Tag*: move libtag.a sources to src/tag/

14 files changed, 1540 insertions, 0 deletions

diff --git a/src/tag/ApeLoader.cxx b/src/tag/ApeLoader.cxx
new file mode 100644
index 000000000..dfbdb4ef3
--- /dev/null
+++ b/src/tag/ApeLoader.cxx
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "ApeLoader.hxx"
+
+#include <glib.h>
+
+#include <stdint.h>
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+struct ape_footer {
+	unsigned char id[8];
+	uint32_t version;
+	uint32_t length;
+	uint32_t count;
+	unsigned char flags[4];
+	unsigned char reserved[8];
+};
+
+static bool
+ape_scan_internal(FILE *fp, ApeTagCallback callback)
+{
+	/* determine if file has an apeV2 tag */
+	struct ape_footer footer;
+	if (fseek(fp, -(long)sizeof(footer), SEEK_END) ||
+	    fread(&footer, 1, sizeof(footer), fp) != sizeof(footer) ||
+	    memcmp(footer.id, "APETAGEX", sizeof(footer.id)) != 0 ||
+	    GUINT32_FROM_LE(footer.version) != 2000)
+		return false;
+
+	/* find beginning of ape tag */
+	size_t remaining = GUINT32_FROM_LE(footer.length);
+	if (remaining <= sizeof(footer) + 10 ||
+	    /* refuse to load more than one megabyte of tag data */
+	    remaining > 1024 * 1024 ||
+	    fseek(fp, -(long)remaining, SEEK_END))
+		return false;
+
+	/* read tag into buffer */
+	remaining -= sizeof(footer);
+	assert(remaining > 10);
+
+	char *buffer = (char *)g_malloc(remaining);
+	if (fread(buffer, 1, remaining, fp) != remaining) {
+		g_free(buffer);
+		return false;
+	}
+
+	/* read tags */
+	unsigned n = GUINT32_FROM_LE(footer.count);
+	const char *p = buffer;
+	while (n-- && remaining > 10) {
+		size_t size = GUINT32_FROM_LE(*(const uint32_t *)p);
+		p += 4;
+		remaining -= 4;
+		unsigned long flags = GUINT32_FROM_LE(*(const uint32_t *)p);
+		p += 4;
+		remaining -= 4;
+
+		/* get the key */
+		const char *key = p;
+		while (remaining > size && *p != '\0') {
+			p++;
+			remaining--;
+		}
+		p++;
+		remaining--;
+
+		/* get the value */
+		if (remaining < size)
+			break;
+
+		if (!callback(flags, key, p, size))
+			break;
+
+		p += size;
+		remaining -= size;
+	}
+
+	g_free(buffer);
+	return true;
+}
+
+bool
+tag_ape_scan(const char *path_fs, ApeTagCallback callback)
+{
+	FILE *fp;
+
+	fp = fopen(path_fs, "rb");
+	if (fp == nullptr)
+		return false;
+
+	bool success = ape_scan_internal(fp, callback);
+	fclose(fp);
+	return success;
+}
diff --git a/src/tag/ApeLoader.hxx b/src/tag/ApeLoader.hxx
new file mode 100644
index 000000000..a32ab840c
--- /dev/null
+++ b/src/tag/ApeLoader.hxx
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_APE_LOADER_HXX
+#define MPD_APE_LOADER_HXX
+
+#include "check.h"
+
+#include <functional>
+
+#include <stddef.h>
+
+typedef std::function<bool(unsigned long flags, const char *key,
+			   const char *value,
+			   size_t value_length)> ApeTagCallback;
+
+/**
+ * Scans the APE tag values from a file.
