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Annotation of OpenXM_contrib/gmp/printf/vasprintf.c, Revision 1.1

1.1     ! ohara       1: /* gmp_vasprintf -- formatted output to an allocated space.
        !             2:
        !             3: Copyright 2001 Free Software Foundation, Inc.
        !             4:
        !             5: This file is part of the GNU MP Library.
        !             6:
        !             7: The GNU MP Library is free software; you can redistribute it and/or modify
        !             8: it under the terms of the GNU Lesser General Public License as published by
        !             9: the Free Software Foundation; either version 2.1 of the License, or (at your
        !            10: option) any later version.
        !            11:
        !            12: The GNU MP Library is distributed in the hope that it will be useful, but
        !            13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
        !            15: License for more details.
        !            16:
        !            17: You should have received a copy of the GNU Lesser General Public License
        !            18: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            20: MA 02111-1307, USA. */
        !            21:
        !            22: #include "config.h"
        !            23:
        !            24: #if HAVE_STDARG
        !            25: #include <stdarg.h>
        !            26: #else
        !            27: #include <varargs.h>
        !            28: #endif
        !            29:
        !            30: #include <stdio.h>
        !            31: #include <stdlib.h>
        !            32: #include <string.h>
        !            33:
        !            34: #include "gmp.h"
        !            35: #include "gmp-impl.h"
        !            36:
        !            37: #if ! HAVE_VSNPRINTF
        !            38: #define vsnprintf  __gmp_replacement_vsnprintf
        !            39: #endif
        !            40:
        !            41:
        !            42: /* vasprintf isn't used since we prefer all GMP allocs to go through
        !            43:    __gmp_allocate_func, and in particular we don't want the -1 return from
        !            44:    vasprintf for out-of-memory, instead __gmp_allocate_func should handle
        !            45:    that.  Using vsnprintf unfortunately means we might have to re-run it if
        !            46:    our current space is insufficient.
        !            47:
        !            48:    The initial guess for the needed space is an arbitrary 256 bytes.  If
        !            49:    that (and any extra GMP_ASPRINTF_T_NEED might give) isn't enough then an
        !            50:    ISO C99 standard vsnprintf will tell us what we really need.
        !            51:
        !            52:    GLIBC 2.0.x vsnprintf returns either -1 or space-1 to indicate overflow,
        !            53:    without giving any indication how much is really needed.  In this case
        !            54:    keep trying with double the space each time.
        !            55:
        !            56:    A return of space-1 is success on a C99 vsnprintf, but we're not
        !            57:    bothering to identify which style vsnprintf we've got, so just take the
        !            58:    pessimistic option and assume it's glibc 2.0.x.
        !            59:
        !            60:    Notice the use of ret+2 for the new space in the C99 case.  This ensures
        !            61:    the next vsnprintf return value will be space-2, which is unambiguously
        !            62:    successful.  But actually GMP_ASPRINTF_T_NEED() will realloc to even
        !            63:    bigger than that ret+2.
        !            64:
        !            65:    vsnprintf might trash it's given ap, so copy it in case we need to use it
        !            66:    more than once.  See comments with gmp_snprintf_format.  */
        !            67:
        !            68: static int
        !            69: gmp_asprintf_format (struct gmp_asprintf_t *d, const char *fmt,
        !            70:                      va_list orig_ap)
        !            71: {
        !            72:   int      ret;
        !            73:   va_list  ap;
        !            74:   size_t   space = 256;
        !            75:
        !            76:   for (;;)
        !            77:     {
        !            78:       GMP_ASPRINTF_T_NEED (d, space);
        !            79:       space = d->alloc - d->size;
        !            80:       va_copy (ap, orig_ap);
        !            81:       ret = vsnprintf (d->buf + d->size, space, fmt, ap);
        !            82:       if (ret == -1)
        !            83:         {
        !            84:           ASSERT (strlen (d->buf + d->size) == space-1);
        !            85:           ret = space-1;
        !            86:         }
        !            87:
        !            88:       /* done if output fits in our space */
        !            89:       if (ret < space-1)
        !            90:         break;
        !            91:
        !            92:       if (ret == space-1)
        !            93:         space *= 2;     /* possible glibc 2.0.x, so double */
        !            94:       else
        !            95:         space = ret+2;  /* C99, so now know space required */
        !            96:     }
        !            97:
        !            98:   d->size += ret;
        !            99:   return ret;
        !           100: }
        !           101:
        !           102: const struct doprnt_funs_t  __gmp_asprintf_funs = {
        !           103:   (doprnt_format_t) gmp_asprintf_format,
        !           104:   (doprnt_memory_t) __gmp_asprintf_memory,
        !           105:   (doprnt_reps_t)   __gmp_asprintf_reps,
        !           106:   (doprnt_final_t)  __gmp_asprintf_final
        !           107: };
        !           108:
        !           109: int
        !           110: gmp_vasprintf (char **result, const char *fmt, va_list ap)
        !           111: {
        !           112:   struct gmp_asprintf_t  d;
        !           113:   GMP_ASPRINTF_T_INIT (d, result);
        !           114:   return __gmp_doprnt (&__gmp_asprintf_funs, &d, fmt, ap);
        !           115: }