {
765 const int j = va_arg(ap, int);
766 uchar_arg = (unsigned char) j; /* standard demands unsigned char */
767 str_arg = (const char *) &uchar_arg;
768 break;
769 }
770 case 's':
771 str_arg = va_arg(ap, const char *);
772 if (!str_arg) str_arg_l = 0;
773 /* make sure not to address string beyond the specified precision !!! */
774 else if (!precision_specified) str_arg_l = strlen(str_arg);
775 /* truncate string if necessary as requested by precision */
776 else if (precision == 0) str_arg_l = 0;
777 else {
778 /* memchr on HP does not like n > 2^31 !!! */
779 const char *const q = (const char *) memchr(str_arg, '\0',
780 precision <= 0x7fffffff ? precision : 0x7fffffff);
781 str_arg_l = !q ? precision : (q-str_arg);
782 }
783 break;
784 default: break;
785 }
786 break;
787 case 'd': case 'u': case 'o': case 'x': case 'X': case 'p': {
788 /* NOTE: the u, o, x, X and p conversion specifiers imply
789 the value is unsigned; d implies a signed value */
790
791 int arg_sign = 0;
792 /* 0 if numeric argument is zero (or if pointer is NULL for 'p'),
793 +1 if greater than zero (or nonzero for unsigned arguments),
794 -1 if negative (unsigned argument is never negative) */
795
796 int int_arg = 0; unsigned int uint_arg = 0;
797 /* only defined for length modifier h, or for no length modifiers */
798
799 long int long_arg = 0; unsigned long int ulong_arg = 0;
800 /* only defined for length modifier l (letter el) */
801
802 void *ptr_arg = NULL;
803 /* pointer argument value - only defined for p conversion */
804
805 #ifdef SNPRINTF_LONGLONG_SUPPORT
806 long long int long_long_arg = 0;
807 unsigned long long int ulong_long_arg = 0;
808 /* only defined for length modifier ll (double letter el) */
809 #endif
810 if (fmt_spec == 'p') {
811 /* HPUX 10: An l, h, ll or L before any other conversion character
812 * (other than d, i, u, o, x, or X) is ignored.
813 * Digital Unix:
814 * not specified, but seems to behave as HPUX does.
815 * Solaris: If an h, l, or L appears before any other conversion
816 * specifier (other than d, i, u, o, x, or X), the behavior
817 * is undefined. (Actually %hp converts only 16-bits of address
818 * and %llp treats address as 64-bit data which is incompatible
819 * with (void *) argument on a 32-bit system).
820 */
821 #ifdef SOLARIS_COMPATIBLE
822 # ifdef SOLARIS_BUG_COMPATIBLE
823 /* keep length modifiers even if it represents 'll' */
824 # else
825 if (length_modifier == '2') length_modifier = '\0';
826 # endif
827 #else
828 length_modifier = '\0';
829 #endif
830 ptr_arg = va_arg(ap, void *);
831 if (ptr_arg != NULL) arg_sign = 1;
832 } else if (fmt_spec == 'd') { /* signed */
833 switch (length_modifier) {
834 case '\0':
835 case 'h':
836 /* It is non-portable to specify char or short as the second argument
837 * to va_arg, because arguments seen by the called function
838 * are not char or short. C converts char and short arguments
839 * to int before passing them to a function.
840 */
841 int_arg = va_arg(ap, int);
842 if (int_arg > 0) arg_sign = 1;
843 else if (int_arg < 0) arg_sign = -1;
844 break;
845 case 'l': /* letter el */
846 long_arg = va_arg(ap, long int);
847 if (long_arg > 0) arg_sign = 1;
848 else if (long_arg < 0) arg_sign = -1;
849 break;
850 #ifdef SNPRINTF_LONGLONG_SUPPORT
851 case '2':
852 long_long_arg = va_arg(ap, long long int);
853 if (long_long_arg > 0) arg_sign = 1;
854 else if (long_long_arg < 0) arg_sign = -1;
855 break;
856 #endif
857 }
858 } else { /* unsigned */
859 switch (length_modifier) {
860 case '\0':
861 case 'h':
862 uint_arg = va_arg(ap, unsigned int);
863 if (uint_arg) arg_sign = 1;
864 break;
865 case 'l': /* letter el */
866 ulong_arg = va_arg(ap, unsigned long int);
867 if (ulong_arg) arg_sign = 1;
868 break;
869 #ifdef SNPRINTF_LONGLONG_SUPPORT
870 case '2':
871 ulong_long_arg = va_arg(ap, unsigned long long int);
872 if (ulong_long_arg) arg_sign = 1;
873 break;
874 #endif
875 }
876 }
877 str_arg = tmp; str_arg_l = 0;
878 /* NOTE:
879 * For d, i, u, o, x, and X conversions, if precision is specified,
880 * the '0' flag should be ignored. This is so with Solaris 2.6,
881 * Digital UNIX 4.0, HPUX 10, Linux, FreeBSD, NetBSD; but not with Perl.