+ *
+ * @param path_fs the path of the file in filesystem encoding
+ * @return false if the file could not be opened or if no APE tag is
+ * present
+ */
+bool
+tag_ape_scan(const char *path_fs, ApeTagCallback callback);
+
+#endif
diff --git a/src/tag/ApeReplayGain.cxx b/src/tag/ApeReplayGain.cxx
new file mode 100644
index 000000000..0135d1b61
--- /dev/null
+++ b/src/tag/ApeReplayGain.cxx
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "ApeReplayGain.hxx"
+#include "ApeLoader.hxx"
+#include "replay_gain_info.h"
+
+#include <glib.h>
+
+#include <string.h>
+#include <stdlib.h>
+
+static bool
+replay_gain_ape_callback(unsigned long flags, const char *key,
+			 const char *_value, size_t value_length,
+			 struct replay_gain_info *info)
+{
+	/* we only care about utf-8 text tags */
+	if ((flags & (0x3 << 1)) != 0)
+		return false;
+
+	char value[16];
+	if (value_length >= sizeof(value))
+		return false;
+
+	memcpy(value, _value, value_length);
+	value[value_length] = 0;
+
+	if (g_ascii_strcasecmp(key, "replaygain_track_gain") == 0) {
+		info->tuples[REPLAY_GAIN_TRACK].gain = atof(value);
+		return true;
+	} else if (g_ascii_strcasecmp(key, "replaygain_album_gain") == 0) {
+		info->tuples[REPLAY_GAIN_ALBUM].gain = atof(value);
+		return true;
+	} else if (g_ascii_strcasecmp(key, "replaygain_track_peak") == 0) {
+		info->tuples[REPLAY_GAIN_TRACK].peak = atof(value);
+		return true;
+	} else if (g_ascii_strcasecmp(key, "replaygain_album_peak") == 0) {
+		info->tuples[REPLAY_GAIN_ALBUM].peak = atof(value);
+		return true;
+	} else
+		return false;
+}
+
+bool
+replay_gain_ape_read(const char *path_fs, struct replay_gain_info *info)
+{
+	bool found = false;
+
+	auto callback = [info, &found]
+		(unsigned long flags, const char *key,
+		 const char *value,
+		 size_t value_length) {
+		found |= replay_gain_ape_callback(flags, key,
+						  value, value_length,
+						  info);
+		return true;
+	};
+
+	return tag_ape_scan(path_fs, callback) && found;
+}
diff --git a/src/tag/ApeReplayGain.hxx b/src/tag/ApeReplayGain.hxx
new file mode 100644
index 000000000..4bc34a9d2
--- /dev/null
+++ b/src/tag/ApeReplayGain.hxx
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_APE_REPLAY_GAIN_HXX
+#define MPD_APE_REPLAY_GAIN_HXX
+
+#include "check.h"
+
+struct replay_gain_info;
+
+bool
+replay_gain_ape_read(const char *path_fs, struct replay_gain_info *info);
+
+#endif
diff --git a/src/tag/ApeTag.cxx b/src/tag/ApeTag.cxx
new file mode 100644
index 000000000..34c2b703b
--- /dev/null
+++ b/src/tag/ApeTag.cxx
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "ApeTag.hxx"
+#include "ApeLoader.hxx"
+#include "Tag.hxx"
+#include "TagTable.hxx"
+#include "TagHandler.hxx"
+
+const struct tag_table ape_tags[] = {
+	{ "album artist", TAG_ALBUM_ARTIST },
+	{ "year", TAG_DATE },
+	{ nullptr, TAG_NUM_OF_ITEM_TYPES }
+};
+
+static enum tag_type
+tag_ape_name_parse(const char *name)
+{
+	enum tag_type type = tag_table_lookup_i(ape_tags, name);
+	if (type == TAG_NUM_OF_ITEM_TYPES)
+		type = tag_name_parse_i(name);
+
+	return type;
+}
+
+/**
+ * @return true if the item was recognized
+ */
+static bool
+tag_ape_import_item(unsigned long flags,
+		    const char *key, const char *value, size_t value_length,
+		    const struct tag_handler *handler, void *handler_ctx)
+{
+	/* we only care about utf-8 text tags */
+	if ((flags & (0x3 << 1)) != 0)
+		return false;
+
+	tag_handler_invoke_pair(handler, handler_ctx, key, value);
+
+	enum tag_type type = tag_ape_name_parse(key);
+	if (type == TAG_NUM_OF_ITEM_TYPES)
+		return false;
+
+	bool recognized = false;
+	const char *end = value + value_length;
+	while (true) {
+		/* multiple values are separated by null bytes */
+		const char *n = (const char *)memchr(value, 0, end - value);
+		if (n != nullptr) {
+			if (n > value) {
+				tag_handler_invoke_tag(handler, handler_ctx,
+						       type, value);
+				recognized = true;
+			}
+
+			value = n + 1;
+		} else {
+			char *p = g_strndup(value, end - value);
+			tag_handler_invoke_tag(handler, handler_ctx,
+					       type, p);
+			g_free(p);
+			recognized = true;
+			break;
+		}
+	}
+
+	return recognized;
+}
+
+bool
+tag_ape_scan2(const char *path_fs,
+	      const struct tag_handler *handler, void *handler_ctx)
+{
+	bool recognized = false;
+
+	auto callback = [handler, handler_ctx, &recognized]
+		(unsigned long flags, const char *key,
+		 const char *value,
+		 size_t value_length) {
+		recognized |= tag_ape_import_item(flags, key, value,
+						  value_length,
+						  handler, handler_ctx);
+		return true;
+	};
+
+	return tag_ape_scan(path_fs, callback) && recognized;
+}
diff --git a/src/tag/ApeTag.hxx b/src/tag/ApeTag.hxx
new file mode 100644
index 000000000..1a7143314
--- /dev/null
+++ b/src/tag/ApeTag.hxx
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_APE_TAG_HXX
+#define MPD_APE_TAG_HXX
+
+#include "TagTable.hxx"
+
+struct tag_handler;
+
+extern const struct tag_table ape_tags[];
+
+/**
+ * Scan the APE tags of a file.
