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1.1 root 1: /*
2: * snprintf.c - a portable implementation of snprintf
3: *
4: * AUTHOR
5: * Mark Martinec <[email protected]>, 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 <[email protected]>
120: * - added main test program, fixed remaining inconsistencies,
121: * added optional (long long int) support;
122: * 1999-04-12 V1.1 Mark Martinec <[email protected]>
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 <[email protected]>
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 <[email protected]>
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 <[email protected]> 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 <[email protected]>
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 <[email protected]>
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 <[email protected]>
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, <[email protected]>\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 = 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: int 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: int 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: int 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: { int 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: int 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
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