mdw@git.distorted.org.uk Git - disorder/blob - lib/snprintf.c

   1 /*
   2  * This file is part of DisOrder
   3  * Copyright (C) 2004, 2007, 2008 Richard Kettlewell
   4  *
   5  * This program is free software: you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation, either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #define NO_MEMORY_ALLOCATION
  20 /* because used from log.c */
  21
  22 #include "common.h"
  23
  24 #include <stdarg.h>
  25 #include <stddef.h>
  26
  27 #include "printf.h"
  28 #include "sink.h"
  29
  30 struct fixedstr_sink {
  31   struct sink s;
  32   char *buffer;
  33   int nbytes;
  34   size_t size;
  35 };
  36
  37 static int fixedstr_write(struct sink *f, const void *buffer, int nbytes) {
  38   struct fixedstr_sink *s = (struct fixedstr_sink *)f;
  39   int count;
  40
  41   if((size_t)s->nbytes < s->size) {
  42     if((size_t)nbytes > s->size - s->nbytes)
  43       count = s->size - s->nbytes;
  44     else
  45       count = nbytes;
  46     memcpy(s->buffer + s->nbytes, buffer, count);
  47   }
  48   s->nbytes += nbytes;
  49   return 0;
  50 }
  51
  52 int byte_vsnprintf(char buffer[],
  53                    size_t bufsize,
  54                    const char *fmt,
  55                    va_list ap) {
  56   struct fixedstr_sink s;
  57   int n, m;
  58
  59   /* We have to make a sink directly here, since we can't safely do memory
  60    * allocation here (we might be formatting the error message from a failed
  61    * memory allocation) */
  62   s.s.write = fixedstr_write;
  63   s.buffer = buffer;
  64   s.nbytes = 0;
  65   s.size = bufsize;
  66   n = byte_vsinkprintf(&s.s, fmt, ap);
  67   if(bufsize) {
  68     /* add the null terminator (even if the printf failed) */
  69     m = s.nbytes;
  70     if((size_t)m >= bufsize) m = bufsize - 1;
  71     buffer[m] = 0;
  72   }
  73   return n;
  74 }
  75
  76 int byte_snprintf(char buffer[], size_t bufsize, const char *fmt, ...) {
  77   int n;
  78   va_list ap;
  79
  80   va_start(ap, fmt);
  81   n = byte_vsnprintf(buffer, bufsize, fmt, ap);
  82   va_end(ap);
  83   return n;
  84 }
  85
  86 /*
  87 Local Variables:
  88 c-basic-offset:2
  89 comment-column:40
  90 End:
  91 */