Initial working version

2022-12-22 20:22:22 +11:00
parent ce9675a1cc
commit ced7fa5092
902 changed files with 150252 additions and 0 deletions
@@ -0,0 +1,54 @@
+var utils = require('./utils');
+
+function checkMagicId3v1(view) {
+	var id3Magic = utils.readBytes(view, view.byteLength - 128, 3);
+	//"TAG"
+	return id3Magic[0] === 84 && id3Magic[1] === 65 && id3Magic[2] === 71;
+}
+
+module.exports = function(buffer) {
+	//read last 128 bytes
+	var view = utils.createView(buffer);
+	if (!checkMagicId3v1(view)) {
+		return null;
+	}
+
+	function trim(value) {
+		return value.replace(/[\s\u0000]+$/, '');
+	}
+
+	try {
+		var offset = view.byteLength - 128 + 3,
+			readAscii = utils.readAscii;
+		var title = readAscii(view, offset, 30),
+			artist = readAscii(view, offset + 30, 30),
+			album = readAscii(view, offset + 60, 30),
+			year = readAscii(view, offset + 90, 4);
+
+		offset += 94;
+
+		var comment = readAscii(view, offset, 28),
+			track = null;
+		offset += 28;
+		if (view.getUint8(offset) === 0) {
+			//next byte is the track
+			track = view.getUint8(offset + 1);
+		} else {
+			comment += readAscii(view, offset, 2);
+		}
+
+		offset += 2;
+		var genre = view.getUint8(offset);
+		return {
+			title: trim(title),
+			artist: trim(artist),
+			album: trim(album),
+			year: trim(year),
+			comment: trim(comment),
+			track: track,
+			genre: genre
+		};
+	} catch (e) {
+		return null;
+	}
+};