/* 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); } 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) { 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); } } 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) { 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; }