added decoder_control.c

The source "decoder_control.c" provides an API for controlling the
decoder.  This replaces various direct accesses to the DecoderControl
struct.

src/decoder_control.c

@@ -0,0 +1,82 @@
+/* the Music Player Daemon (MPD)
+ * Copyright (C) 2008 Max Kellermann <max@duempel.org>
+ * 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 "decode.h"
+#include "playerData.h"
+
+void dc_command_wait(Notify *notify)
+{
+	while (dc.command != DECODE_COMMAND_NONE) {
+		notify_signal(&dc.notify);
+		notify_wait(notify);
+	}
+}
+
+static void dc_command(Notify *notify, enum decoder_command cmd)
+{
+	dc.command = cmd;
+	dc_command_wait(notify);
+}
+
+static void dc_command_async(enum decoder_command cmd)
+{
+	dc.command = cmd;
+	notify_signal(&dc.notify);
+}
+
+void dc_start(Notify *notify, Song *song)
+{
+	assert(song != NULL);
+
+	dc.next_song = song;
+	dc.error = DECODE_ERROR_NOERROR;
+	dc_command(notify, DECODE_COMMAND_START);
+}
+
+void dc_start_async(Song *song)
+{
+	assert(song != NULL);
+
+	dc.next_song = song;
+	dc.error = DECODE_ERROR_NOERROR;
+	dc_command_async(DECODE_COMMAND_START);
+}
+
+void dc_stop(Notify *notify)
+{
+	if (dc.command == DECODE_COMMAND_START ||
+	    dc.state != DECODE_STATE_STOP)
+		dc_command(notify, DECODE_COMMAND_STOP);
+}
+
+int dc_seek(Notify *notify, double where)
+{
+	assert(where >= 0.0);
+
+	if (dc.state == DECODE_STATE_STOP || !dc.seekable)
+		return -1;
+
+	dc.seekWhere = where;
+	dc.seekError = 0;
+	dc_command(notify, DECODE_COMMAND_SEEK);
+
+	if (dc.seekError)
+		return -1;
+
+	return 0;
+}