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 "common/buffer.h"
  31
  32 #include <sysexits.h>
  33 #include <stdio.h>
  34
  35 char buffer_slop[1];
  36
  37 void
  38 buffer_ensure(buffer_t *buf, int newlen)
  39 {
  40     if (newlen < 0)
  41         exit(EX_SOFTWARE);
  42
  43     if (newlen < buf->size)
  44         return;
  45
  46     if (newlen < buf->offs + buf->size && buf->offs > buf->size / 4)
  47     {
  48         /* Data fits in the current area, shift it left */
  49         memmove(buf->s - buf->offs, buf->s, buf->len + 1);
  50         buf->s    -= buf->offs;
  51         buf->size += buf->offs;
  52         buf->offs  = 0;
  53         return;
  54     }
  55
  56     buf->size = p_alloc_nr(buf->size + buf->offs);
  57     if (buf->size < newlen + 1)
  58         buf->size = newlen + 1;
  59     if (buf->alloced && !buf->offs)
  60         p_realloc(&buf->s, buf->size);
  61     else
  62     {
  63         char *new_area = xmalloc(buf->size);
  64         memcpy(new_area, buf->s, buf->len + 1);
  65         if (buf->alloced)
  66             free(buf->s - buf->offs);
  67         buf->alloced = true;
  68         buf->s = new_area;
  69         buf->offs = 0;
  70     }
  71 }
  72
  73 void
  74 buffer_addvf(buffer_t *buf, const char *fmt, va_list args)
  75 {
  76     int len;
  77     va_list ap;
  78
  79     va_copy(ap, args);
  80     buffer_ensure(buf, BUFSIZ);
  81
  82     len = vsnprintf(buf->s + buf->len, buf->size - buf->len, fmt, args);
  83     if (unlikely(len < 0))
  84         return;
  85     if (len >= buf->size - buf->len)
  86     {
  87         buffer_ensure(buf, len);
  88         vsnprintf(buf->s + buf->len, buf->size - buf->len, fmt, ap);
  89     }
  90     buf->len += len;
  91     buf->s[buf->len] = '\0';
  92 }
  93
  94 void
  95 buffer_addf(buffer_t *buf, const char *fmt, ...)
  96 {
  97     va_list args;
  98     va_start(args, fmt);
  99     buffer_addvf(buf, fmt, args);
 100     va_end(args);
 101 }
 102
 103 /** Detach the data from a buffer.
 104  * \param Buffer from which detach.
 105  * \return The data.
 106  */
 107 char *
 108 buffer_detach(buffer_t *buf)
 109 {
 110     char *res = buf->s;
 111     if (!buf->alloced)
 112         res = a_strdup(buf->s);
 113     buffer_init(buf);
 114     return res;
 115 }