snprintf_2.2/snprintf.c@87e3bb5086e8
snprintf_2.2/snprintf.c
Mon, 20 Apr 2020 10:14:32 -0500
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- Tuomo Valkonen <tuomov@iki.fi>
- date
- Mon, 20 Apr 2020 10:14:32 -0500
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- 87e3bb5086e8
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Convert README to markdown
#include <stdarg.h> #define NEED_ASPRINTF #define NEED_VASPRINTF /* * snprintf.c - a portable implementation of snprintf * * AUTHOR * Mark Martinec <mark.martinec@ijs.si>, April 1999. * * Copyright 1999, Mark Martinec. All rights reserved. * * TERMS AND CONDITIONS * This program is free software; you can redistribute it and/or modify * it under the terms of the "Frontier Artistic License" which comes * with this Kit. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * See the Frontier Artistic License for more details. * * You should have received a copy of the Frontier Artistic License * with this Kit in the file named LICENSE.txt . * If not, I'll be glad to provide one. * * FEATURES * - careful adherence to specs regarding flags, field width and precision; * - good performance for large string handling (large format, large * argument or large paddings). Performance is similar to system's sprintf * and in several cases significantly better (make sure you compile with * optimizations turned on, tell the compiler the code is strict ANSI * if necessary to give it more freedom for optimizations); * - return value semantics per ISO/IEC 9899:1999 ("ISO C99"); * - written in standard ISO/ANSI C - requires an ANSI C compiler. * * SUPPORTED CONVERSION SPECIFIERS AND DATA TYPES * * This snprintf only supports the following conversion specifiers: * s, c, d, u, o, x, X, p (and synonyms: i, D, U, O - see below) * with flags: '-', '+', ' ', '0' and '#'. * An asterisk is supported for field width as well as precision. * * Length modifiers 'h' (short int), 'l' (long int), * and 'll' (long long int) are supported. * NOTE: * If macro SNPRINTF_LONGLONG_SUPPORT is not defined (default) the * length modifier 'll' is recognized but treated the same as 'l', * which may cause argument value truncation! Defining * SNPRINTF_LONGLONG_SUPPORT requires that your system's sprintf also * handles length modifier 'll'. long long int is a language extension * which may not be portable. * * Conversion of numeric data (conversion specifiers d, u, o, x, X, p) * with length modifiers (none or h, l, ll) is left to the system routine * sprintf, but all handling of flags, field width and precision as well as * c and s conversions is done very carefully by this portable routine. * If a string precision (truncation) is specified (e.g. %.8s) it is * guaranteed the string beyond the specified precision will not be referenced. * * Length modifiers h, l and ll are ignored for c and s conversions (data * types wint_t and wchar_t are not supported). * * The following common synonyms for conversion characters are supported: * - i is a synonym for d * - D is a synonym for ld, explicit length modifiers are ignored * - U is a synonym for lu, explicit length modifiers are ignored * - O is a synonym for lo, explicit length modifiers are ignored * The D, O and U conversion characters are nonstandard, they are supported * for backward compatibility only, and should not be used for new code. * * The following is specifically NOT supported: * - flag ' (thousands' grouping character) is recognized but ignored * - numeric conversion specifiers: f, e, E, g, G and synonym F, * as well as the new a and A conversion specifiers * - length modifier 'L' (long double) and 'q' (quad - use 'll' instead) * - wide character/string conversions: lc, ls, and nonstandard * synonyms C and S * - writeback of converted string length: conversion character n * - the n$ specification for direct reference to n-th argument * - locales * * It is permitted for str_m to be zero, and it is permitted to specify NULL * pointer for resulting string argument if str_m is zero (as per ISO C99). * * The return value is the number of characters which would be generated * for the given input, excluding the trailing null. If this value * is greater or equal to str_m, not all characters from the result * have been stored in str, output bytes beyond the (str_m-1) -th character * are discarded. If str_m is greater than zero it is guaranteed * the resulting string will be null-terminated. * * NOTE that this matches the ISO C99, OpenBSD, and GNU C library 2.1, * but is different from some older and vendor implementations, * and is also different from XPG, XSH5, SUSv2 specifications. * For historical discussion