Samuel Kent
54 lines
1.2 KiB
JavaScript
54 lines
1.2 KiB
JavaScript
var utils = require('./utils');
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function checkMagicId3v1(view) {
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var id3Magic = utils.readBytes(view, view.byteLength - 128, 3);
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//"TAG"
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return id3Magic[0] === 84 && id3Magic[1] === 65 && id3Magic[2] === 71;
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}
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module.exports = function(buffer) {
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//read last 128 bytes
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var view = utils.createView(buffer);
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if (!checkMagicId3v1(view)) {
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return null;
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}
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function trim(value) {
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return value.replace(/[\s\u0000]+$/, '');
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}
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try {
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var offset = view.byteLength - 128 + 3,
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readAscii = utils.readAscii;
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var title = readAscii(view, offset, 30),
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artist = readAscii(view, offset + 30, 30),
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album = readAscii(view, offset + 60, 30),
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year = readAscii(view, offset + 90, 4);
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offset += 94;
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var comment = readAscii(view, offset, 28),
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track = null;
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offset += 28;
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if (view.getUint8(offset) === 0) {
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//next byte is the track
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track = view.getUint8(offset + 1);
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} else {
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comment += readAscii(view, offset, 2);
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}
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offset += 2;
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var genre = view.getUint8(offset);
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return {
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title: trim(title),
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artist: trim(artist),
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album: trim(album),
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year: trim(year),
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comment: trim(comment),
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track: track,
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genre: genre
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};
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} catch (e) {
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return null;
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}
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}; |