882 */
883 #ifndef PERL_COMPATIBLE
884 if (precision_specified) zero_padding = 0;
885 #endif
886 if (fmt_spec == 'd') {
887 if (force_sign && arg_sign >= 0)
888 tmp[str_arg_l++] = space_for_positive ? ' ' : '+';
889 /* leave negative numbers for sprintf to handle,
890 to avoid handling tricky cases like (short int)(-32768) */
891 #ifdef LINUX_COMPATIBLE
892 } else if (fmt_spec == 'p' && force_sign && arg_sign > 0) {
893 tmp[str_arg_l++] = space_for_positive ? ' ' : '+';
894 #endif
895 } else if (alternate_form) {
896 if (arg_sign != 0 && (fmt_spec == 'x' || fmt_spec == 'X') )
897 { tmp[str_arg_l++] = '0'; tmp[str_arg_l++] = fmt_spec; }
898 /* alternate form should have no effect for p conversion, but ... */
899 #ifdef HPUX_COMPATIBLE
900 else if (fmt_spec == 'p'
901 /* HPUX 10: for an alternate form of p conversion,
902 * a nonzero result is prefixed by 0x. */
903 #ifndef HPUX_BUG_COMPATIBLE
904 /* Actually it uses 0x prefix even for a zero value. */
905 && arg_sign != 0
906 #endif
907 ) { tmp[str_arg_l++] = '0'; tmp[str_arg_l++] = 'x'; }
908 #endif
909 }
910 zero_padding_insertion_ind = str_arg_l;
911 if (!precision_specified) precision = 1; /* default precision is 1 */
912 if (precision == 0 && arg_sign == 0
913 #if defined(HPUX_BUG_COMPATIBLE) || defined(LINUX_COMPATIBLE)
914 && fmt_spec != 'p'
915 /* HPUX 10 man page claims: With conversion character p the result of
916 * converting a zero value with a precision of zero is a null string.
917 * Actually HP returns all zeroes, and Linux returns "(nil)". */
918 #endif
919 ) {
920 /* converted to null string */
921 /* When zero value is formatted with an explicit precision 0,
922 the resulting formatted string is empty (d, i, u, o, x, X, p). */
923 } else {
924 static int sprintf_return_value_is_ansi_compliant = -1; /* unknown */
925 char f[5]; int f_l = 0, sprintf_l = 0;
926 f[f_l++] = '%'; /* construct a simple format string for sprintf */
927 if (!length_modifier) { }
928 else if (length_modifier=='2') { f[f_l++] = 'l'; f[f_l++] = 'l'; }
929 else f[f_l++] = length_modifier;
930 f[f_l++] = fmt_spec; f[f_l++] = '\0';
931 if (sprintf_return_value_is_ansi_compliant < 0) { /* not yet known */
932 /* let's do a little run-time experiment (only once) to see if the
933 * native sprintf returns a string length as required by ANSI, or has
934 * some other ideas like the old SunOS which returns buffer address */
935 sprintf_return_value_is_ansi_compliant =
936 (sprintf(tmp+str_arg_l, "%d", 19) == 2);
937 }
938 if (fmt_spec == 'p') sprintf_l=sprintf(tmp+str_arg_l, f, ptr_arg);
939 else if (fmt_spec == 'd') { /* signed */
940 switch (length_modifier) {
941 case '\0':
942 case 'h': sprintf_l=sprintf(tmp+str_arg_l, f, int_arg); break;
943 case 'l': sprintf_l=sprintf(tmp+str_arg_l, f, long_arg); break;
944 #ifdef SNPRINTF_LONGLONG_SUPPORT
945 case '2': sprintf_l=sprintf(tmp+str_arg_l,f,long_long_arg); break;
946 #endif
947 }
948 } else { /* unsigned */
949 switch (length_modifier) {
950 case '\0':
951 case 'h': sprintf_l=sprintf(tmp+str_arg_l, f, uint_arg); break;
952 case 'l': sprintf_l=sprintf(tmp+str_arg_l, f, ulong_arg); break;
953 #ifdef SNPRINTF_LONGLONG_SUPPORT
954 case '2': sprintf_l=sprintf(tmp+str_arg_l,f,ulong_long_arg);break;
955 #endif
956 }
957 }
958 if (!sprintf_return_value_is_ansi_compliant) { /* broken sprintf? */