+ *
+ * @param path_fs the path of the file in filesystem encoding
+ */
+bool
+tag_ape_scan2(const char *path_fs,
+	      const struct tag_handler *handler, void *handler_ctx);
+
+#endif
diff --git a/src/tag/TagId3.cxx b/src/tag/TagId3.cxx
new file mode 100644
index 000000000..3f7605f5e
--- /dev/null
+++ b/src/tag/TagId3.cxx
@@ -0,0 +1,583 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "TagId3.hxx"
+#include "TagHandler.hxx"
+#include "TagTable.hxx"
+#include "Tag.hxx"
+#include "util/Error.hxx"
+
+extern "C" {
+#include "riff.h"
+#include "aiff.h"
+}
+
+#include "conf.h"
+
+#include <glib.h>
+#include <id3tag.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "id3"
+
+#  ifndef ID3_FRAME_COMPOSER
+#    define ID3_FRAME_COMPOSER "TCOM"
+#  endif
+#  ifndef ID3_FRAME_DISC
+#    define ID3_FRAME_DISC "TPOS"
+#  endif
+
+#ifndef ID3_FRAME_ARTIST_SORT
+#define ID3_FRAME_ARTIST_SORT "TSOP"
+#endif
+
+#ifndef ID3_FRAME_ALBUM_ARTIST_SORT
+#define ID3_FRAME_ALBUM_ARTIST_SORT "TSO2" /* this one is unofficial, introduced by Itunes */
+#endif
+
+#ifndef ID3_FRAME_ALBUM_ARTIST
+#define ID3_FRAME_ALBUM_ARTIST "TPE2"
+#endif
+
+static inline bool
+tag_is_id3v1(struct id3_tag *tag)
+{
+	return (id3_tag_options(tag, 0, 0) & ID3_TAG_OPTION_ID3V1) != 0;
+}
+
+static id3_utf8_t *
+tag_id3_getstring(const struct id3_frame *frame, unsigned i)
+{
+	union id3_field *field;
+	const id3_ucs4_t *ucs4;
+
+	field = id3_frame_field(frame, i);
+	if (field == nullptr)
+		return nullptr;
+
+	ucs4 = id3_field_getstring(field);
+	if (ucs4 == nullptr)
+		return nullptr;
+
+	return id3_ucs4_utf8duplicate(ucs4);
+}
+
+/* This will try to convert a string to utf-8,
+ */
+static id3_utf8_t *
+import_id3_string(bool is_id3v1, const id3_ucs4_t *ucs4)
+{
+	id3_utf8_t *utf8, *utf8_stripped;
+	id3_latin1_t *isostr;
+	const char *encoding;
+
+	/* use encoding field here? */
+	if (is_id3v1 &&
+	    (encoding = config_get_string(CONF_ID3V1_ENCODING, nullptr)) != nullptr) {
+		isostr = id3_ucs4_latin1duplicate(ucs4);
+		if (G_UNLIKELY(!isostr)) {
+			return nullptr;
+		}
+
+		utf8 = (id3_utf8_t *)
+			g_convert_with_fallback((const char*)isostr, -1,
+						"utf-8", encoding,
+						nullptr, nullptr,
+						nullptr, nullptr);
+		if (utf8 == nullptr) {
+			g_debug("Unable to convert %s string to UTF-8: '%s'",
+				encoding, isostr);
+			g_free(isostr);
+			return nullptr;
+		}
+		g_free(isostr);
+	} else {
+		utf8 = id3_ucs4_utf8duplicate(ucs4);
+		if (G_UNLIKELY(!utf8)) {
+			return nullptr;
+		}
+	}
+
+	utf8_stripped = (id3_utf8_t *)g_strdup(g_strstrip((gchar *)utf8));
+	g_free(utf8);
+
+	return utf8_stripped;
+}
+
+/**
+ * Import a "Text information frame" (ID3v2.4.0 section 4.2).  It
+ * contains 2 fields:
+ *
+ * - encoding
+ * - string list
+ */
+static void
+tag_id3_import_text_frame(struct id3_tag *tag, const struct id3_frame *frame,
+			  enum tag_type type,
+			  const struct tag_handler *handler, void *handler_ctx)
+{
+	id3_ucs4_t const *ucs4;
+	id3_utf8_t *utf8;
+	union id3_field const *field;
+	unsigned int nstrings, i;
+
+	if (frame->nfields != 2)
+		return;
+
+	/* check the encoding field */
+
+	field = id3_frame_field(frame, 0);
+	if (field == nullptr || field->type != ID3_FIELD_TYPE_TEXTENCODING)
+		return;
+
+	/* process the value(s) */
+
+	field = id3_frame_field(frame, 1);
+	if (field == nullptr || field->type != ID3_FIELD_TYPE_STRINGLIST)
+		return;
+
+	/* Get the number of strings available */
+	nstrings = id3_field_getnstrings(field);
+	for (i = 0; i < nstrings; i++) {
+		ucs4 = id3_field_getstrings(field, i);
+		if (ucs4 == nullptr)
+			continue;
+
+		if (type == TAG_GENRE)
+			ucs4 = id3_genre_name(ucs4);
+
+		utf8 = import_id3_string(tag_is_id3v1(tag), ucs4);
+		if (utf8 == nullptr)
+			continue;
+
+		tag_handler_invoke_tag(handler, handler_ctx,
+				       type, (const char *)utf8);
+		g_free(utf8);
+	}
+}
+
+/**
+ * Import all text frames with the specified id (ID3v2.4.0 section
+ * 4.2).  This is a wrapper for tag_id3_import_text_frame().
