WaveFileReader.readBextChunk_ - Code Metrics - Inspection of "Move LIST reading methods to WaveFileReader" - rochars/wavefile - Measure and Improve Code Quality continuously with Scrutinizer

Passed
Branch — wavefile-reader (73452d)

by Rafael S.
created 2019-08-12 18:24 UTC
WaveFileReader.readBextChunk_ A

↳ Parent: WaveFileReader
Complexity

Conditions
Size

Total Lines	27
Code Lines	24
Duplication

Lines	0
Ratio	0 %
Importance

Changes
Metric	Value
eloc	24
dl	0
loc	27
rs	9.304
c	0
b	0
f	0
cc	2
/*
 * Copyright (c) 2017-2019 Rafael da Silva Rocha.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

/**
 * @fileoverview The WaveFileReader class.
 * @see https://github.com/rochars/wavefile
 */

/** @module wavefile */

import RIFFFile from './riff-file';
import validateNumChannels from './validate-num-channels'; 
import validateSampleRate from './validate-sample-rate';
import {unpackString, unpack} from 'byte-data';

/**
 * A class to read wav files.
 */
export default class WaveFileReader extends RIFFFile {

  /**
   * @param {?Uint8Array=} wavBuffer A wave file buffer.
   * @throws {Error} If container is not RIFF, RIFX or RF64.
   * @throws {Error} If format is not WAVE.
   * @throws {Error} If no 'fmt ' chunk is found.
   * @throws {Error} If no 'data' chunk is found.
   */
  constructor(wavBuffer=null) {
    super();
    // Include 'RF64' as a supported container format
    this.supported_containers.push('RF64');
    /**
     * Audio formats.
     * Formats not listed here should be set to 65534,
     * the code for WAVE_FORMAT_EXTENSIBLE
     * @enum {number}
     * @protected
     */
    this.WAV_AUDIO_FORMATS = {
      '4': 17,
      '8': 1,
      '8a': 6,
      '8m': 7,
      '16': 1,
      '24': 1,
      '32': 1,
      '32f': 3,
      '64': 3
    };
    /**
     * The data of the 'fmt' chunk.
     * @type {!Object<string, *>}
     */
    this.fmt = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {number} */
      audioFormat: 0,
      /** @type {number} */
      numChannels: 0,
      /** @type {number} */
      sampleRate: 0,
      /** @type {number} */
      byteRate: 0,
      /** @type {number} */
      blockAlign: 0,
      /** @type {number} */
      bitsPerSample: 0,
      /** @type {number} */
      cbSize: 0,
      /** @type {number} */
      validBitsPerSample: 0,
      /** @type {number} */
      dwChannelMask: 0,
      /**
       * 4 32-bit values representing a 128-bit ID
       * @type {!Array<number>}
       */
      subformat: []
    };
    /**
     * The data of the 'fact' chunk.
     * @type {!Object<string, *>}
     */
    this.fact = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {number} */
      dwSampleLength: 0
    };
    /**
     * The data of the 'cue ' chunk.
     * @type {!Object<string, *>}
     */
    this.cue = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {number} */
      dwCuePoints: 0,
      /** @type {!Array<!Object>} */
      points: [],
    };
    /**
     * The data of the 'smpl' chunk.
     * @type {!Object<string, *>}
     */
    this.smpl = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {number} */
      dwManufacturer: 0,
      /** @type {number} */
      dwProduct: 0,
      /** @type {number} */
      dwSamplePeriod: 0,
      /** @type {number} */
      dwMIDIUnityNote: 0,
      /** @type {number} */
      dwMIDIPitchFraction: 0,
      /** @type {number} */
      dwSMPTEFormat: 0,
      /** @type {number} */
      dwSMPTEOffset: 0,
      /** @type {number} */
      dwNumSampleLoops: 0,
      /** @type {number} */
      dwSamplerData: 0,
      /** @type {!Array<!Object>} */
      loops: []
    };
    /**
     * The data of the 'bext' chunk.
     * @type {!Object<string, *>}
     */
    this.bext = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {string} */
      description: '', //256
      /** @type {string} */