959 tmp[sizeof(tmp)-1] = '\0'; sprintf_l = strlen(tmp+str_arg_l);
960 }
961 assert(sprintf_l >= 0); /* should not happen; problem in sprintf? */
962 assert(sprintf_l+str_arg_l < sizeof(tmp)); /*better late then never*/
963 str_arg_l += sprintf_l;
964 /* include the optional minus sign and possible "0x"
965 in the region before the zero padding insertion point */
966 if (zero_padding_insertion_ind < str_arg_l &&
967 tmp[zero_padding_insertion_ind] == '-') {
968 zero_padding_insertion_ind++;
969 }
970 if (zero_padding_insertion_ind+1 < str_arg_l &&
971 tmp[zero_padding_insertion_ind] == '0' &&
972 (tmp[zero_padding_insertion_ind+1] == 'x' ||
973 tmp[zero_padding_insertion_ind+1] == 'X') ) {
974 zero_padding_insertion_ind += 2;
975 }
976 }
977 { const size_t num_of_digits = str_arg_l - zero_padding_insertion_ind;
978 if (alternate_form && fmt_spec == 'o'
979 #ifdef HPUX_COMPATIBLE /* ("%#.o",0) -> "" */
980 && (str_arg_l > 0)
981 #endif
982 #ifdef DIGITAL_UNIX_BUG_COMPATIBLE /* ("%#o",0) -> "00" */
983 #else
984 /* unless zero is already the first character */
985 && !(zero_padding_insertion_ind < str_arg_l
986 && tmp[zero_padding_insertion_ind] == '0')
987 #endif
988 ) { /* assure leading zero for alternate-form octal numbers */
989 if (!precision_specified || precision < num_of_digits+1) {
990 /* precision is increased to force the first character to be zero,
991 except if a zero value is formatted with an explicit precision
992 of zero */
993 precision = num_of_digits+1; precision_specified = 1;
994 }
995 }
996 /* zero padding to specified precision? */
997 if (num_of_digits < precision)
998 number_of_zeros_to_pad = precision - num_of_digits;
999 }
1000 /* zero padding to specified minimal field width? */
1001 if (!justify_left && zero_padding) {
1002 const int n = min_field_width - (str_arg_l+number_of_zeros_to_pad);
1003 if (n > 0) number_of_zeros_to_pad += n;
1004 }
1005 break;
1006 }
1007 case 'n': {
1008 void *const ptr = va_arg(ap, void *);
1009 if (ptr != NULL) {
1010 /* same problem of size_t -> int type conversion as with the
1011 * snprintf return value - see comment at the end of this procedure */
1012 switch (length_modifier) {
1013 case '\0': *( int *const)ptr = str_l; break;
1014 case 'h': *(short int *const)ptr = str_l; break;
1015 case 'l': *(long int *const)ptr = str_l; break;
1016 #ifdef SNPRINTF_LONGLONG_SUPPORT
1017 case '2': *(long long int *const)ptr = str_l; break;
1018 #endif
1019 }
1020 }
1021 /* no argument converted */
1022 min_field_width = number_of_zeros_to_pad = str_arg_l = 0;
1023 break;
1024 }
1025 default: /* unrecognized conversion specifier, keep format string as-is*/
1026 zero_padding = 0; /* turn zero padding off for non-numeric convers. */
1027 #ifndef DIGITAL_UNIX_COMPATIBLE
1028 justify_left = 1; min_field_width = 0; /* reset flags */
1029 #endif
1030 #if defined(PERL_COMPATIBLE) || defined(LINUX_COMPATIBLE)
1031 /* keep the entire format string unchanged */
1032 str_arg = starting_p; str_arg_l = p - starting_p;
1033 /* well, not exactly so for Linux, which does something inbetween,
1034 * and I don't feel an urge to imitate it: "%+++++hy" -> "%+y" */
1035 #else
1036 /* discard the unrecognized conversion, just keep *
1037 * the unrecognized conversion character */
1038 str_arg = p; str_arg_l = 0;
1039 #endif
1040 if (*p) str_arg_l++; /* include invalid conversion specifier unchanged