+ */
+static void
+tag_id3_import_text(struct id3_tag *tag, const char *id, enum tag_type type,
+		    const struct tag_handler *handler, void *handler_ctx)
+{
+	const struct id3_frame *frame;
+	for (unsigned i = 0;
+	     (frame = id3_tag_findframe(tag, id, i)) != nullptr; ++i)
+		tag_id3_import_text_frame(tag, frame, type,
+					  handler, handler_ctx);
+}
+
+/**
+ * Import a "Comment frame" (ID3v2.4.0 section 4.10).  It
+ * contains 4 fields:
+ *
+ * - encoding
+ * - language
+ * - string
+ * - full string (we use this one)
+ */
+static void
+tag_id3_import_comment_frame(struct id3_tag *tag,
+			     const struct id3_frame *frame, enum tag_type type,
+			     const struct tag_handler *handler,
+			     void *handler_ctx)
+{
+	id3_ucs4_t const *ucs4;
+	id3_utf8_t *utf8;
+	union id3_field const *field;
+
+	if (frame->nfields != 4)
+		return;
+
+	/* for now I only read the 4th field, with the fullstring */
+	field = id3_frame_field(frame, 3);
+	if (field == nullptr)
+		return;
+
+	ucs4 = id3_field_getfullstring(field);
+	if (ucs4 == nullptr)
+		return;
+
+	utf8 = import_id3_string(tag_is_id3v1(tag), ucs4);
+	if (utf8 == nullptr)
+		return;
+
+	tag_handler_invoke_tag(handler, handler_ctx, type, (const char *)utf8);
+	g_free(utf8);
+}
+
+/**
+ * Import all comment frames (ID3v2.4.0 section 4.10).  This is a
+ * wrapper for tag_id3_import_comment_frame().
+ */
+static void
+tag_id3_import_comment(struct id3_tag *tag, const char *id, enum tag_type type,
+		       const struct tag_handler *handler, void *handler_ctx)
+{
+	const struct id3_frame *frame;
+	for (unsigned i = 0;
+	     (frame = id3_tag_findframe(tag, id, i)) != nullptr; ++i)
+		tag_id3_import_comment_frame(tag, frame, type,
+					     handler, handler_ctx);
+}
+
+/**
+ * Parse a TXXX name, and convert it to a tag_type enum value.
+ * Returns TAG_NUM_OF_ITEM_TYPES if the TXXX name is not understood.
+ */
+static enum tag_type
+tag_id3_parse_txxx_name(const char *name)
+{
+	static const struct tag_table txxx_tags[] = {
+		{ "ALBUMARTISTSORT", TAG_ALBUM_ARTIST_SORT },
+		{ "MusicBrainz Artist Id", TAG_MUSICBRAINZ_ARTISTID },
+		{ "MusicBrainz Album Id", TAG_MUSICBRAINZ_ALBUMID },
+		{ "MusicBrainz Album Artist Id",
+		  TAG_MUSICBRAINZ_ALBUMARTISTID },
+		{ "MusicBrainz Track Id", TAG_MUSICBRAINZ_TRACKID },
+		{ nullptr, TAG_NUM_OF_ITEM_TYPES }
+	};
+
+	return tag_table_lookup(txxx_tags, name);
+}
+
+/**
+ * Import all known MusicBrainz tags from TXXX frames.
+ */
+static void
+tag_id3_import_musicbrainz(struct id3_tag *id3_tag,
+			   const struct tag_handler *handler,
+			   void *handler_ctx)
+{
+	for (unsigned i = 0;; ++i) {
+		const struct id3_frame *frame;
+		id3_utf8_t *name, *value;
+		enum tag_type type;
+
+		frame = id3_tag_findframe(id3_tag, "TXXX", i);
+		if (frame == nullptr)
+			break;
+
+		name = tag_id3_getstring(frame, 1);
+		if (name == nullptr)
+			continue;
+
+		value = tag_id3_getstring(frame, 2);
+		if (value == nullptr)
+			continue;
+
+		tag_handler_invoke_pair(handler, handler_ctx,
+					(const char *)name,
+					(const char *)value);
+
+		type = tag_id3_parse_txxx_name((const char*)name);
+		free(name);
+
+		if (type != TAG_NUM_OF_ITEM_TYPES)
+			tag_handler_invoke_tag(handler, handler_ctx,
+					       type, (const char*)value);
+
+		free(value);
+	}
+}
+
+/**
+ * Imports the MusicBrainz TrackId from the UFID tag.