      originator: '', //32
      /** @type {string} */
      originatorReference: '', //32
      /** @type {string} */
      originationDate: '', //10
      /** @type {string} */
      originationTime: '', //8
      /**
       * 2 32-bit values, timeReference high and low
       * @type {!Array<number>}
       */
      timeReference: [0, 0],
      /** @type {number} */
      version: 0, //WORD
      /** @type {string} */
      UMID: '', // 64 chars
      /** @type {number} */
      loudnessValue: 0, //WORD
      /** @type {number} */
      loudnessRange: 0, //WORD
      /** @type {number} */
      maxTruePeakLevel: 0, //WORD
      /** @type {number} */
      maxMomentaryLoudness: 0, //WORD
      /** @type {number} */
      maxShortTermLoudness: 0, //WORD
      /** @type {string} */
      reserved: '', //180
      /** @type {string} */
      codingHistory: '' // string, unlimited
    };
    /**
     * The data of the 'ds64' chunk.
     * Used only with RF64 files.
     * @type {!Object<string, *>}
     */
    this.ds64 = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {number} */
      riffSizeHigh: 0, // DWORD
      /** @type {number} */
      riffSizeLow: 0, // DWORD
      /** @type {number} */
      dataSizeHigh: 0, // DWORD
      /** @type {number} */
      dataSizeLow: 0, // DWORD
      /** @type {number} */
      originationTime: 0, // DWORD
      /** @type {number} */
      sampleCountHigh: 0, // DWORD
      /** @type {number} */
      sampleCountLow: 0 // DWORD
      /** @type {number} */
      //'tableLength': 0, // DWORD
      /** @type {!Array<number>} */
      //'table': []
    };
    /**
     * The data of the 'data' chunk.
     * @type {!Object<string, *>}
     */
    this.data = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {!Uint8Array} */
      samples: new Uint8Array(0)
    };
    /**
     * The data of the 'LIST' chunks.
     * Each item in this list look like this:
     *  {
     *      chunkId: '',
     *      chunkSize: 0,
     *      format: '',
     *      subChunks: []
     *   }
     * @type {!Array<!Object>}
     */
    this.LIST = [];
    /**
     * The data of the 'junk' chunk.
     * @type {!Object<string, *>}
     */
    this.junk = {
      /** @type {string} */
      chunkId: '',
      /** @type {number} */
      chunkSize: 0,
      /** @type {!Array<number>} */
      chunkData: []
    };
    /**
     * The bit depth code according to the samples.
     * @type {string}
     */
    this.bitDepth = '0';
    /**
     * @type {!Object}
     * @protected
     */
    this.dataType = {};
    /**
     * @type {!Object}
     * @protected
     */
    this.uInt16 = {bits: 16, be: false};
    // Load a file from the buffer if one was passed
    // when creating the object
    if (wavBuffer) {
      this.fromBuffer(wavBuffer);
    }
  }

  /**
   * Set up the WaveFileParser object from a byte buffer.
   * @param {!Uint8Array} wavBuffer The buffer.
   * @param {boolean=} samples True if the samples should be loaded.
   * @throws {Error} If container is not RIFF, RIFX or RF64.
   * @throws {Error} If format is not WAVE.
   * @throws {Error} If no 'fmt ' chunk is found.
   * @throws {Error} If no 'data' chunk is found.
   */
  fromBuffer(wavBuffer, samples=true) {
    this.clearHeader();
    this.setSignature(wavBuffer);
    this.uInt16.be = this.uInt32.be;
    if (this.format != 'WAVE') {
      throw Error('Could not find the "WAVE" format identifier');
    }
    this.readDs64Chunk_(wavBuffer);
    this.readFmtChunk_(wavBuffer);
    this.readFactChunk_(wavBuffer);
    this.readBextChunk_(wavBuffer);
    this.readCueChunk_(wavBuffer);
    this.readSmplChunk_(wavBuffer);
    this.readDataChunk_(wavBuffer, samples);
    this.readJunkChunk_(wavBuffer);
    this.readLISTChunk_(wavBuffer);
    this.bitDepthFromFmt_();
    this.updateDataType();
  }

