1026 lines
41 KiB
C
1026 lines
41 KiB
C
/*
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* snprintf.c - a portable implementation of snprintf
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*
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* AUTHOR
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* Mark Martinec <mark.martinec@ijs.si>, April 1999.
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*
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* Copyright 1999, Mark Martinec. All rights reserved.
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*
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* TERMS AND CONDITIONS
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the "Frontier Artistic License" which comes
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* with this Kit.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the Frontier Artistic License for more details.
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*
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* You should have received a copy of the Frontier Artistic License
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* with this Kit in the file named LICENSE.txt .
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* If not, I'll be glad to provide one.
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*
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* FEATURES
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* - careful adherence to specs regarding flags, field width and precision;
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* - good performance for large string handling (large format, large
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* argument or large paddings). Performance is similar to system's sprintf
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* and in several cases significantly better (make sure you compile with
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* optimizations turned on, tell the compiler the code is strict ANSI
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* if necessary to give it more freedom for optimizations);
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* - return value semantics per ISO/IEC 9899:1999 ("ISO C99");
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* - written in standard ISO/ANSI C - requires an ANSI C compiler.
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*
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* SUPPORTED CONVERSION SPECIFIERS AND DATA TYPES
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*
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* This snprintf only supports the following conversion specifiers:
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* s, c, d, u, o, x, X, p (and synonyms: i, D, U, O - see below)
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* with flags: '-', '+', ' ', '0' and '#'.
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* An asterisk is supported for field width as well as precision.
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*
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* Length modifiers 'h' (short int), 'l' (long int),
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* and 'll' (long long int) are supported.
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* NOTE:
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* If macro SNPRINTF_LONGLONG_SUPPORT is not defined (default) the
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* length modifier 'll' is recognized but treated the same as 'l',
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* which may cause argument value truncation! Defining
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* SNPRINTF_LONGLONG_SUPPORT requires that your system's sprintf also
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* handles length modifier 'll'. long long int is a language extension
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* which may not be portable.
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*
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* Conversion of numeric data (conversion specifiers d, u, o, x, X, p)
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* with length modifiers (none or h, l, ll) is left to the system routine
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* sprintf, but all handling of flags, field width and precision as well as
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* c and s conversions is done very carefully by this portable routine.
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* If a string precision (truncation) is specified (e.g. %.8s) it is
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* guaranteed the string beyond the specified precision will not be referenced.
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*
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* Length modifiers h, l and ll are ignored for c and s conversions (data
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* types wint_t and wchar_t are not supported).
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*
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* The following common synonyms for conversion characters are supported:
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* - i is a synonym for d
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* - D is a synonym for ld, explicit length modifiers are ignored
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* - U is a synonym for lu, explicit length modifiers are ignored
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* - O is a synonym for lo, explicit length modifiers are ignored
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* The D, O and U conversion characters are nonstandard, they are supported
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* for backward compatibility only, and should not be used for new code.
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*
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* The following is specifically NOT supported:
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* - flag ' (thousands' grouping character) is recognized but ignored
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* - numeric conversion specifiers: f, e, E, g, G and synonym F,
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* as well as the new a and A conversion specifiers
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* - length modifier 'L' (long double) and 'q' (quad - use 'll' instead)
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* - wide character/string conversions: lc, ls, and nonstandard
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* synonyms C and S
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* - writeback of converted string length: conversion character n
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* - the n$ specification for direct reference to n-th argument
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* - locales
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*
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* It is permitted for str_m to be zero, and it is permitted to specify NULL
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* pointer for resulting string argument if str_m is zero (as per ISO C99).
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*
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* The return value is the number of characters which would be generated
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* for the given input, excluding the trailing null. If this value
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* is greater or equal to str_m, not all characters from the result
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* have been stored in str, output bytes beyond the (str_m-1) -th character
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* are discarded. If str_m is greater than zero it is guaranteed
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* the resulting string will be null-terminated.