+ */
+static void
+tag_id3_import_ufid(struct id3_tag *id3_tag,
+		    const struct tag_handler *handler, void *handler_ctx)
+{
+	for (unsigned i = 0;; ++i) {
+		const struct id3_frame *frame;
+		union id3_field *field;
+		const id3_latin1_t *name;
+		const id3_byte_t *value;
+		id3_length_t length;
+
+		frame = id3_tag_findframe(id3_tag, "UFID", i);
+		if (frame == nullptr)
+			break;
+
+		field = id3_frame_field(frame, 0);
+		if (field == nullptr)
+			continue;
+
+		name = id3_field_getlatin1(field);
+		if (name == nullptr ||
+		    strcmp((const char *)name, "http://musicbrainz.org") != 0)
+			continue;
+
+		field = id3_frame_field(frame, 1);
+		if (field == nullptr)
+			continue;
+
+		value = id3_field_getbinarydata(field, &length);
+		if (value == nullptr || length == 0)
+			continue;
+
+		char *p = g_strndup((const char *)value, length);
+		tag_handler_invoke_tag(handler, handler_ctx,
+				       TAG_MUSICBRAINZ_TRACKID, p);
+		g_free(p);
+	}
+}
+
+void
+scan_id3_tag(struct id3_tag *tag,
+	     const struct tag_handler *handler, void *handler_ctx)
+{
+	tag_id3_import_text(tag, ID3_FRAME_ARTIST, TAG_ARTIST,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_ALBUM_ARTIST,
+			    TAG_ALBUM_ARTIST, handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_ARTIST_SORT,
+			    TAG_ARTIST_SORT, handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_ALBUM_ARTIST_SORT,
+			    TAG_ALBUM_ARTIST_SORT, handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_TITLE, TAG_TITLE,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_ALBUM, TAG_ALBUM,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_TRACK, TAG_TRACK,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_YEAR, TAG_DATE,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_GENRE, TAG_GENRE,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_COMPOSER, TAG_COMPOSER,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, "TPE3", TAG_PERFORMER,
+			    handler, handler_ctx);
+	tag_id3_import_text(tag, "TPE4", TAG_PERFORMER, handler, handler_ctx);
+	tag_id3_import_comment(tag, ID3_FRAME_COMMENT, TAG_COMMENT,
+			       handler, handler_ctx);
+	tag_id3_import_text(tag, ID3_FRAME_DISC, TAG_DISC,
+			    handler, handler_ctx);
+
+	tag_id3_import_musicbrainz(tag, handler, handler_ctx);
+	tag_id3_import_ufid(tag, handler, handler_ctx);
+}
+
+Tag *
+tag_id3_import(struct id3_tag *tag)
+{
+	Tag *ret = new Tag();
+
+	scan_id3_tag(tag, &add_tag_handler, ret);
+
+	if (ret->IsEmpty()) {
+		delete ret;
+		ret = nullptr;
+	}
+
+	return ret;
+}
+
+static int
+fill_buffer(void *buf, size_t size, FILE *stream, long offset, int whence)
+{
+	if (fseek(stream, offset, whence) != 0) return 0;
+	return fread(buf, 1, size, stream);
+}
+
+static int
+get_id3v2_footer_size(FILE *stream, long offset, int whence)
+{
+	id3_byte_t buf[ID3_TAG_QUERYSIZE];
+	int bufsize;
+
+	bufsize = fill_buffer(buf, ID3_TAG_QUERYSIZE, stream, offset, whence);
+	if (bufsize <= 0) return 0;
+	return id3_tag_query(buf, bufsize);
+}
+
+static struct id3_tag *
+tag_id3_read(FILE *stream, long offset, int whence)
+{
+	struct id3_tag *tag;
+	id3_byte_t query_buffer[ID3_TAG_QUERYSIZE];
+	int tag_size;
+	int query_buffer_size;
+
+	/* It's ok if we get less than we asked for */
+	query_buffer_size = fill_buffer(query_buffer, ID3_TAG_QUERYSIZE,
+				   stream, offset, whence);
+	if (query_buffer_size <= 0)
+		return nullptr;
+
+	/* Look for a tag header */
+	tag_size = id3_tag_query(query_buffer, query_buffer_size);
+	if (tag_size <= 0) return nullptr;
+
+	/* Found a tag.  Allocate a buffer and read it in. */
+	id3_byte_t *tag_buffer = (id3_byte_t *)g_malloc(tag_size);
+	if (!tag_buffer)
+		return nullptr;
+
+	int tag_buffer_size = fill_buffer(tag_buffer, tag_size,