on changes in the semantics and standards * of snprintf see printf(3) man page in the Linux programmers manual. * * Routines asprintf and vasprintf return a pointer (in the ptr argument) * to a buffer sufficiently large to hold the resulting string. This pointer * should be passed to free(3) to release the allocated storage when it is * no longer needed. If sufficient space cannot be allocated, these functions * will return -1 and set ptr to be a NULL pointer. These two routines are a * GNU C library extensions (glibc). * * Routines asnprintf and vasnprintf are similar to asprintf and vasprintf, * yet, like snprintf and vsnprintf counterparts, will write at most str_m-1 * characters into the allocated output string, the last character in the * allocated buffer then gets the terminating null. If the formatted string * length (the return value) is greater than or equal to the str_m argument, * the resulting string was truncated and some of the formatted characters * were discarded. These routines present a handy way to limit the amount * of allocated memory to some sane value. * * AVAILABILITY * http://www.ijs.si/software/snprintf/ * * REVISION HISTORY * 1999-04 V0.9 Mark Martinec * - initial version, some modifications after comparing printf * man pages for Digital Unix 4.0, Solaris 2.6 and HPUX 10, * and checking how Perl handles sprintf (differently!); * 1999-04-09 V1.0 Mark Martinec <mark.martinec@ijs.si> * - added main test program, fixed remaining inconsistencies, * added optional (long long int) support; * 1999-04-12 V1.1 Mark Martinec <mark.martinec@ijs.si> * - support the 'p' conversion (pointer to void); * - if a string precision is specified * make sure the string beyond the specified precision * will not be referenced (e.g. by strlen); * 1999-04-13 V1.2 Mark Martinec <mark.martinec@ijs.si> * - support synonyms %D=%ld, %U=%lu, %O=%lo; * - speed up the case of long format string with few conversions; * 1999-06-30 V1.3 Mark Martinec <mark.martinec@ijs.si> * - fixed runaway loop (eventually crashing when str_l wraps * beyond 2^31) while copying format string without * conversion specifiers to a buffer that is too short * (thanks to Edwin Young <edwiny@autonomy.com> for * spotting the problem); * - added macros PORTABLE_SNPRINTF_VERSION_(MAJOR|MINOR) * to snprintf.h * 2000-02-14 V2.0 (never released) Mark Martinec <mark.martinec@ijs.si> * - relaxed license terms: The Artistic License now applies. * You may still apply the GNU GENERAL PUBLIC LICENSE * as was distributed with previous versions, if you prefer; * - changed REVISION HISTORY dates to use ISO 8601 date format; * - added vsnprintf (patch also independently proposed by * Caolan McNamara 2000-05-04, and Keith M Willenson 2000-06-01) * 2000-06-27 V2.1 Mark Martinec <mark.martinec@ijs.si> * - removed POSIX check for str_m<1; value 0 for str_m is * allowed by ISO C99 (and GNU C library 2.1) - (pointed out * on 2000-05-04 by Caolan McNamara, caolan@ csn dot ul dot ie). * Besides relaxed license this change in standards adherence * is the main reason to bump up the major version number; * - added nonstandard routines asnprintf, vasnprintf, asprintf, * vasprintf that dynamically allocate storage for the * resulting string; these routines are not compiled by default, * see comments where NEED_V?ASN?PRINTF macros are defined; * - autoconf contributed by Caolan McNamara * 2000-10-06 V2.2 Mark Martinec <mark.martinec@ijs.si> * - BUG FIX: the %c conversion used a temporary variable * that was no longer in scope when referenced, * possibly causing incorrect resulting character; * - BUG FIX: make precision and minimal field width unsigned * to handle huge values (2^31 <= n < 2^32) correctly; * also be more careful in the use of signed/unsigned/size_t * internal variables - probably more careful than many * vendor implementations, but there may still be a case * where huge values of str_m, precision or minimal field * could cause incorrect behaviour; * - use separate variables for signed/unsigned arguments, * and for short/int, long, and long long argument lengths * to avoid possible incompatibilities on certain * computer architectures. Also use separate variable * arg_sign to hold sign of a numeric argument, * to make code more transparent; * - some fiddling with zero padding and "0x" to make it * Linux compatible; * - systematically use macros fast_memcpy and fast_memset * instead of case-by-case hand optimization; determine some * breakeven string lengths for different architectures; * - terminology change: 'format' -> 'conversion specifier', * 'C9x' -> 'ISO/IEC 9899:1999 ("ISO C99")', * 'alternative form' -> 'alternate