src/pcm_buffer.h

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   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,
  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 along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #ifndef PCM_BUFFER_H
  21 #define PCM_BUFFER_H
  22
  23 #include <glib.h>
  24
  25 /**
  26  * Manager for a temporary buffer which grows as needed.  We could
  27  * allocate a new buffer every time pcm_convert() is called, but that
  28  * would put too much stress on the allocator.
  29  */
  30 struct pcm_buffer {
  31         char *buffer;
  32
  33         size_t size;
  34 };
  35
  36 /**
  37  * Initialize the buffer, but don't allocate anything yet.
  38  */
  39 static inline void
  40 pcm_buffer_init(struct pcm_buffer *buffer)
  41 {
  42         buffer->buffer = NULL;
  43         buffer->size = 0;
  44 }
  45
  46 /**
  47  * Free resources.  This function may be called more than once.
  48  */
  49 static inline void
  50 pcm_buffer_deinit(struct pcm_buffer *buffer)
  51 {
  52         g_free(buffer->buffer);
  53
  54         buffer->buffer = NULL;
  55 }
  56
  57 /**
  58  * Get the buffer, and guarantee a minimum size.  This buffer becomes
  59  * invalid with the next pcm_buffer_get() call.
  60  */
  61 static inline void *
  62 pcm_buffer_get(struct pcm_buffer *buffer, size_t size)
  63 {
  64         if (buffer->size < size) {
  65                 /* free the old buffer */
  66                 g_free(buffer->buffer);
  67
  68                 /* allocate a new buffer; align at 64kB boundaries */
  69                 buffer->size = (size | 0xffff) + 1;
  70                 buffer->buffer = g_malloc(buffer->size);
  71         }
  72
  73         return buffer->buffer;
  74 }
  75
  76 #endif