  /**
   * Return the value of a RIFF tag in the INFO chunk.
   * @param {string} tag The tag name.
   * @return {?string} The value if the tag is found, null otherwise.
   */
  getTag(tag) {
    /** @type {!Object} */
    let index = this.getTagIndex_(tag);
    if (index.TAG !== null) {
      return this.LIST[index.LIST].subChunks[index.TAG].value;
    }
    return null;
  }

  /**
   * Return a Object<tag, value> with the RIFF tags in the file.
   * @return {!Object<string, string>} The file tags.
   */
  listTags() {
    /** @type {?number} */
    let index = this.getLISTINFOIndex_();
    /** @type {!Object} */
    let tags = {};
    if (index !== null) {
      for (let i = 0, len = this.LIST[index].subChunks.length; i < len; i++) {
        tags[this.LIST[index].subChunks[i].chunkId] =
          this.LIST[index].subChunks[i].value;
      }
    }
    return tags;
  }

  /**
   * Return an array with all cue points in the file, in the order they appear
   * in the file.
   * The difference between this method and using the list in WaveFile.cue
   * is that the return value of this method includes the position in
   * milliseconds of each cue point (WaveFile.cue only have the sample offset)
   * @return {!Array<!Object>}
   */
  listCuePoints() {
    /** @type {!Array<!Object>} */
    let points = this.getCuePoints_();
    for (let i = 0, len = points.length; i < len; i++) {
      points[i].milliseconds =
        (points[i].dwPosition / this.fmt.sampleRate) * 1000;
    }
    return points;
  }

  /**
   * Reset some attributes of the object.
   * @protected
   * @ignore
   */
  clearHeader() {
    this.fmt.cbSize = 0;
    this.fmt.validBitsPerSample = 0;
    this.fact.chunkId = '';
    this.ds64.chunkId = '';
  }

  /**
   * Update the type definition used to read and write the samples.
   * @protected
   */
  updateDataType() {
    this.dataType = {
      bits: ((parseInt(this.bitDepth, 10) - 1) | 7) + 1,
      fp: this.bitDepth == '32f' || this.bitDepth == '64',
      signed: this.bitDepth != '8',
      be: this.container == 'RIFX'
    };
    if (['4', '8a', '8m'].indexOf(this.bitDepth) > -1 ) {
      this.dataType.bits = 8;
      this.dataType.signed = false;
    }
  }

  /**
   * Set the string code of the bit depth based on the 'fmt ' chunk.
   * @private
   */
  bitDepthFromFmt_() {
    if (this.fmt.audioFormat === 3 && this.fmt.bitsPerSample === 32) {
      this.bitDepth = '32f';
    } else if (this.fmt.audioFormat === 6) {
      this.bitDepth = '8a';
    } else if (this.fmt.audioFormat === 7) {
      this.bitDepth = '8m';
    } else {
      this.bitDepth = this.fmt.bitsPerSample.toString();
    }
  }

  /**
   * Return an array with all cue points in the file, in the order they appear
   * in the file.
   * @return {!Array<!Object>}
   * @private
   */
  getCuePoints_() {
    /** @type {!Array<!Object>} */
    let points = [];
    for (let i = 0, len = this.cue.points.length; i < len; i++) {
      points.push({
        dwPosition: this.cue.points[i].dwPosition,
        label: this.getLabelForCuePoint_(
          this.cue.points[i].dwName)});
    }
    return points;
  }