form', * 'data type modifier' -> 'length modifier'; * - several comments rephrased and new ones added; * - make compiler not complain about 'credits' defined but * not used; */ /* Define HAVE_SNPRINTF if your system already has snprintf and vsnprintf. * * If HAVE_SNPRINTF is defined this module will not produce code for * snprintf and vsnprintf, unless PREFER_PORTABLE_SNPRINTF is defined as well, * causing this portable version of snprintf to be called portable_snprintf * (and portable_vsnprintf). */ /* #define HAVE_SNPRINTF */ /* Define PREFER_PORTABLE_SNPRINTF if your system does have snprintf and * vsnprintf but you would prefer to use the portable routine(s) instead. * In this case the portable routine is declared as portable_snprintf * (and portable_vsnprintf) and a macro 'snprintf' (and 'vsnprintf') * is defined to expand to 'portable_v?snprintf' - see file snprintf.h . * Defining this macro is only useful if HAVE_SNPRINTF is also defined, * but does does no harm if defined nevertheless. */ /* #define PREFER_PORTABLE_SNPRINTF */ /* Define SNPRINTF_LONGLONG_SUPPORT if you want to support * data type (long long int) and length modifier 'll' (e.g. %lld). * If undefined, 'll' is recognized but treated as a single 'l'. * * If the system's sprintf does not handle 'll' * the SNPRINTF_LONGLONG_SUPPORT must not be defined! * * This is off by default as (long long int) is a language extension. */ /* #define SNPRINTF_LONGLONG_SUPPORT */ /* Define NEED_SNPRINTF_ONLY if you only need snprintf, and not vsnprintf. * If NEED_SNPRINTF_ONLY is defined, the snprintf will be defined directly, * otherwise both snprintf and vsnprintf routines will be defined * and snprintf will be a simple wrapper around vsnprintf, at the expense * of an extra procedure call. */ /* #define NEED_SNPRINTF_ONLY */ /* Define NEED_V?ASN?PRINTF macros if you need library extension * routines asprintf, vasprintf, asnprintf, vasnprintf respectively, * and your system library does not provide them. They are all small * wrapper routines around portable_vsnprintf. Defining any of the four * NEED_V?ASN?PRINTF macros automatically turns off NEED_SNPRINTF_ONLY * and turns on PREFER_PORTABLE_SNPRINTF. * * Watch for name conflicts with the system library if these routines * are already present there. * * NOTE: vasprintf and vasnprintf routines need va_copy() from stdarg.h, as * specified by C99, to be able to traverse the same list of arguments twice. * I don't know of any other standard and portable way of achieving the same. * With some versions of gcc you may use __va_copy(). You might even get away * with "ap2 = ap", in this case you must not call va_end(ap2) ! * #define va_copy(ap2,ap) ap2 = ap */ #ifndef va_copy #define va_copy(ap2,ap) ap2 = ap #endif /* #define NEED_ASPRINTF */ /* #define NEED_ASNPRINTF */ /* #define NEED_VASPRINTF */ /* #define NEED_VASNPRINTF */ /* Define the following macros if desired: * SOLARIS_COMPATIBLE, SOLARIS_BUG_COMPATIBLE, * HPUX_COMPATIBLE, HPUX_BUG_COMPATIBLE, LINUX_COMPATIBLE, * DIGITAL_UNIX_COMPATIBLE, DIGITAL_UNIX_BUG_COMPATIBLE, * PERL_COMPATIBLE, PERL_BUG_COMPATIBLE, * * - For portable applications it is best not to rely on peculiarities * of a given implementation so it may be best not to define any * of the macros that select compatibility and to avoid features * that vary among the systems. * * - Selecting compatibility with more than one operating system * is not strictly forbidden but is not recommended. * * - 'x'_BUG_COMPATIBLE implies 'x'_COMPATIBLE . * * - 'x'_COMPATIBLE refers to (and enables) a behaviour that is * documented in a sprintf man page on a given operating system * and actually adhered to by the system's sprintf (but not on * most other operating systems). It may also refer to and enable * a behaviour that is declared 'undefined' or 'implementation specific' * in the man page but a given implementation behaves predictably * in a certain way. * * - 'x'_BUG_COMPATIBLE refers to (and enables) a behaviour of system's sprintf * that contradicts the sprintf man page on the same operating system. * * - I do not claim that the 'x'_COMPATIBLE and 'x'_BUG_COMPATIBLE * conditionals take into account all idiosyncrasies of a particular * implementation, there may be other incompatibilities. */ /* ============================================= */ /* NO USER SERVICABLE PARTS FOLLOWING THIS POINT */ /* ============================================= */ #define PORTABLE_SNPRINTF_VERSION_MAJOR 2 #define PORTABLE_SNPRINTF_VERSION_MINOR 2 #if defined(NEED_ASPRINTF) || defined(NEED_ASNPRINTF) || defined(NEED_VASPRINTF) || defined(NEED_VASNPRINTF) # if defined(NEED_SNPRINTF_ONLY) # undef