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*
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* NOTE that this matches the ISO C99, OpenBSD, and GNU C library 2.1,
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* but is different from some older and vendor implementations,
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* and is also different from XPG, XSH5, SUSv2 specifications.
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* For historical discussion on changes in the semantics and standards
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* of snprintf see printf(3) man page in the Linux programmers manual.
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*
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* Routines asprintf and vasprintf return a pointer (in the ptr argument)
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* to a buffer sufficiently large to hold the resulting string. This pointer
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* should be passed to free(3) to release the allocated storage when it is
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* no longer needed. If sufficient space cannot be allocated, these functions
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* will return -1 and set ptr to be a NULL pointer. These two routines are a
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* GNU C library extensions (glibc).
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*
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* Routines asnprintf and vasnprintf are similar to asprintf and vasprintf,
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* yet, like snprintf and vsnprintf counterparts, will write at most str_m-1
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* characters into the allocated output string, the last character in the
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* allocated buffer then gets the terminating null. If the formatted string
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* length (the return value) is greater than or equal to the str_m argument,
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* the resulting string was truncated and some of the formatted characters
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* were discarded. These routines present a handy way to limit the amount
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* of allocated memory to some sane value.
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*
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* AVAILABILITY
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* http://www.ijs.si/software/snprintf/
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*
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* REVISION HISTORY
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* 1999-04 V0.9 Mark Martinec
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* - initial version, some modifications after comparing printf
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* man pages for Digital Unix 4.0, Solaris 2.6 and HPUX 10,
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* and checking how Perl handles sprintf (differently!);
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* 1999-04-09 V1.0 Mark Martinec <mark.martinec@ijs.si>
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* - added main test program, fixed remaining inconsistencies,
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* added optional (long long int) support;
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* 1999-04-12 V1.1 Mark Martinec <mark.martinec@ijs.si>
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* - support the 'p' conversion (pointer to void);
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* - if a string precision is specified
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* make sure the string beyond the specified precision
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* will not be referenced (e.g. by strlen);
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* 1999-04-13 V1.2 Mark Martinec <mark.martinec@ijs.si>
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* - support synonyms %D=%ld, %U=%lu, %O=%lo;
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* - speed up the case of long format string with few conversions;
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* 1999-06-30 V1.3 Mark Martinec <mark.martinec@ijs.si>
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* - fixed runaway loop (eventually crashing when str_l wraps
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* beyond 2^31) while copying format string without
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* conversion specifiers to a buffer that is too short
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* (thanks to Edwin Young <edwiny@autonomy.com> for
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* spotting the problem);
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* - added macros PORTABLE_SNPRINTF_VERSION_(MAJOR|MINOR)
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* to snprintf.h
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* 2000-02-14 V2.0 (never released) Mark Martinec <mark.martinec@ijs.si>
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* - relaxed license terms: The Artistic License now applies.
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* You may still apply the GNU GENERAL PUBLIC LICENSE
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* as was distributed with previous versions, if you prefer;
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* - changed REVISION HISTORY dates to use ISO 8601 date format;
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* - added vsnprintf (patch also independently proposed by
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* Caolan McNamara 2000-05-04, and Keith M Willenson 2000-06-01)
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* 2000-06-27 V2.1 Mark Martinec <mark.martinec@ijs.si>
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* - removed POSIX check for str_m<1; value 0 for str_m is
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* allowed by ISO C99 (and GNU C library 2.1) - (pointed out
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* on 2000-05-04 by Caolan McNamara, caolan@ csn dot ul dot ie).