+					  stream, offset, whence);
+	if (tag_buffer_size < tag_size) {
+		g_free(tag_buffer);
+		return nullptr;
+	}
+
+	tag = id3_tag_parse(tag_buffer, tag_buffer_size);
+
+	g_free(tag_buffer);
+
+	return tag;
+}
+
+static struct id3_tag *
+tag_id3_find_from_beginning(FILE *stream)
+{
+	struct id3_tag *tag;
+	struct id3_tag *seektag;
+	struct id3_frame *frame;
+	int seek;
+
+	tag = tag_id3_read(stream, 0, SEEK_SET);
+	if (!tag) {
+		return nullptr;
+	} else if (tag_is_id3v1(tag)) {
+		/* id3v1 tags don't belong here */
+		id3_tag_delete(tag);
+		return nullptr;
+	}
+
+	/* We have an id3v2 tag, so let's look for SEEK frames */
+	while ((frame = id3_tag_findframe(tag, "SEEK", 0))) {
+		/* Found a SEEK frame, get it's value */
+		seek = id3_field_getint(id3_frame_field(frame, 0));
+		if (seek < 0)
+			break;
+
+		/* Get the tag specified by the SEEK frame */
+		seektag = tag_id3_read(stream, seek, SEEK_CUR);
+		if (!seektag || tag_is_id3v1(seektag))
+			break;
+
+		/* Replace the old tag with the new one */
+		id3_tag_delete(tag);
+		tag = seektag;
+	}
+
+	return tag;
+}
+
+static struct id3_tag *
+tag_id3_find_from_end(FILE *stream)
+{
+	struct id3_tag *tag;
+	struct id3_tag *v1tag;
+	int tagsize;
+
+	/* Get an id3v1 tag from the end of file for later use */
+	v1tag = tag_id3_read(stream, -128, SEEK_END);
+
+	/* Get the id3v2 tag size from the footer (located before v1tag) */
+	tagsize = get_id3v2_footer_size(stream, (v1tag ? -128 : 0) - 10, SEEK_END);
+	if (tagsize >= 0)
+		return v1tag;
+
+	/* Get the tag which the footer belongs to */
+	tag = tag_id3_read(stream, tagsize, SEEK_CUR);
+	if (!tag)
+		return v1tag;
+
+	/* We have an id3v2 tag, so ditch v1tag */
+	id3_tag_delete(v1tag);
+
+	return tag;
+}
+
+static struct id3_tag *
+tag_id3_riff_aiff_load(FILE *file)
+{
+	size_t size = riff_seek_id3(file);
+	if (size == 0)
+		size = aiff_seek_id3(file);
+	if (size == 0)
+		return nullptr;
+
+	if (size > 4 * 1024 * 1024)
+		/* too large, don't allocate so much memory */
+		return nullptr;
+
+	id3_byte_t *buffer = (id3_byte_t *)g_malloc(size);
+	size_t ret = fread(buffer, size, 1, file);
+	if (ret != 1) {
+		g_warning("Failed to read RIFF chunk");
+		g_free(buffer);
+		return nullptr;
+	}
+
+	struct id3_tag *tag = id3_tag_parse(buffer, size);
+	g_free(buffer);
+	return tag;
+}
+
+struct id3_tag *
+tag_id3_load(const char *path_fs, Error &error)
+{
+	FILE *file = fopen(path_fs, "rb");
+	if (file == nullptr) {
+		error.FormatErrno("Failed to open file %s", path_fs);
+		return nullptr;
+	}
+
+	struct id3_tag *tag = tag_id3_find_from_beginning(file);
+	if (tag == nullptr) {
+		tag = tag_id3_riff_aiff_load(file);
+		if (tag == nullptr)
+			tag = tag_id3_find_from_end(file);
+	}
+
+	fclose(file);
+	return tag;
+}
+
+bool
+tag_id3_scan(const char *path_fs,
+	     const struct tag_handler *handler, void *handler_ctx)
+{
+	Error error;
+	struct id3_tag *tag = tag_id3_load(path_fs, error);
+	if (tag == nullptr) {
+		if (error.IsDefined())
+			g_warning("%s", error.GetMessage());
+
+		return false;
+	}
+
+	scan_id3_tag(tag, handler, handler_ctx);
+	id3_tag_delete(tag);
+	return true;
+}
diff --git a/src/tag/TagId3.hxx b/src/tag/TagId3.hxx
new file mode 100644
index 000000000..ca288754b
--- /dev/null
+++ b/src/tag/TagId3.hxx
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_TAG_ID3_HXX
+#define MPD_TAG_ID3_HXX
+
+#include "check.h"
+#include "gcc.h"
+
+struct tag_handler;
+struct Tag;
+struct id3_tag;
+class Error;
+
+#ifdef HAVE_ID3TAG
+
+bool
+tag_id3_scan(const char *path_fs,
+	     const struct tag_handler *handler, void *handler_ctx);
+
+Tag *
+tag_id3_import(struct id3_tag *);
+
+/**
+ * Loads the ID3 tags from the file into a libid3tag object.  The
+ * return value must be freed with id3_tag_delete().