NEED_SNPRINTF_ONLY # endif # if !defined(PREFER_PORTABLE_SNPRINTF) # define PREFER_PORTABLE_SNPRINTF # endif #endif #if defined(SOLARIS_BUG_COMPATIBLE) && !defined(SOLARIS_COMPATIBLE) #define SOLARIS_COMPATIBLE #endif #if defined(HPUX_BUG_COMPATIBLE) && !defined(HPUX_COMPATIBLE) #define HPUX_COMPATIBLE #endif #if defined(DIGITAL_UNIX_BUG_COMPATIBLE) && !defined(DIGITAL_UNIX_COMPATIBLE) #define DIGITAL_UNIX_COMPATIBLE #endif #if defined(PERL_BUG_COMPATIBLE) && !defined(PERL_COMPATIBLE) #define PERL_COMPATIBLE #endif #if defined(LINUX_BUG_COMPATIBLE) && !defined(LINUX_COMPATIBLE) #define LINUX_COMPATIBLE #endif #include <sys/types.h> #include <string.h> #include <stdlib.h> #include <stdio.h> #include <stdarg.h> #include <assert.h> #include <errno.h> #ifdef isdigit #undef isdigit #endif #define isdigit(c) ((c) >= '0' && (c) <= '9') /* For copying strings longer or equal to 'breakeven_point' * it is more efficient to call memcpy() than to do it inline. * The value depends mostly on the processor architecture, * but also on the compiler and its optimization capabilities. * The value is not critical, some small value greater than zero * will be just fine if you don't care to squeeze every drop * of performance out of the code. * * Small values favor memcpy, large values favor inline code. */ #if defined(__alpha__) || defined(__alpha) # define breakeven_point 2 /* AXP (DEC Alpha) - gcc or cc or egcs */ #endif #if defined(__i386__) || defined(__i386) # define breakeven_point 12 /* Intel Pentium/Linux - gcc 2.96 */ #endif #if defined(__hppa) # define breakeven_point 10 /* HP-PA - gcc */ #endif #if defined(__sparc__) || defined(__sparc) # define breakeven_point 33 /* Sun Sparc 5 - gcc 2.8.1 */ #endif /* some other values of possible interest: */ /* #define breakeven_point 8 */ /* VAX 4000 - vaxc */ /* #define breakeven_point 19 */ /* VAX 4000 - gcc 2.7.0 */ #ifndef breakeven_point # define breakeven_point 6 /* some reasonable one-size-fits-all value */ #endif #define fast_memcpy(d,s,n) \ { register size_t nn = (size_t)(n); \ if (nn >= breakeven_point) memcpy((d), (s), nn); \ else if (nn > 0) { /* proc call overhead is worth only for large strings*/\ register char *dd; register const char *ss; \ for (ss=(s), dd=(d); nn>0; nn--) *dd++ = *ss++; } } #define fast_memset(d,c,n) \ { register size_t nn = (size_t)(n); \ if (nn >= breakeven_point) memset((d), (int)(c), nn); \ else if (nn > 0) { /* proc call overhead is worth only for large strings*/\ register char *dd; register const int cc=(int)(c); \ for (dd=(d); nn>0; nn--) *dd++ = cc; } } /* prototypes */ #if defined(NEED_ASPRINTF) int asprintf (char **ptr, const char *fmt, /*args*/ ...); #endif #if defined(NEED_VASPRINTF) int vasprintf (char **ptr, const char *fmt, va_list ap); #endif #if defined(NEED_ASNPRINTF) int asnprintf (char **ptr, size_t str_m, const char *fmt, /*args*/ ...); #endif #if defined(NEED_VASNPRINTF) int vasnprintf (char **ptr, size_t str_m, const char *fmt, va_list ap); #endif #if defined(HAVE_SNPRINTF) /* declare our portable snprintf routine under name portable_snprintf */ /* declare our portable vsnprintf routine under name portable_vsnprintf */ #else /* declare our portable routines under names snprintf and vsnprintf */ #define portable_snprintf snprintf #if !defined(NEED_SNPRINTF_ONLY) #define portable_vsnprintf vsnprintf #endif #endif #if !defined(HAVE_SNPRINTF) || defined(PREFER_PORTABLE_SNPRINTF) int portable_snprintf(char *str, size_t str_m, const char *fmt, /*args*/ ...); #if !defined(NEED_SNPRINTF_ONLY) int portable_vsnprintf(char *str, size_t str_m, const char *fmt, va_list ap); #endif #endif /* declarations */ static char credits[] = "\n\ @(#)snprintf.c, v2.2: Mark Martinec, <mark.martinec@ijs.si>\n\ @(#)snprintf.c, v2.2: Copyright 1999, Mark Martinec. Frontier Artistic License applies.\n\ @(#)snprintf.c, v2.2: http://www.ijs.si/software/snprintf/\n"; #if defined(NEED_ASPRINTF) int asprintf(char **ptr, const char *fmt, /*args*/ ...) { va_list ap; size_t str_m; int str_l; *ptr = NULL; va_start(ap, fmt); /* measure the required size */ str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap); va_end(ap); assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */ *ptr = (char *) malloc(str_m = (size_t)str_l + 1); if (*ptr == NULL) { errno = ENOMEM; str_l = -1; } else { int str_l2; va_start(ap, fmt); str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap); va_end(ap); assert(str_l2 == str_l); } return str_l; } #endif #if defined(NEED_VASPRINTF) int vasprintf(char **ptr, const char *fmt, va_list ap) { size_t str_m; int str_l; *ptr = NULL; { va_list ap2; va_copy(ap2, ap); /* don't consume the original