Borewit / music-metadata / 10322871056

import initDebug from 'debug';

import * as strtok3 from 'strtok3';

import { StringType } from 'token-types';

import { uint8ArrayToString } from 'uint8array-extras';

import * as util from '../common/Util.js';

import type { IOptions, IRandomReader, IApeHeader } from '../type.js';

import type { INativeMetadataCollector } from '../common/MetadataCollector.js';

import { BasicParser } from '../common/BasicParser.js';

import {

  DataType,

  DescriptorParser,

  Header,

  type IDescriptor,

  type IFooter,

  type IHeader, type ITagItemHeader,

  TagFooter,

  TagItemHeader

} from './APEv2Token.js';

const debug = initDebug('music-metadata:parser:APEv2');

const tagFormat = 'APEv2';

interface IApeInfo {

  descriptor?: IDescriptor,

  header?: IHeader,

  footer?: IFooter

}

const preamble = 'APETAGEX';

export class APEv2Parser extends BasicParser {

  public static tryParseApeHeader(metadata: INativeMetadataCollector, tokenizer: strtok3.ITokenizer, options: IOptions) {

    const apeParser = new APEv2Parser();

    apeParser.init(metadata, tokenizer, options);

    return apeParser.tryParseApeHeader();

  }

  /**

   * Calculate the media file duration

   * @param ah ApeHeader

   * @return {number} duration in seconds

   */

  public static calculateDuration(ah: IHeader): number {

    duration += ah.finalFrameBlocks;

    return duration / ah.sampleRate;

  }

  /**

   * Calculates the APEv1 / APEv2 first field offset

   * @param reader

   * @param offset

   */

  public static async findApeFooterOffset(reader: IRandomReader, offset: number): Promise<IApeHeader | undefined> {

    // Search for APE footer header at the end of the file

    const apeBuf = new Uint8Array(TagFooter.len);

    await reader.randomRead(apeBuf, 0, TagFooter.len, offset - TagFooter.len);

    const tagFooter = TagFooter.get(apeBuf, 0);

    if (tagFooter.ID === 'APETAGEX') {

      } else {

        debug(`APE Footer found at offset=${offset - TagFooter.len}`);

        offset -= tagFooter.size;

      }

      return {footer: tagFooter, offset};

    }

  }

  private static parseTagFooter(metadata: INativeMetadataCollector, buffer: Uint8Array, options: IOptions): Promise<void> {

    const footer = TagFooter.get(buffer, buffer.length - TagFooter.len);

    strtok3.fromBuffer(buffer);

    const apeParser = new APEv2Parser();

    apeParser.init(metadata, strtok3.fromBuffer(buffer), options);

    return apeParser.parseTags(footer);

  }

  private ape: IApeInfo = {};

  /**

   * Parse APEv1 / APEv2 header if header signature found

   */

  public async tryParseApeHeader(): Promise<void> {

    if (this.tokenizer.fileInfo.size && this.tokenizer.fileInfo.size - this.tokenizer.position < TagFooter.len) {

      debug("No APEv2 header found, end-of-file reached");

      return;

    }

    const footer = await this.tokenizer.peekToken<IFooter>(TagFooter);

    if (footer.ID === preamble) {

      await this.tokenizer.ignore(TagFooter.len);

      return this.parseTags(footer);

    }

      debug(`APEv2 header not found at offset=${this.tokenizer.position}`);

      if (this.tokenizer.fileInfo.size) {

        // Try to read the APEv2 header using just the footer-header

        const remaining = this.tokenizer.fileInfo.size - this.tokenizer.position; // ToDo: take ID3v1 into account

        const buffer = new Uint8Array(remaining);

        await this.tokenizer.readBuffer(buffer);

        return APEv2Parser.parseTagFooter(this.metadata, buffer, this.options);

      }

  }

  public async parse(): Promise<void> {

    const descriptor = await this.tokenizer.readToken<IDescriptor>(DescriptorParser);

    this.ape.descriptor = descriptor;

    const lenExp = descriptor.descriptorBytes - DescriptorParser.len;

    await this.tokenizer.ignore(header.forwardBytes);

    return this.tryParseApeHeader();

  }

  public async parseTags(footer: IFooter): Promise<void> {

    const keyBuffer = new Uint8Array(256); // maximum tag key length

    let bytesRemaining = footer.size - TagFooter.len;

    debug(`Parse APE tags at offset=${this.tokenizer.position}, size=${bytesRemaining}`);

    for (let i = 0; i < footer.fields; i++) {

      if (bytesRemaining < TagItemHeader.len) {

        this.metadata.addWarning(`APEv2 Tag-header: ${footer.fields - i} items remaining, but no more tag data to read.`);

        break;

      }

      // Only APEv2 tag has tag item headers

      const tagItemHeader = await this.tokenizer.readToken<ITagItemHeader>(TagItemHeader);

      bytesRemaining -= TagItemHeader.len + tagItemHeader.size;

      await this.tokenizer.peekBuffer(keyBuffer, {length: Math.min(keyBuffer.length, bytesRemaining)});

      let zero = util.findZero(keyBuffer, 0, keyBuffer.length);

      const key = await this.tokenizer.readToken<string>(new StringType(zero, 'ascii'));

      await this.tokenizer.ignore(1);

      bytesRemaining -= key.length + 1;

      switch (tagItemHeader.flags.dataType) {

        case DataType.text_utf8: { // utf-8 text-string

          const value = await this.tokenizer.readToken<string>(new StringType(tagItemHeader.size, 'utf8'));

          const values = value.split(/\x00/g);

          await Promise.all(values.map(val => this.metadata.addTag(tagFormat, key, val)));

          break;

        }

        case DataType.binary: // binary (probably artwork)

          if (this.options.skipCovers) {

            await this.tokenizer.ignore(tagItemHeader.size);

          } else {

            const picData = new Uint8Array(tagItemHeader.size);

            await this.tokenizer.readBuffer(picData);

            zero = util.findZero(picData, 0, picData.length);

            const description = uint8ArrayToString(picData.slice(0, zero));

            const data = picData.slice(zero + 1);

            await this.metadata.addTag(tagFormat, key, {

              description,

              data

            });

          }

          break;

      }

    }

  }

  private async parseDescriptorExpansion(lenExp: number): Promise<{ forwardBytes: number }> {

  private async parseHeader(): Promise<{ forwardBytes: number }> {

    const header = await this.tokenizer.readToken(Header);

    // ToDo before

    this.metadata.setFormat('lossless', true);

    this.metadata.setFormat('container', 'Monkey\'s Audio');

    this.metadata.setFormat('bitsPerSample', header.bitsPerSample);

    this.metadata.setFormat('sampleRate', header.sampleRate);

    this.metadata.setFormat('numberOfChannels', header.channel);

    this.metadata.setFormat('duration', APEv2Parser.calculateDuration(header));

    return {

      forwardBytes: this.ape.descriptor.seekTableBytes + this.ape.descriptor.headerDataBytes +

        this.ape.descriptor.apeFrameDataBytes + this.ape.descriptor.terminatingDataBytes

    };

  }

}