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 2 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, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * 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, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20
  21 #define NO_MEMORY_ALLOCATION
  22 /* because used from log.c */
  23
  24 #include "common.h"
  25
  26 #include <stdarg.h>
  27 #include <stddef.h>
  28
  29 #include "printf.h"
  30 #include "sink.h"
  31
  32 struct fixedstr_sink {
  33   struct sink s;
  34   char *buffer;
  35   int nbytes;
  36   size_t size;
  37 };
  38
  39 static int fixedstr_write(struct sink *f, const void *buffer, int nbytes) {
  40   struct fixedstr_sink *s = (struct fixedstr_sink *)f;
  41   int count;
  42
  43   if((size_t)s->nbytes < s->size) {
  44     if((size_t)nbytes > s->size - s->nbytes)
  45       count = s->size - s->nbytes;
  46     else
  47       count = nbytes;
  48     memcpy(s->buffer + s->nbytes, buffer, count);
  49   }
  50   s->nbytes += nbytes;
  51   return 0;
  52 }
  53
  54 int byte_vsnprintf(char buffer[],
  55                    size_t bufsize,
  56                    const char *fmt,
  57                    va_list ap) {
  58   struct fixedstr_sink s;
  59   int n, m;
  60
  61   /* We have to make a sink directly here, since we can't safely do memory
  62    * allocation here (we might be formatting the error message from a failed
  63    * memory allocation) */
  64   s.s.write = fixedstr_write;
  65   s.buffer = buffer;
  66   s.nbytes = 0;
  67   s.size = bufsize;
  68   n = byte_vsinkprintf(&s.s, fmt, ap);
  69   if(bufsize) {
  70     /* add the null terminator (even if the printf failed) */
  71     m = s.nbytes;
  72     if((size_t)m >= bufsize) m = bufsize - 1;
  73     buffer[m] = 0;
  74   }
  75   return n;
  76 }
  77
  78 int byte_snprintf(char buffer[], size_t bufsize, const char *fmt, ...) {
  79   int n;
  80   va_list ap;
  81
  82   va_start(ap, fmt);
  83   n = byte_vsnprintf(buffer, bufsize, fmt, ap);
  84   va_end(ap);
  85   return n;
  86 }
  87
  88 /*
  89 Local Variables:
  90 c-basic-offset:2
  91 comment-column:40
  92 End:
  93 */