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* Besides relaxed license this change in standards adherence
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* is the main reason to bump up the major version number;
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* - added nonstandard routines asnprintf, vasnprintf, asprintf,
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* vasprintf that dynamically allocate storage for the
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* resulting string; these routines are not compiled by default,
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* see comments where NEED_V?ASN?PRINTF macros are defined;
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* - autoconf contributed by Caolan McNamara
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* 2000-10-06 V2.2 Mark Martinec <mark.martinec@ijs.si>
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* - BUG FIX: the %c conversion used a temporary variable
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* that was no longer in scope when referenced,
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* possibly causing incorrect resulting character;
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* - BUG FIX: make precision and minimal field width unsigned
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* to handle huge values (2^31 <= n < 2^32) correctly;
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* also be more careful in the use of signed/unsigned/size_t
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* internal variables - probably more careful than many
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* vendor implementations, but there may still be a case
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* where huge values of str_m, precision or minimal field
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* could cause incorrect behaviour;
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* - use separate variables for signed/unsigned arguments,
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* and for short/int, long, and long long argument lengths
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* to avoid possible incompatibilities on certain
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* computer architectures. Also use separate variable
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* arg_sign to hold sign of a numeric argument,
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* to make code more transparent;
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* - some fiddling with zero padding and "0x" to make it
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* Linux compatible;
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* - systematically use macros fast_memcpy and fast_memset
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* instead of case-by-case hand optimization; determine some
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* breakeven string lengths for different architectures;
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* - terminology change: 'format' -> 'conversion specifier',
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* 'C9x' -> 'ISO/IEC 9899:1999 ("ISO C99")',
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* 'alternative form' -> 'alternate form',
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* 'data type modifier' -> 'length modifier';
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* - several comments rephrased and new ones added;
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* - make compiler not complain about 'credits' defined but
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* not used;
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*/
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/* Define HAVE_SNPRINTF if your system already has snprintf and vsnprintf.
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*
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* If HAVE_SNPRINTF is defined this module will not produce code for
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* snprintf and vsnprintf, unless PREFER_PORTABLE_SNPRINTF is defined as well,
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* causing this portable version of snprintf to be called portable_snprintf
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* (and portable_vsnprintf).
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*/
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/* #define HAVE_SNPRINTF */
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/* Define PREFER_PORTABLE_SNPRINTF if your system does have snprintf and
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* vsnprintf but you would prefer to use the portable routine(s) instead.
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* In this case the portable routine is declared as portable_snprintf
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* (and portable_vsnprintf) and a macro 'snprintf' (and 'vsnprintf')
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* is defined to expand to 'portable_v?snprintf' - see file snprintf.h .
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* Defining this macro is only useful if HAVE_SNPRINTF is also defined,
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* but does does no harm if defined nevertheless.
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*/
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/* #define PREFER_PORTABLE_SNPRINTF */
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/* Define SNPRINTF_LONGLONG_SUPPORT if you want to support
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* data type (long long int) and length modifier 'll' (e.g. %lld).
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* If undefined, 'll' is recognized but treated as a single 'l'.
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*
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* If the system's sprintf does not handle 'll'
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* the SNPRINTF_LONGLONG_SUPPORT must not be defined!
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*
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* This is off by default as (long long int) is a language extension.
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*/
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/* #define SNPRINTF_LONGLONG_SUPPORT */
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/* Define NEED_SNPRINTF_ONLY if you only need snprintf, and not vsnprintf.
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* If NEED_SNPRINTF_ONLY is defined, the snprintf will be defined directly,
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* otherwise both snprintf and vsnprintf routines will be defined
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* and snprintf will be a simple wrapper around vsnprintf, at the expense
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* of an extra procedure call.
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*/
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/* #define NEED_SNPRINTF_ONLY */
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/* Define NEED_V?ASN?PRINTF macros if you need library extension
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* routines asprintf, vasprintf, asnprintf, vasnprintf respectively,
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* and your system library does not provide them. They are all small
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* wrapper routines around portable_vsnprintf. Defining any of the four
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* NEED_V?ASN?PRINTF macros automatically turns off NEED_SNPRINTF_ONLY
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* and turns on PREFER_PORTABLE_SNPRINTF.
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*
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* Watch for name conflicts with the system library if these routines
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* are already present there.
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*
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* NOTE: vasprintf and vasnprintf routines need va_copy() from stdarg.h, as
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* specified by C99, to be able to traverse the same list of arguments twice.
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* I don't know of any other standard and portable way of achieving the same.
