common/buffer.c

   1 /*
   2  *  Copyright © 2006,2007,2008 Pierre Habouzit
   3  *
   4  *  Redistribution and use in source and binary forms, with or without
   5  *  modification, are permitted provided that the following conditions
   6  *  are met:
   7  *
   8  *  1. Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  *  2. Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  *  3. The names of its contributors may not be used to endorse or promote
  14  *     products derived from this software without specific prior written
  15  *     permission.
  16  *
  17  *  THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
  18  *  OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  *  WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  *  DISCLAIMED.  IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
  21  *  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  25  *  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  26  *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  27  *  POSSIBILITY OF SUCH DAMAGE.
  28  */
  29
  30 #include <assert.h>
  31 #include <sysexits.h>
  32 #include <stdio.h>
  33
  34 #include "common/buffer.h"
  35
  36 char buffer_slop[1];
  37
  38 void
  39 buffer_ensure(buffer_t *buf, int newlen)
  40 {
  41     if (newlen < 0)
  42         exit(EX_SOFTWARE);
  43
  44     if (newlen < buf->size)
  45         return;
  46
  47     if (newlen < buf->offs + buf->size && buf->offs > buf->size / 4)
  48     {
  49         /* Data fits in the current area, shift it left */
  50         memmove(buf->s - buf->offs, buf->s, buf->len + 1);
  51         buf->s    -= buf->offs;
  52         buf->size += buf->offs;
  53         buf->offs  = 0;
  54         return;
  55     }
  56
  57     buf->size = p_alloc_nr(buf->size + buf->offs);
  58     if (buf->size < newlen + 1)
  59         buf->size = newlen + 1;
  60     if (buf->alloced && !buf->offs)
  61         p_realloc(&buf->s, buf->size);
  62     else
  63     {
  64         char *new_area = xmalloc(buf->size);
  65         memcpy(new_area, buf->s, buf->len + 1);
  66         if (buf->alloced)
  67             free(buf->s - buf->offs);
  68         buf->alloced = true;
  69         buf->s = new_area;
  70         buf->offs = 0;
  71     }
  72 }
  73
  74 void
  75 buffer_addvf(buffer_t *buf, const char *fmt, va_list args)
  76 {
  77     int len;
  78     va_list ap;
  79
  80     va_copy(ap, args);
  81     buffer_ensure(buf, BUFSIZ);
  82
  83     len = vsnprintf(buf->s + buf->len, buf->size - buf->len, fmt, args);
  84     if (unlikely(len < 0))
  85         return;
  86     if (len >= buf->size - buf->len)
  87     {
  88         buffer_ensure(buf, len);
  89         vsnprintf(buf->s + buf->len, buf->size - buf->len, fmt, ap);
  90     }
  91     buf->len += len;
  92     buf->s[buf->len] = '\0';
  93 }
  94
  95 void
  96 buffer_addf(buffer_t *buf, const char *fmt, ...)
  97 {
  98     va_list args;
  99     va_start(args, fmt);
 100     buffer_addvf(buf, fmt, args);
 101     va_end(args);
 102 }
 103
 104 /** Detach the data from a buffer.
 105  * \param Buffer from which detach.
 106  * \return The data.
 107  */
 108 char *
 109 buffer_detach(buffer_t *buf)
 110 {
 111     char *res = buf->s;
 112     if (!buf->alloced)
 113         res = a_strdup(buf->s);
 114     buffer_init(buf);
 115     return res;
 116 }