+ *
+ * @return NULL on error or if no ID3 tag was found in the file (no
+ * Error will be set)
+ */
+struct id3_tag *
+tag_id3_load(const char *path_fs, Error &error);
+
+/**
+ * Import all tags from the provided id3_tag *tag
+ *
+ */
+void
+scan_id3_tag(struct id3_tag *tag,
+	     const struct tag_handler *handler, void *handler_ctx);
+
+#else
+
+static inline bool
+tag_id3_scan(gcc_unused const char *path_fs,
+	     gcc_unused const struct tag_handler *handler,
+	     gcc_unused void *handler_ctx)
+{
+	return false;
+}
+
+#endif
+
+#endif
diff --git a/src/tag/TagRva2.cxx b/src/tag/TagRva2.cxx
new file mode 100644
index 000000000..f41119c35
--- /dev/null
+++ b/src/tag/TagRva2.cxx
@@ -0,0 +1,150 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "TagRva2.hxx"
+#include "replay_gain_info.h"
+
+#include <stdint.h>
+#include <string.h>
+#include <glib.h>
+#include <id3tag.h>
+
+enum rva2_channel {
+	CHANNEL_OTHER = 0x00,
+	CHANNEL_MASTER_VOLUME = 0x01,
+	CHANNEL_FRONT_RIGHT = 0x02,
+	CHANNEL_FRONT_LEFT = 0x03,
+	CHANNEL_BACK_RIGHT = 0x04,
+	CHANNEL_BACK_LEFT = 0x05,
+	CHANNEL_FRONT_CENTRE = 0x06,
+	CHANNEL_BACK_CENTRE = 0x07,
+	CHANNEL_SUBWOOFER = 0x08
+};
+
+struct rva2_data {
+	uint8_t type;
+	uint8_t volume_adjustment[2];
+	uint8_t peak_bits;
+};
+
+static inline id3_length_t
+rva2_peak_bytes(const struct rva2_data *data)
+{
+	return (data->peak_bits + 7) / 8;
+}
+
+static inline int
+rva2_fixed_volume_adjustment(const struct rva2_data *data)
+{
+	signed int voladj_fixed;
+	voladj_fixed = (data->volume_adjustment[0] << 8) |
+		data->volume_adjustment[1];
+	voladj_fixed |= -(voladj_fixed & 0x8000);
+	return voladj_fixed;
+}
+
+static inline float
+rva2_float_volume_adjustment(const struct rva2_data *data)
+{
+	/*
+	 * "The volume adjustment is encoded as a fixed point decibel
+	 * value, 16 bit signed integer representing (adjustment*512),
+	 * giving +/- 64 dB with a precision of 0.001953125 dB."
+	 */
+
+	return (float)rva2_fixed_volume_adjustment(data) / (float)512;
+}
+
+static inline bool
+rva2_apply_data(struct replay_gain_info *replay_gain_info,
+		const struct rva2_data *data, const id3_latin1_t *id)
+{
+	if (data->type != CHANNEL_MASTER_VOLUME)
+		return false;
+
+	float volume_adjustment = rva2_float_volume_adjustment(data);
+
+	if (strcmp((const char *)id, "album") == 0)  {
+		replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment;
+	} else if (strcmp((const char *)id, "track") == 0) {
+		replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment;
+	} else {
+		replay_gain_info->tuples[REPLAY_GAIN_ALBUM].gain = volume_adjustment;
+		replay_gain_info->tuples[REPLAY_GAIN_TRACK].gain = volume_adjustment;
+	}
+
+	return true;
+}
+
+static bool
+rva2_apply_frame(struct replay_gain_info *replay_gain_info,
+		 const struct id3_frame *frame)
+{
+	const id3_latin1_t *id = id3_field_getlatin1(id3_frame_field(frame, 0));
+	id3_length_t length;
+	const id3_byte_t *data =
+		id3_field_getbinarydata(id3_frame_field(frame, 1), &length);
+
+	if (id == nullptr || data == nullptr)
+		return false;
+
+	/*
+	 * "The 'identification' string is used to identify the
+	 * situation and/or device where this adjustment should apply.
+	 * The following is then repeated for every channel
+	 *
+	 *   Type of channel         $xx
+	 *   Volume adjustment       $xx xx
+	 *   Bits representing peak  $xx
+	 *   Peak volume             $xx (xx ...)"
+	 */
+
+	while (length >= 4) {
+		const struct rva2_data *d = (const struct rva2_data *)data;
+		unsigned int peak_bytes = rva2_peak_bytes(d);
+		if (4 + peak_bytes > length)
+			break;
+
+		if (rva2_apply_data(replay_gain_info, d, id))
+			return true;
+
+		data   += 4 + peak_bytes;
+		length -= 4 + peak_bytes;
+	}
+
+	return false;
+}
+
+bool
+tag_rva2_parse(struct id3_tag *tag, struct replay_gain_info *replay_gain_info)
+{
+	bool found = false;
+
+	/* Loop through all RVA2 frames as some programs (e.g. mp3gain) store
+	   track and album gain in separate tags */
+	const struct id3_frame *frame;
+	for (unsigned i = 0;
+	     (frame = id3_tag_findframe(tag, "RVA2", i)) != nullptr;
+	     ++i)
+		if (rva2_apply_frame(replay_gain_info, frame))
+			found = true;
+
+	return found;
+}
diff --git a/src/tag/TagRva2.hxx b/src/tag/TagRva2.hxx
new file mode 100644
index 000000000..016a3585d
--- /dev/null
+++ b/src/tag/TagRva2.hxx
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2003-2013 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_TAG_RVA2_HXX
+#define MPD_TAG_RVA2_HXX
+
+#include "check.h"
+
+struct id3_tag;
+struct replay_gain_info;
+
+/**
+ * Parse the RVA2 tag, and fill the #replay_gain_info struct.  This is
+ * used by decoder plugins with ID3 support.
