1 /* __gmp_snprintf_funs -- support for gmp_snprintf and gmp_vsnprintf. 2 3 THE FUNCTIONS IN THIS FILE ARE FOR INTERNAL USE ONLY. THEY'RE ALMOST 4 CERTAIN TO BE SUBJECT TO INCOMPATIBLE CHANGES OR DISAPPEAR COMPLETELY IN 5 FUTURE GNU MP RELEASES. 6 7 Copyright 2001, 2002 Free Software Foundation, Inc. 8 9 This file is part of the GNU MP Library. 10 11 The GNU MP Library is free software; you can redistribute it and/or modify 12 it under the terms of the GNU Lesser General Public License as published by 13 the Free Software Foundation; either version 3 of the License, or (at your 14 option) any later version. 15 16 The GNU MP Library is distributed in the hope that it will be useful, but 17 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 18 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 19 License for more details. 20 21 You should have received a copy of the GNU Lesser General Public License 22 along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */ 23 24 #include "config.h" 25 26 #if HAVE_STDARG 27 #include <stdarg.h> 28 #else 29 #include <varargs.h> 30 #endif 31 32 #include <stdio.h> 33 #include <string.h> 34 35 #include "gmp.h" 36 #include "gmp-impl.h" 37 38 39 #if ! HAVE_VSNPRINTF 40 #define vsnprintf __gmp_replacement_vsnprintf 41 #endif 42 43 44 /* glibc 2.0.x vsnprintf returns either -1 or size-1 for an overflow, with 45 no indication how big the output would have been. It's necessary to 46 re-run to determine that size. 47 48 "size-1" would mean sucess from a C99 vsnprintf, and the re-run is 49 unnecessary in this case, but we don't bother to try to detect what sort 50 of vsnprintf we've got. size-1 should occur rarely in normal 51 circumstances. 52 53 vsnprintf might trash it's given ap (it does for instance in glibc 2.1.3 54 on powerpc), so copy it in case we need to use it to probe for the size 55 output that would have been produced. Note there's no need to preserve 56 it for our callers, just for ourselves. */ 57 58 static int 59 gmp_snprintf_format (struct gmp_snprintf_t *d, const char *fmt, 60 va_list orig_ap) 61 { 62 int ret, step, alloc, avail; 63 va_list ap; 64 char *p; 65 66 ASSERT (d->size >= 0); 67 68 avail = d->size; 69 if (avail > 1) 70 { 71 va_copy (ap, orig_ap); 72 ret = vsnprintf (d->buf, avail, fmt, ap); 73 if (ret == -1) 74 { 75 ASSERT (strlen (d->buf) == avail-1); 76 ret = avail-1; 77 } 78 79 step = MIN (ret, avail-1); 80 d->size -= step; 81 d->buf += step; 82 83 if (ret != avail-1) 84 return ret; 85 86 /* probably glibc 2.0.x truncated output, probe for actual size */ 87 alloc = MAX (128, ret); 88 } 89 else 90 { 91 /* no space to write anything, just probe for size */ 92 alloc = 128; 93 } 94 95 do 96 { 97 alloc *= 2; 98 p = __GMP_ALLOCATE_FUNC_TYPE (alloc, char); 99 va_copy (ap, orig_ap); 100 ret = vsnprintf (p, alloc, fmt, ap); 101 (*__gmp_free_func) (p, alloc); 102 } 103 while (ret == alloc-1 || ret == -1); 104 105 return ret; 106 } 107 108 static int 109 gmp_snprintf_memory (struct gmp_snprintf_t *d, const char *str, size_t len) 110 { 111 size_t n; 112 113 ASSERT (d->size >= 0); 114 115 if (d->size > 1) 116 { 117 n = MIN (d->size-1, len); 118 memcpy (d->buf, str, n); 119 d->buf += n; 120 d->size -= n; 121 } 122 return len; 123 } 124 125 static int 126 gmp_snprintf_reps (struct gmp_snprintf_t *d, int c, int reps) 127 { 128 size_t n; 129 130 ASSERT (reps >= 0); 131 ASSERT (d->size >= 0); 132 133 if (d->size > 1) 134 { 135 n = MIN (d->size-1, reps); 136 memset (d->buf, c, n); 137 d->buf += n; 138 d->size -= n; 139 } 140 return reps; 141 } 142 143 static int 144 gmp_snprintf_final (struct gmp_snprintf_t *d) 145 { 146 if (d->size >= 1) 147 d->buf[0] = '\0'; 148 return 0; 149 } 150 151 const struct doprnt_funs_t __gmp_snprintf_funs = { 152 (doprnt_format_t) gmp_snprintf_format, 153 (doprnt_memory_t) gmp_snprintf_memory, 154 (doprnt_reps_t) gmp_snprintf_reps, 155 (doprnt_final_t) gmp_snprintf_final 156 }; 157