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 /** @file lib/snprintf.c
  19  * @brief UTF-8 capable *snprintf workalikes
  20  */
  21
  22 #define NO_MEMORY_ALLOCATION
  23 /* because used from log.c */
  24
  25 #include "common.h"
  26
  27 #include <stdarg.h>
  28 #include <stddef.h>
  29
  30 #include "printf.h"
  31 #include "log.h"
  32 #include "sink.h"
  33
  34 /** @brief A @ref sink that stores to a fixed buffer
  35  *
  36  * If there is too much output, it is truncated.
  37  */
  38 struct fixedstr_sink {
  39   /** @brief Base */
  40   struct sink s;
  41
  42   /** @brief Output buffer */
  43   char *buffer;
  44
  45   /** @brief Bytes written so far */
  46   int nbytes;
  47
  48   /** @brief Size of buffer */
  49   size_t size;
  50 };
  51
  52 static int fixedstr_write(struct sink *f, const void *buffer, int nbytes) {
  53   struct fixedstr_sink *s = (struct fixedstr_sink *)f;
  54   int count;
  55
  56   if((size_t)s->nbytes < s->size) {
  57     if((size_t)nbytes > s->size - s->nbytes)
  58       count = s->size - s->nbytes;
  59     else
  60       count = nbytes;
  61     memcpy(s->buffer + s->nbytes, buffer, count);
  62   }
  63   s->nbytes += nbytes;
  64   return 0;
  65 }
  66
  67 int byte_vsnprintf(char buffer[],
  68                    size_t bufsize,
  69                    const char *fmt,
  70                    va_list ap) {
  71   struct fixedstr_sink s;
  72   int n, m;
  73
  74   /* We have to make a sink directly here, since we can't safely do memory
  75    * allocation here (we might be formatting the error message from a failed
  76    * memory allocation) */
  77   s.s.write = fixedstr_write;
  78   s.buffer = buffer;
  79   s.nbytes = 0;
  80   s.size = bufsize;
  81   n = byte_vsinkprintf(&s.s, fmt, ap);
  82   if(bufsize) {
  83     /* add the null terminator (even if the printf failed) */
  84     m = s.nbytes;
  85     if((size_t)m >= bufsize) m = bufsize - 1;
  86     buffer[m] = 0;
  87   }
  88   return n;
  89 }
  90
  91 int byte_snprintf(char buffer[], size_t bufsize, const char *fmt, ...) {
  92   int n;
  93   va_list ap;
  94
  95   va_start(ap, fmt);
  96   n = byte_vsnprintf(buffer, bufsize, fmt, ap);
  97   va_end(ap);
  98   return n;
  99 }
 100
 101 /*
 102 Local Variables:
 103 c-basic-offset:2
 104 comment-column:40
 105 End:
 106 */