Initial working version
This commit is contained in:
Samuel Kent
+162
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.APEv2Parser = void 0;
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const initDebug = require("debug");
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const strtok3 = require("strtok3/lib/core");
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const util = require("../common/Util");
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const BasicParser_1 = require("../common/BasicParser");
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const APEv2Token_1 = require("./APEv2Token");
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const token_types_1 = require("token-types");
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const debug = initDebug('music-metadata:parser:APEv2');
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const tagFormat = 'APEv2';
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const preamble = 'APETAGEX';
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class APEv2Parser extends BasicParser_1.BasicParser {
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constructor() {
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super(...arguments);
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this.ape = {};
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}
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static tryParseApeHeader(metadata, tokenizer, options) {
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const apeParser = new APEv2Parser();
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apeParser.init(metadata, tokenizer, options);
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return apeParser.tryParseApeHeader();
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}
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/**
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* Calculate the media file duration
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* @param ah ApeHeader
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* @return {number} duration in seconds
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*/
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static calculateDuration(ah) {
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let duration = ah.totalFrames > 1 ? ah.blocksPerFrame * (ah.totalFrames - 1) : 0;
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duration += ah.finalFrameBlocks;
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return duration / ah.sampleRate;
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}
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/**
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* Calculates the APEv1 / APEv2 first field offset
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* @param reader
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* @param offset
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*/
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static async findApeFooterOffset(reader, offset) {
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// Search for APE footer header at the end of the file
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const apeBuf = Buffer.alloc(APEv2Token_1.TagFooter.len);
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await reader.randomRead(apeBuf, 0, APEv2Token_1.TagFooter.len, offset - APEv2Token_1.TagFooter.len);
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const tagFooter = APEv2Token_1.TagFooter.get(apeBuf, 0);
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if (tagFooter.ID === 'APETAGEX') {
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debug(`APE footer header at offset=${offset}`);
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return { footer: tagFooter, offset: offset - tagFooter.size };
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}
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}
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static parseTagFooter(metadata, buffer, options) {
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const footer = APEv2Token_1.TagFooter.get(buffer, buffer.length - APEv2Token_1.TagFooter.len);
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if (footer.ID !== preamble)
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throw new Error('Unexpected APEv2 Footer ID preamble value.');
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strtok3.fromBuffer(buffer);
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const apeParser = new APEv2Parser();
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apeParser.init(metadata, strtok3.fromBuffer(buffer), options);
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return apeParser.parseTags(footer);
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}
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/**
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* Parse APEv1 / APEv2 header if header signature found
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*/
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async tryParseApeHeader() {
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if (this.tokenizer.fileInfo.size && this.tokenizer.fileInfo.size - this.tokenizer.position < APEv2Token_1.TagFooter.len) {
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debug(`No APEv2 header found, end-of-file reached`);
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return;
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}
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const footer = await this.tokenizer.peekToken(APEv2Token_1.TagFooter);
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if (footer.ID === preamble) {
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await this.tokenizer.ignore(APEv2Token_1.TagFooter.len);
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return this.parseTags(footer);
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}
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else {
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debug(`APEv2 header not found at offset=${this.tokenizer.position}`);
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if (this.tokenizer.fileInfo.size) {
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// Try to read the APEv2 header using just the footer-header
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const remaining = this.tokenizer.fileInfo.size - this.tokenizer.position; // ToDo: take ID3v1 into account
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const buffer = Buffer.alloc(remaining);
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await this.tokenizer.readBuffer(buffer);
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return APEv2Parser.parseTagFooter(this.metadata, buffer, this.options);
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}
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}
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}
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async parse() {
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const descriptor = await this.tokenizer.readToken(APEv2Token_1.DescriptorParser);
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if (descriptor.ID !== 'MAC ')
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throw new Error('Unexpected descriptor ID');
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this.ape.descriptor = descriptor;
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const lenExp = descriptor.descriptorBytes - APEv2Token_1.DescriptorParser.len;
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const header = await (lenExp > 0 ? this.parseDescriptorExpansion(lenExp) : this.parseHeader());
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await this.tokenizer.ignore(header.forwardBytes);
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return this.tryParseApeHeader();
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}
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async parseTags(footer) {
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const keyBuffer = Buffer.alloc(256); // maximum tag key length
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let bytesRemaining = footer.size - APEv2Token_1.TagFooter.len;
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debug(`Parse APE tags at offset=${this.tokenizer.position}, size=${bytesRemaining}`);
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for (let i = 0; i < footer.fields; i++) {
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if (bytesRemaining < APEv2Token_1.TagItemHeader.len) {
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this.metadata.addWarning(`APEv2 Tag-header: ${footer.fields - i} items remaining, but no more tag data to read.`);
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break;
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}
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// Only APEv2 tag has tag item headers
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const tagItemHeader = await this.tokenizer.readToken(APEv2Token_1.TagItemHeader);
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bytesRemaining -= APEv2Token_1.TagItemHeader.len + tagItemHeader.size;
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await this.tokenizer.peekBuffer(keyBuffer, { length: Math.min(keyBuffer.length, bytesRemaining) });
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let zero = util.findZero(keyBuffer, 0, keyBuffer.length);
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const key = await this.tokenizer.readToken(new token_types_1.StringType(zero, 'ascii'));
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await this.tokenizer.ignore(1);
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bytesRemaining -= key.length + 1;
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switch (tagItemHeader.flags.dataType) {
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case APEv2Token_1.DataType.text_utf8: { // utf-8 textstring
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const value = await this.tokenizer.readToken(new token_types_1.StringType(tagItemHeader.size, 'utf8'));
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const values = value.split(/\x00/g);
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/*jshint loopfunc:true */
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for (const val of values) {
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this.metadata.addTag(tagFormat, key, val);
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}
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break;
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}
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case APEv2Token_1.DataType.binary: // binary (probably artwork)
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if (this.options.skipCovers) {
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await this.tokenizer.ignore(tagItemHeader.size);
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}
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else {
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const picData = Buffer.alloc(tagItemHeader.size);
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await this.tokenizer.readBuffer(picData);
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zero = util.findZero(picData, 0, picData.length);
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const description = picData.toString('utf8', 0, zero);
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const data = Buffer.from(picData.slice(zero + 1));
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this.metadata.addTag(tagFormat, key, {
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description,
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data
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});
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}
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break;
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case APEv2Token_1.DataType.external_info:
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debug(`Ignore external info ${key}`);
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await this.tokenizer.ignore(tagItemHeader.size);
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break;
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default:
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throw new Error(`Unexpected data-type: ${tagItemHeader.flags.dataType}`);
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}
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}
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}
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async parseDescriptorExpansion(lenExp) {
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await this.tokenizer.ignore(lenExp);
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return this.parseHeader();
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}
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async parseHeader() {
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const header = await this.tokenizer.readToken(APEv2Token_1.Header);
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// ToDo before
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this.metadata.setFormat('lossless', true);
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this.metadata.setFormat('container', 'Monkey\'s Audio');
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this.metadata.setFormat('bitsPerSample', header.bitsPerSample);
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this.metadata.setFormat('sampleRate', header.sampleRate);
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this.metadata.setFormat('numberOfChannels', header.channel);
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this.metadata.setFormat('duration', APEv2Parser.calculateDuration(header));
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return {
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forwardBytes: this.ape.descriptor.seekTableBytes + this.ape.descriptor.headerDataBytes +
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this.ape.descriptor.apeFrameDataBytes + this.ape.descriptor.terminatingDataBytes
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};
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}
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}
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exports.APEv2Parser = APEv2Parser;
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