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/* the Music Player Daemon (MPD)
* Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
* This project's homepage is: http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "pipe.h"
#include "buffer.h"
#include "chunk.h"
#include <glib.h>
#include <assert.h>
struct music_pipe {
/** the first chunk */
struct music_chunk *head;
/** a pointer to the tail of the chunk */
struct music_chunk **tail_r;
/** the current number of chunks */
unsigned size;
/** a mutex which protects #head and #tail_r */
GMutex *mutex;
};
struct music_pipe *
music_pipe_new(void)
{
struct music_pipe *mp = g_new(struct music_pipe, 1);
mp->head = NULL;
mp->tail_r = &mp->head;
mp->size = 0;
mp->mutex = g_mutex_new();
return mp;
}
void
music_pipe_free(struct music_pipe *mp)
{
assert(mp->head == NULL);
assert(mp->tail_r == &mp->head);
g_mutex_free(mp->mutex);
g_free(mp);
}
const struct music_chunk *
music_pipe_peek(const struct music_pipe *mp)
{
return mp->head;
}
struct music_chunk *
music_pipe_shift(struct music_pipe *mp)
{
struct music_chunk *chunk;
g_mutex_lock(mp->mutex);
chunk = mp->head;
if (chunk != NULL) {
assert(!music_chunk_is_empty(chunk));
mp->head = chunk->next;
--mp->size;
if (mp->head == NULL) {
assert(mp->size == 0);
assert(mp->tail_r == &chunk->next);
mp->tail_r = &mp->head;
} else {
assert(mp->size > 0);
assert(mp->tail_r != &chunk->next);
}
#ifndef NDEBUG
/* poison the "next" reference */
chunk->next = (void*)0x01010101;
#endif
}
g_mutex_unlock(mp->mutex);
return chunk;
}
void
music_pipe_clear(struct music_pipe *mp, struct music_buffer *buffer)
{
struct music_chunk *chunk;
while ((chunk = music_pipe_shift(mp)) != NULL)
music_buffer_return(buffer, chunk);
}
void
music_pipe_push(struct music_pipe *mp, struct music_chunk *chunk)
{
assert(!music_chunk_is_empty(chunk));
g_mutex_lock(mp->mutex);
chunk->next = NULL;
*mp->tail_r = chunk;
mp->tail_r = &chunk->next;
++mp->size;
g_mutex_unlock(mp->mutex);
}
unsigned
music_pipe_size(const struct music_pipe *mp)
{
return mp->size;
}
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