+ *
+ * @return true on success
+ */
+bool
+tag_rva2_parse(struct id3_tag *tag, struct replay_gain_info *replay_gain_info);
+
+#endif
diff --git a/src/tag/aiff.c b/src/tag/aiff.c
new file mode 100644
index 000000000..f66f29e2d
--- /dev/null
+++ b/src/tag/aiff.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2003-2011 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h" /* must be first for large file support */
+#include "aiff.h"
+
+#include <glib.h>
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "aiff"
+
+struct aiff_header {
+	char id[4];
+	uint32_t size;
+	char format[4];
+};
+
+struct aiff_chunk_header {
+	char id[4];
+	uint32_t size;
+};
+
+size_t
+aiff_seek_id3(FILE *file)
+{
+	int ret;
+	struct stat st;
+	struct aiff_header header;
+	struct aiff_chunk_header chunk;
+	size_t size;
+
+	/* determine the file size */
+
+	ret = fstat(fileno(file), &st);
+	if (ret < 0) {
+		g_warning("Failed to stat file descriptor: %s",
+			  g_strerror(errno));
+		return 0;
+	}
+
+	/* seek to the beginning and read the AIFF header */
+
+	ret = fseek(file, 0, SEEK_SET);
+	if (ret != 0) {
+		g_warning("Failed to seek: %s", g_strerror(errno));
+		return 0;
+	}
+
+	size = fread(&header, sizeof(header), 1, file);
+	if (size != 1 ||
+	    memcmp(header.id, "FORM", 4) != 0 ||
+	    GUINT32_FROM_BE(header.size) > (uint32_t)st.st_size ||
+	    (memcmp(header.format, "AIFF", 4) != 0 &&
+	     memcmp(header.format, "AIFC", 4) != 0))
+		/* not a AIFF file */
+		return 0;
+
+	while (true) {
+		/* read the chunk header */
+
+		size = fread(&chunk, sizeof(chunk), 1, file);
+		if (size != 1)
+			return 0;
+
+		size = GUINT32_FROM_BE(chunk.size);
+		if (size > G_MAXINT32)
+			/* too dangerous, bail out: possible integer
+			   underflow when casting to off_t */
+			return 0;
+
+		if (size % 2 != 0)
+			/* pad byte */
+			++size;
+
+		if (memcmp(chunk.id, "ID3 ", 4) == 0)
+			/* found it! */
+			return size;
+
+		ret = fseek(file, size, SEEK_CUR);
+		if (ret != 0)
+			return 0;
+	}
+}
diff --git a/src/tag/aiff.h b/src/tag/aiff.h
new file mode 100644
index 000000000..a0ae2d41a
--- /dev/null
+++ b/src/tag/aiff.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2003-2011 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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
diff --git a/src/tag/riff.c b/src/tag/riff.c
new file mode 100644
index 000000000..9ee916971
--- /dev/null
+++ b/src/tag/riff.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2003-2011 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h" /* must be first for large file support */
+#include "riff.h"
+
+#include <glib.h>
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#undef G_LOG_DOMAIN
+#define G_LOG_DOMAIN "riff"
+
+struct riff_header {
+	char id[4];
+	uint32_t size;
+	char format[4];
+};
+
+struct riff_chunk_header {
+	char id[4];
+	uint32_t size;
+};
+
+size_t
+riff_seek_id3(FILE *file)
+{
+	int ret;
+	struct stat st;
+	struct riff_header header;
+	struct riff_chunk_header chunk;
+	size_t size;
+
+	/* determine the file size */
+
+	ret = fstat(fileno(file), &st);
+	if (ret < 0) {
+		g_warning("Failed to stat file descriptor: %s",
+			  g_strerror(errno));
+		return 0;
+	}
+
+	/* seek to the beginning and read the RIFF header */
+
+	ret = fseek(file, 0, SEEK_SET);
+	if (ret != 0) {
+		g_warning("Failed to seek: %s", g_strerror(errno));
+		return 0;
+	}
+
+	size = fread(&header, sizeof(header), 1, file);
+	if (size != 1 ||
+	    memcmp(header.id, "RIFF", 4) != 0 ||
+	    GUINT32_FROM_LE(header.size) > (uint32_t)st.st_size)
+		/* not a RIFF file */
+		return 0;
+
+	while (true) {
+		/* read the chunk header */
+
+		size = fread(&chunk, sizeof(chunk), 1, file);
+		if (size != 1)
+			return 0;
+
+		size = GUINT32_FROM_LE(chunk.size);
+		if (size > G_MAXINT32)
+			/* too dangerous, bail out: possible integer
+			   underflow when casting to off_t */
+			return 0;
+
+		if (size % 2 != 0)
+			/* pad byte */
+			++size;
+
+		if (memcmp(chunk.id, "id3 ", 4) == 0)
+			/* found it! */
+			return size;
+
+		ret = fseek(file, size, SEEK_CUR);
+		if (ret != 0)
+			return 0;
+	}
+}
diff --git a/src/tag/riff.h b/src/tag/riff.h
new file mode 100644
index 000000000..7b35e092a
--- /dev/null
+++ b/src/tag/riff.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2003-2011 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/** \file
+ *
+ * A parser for the RIFF file format (e.g. WAV).
+ */
+
+#ifndef MPD_RIFF_H
+#define MPD_RIFF_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+
+/**
+ * Seeks the RIFF file to the ID3 chunk.
+ *
+ * @return the size of the ID3 chunk on success, or 0 if this is not a
+ * RIFF file or no ID3 chunk was found
+ */
+size_t
+riff_seek_id3(FILE *file);
+
+#endif