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* With some versions of gcc you may use __va_copy(). You might even get away
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* with "ap2 = ap", in this case you must not call va_end(ap2) !
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* #define va_copy(ap2,ap) ap2 = ap
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*/
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/* #define NEED_ASPRINTF */
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/* #define NEED_ASNPRINTF */
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/* #define NEED_VASPRINTF */
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/* #define NEED_VASNPRINTF */
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/* Define the following macros if desired:
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* SOLARIS_COMPATIBLE, SOLARIS_BUG_COMPATIBLE,
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* HPUX_COMPATIBLE, HPUX_BUG_COMPATIBLE, LINUX_COMPATIBLE,
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* DIGITAL_UNIX_COMPATIBLE, DIGITAL_UNIX_BUG_COMPATIBLE,
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* PERL_COMPATIBLE, PERL_BUG_COMPATIBLE,
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*
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* - For portable applications it is best not to rely on peculiarities
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* of a given implementation so it may be best not to define any
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* of the macros that select compatibility and to avoid features
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* that vary among the systems.
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*
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* - Selecting compatibility with more than one operating system
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* is not strictly forbidden but is not recommended.
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*
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* - 'x'_BUG_COMPATIBLE implies 'x'_COMPATIBLE .
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*
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* - 'x'_COMPATIBLE refers to (and enables) a behaviour that is
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* documented in a sprintf man page on a given operating system
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* and actually adhered to by the system's sprintf (but not on
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* most other operating systems). It may also refer to and enable
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* a behaviour that is declared 'undefined' or 'implementation specific'
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* in the man page but a given implementation behaves predictably
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* in a certain way.
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*
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* - 'x'_BUG_COMPATIBLE refers to (and enables) a behaviour of system's sprintf
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* that contradicts the sprintf man page on the same operating system.
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*
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* - I do not claim that the 'x'_COMPATIBLE and 'x'_BUG_COMPATIBLE
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* conditionals take into account all idiosyncrasies of a particular
|
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* implementation, there may be other incompatibilities.
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*/
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/* ============================================= */
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/* NO USER SERVICABLE PARTS FOLLOWING THIS POINT */
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/* ============================================= */
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#define PORTABLE_SNPRINTF_VERSION_MAJOR 2
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#define PORTABLE_SNPRINTF_VERSION_MINOR 2
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#if defined(NEED_ASPRINTF) || defined(NEED_ASNPRINTF) || defined(NEED_VASPRINTF) || defined(NEED_VASNPRINTF)
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# if defined(NEED_SNPRINTF_ONLY)
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# undef NEED_SNPRINTF_ONLY
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# endif
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# if !defined(PREFER_PORTABLE_SNPRINTF)
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# define PREFER_PORTABLE_SNPRINTF
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# endif
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#endif
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#if defined(SOLARIS_BUG_COMPATIBLE) && !defined(SOLARIS_COMPATIBLE)
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#define SOLARIS_COMPATIBLE
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#endif
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||
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#if defined(HPUX_BUG_COMPATIBLE) && !defined(HPUX_COMPATIBLE)
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#define HPUX_COMPATIBLE
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||
#endif
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||
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#if defined(DIGITAL_UNIX_BUG_COMPATIBLE) && !defined(DIGITAL_UNIX_COMPATIBLE)
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#define DIGITAL_UNIX_COMPATIBLE
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#endif
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||
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#if defined(PERL_BUG_COMPATIBLE) && !defined(PERL_COMPATIBLE)
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#define PERL_COMPATIBLE
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||
#endif
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||
|
||
#if defined(LINUX_BUG_COMPATIBLE) && !defined(LINUX_COMPATIBLE)
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#define LINUX_COMPATIBLE
|
||
#endif
|
||
|
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#include <sys/types.h>
|
||
#include <string.h>
|
||
#include <stdlib.h>
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||
#include <stdio.h>
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||
#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) : (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 : (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) {
|
||
size_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) {
|
||
size_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) {
|
||
size_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) {
|
||
size_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) {
|
||
size_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
|