ap, we'll need it again */ str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap2);/*get required size*/ va_end(ap2); } assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */ *ptr = (char *) malloc(str_m = (size_t)str_l + 1); if (*ptr == NULL) { errno = ENOMEM; str_l = -1; } else { int str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap); assert(str_l2 == str_l); } return str_l; } #endif #if defined(NEED_ASNPRINTF) int asnprintf (char **ptr, size_t str_m, const char *fmt, /*args*/ ...) { va_list ap; int str_l; *ptr = NULL; va_start(ap, fmt); /* measure the required size */ str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap); va_end(ap); assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */ if ((size_t)str_l + 1 < str_m) str_m = (size_t)str_l + 1; /* truncate */ /* if str_m is 0, no buffer is allocated, just set *ptr to NULL */ if (str_m == 0) { /* not interested in resulting string, just return size */ } else { *ptr = (char *) malloc(str_m); if (*ptr == NULL) { errno = ENOMEM; str_l = -1; } else { int str_l2; va_start(ap, fmt); str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap); va_end(ap); assert(str_l2 == str_l); } } return str_l; } #endif #if defined(NEED_VASNPRINTF) int vasnprintf (char **ptr, size_t str_m, const char *fmt, va_list ap) { int str_l; *ptr = NULL; { va_list ap2; va_copy(ap2, ap); /* don't consume the original ap, we'll need it again */ str_l = portable_vsnprintf(NULL, (size_t)0, fmt, ap2);/*get required size*/ va_end(ap2); } assert(str_l >= 0); /* possible integer overflow if str_m > INT_MAX */ if ((size_t)str_l + 1 < str_m) str_m = (size_t)str_l + 1; /* truncate */ /* if str_m is 0, no buffer is allocated, just set *ptr to NULL */ if (str_m == 0) { /* not interested in resulting string, just return size */ } else { *ptr = (char *) malloc(str_m); if (*ptr == NULL) { errno = ENOMEM; str_l = -1; } else { int str_l2 = portable_vsnprintf(*ptr, str_m, fmt, ap); assert(str_l2 == str_l); } } return str_l; } #endif /* * If the system does have snprintf and the portable routine is not * specifically required, this module produces no code for snprintf/vsnprintf. */ #if !defined(HAVE_SNPRINTF) || defined(PREFER_PORTABLE_SNPRINTF) #if !defined(NEED_SNPRINTF_ONLY) int portable_snprintf(char *str, size_t str_m, const char *fmt, /*args*/ ...) { va_list ap; int str_l; va_start(ap, fmt); str_l = portable_vsnprintf(str, str_m, fmt, ap); va_end(ap); return str_l; } #endif #if defined(NEED_SNPRINTF_ONLY) int portable_snprintf(char *str, size_t str_m, const char *fmt, /*args*/ ...) { #else int portable_vsnprintf(char *str, size_t str_m, const char *fmt, va_list ap) { #endif #if defined(NEED_SNPRINTF_ONLY) va_list ap; #endif size_t str_l = 0; const char *p = fmt; /* In contrast with POSIX, the ISO C99 now says * that str can be NULL and str_m can be 0. * This is more useful than the old: if (str_m < 1) return -1; */ #if defined(NEED_SNPRINTF_ONLY) va_start(ap, fmt); #endif if (!p) p = ""; while (*p) { if (*p != '%') { /* if (str_l < str_m) str[str_l++] = *p++; -- this would be sufficient */ /* but the following code achieves better performance for cases * where format string is long and contains few conversions */ const char *q = strchr(p+1,'%'); size_t n = !q ? strlen(p) : (size_t)(q-p); if (str_l < str_m) { size_t avail = str_m-str_l; fast_memcpy(str+str_l, p, (n>avail?avail:n)); } p += n; str_l += n; } else { const char *starting_p; size_t min_field_width = 0, precision = 0; int zero_padding = 0, precision_specified = 0, justify_left = 0; int alternate_form = 0, force_sign = 0; int space_for_positive = 1; /* If both the ' ' and '+' flags appear, the ' ' flag should be ignored. */ char length_modifier = '\0'; /* allowed values: \0, h, l, L */ char tmp[32];/* temporary buffer for simple numeric->string conversion */ const char *str_arg; /* string address in case of string argument */ size_t str_arg_l; /* natural field width of arg without padding and sign */ unsigned char uchar_arg; /* unsigned char argument value - only defined for c conversion. N.B. standard explicitly states the char argument for the c conversion is unsigned */ size_t number_of_zeros_to_pad = 0; /* number of zeros to be inserted for numeric conversions as required by the precision or minimal field width */ size_t zero_padding_insertion_ind = 0; /* index into tmp where zero padding is to be inserted */ char fmt_spec = '\0'; /* current conversion specifier character */ str_arg = credits;/* just to make compiler happy (defined but not used)*/ str_arg = NULL; starting_p = p; p++; /* skip '%' */ /* parse flags */ while (*p == '0' || *p == '-' || *p == '+' || *p == ' ' || *p == '#' || *p == '\'') { switch (*p) { case '0': zero_padding = 1; break; case '-': justify_left = 1; break; case '+': force_sign = 1; space_for_positive = 0; break; case ' ': force_sign = 1; /* If both the ' ' and '+' flags appear, the ' ' flag should be ignored */ #ifdef PERL_COMPATIBLE /* ... but in Perl the last of ' ' and '+' applies */ space_for_positive = 1; #endif break; case '#': alternate_form = 1; break; case '\'': break; } p++; } /* If the '0' and '-' flags both appear, the '0' flag should be ignored. */ /* parse field width */ if (*p == '*') { int j; p++; j = va_arg(ap, int); if (j >= 0) min_field_width = j; else { min_field_width = -j; justify_left = 1; } } else if (isdigit((int)(*p))) { /* size_t could be wider than unsigned int; make sure we treat argument like common implementations do */ unsigned int uj = *p++ - '0'; while (isdigit((int)(*p))) uj = 10*uj + (unsigned int)(*p++ - '0'); min_field_width = uj; } /* parse precision */ if (*p == '.') { p++; precision_specified = 1; if (*p == '*') { int j = va_arg(ap, int); p++; if (j >= 0) precision = j; else { precision_specified = 0; precision = 0; /* NOTE: * Solaris 2.6 man page claims that in this case the precision * should be set to 0. Digital Unix 4.0, HPUX 10 and BSD man page * claim that this case should be treated as unspecified precision, * which is what we do here. */ } } else if (isdigit((int)(*p))) { /* size_t could be wider than unsigned int; make sure we treat argument like common implementations do */ unsigned int uj = *p++ - '0'; while (isdigit((int)(*p))) uj = 10*uj + (unsigned int)(*p++ - '0'); precision = uj; } } /* parse 'h', 'l' and 'll' length modifiers */ if (*p == 'h' || *p == 'l') { length_modifier = *p; p++; if (length_modifier == 'l' && *p == 'l') { /* double l = long long */ #ifdef SNPRINTF_LONGLONG_SUPPORT length_modifier = '2'; /* double l encoded as '2' */ #else length_modifier = 'l'; /* treat it as a single 'l' */ #endif p++; } } fmt_spec = *p; /* common synonyms: */ switch (fmt_spec) { case 'i': fmt_spec = 'd'; break; case 'D': fmt_spec = 'd'; length_modifier = 'l'; break; case 'U': fmt_spec = 'u'; length_modifier = 'l'; break; case 'O': fmt_spec = 'o'; length_modifier = 'l'; break; default: break; } /* get parameter value, do initial processing */ switch (fmt_spec) { case '%': /* % behaves similar to 's' regarding flags and field widths */ case 'c': /* c behaves similar to 's' regarding flags and field widths */ case 's': length_modifier = '\0'; /* wint_t and wchar_t not supported */ /* the result of zero padding flag with non-numeric conversion specifier*/ /* is undefined. Solaris and HPUX 10 does zero padding in this case, */ /* Digital Unix and Linux does not. */ #if !defined(SOLARIS_COMPATIBLE) && !defined(HPUX_COMPATIBLE) zero_padding = 0; /* turn zero padding off for string conversions */ #endif str_arg_l = 1; switch (fmt_spec) { case '%': str_arg = p; break; case 'c': { int j = va_arg(ap, int); uchar_arg = (unsigned char) j; /* standard demands unsigned char */ str_arg = (const char *) &uchar_arg; break; } case 's': str_arg = va_arg(ap, const char *); if (!str_arg) str_arg_l = 0; /* make sure not to address string beyond the specified precision !!! */ else if (!precision_specified) str_arg_l = strlen(str_arg); /* truncate string if necessary as requested by precision */ else if (precision == 0) str_arg_l = 0; else { /* memchr on HP does not like n > 2^31 !!! */ const char *q = memchr(str_arg, '\0', precision <= 0x7fffffff ? precision : 0x7fffffff); str_arg_l = !q ? precision : (size_t)(q-str_arg); } break; default: break; } break; case 'd': case 'u': case 'o': case 'x': case 'X': case 'p': { /* NOTE: the u, o, x, X and p conversion specifiers imply the value is unsigned; d implies a signed value */ int arg_sign = 0; /* 0 if numeric argument is zero (or if pointer is NULL for 'p'), +1 if greater than zero (or nonzero for unsigned arguments), -1 if negative (unsigned argument is never negative) */ int int_arg = 0; unsigned int uint_arg = 0; /* only defined for length modifier h, or for no length modifiers */ long int long_arg = 0; unsigned long int ulong_arg = 0; /* only defined for length modifier l */ void *ptr_arg = NULL; /* pointer argument value -only defined for p conversion */ #ifdef SNPRINTF_LONGLONG_SUPPORT long long int long_long_arg = 0; unsigned long long int ulong_long_arg = 0; /* only defined for length modifier ll */ #endif if (fmt_spec == 'p') { /* HPUX 10: An l, h, ll or L before any other conversion character * (other than d, i, u, o, x, or X) is ignored. * Digital Unix: * not specified, but seems to behave as HPUX does. * Solaris: If an h, l, or L