tag_id3: parse ID3 tags in AIFF files

Added a small AIFF parser library, code copied from the RIFF parser
(big-endian integers).  Look for an "ID3" chunk, and let libid3tag
parse it.

src/aiff.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * 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
+ */
+
+/** \file
+ *
+ * A parser for the AIFF file format.
+ */
+
+#ifndef MPD_AIFF_H
+#define MPD_AIFF_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+
+/**
+ * Seeks the AIFF file to the ID3 chunk.
+ *
+ * @return the size of the ID3 chunk on success, or 0 if this is not a
+ * AIFF file or no ID3 chunk was found
+ */
+size_t
+aiff_seek_id3(FILE *file);
+
+#endif