From 566d311638aca1ed21da78a5dce320e94134160b Mon Sep 17 00:00:00 2001
From: Jon Bergli Heier <snakebite@jvnv.net>
Date: Wed, 18 Aug 2010 21:23:40 +0200
Subject: Basic ID3 tag implementation, using libid3tag.

---
 SConstruct |  1 +
 music.c    |  4 ++++
 music.h    |  4 ++++
 tag.c      | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tag.h      | 24 +++++++++++++++++++++
 5 files changed, 105 insertions(+)
 create mode 100644 tag.c
 create mode 100644 tag.h

diff --git a/SConstruct b/SConstruct
index e880366..f85f2a3 100644
--- a/SConstruct
+++ b/SConstruct
@@ -16,6 +16,7 @@ else:
 env.ParseConfig('pkg-config --cflags --libs glib-2.0')
 env.ParseConfig('pkg-config --cflags --libs gio-2.0')
 env.ParseConfig('pkg-config --cflags --libs libmpg123')
+env.ParseConfig('pkg-config --cflags --libs id3tag')
 
 env.Program('foo', Glob('*.c') + Glob('decoders/*.c') + Glob('encoders/*.c'))
 
diff --git a/music.c b/music.c
index 84dd1c7..c81d4dd 100644
--- a/music.c
+++ b/music.c
@@ -43,6 +43,10 @@ gboolean music_scan(struct directory *directory) {
 			directory->files = g_slist_prepend(directory->files, f);
 
 			g_debug("added file %s to %s", entry, directory->path);
+			struct tag *tag = tag_read(fullpath);
+			if(tag) {
+				f->tag = tag;
+			}
 		} else if(S_ISDIR(st.st_mode)) {
 			struct directory *d = g_new0(struct directory, 1);
 			d->path = g_build_filename(directory->path, entry, NULL);
diff --git a/music.h b/music.h
index e0e4fcb..2b08c39 100644
--- a/music.h
+++ b/music.h
@@ -1,11 +1,15 @@
 #ifndef _MUSIC_H_
 #define _MUSIC_H_
 
+#include "tag.h"
+
 #include <glib.h>
 
 struct file {
 	gchar *name;
 	gssize size;
+
+	struct tag *tag;
 };
 
 struct directory {
diff --git a/tag.c b/tag.c
new file mode 100644
index 0000000..ca56106
--- /dev/null
+++ b/tag.c
@@ -0,0 +1,72 @@
+#include "tag.h"
+
+#include <id3tag.h>
+
+static void tag_add(struct tag *tag, enum tag_type type, const gchar *value) {
+	struct tag_field *field = g_new0(struct tag_field, 1);
+	if(field == 0) {
+		g_error("tag_add: g_new0 returned NULL");
+	}
+
+	field->type = type;
+	field->string = g_strdup(value);
+	tag->fields = g_slist_prepend(tag->fields, field);
+}
+
+static void tag_add_string(struct tag *tag, struct id3_tag *id3tag,
+		enum tag_type type, const gchar *id) {
+	struct id3_frame *frame = id3_tag_findframe(id3tag, id, 0);
+
+	if(frame == NULL) {
+		return;
+	}
+
+	if(frame->nfields != 2) {
+		g_debug("unexpected nfields value");
+		return;
+	}
+
+	const union id3_field *field = id3_frame_field(frame, 1);
+	guint nstrings = id3_field_getnstrings(field);
+
+	for(guint i = 0; i < nstrings; i++) {
+		const id3_ucs4_t *ucs4 = id3_field_getstrings(field, i);
+
+		if(ucs4 == NULL) {
+			g_warning("ucs4 is NULL");
+			continue;
+		}
+
+		id3_utf8_t *utf8 = id3_ucs4_utf8duplicate(ucs4);
+		tag_add(tag, type, (gchar*)utf8);
+		g_free(utf8);
+	}
+}
+
+/* TODO: support other tag formats beside ID3 */
+struct tag *tag_read(const gchar *path) {
+	struct id3_file *file = id3_file_open(path, ID3_FILE_MODE_READONLY);
+
+	if(file == NULL) {
+		g_warning("file is NULL");
+		return NULL;
+	}
+
+	struct id3_tag *id3tag = id3_file_tag(file);
+
+	if(id3tag == NULL) {
+		g_debug("tag is NULL");
+		return NULL;
+	}
+
+	struct tag *tag = g_new0(struct tag, 1);
+
+	/* TODO: add more interesting data */
+	tag_add_string(tag, id3tag, TAG_TYPE_ARTIST, ID3_FRAME_ARTIST);
+	tag_add_string(tag, id3tag, TAG_TYPE_ALBUM, ID3_FRAME_ALBUM);
+	tag_add_string(tag, id3tag, TAG_TYPE_TITLE, ID3_FRAME_TITLE);
+
+	id3_file_close(file);
+
+	return tag;
+}
diff --git a/tag.h b/tag.h
new file mode 100644
index 0000000..e0e5a7d
--- /dev/null
+++ b/tag.h
@@ -0,0 +1,24 @@
+#ifndef _TAG_H_
+#define _TAG_H_
+
+#include <glib.h>
+
+enum tag_type {
+	TAG_TYPE_ARTIST,
+	TAG_TYPE_ALBUM,
+	TAG_TYPE_TITLE,
+};
+
+struct tag_field {
+	enum tag_type type;
+	gchar *string;
+};
+
+struct tag {
+	GSList *fields;
+};
+
+void tag_list_all(const gchar *path);
+struct tag *tag_read(const gchar *path);
+
+#endif
-- 
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