appears before any other conversion * specifier (other than d, i, u, o, x, or X), the behavior * is undefined. (Actually %hp converts only 16-bits of address * and %llp treats address as 64-bit data which is incompatible * with (void *) argument on a 32-bit system). */ #ifdef SOLARIS_COMPATIBLE # ifdef SOLARIS_BUG_COMPATIBLE /* keep length modifiers even if it represents 'll' */ # else if (length_modifier == '2') length_modifier = '\0'; # endif #else length_modifier = '\0'; #endif ptr_arg = va_arg(ap, void *); if (ptr_arg != NULL) arg_sign = 1; } else if (fmt_spec == 'd') { /* signed */ switch (length_modifier) { case '\0': case 'h': /* It is non-portable to specify a second argument of char or short * to va_arg, because arguments seen by the called function * are not char or short. C converts char and short arguments * to int before passing them to a function. */ int_arg = va_arg(ap, int); if (int_arg > 0) arg_sign = 1; else if (int_arg < 0) arg_sign = -1; break; case 'l': long_arg = va_arg(ap, long int); if (long_arg > 0) arg_sign = 1; else if (long_arg < 0) arg_sign = -1; break; #ifdef SNPRINTF_LONGLONG_SUPPORT case '2': long_long_arg = va_arg(ap, long long int); if (long_long_arg > 0) arg_sign = 1; else if (long_long_arg < 0) arg_sign = -1; break; #endif } } else { /* unsigned */ switch (length_modifier) { case '\0': case 'h': uint_arg = va_arg(ap, unsigned int); if (uint_arg) arg_sign = 1; break; case 'l': ulong_arg = va_arg(ap, unsigned long int); if (ulong_arg) arg_sign = 1; break; #ifdef SNPRINTF_LONGLONG_SUPPORT case '2': ulong_long_arg = va_arg(ap, unsigned long long int); if (ulong_long_arg) arg_sign = 1; break; #endif } } str_arg = tmp; str_arg_l = 0; /* NOTE: * For d, i, u, o, x, and X conversions, if precision is specified, * the '0' flag should be ignored. This is so with Solaris 2.6, * Digital UNIX 4.0, HPUX 10, Linux, FreeBSD, NetBSD; but not with Perl. */ #ifndef PERL_COMPATIBLE if (precision_specified) zero_padding = 0; #endif if (fmt_spec == 'd') { if (force_sign && arg_sign >= 0) tmp[str_arg_l++] = space_for_positive ? ' ' : '+'; /* leave negative numbers for sprintf to handle, to avoid handling tricky cases like (short int)(-32768) */ #ifdef LINUX_COMPATIBLE } else if (fmt_spec == 'p' && force_sign && arg_sign > 0) { tmp[str_arg_l++] = space_for_positive ? ' ' : '+'; #endif } else if (alternate_form) { if (arg_sign != 0 && (fmt_spec == 'x' || fmt_spec == 'X') ) { tmp[str_arg_l++] = '0'; tmp[str_arg_l++] = fmt_spec; } /* alternate form should have no effect for p conversion, but ... */ #ifdef HPUX_COMPATIBLE else if (fmt_spec == 'p' /* HPUX 10: for an alternate form of p conversion, * a nonzero result is prefixed by 0x. */ #ifndef HPUX_BUG_COMPATIBLE /* Actually it uses 0x prefix even for a zero value. */ && arg_sign != 0 #endif ) { tmp[str_arg_l++] = '0'; tmp[str_arg_l++] = 'x'; } #endif } zero_padding_insertion_ind = str_arg_l; if (!precision_specified) precision = 1; /* default precision is 1 */ if (precision == 0 && arg_sign == 0 #if defined(HPUX_BUG_COMPATIBLE) || defined(LINUX_COMPATIBLE) && fmt_spec != 'p' /* HPUX 10 man page claims: With conversion character p the result of * converting a zero value with a precision of zero is a null string. * Actually HP returns all zeroes, and Linux returns "(nil)". */ #endif ) { /* converted to null string */ /* When zero value is formatted with an explicit precision 0, the resulting formatted string is empty (d, i, u, o, x, X, p). */ } else { char f[5]; int f_l = 0; f[f_l++] = '%'; /* construct a simple format string for sprintf */ if (!length_modifier) { } else if (length_modifier=='2') { f[f_l++] = 'l'; f[f_l++] = 'l'; } else f[f_l++] = length_modifier; f[f_l++] = fmt_spec; f[f_l++] = '\0'; if (fmt_spec == 'p') str_arg_l += sprintf(tmp+str_arg_l, f, ptr_arg); else if (fmt_spec == 'd') { /* signed */ switch (length_modifier) { case '\0': case 'h': str_arg_l+=sprintf(tmp+str_arg_l, f, int_arg); break; case 'l': str_arg_l+=sprintf(tmp+str_arg_l, f, long_arg); break; #ifdef SNPRINTF_LONGLONG_SUPPORT case '2': str_arg_l+=sprintf(tmp+str_arg_l,f,long_long_arg); break; #endif } } else { /* unsigned */ switch (length_modifier) { case '\0': case 'h': str_arg_l+=sprintf(tmp+str_arg_l, f, uint_arg); break; case 'l': str_arg_l+=sprintf(tmp+str_arg_l, f, ulong_arg); break; #ifdef SNPRINTF_LONGLONG_SUPPORT case '2': str_arg_l+=sprintf(tmp+str_arg_l,f,ulong_long_arg);break; #endif } } /* include the optional minus sign and possible "0x" in the region before the zero padding insertion point */ if (zero_padding_insertion_ind < str_arg_l && tmp[zero_padding_insertion_ind] == '-') { zero_padding_insertion_ind++; } if (zero_padding_insertion_ind+1 < str_arg_l && tmp[zero_padding_insertion_ind] == '0' && (tmp[zero_padding_insertion_ind+1] == 'x' || tmp[zero_padding_insertion_ind+1] == 'X') ) { zero_padding_insertion_ind += 2; } } { size_t num_of_digits = str_arg_l - zero_padding_insertion_ind; if (alternate_form && fmt_spec == 'o' #ifdef HPUX_COMPATIBLE /* ("%#.o",0) -> "" */ && (str_arg_l > 0) #endif #ifdef DIGITAL_UNIX_BUG_COMPATIBLE /* ("%#o",0) -> "00" */ #else /* unless zero is already the first character */ && !