1041 if not at end-of-string */
1042 break;
1043 }
1044 if (*p) p++; /* step over the just processed conversion specifier */
1045 /* insert padding to the left as requested by min_field_width;
1046 this does not include the zero padding in case of numerical conversions*/
1047 if (!justify_left) { /* left padding with blank or zero */
1048 const int n = min_field_width - (str_arg_l+number_of_zeros_to_pad);
1049 if (n > 0) {
1050 if (str_l < str_m) {
1051 const size_t avail = str_m-str_l;
1052 fast_memset(str+str_l, (zero_padding?'0':' '),
1053 ((unsigned int)n > avail ? avail : (unsigned int)n));
1054 }
1055 str_l += n;
1056 }
1057 }
1058 /* is zero padding as requested by the precision or by the
1059 * minimal field width for numeric conversions required? */
1060 if (number_of_zeros_to_pad <= 0) {
1061 /* will not copy the first part of numeric right now, *
1062 * force it to be copied later in its entirety */
1063 zero_padding_insertion_ind = 0;
1064 } else {
1065 /* insert first part of numerics (sign or '0x') before zero padding */
1066 { const int n = zero_padding_insertion_ind;
1067 if (n > 0) {
1068 if (str_l < str_m) {
1069 const size_t avail = str_m-str_l;
1070 fast_memcpy(str+str_l, str_arg,
1071 ((unsigned int)n > avail ? avail : (unsigned int)n));
1072 }
1073 str_l += n;
1074 }
1075 }
1076 /* insert zero padding as requested by the precision or min field width */
1077 { const int n = number_of_zeros_to_pad;
1078 if (n > 0) {
1079 if (str_l < str_m) {
1080 const size_t avail = str_m-str_l;
1081 fast_memset(str+str_l, '0',
1082 ((unsigned int)n > avail ? avail : (unsigned int)n));
1083 }
1084 str_l += n;
1085 }
1086 }
1087 }
1088 /* insert formatted string
1089 * (or as-is conversion specifier for unknown conversions) */
1090 { const int n = str_arg_l - zero_padding_insertion_ind;
1091 if (n > 0) {
1092 if (str_l < str_m) {
1093 const size_t avail = str_m-str_l;
1094 fast_memcpy(str+str_l, str_arg+zero_padding_insertion_ind,
1095 ((unsigned int)n > avail ? avail : (unsigned int)n));
1096 }
1097 str_l += n;
1098 }
1099 }
1100 /* insert right padding */
1101 if (justify_left) { /* right blank padding to the field width */
1102 const int n = min_field_width - (str_arg_l+number_of_zeros_to_pad);
1103 if (n > 0) {
1104 if (str_l < str_m) {
1105 const size_t avail = str_m-str_l;
1106 fast_memset(str+str_l, ' ',
1107 ((unsigned int)n > avail ? avail : (unsigned int)n));
1108 }
1109 str_l += n;
1110 }
1111 }
1112 }
1113 }
1114 #if defined(NEED_SNPRINTF_ONLY)
1115 va_end(ap);
1116 #endif
1117 if (str_m > 0) { /* make sure the string is null-terminated, possibly
1118 at the expense of overwriting the last character */
1119 str[str_l <= str_m-1 ? str_l : str_m-1] = '\0';
1120 }
1121 /* Return the number of characters formatted (excluding trailing null
1122 * character), that is, the number of characters that would have been
1123 * written to the buffer if it were large enough.
1124 *
1125 * The value of str_l should be returned, but str_l is of unsigned type
1126 * size_t, and snprintf is int, possibly leading to an undetected
1127 * integer overflow, resulting in a negative return value, which is invalid.
1128 * Both XSH5 and ISO C99 (at least the draft) are silent on this issue.
1129 * Should errno be set to EOVERFLOW and EOF returned in this case???
1130 */
1131 return (int) str_l;
1132 }
1133 #endif
1134