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


log4cpp
Author(s): Stephen Roderick, Bastiaan Bakker, Cedric Le Goater, Steve Ostlind, Marcel Harkema, Walter Stroebel, Glenn Scott and Tony Cheung
autogenerated on Sun Jun 23 2019 19:10:00