(zero_padding_insertion_ind < str_arg_l && tmp[zero_padding_insertion_ind] == '0') #endif ) { /* assure leading zero for alternate-form octal numbers */ if (!precision_specified || precision < num_of_digits+1) { /* precision is increased to force the first character to be zero, except if a zero value is formatted with an explicit precision of zero */ precision = num_of_digits+1; precision_specified = 1; } } /* zero padding to specified precision? */ if (num_of_digits < precision) number_of_zeros_to_pad = precision - num_of_digits; } /* zero padding to specified minimal field width? */ if (!justify_left && zero_padding) { int n = min_field_width - (str_arg_l+number_of_zeros_to_pad); if (n > 0) number_of_zeros_to_pad += n; } break; } default: /* unrecognized conversion specifier, keep format string as-is*/ zero_padding = 0; /* turn zero padding off for non-numeric convers. */ #ifndef DIGITAL_UNIX_COMPATIBLE justify_left = 1; min_field_width = 0; /* reset flags */ #endif #if defined(PERL_COMPATIBLE) || defined(LINUX_COMPATIBLE) /* keep the entire format string unchanged */ str_arg = starting_p; str_arg_l = p - starting_p; /* well, not exactly so for Linux, which does something inbetween, * and I don't feel an urge to imitate it: "%+++++hy" -> "%+y" */ #else /* discard the unrecognized conversion, just keep * * the unrecognized conversion character */ str_arg = p; str_arg_l = 0; #endif if (*p) str_arg_l++; /* include invalid conversion specifier unchanged if not at end-of-string */ break; } if (*p) p++; /* step over the just processed conversion specifier */ /* insert padding to the left as requested by min_field_width; this does not include the zero padding in case of numerical conversions*/ if (!justify_left) { /* left padding with blank or zero */ int n = min_field_width - (str_arg_l+number_of_zeros_to_pad); if (n > 0) { if (str_l < str_m) { ssize_t avail = str_m-str_l; fast_memset(str+str_l, (zero_padding?'0':' '), (n>avail?avail:n)); } str_l += n; } } /* zero padding as requested by the precision or by the minimal field width * for numeric conversions required? */ if (number_of_zeros_to_pad <= 0) { /* will not copy first part of numeric right now, * * force it to be copied later in its entirety */ zero_padding_insertion_ind = 0; } else { /* insert first part of numerics (sign or '0x') before zero padding */ int n = zero_padding_insertion_ind; if (n > 0) { if (str_l < str_m) { ssize_t avail = str_m-str_l; fast_memcpy(str+str_l, str_arg, (n>avail?avail:n)); } str_l += n; } /* insert zero padding as requested by the precision or min field width */ n = number_of_zeros_to_pad; if (n > 0) { if (str_l < str_m) { ssize_t avail = str_m-str_l; fast_memset(str+str_l, '0', (n>avail?avail:n)); } str_l += n; } } /* insert formatted string * (or as-is conversion specifier for unknown conversions) */ { int n = str_arg_l - zero_padding_insertion_ind; if (n > 0) { if (str_l < str_m) { ssize_t avail = str_m-str_l; fast_memcpy(str+str_l, str_arg+zero_padding_insertion_ind, (n>avail?avail:n)); } str_l += n; } } /* insert right padding */ if (justify_left) { /* right blank padding to the field width */ int n = min_field_width - (str_arg_l+number_of_zeros_to_pad); if (n > 0) { if (str_l < str_m) { ssize_t avail = str_m-str_l; fast_memset(str+str_l, ' ', (n>avail?avail:n)); } str_l += n; } } } } #if defined(NEED_SNPRINTF_ONLY) va_end(ap); #endif if (str_m > 0) { /* make sure the string is null-terminated even at the expense of overwriting the last character (shouldn't happen, but just in case) */ str[str_l <= str_m-1 ? str_l : str_m-1] = '\0'; } /* Return the number of characters formatted (excluding trailing null * character), that is, the number of characters that would have been * written to the buffer if it were large enough. * * The value of str_l should be returned, but str_l is of unsigned type * size_t, and snprintf is int, possibly leading to an undetected * integer overflow, resulting in a negative return value, which is illegal. * Both XSH5 and ISO C99 (at least the draft) are silent on this issue. * Should errno be set to EOVERFLOW and EOF returned in this case??? */ return (int) str_l; } #endif