  /**
   * Return the label of a cue point.
   * @param {number} pointDwName The ID of the cue point.
   * @return {string}
   * @private
   */
  getLabelForCuePoint_(pointDwName) {
    /** @type {?number} */
    let cIndex = this.getAdtlChunk_();
    if (cIndex !== null) {
      for (let i = 0, len = this.LIST[cIndex].subChunks.length; i < len; i++) {
        if (this.LIST[cIndex].subChunks[i].dwName ==
            pointDwName) {
          return this.LIST[cIndex].subChunks[i].value;
        }
      }
    }
    return '';
  }

  /**
   * Return the index of the INFO chunk in the LIST chunk.
   * @return {?number} the index of the INFO chunk.
   * @private
   */
  getLISTINFOIndex_() {
    /** @type {?number} */
    let index = null;
    for (let i = 0, len = this.LIST.length; i < len; i++) {
      if (this.LIST[i].format === 'INFO') {
        index = i;
        break;
      }
    }
    return index;
  }

  /**
   * Return the index of the 'adtl' LIST in this.LIST.
   * @return {?number}
   * @private
   */
  getAdtlChunk_() {
    for (let i = 0, len = this.LIST.length; i < len; i++) {
      if (this.LIST[i].format == 'adtl') {
        return i;
      }
    }
    return null;
  }

  /**
   * Return the index of a tag in a FILE chunk.
   * @param {string} tag The tag name.
   * @return {!Object<string, ?number>}
   *    Object.LIST is the INFO index in LIST
   *    Object.TAG is the tag index in the INFO
   * @private
   */
  getTagIndex_(tag) {
    /** @type {!Object<string, ?number>} */
    let index = {LIST: null, TAG: null};
    for (let i = 0, len = this.LIST.length; i < len; i++) {
      if (this.LIST[i].format == 'INFO') {
        index.LIST = i;
        for (let j=0, subLen = this.LIST[i].subChunks.length; j < subLen; j++) {
          if (this.LIST[i].subChunks[j].chunkId == tag) {
            index.TAG = j;
            break;
          }
        }
        break;
      }
    }
    return index;
  }

  /**
   * Read the 'fmt ' chunk of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @throws {Error} If no 'fmt ' chunk is found.
   * @private
   */
  readFmtChunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('fmt ');
    if (chunk) {
      this.head = chunk.chunkData.start;
      this.fmt.chunkId = chunk.chunkId;
      this.fmt.chunkSize = chunk.chunkSize;
      this.fmt.audioFormat = this.readUInt16(buffer);
      this.fmt.numChannels = this.readUInt16(buffer);
      this.fmt.sampleRate = this.readUInt32(buffer);
      this.fmt.byteRate = this.readUInt32(buffer);
      this.fmt.blockAlign = this.readUInt16(buffer);
      this.fmt.bitsPerSample = this.readUInt16(buffer);
      this.readFmtExtension_(buffer);
    } else {
      throw Error('Could not find the "fmt " chunk');
    }
  }

  /**
   * Read the 'fmt ' chunk extension.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readFmtExtension_(buffer) {
    if (this.fmt.chunkSize > 16) {
      this.fmt.cbSize = this.readUInt16(buffer);
      if (this.fmt.chunkSize > 18) {
        this.fmt.validBitsPerSample = this.readUInt16(buffer);
        if (this.fmt.chunkSize > 20) {
          this.fmt.dwChannelMask = this.readUInt32(buffer);
          this.fmt.subformat = [
            this.readUInt32(buffer),
            this.readUInt32(buffer),
            this.readUInt32(buffer),
            this.readUInt32(buffer)];
        }
      }
    }
  }

  /**
   * Read the 'fact' chunk of a wav file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readFactChunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('fact');
    if (chunk) {
      this.head = chunk.chunkData.start;
      this.fact.chunkId = chunk.chunkId;
      this.fact.chunkSize = chunk.chunkSize;
      this.fact.dwSampleLength = this.readUInt32(buffer);
    }
  }

  /**
   * Read the 'cue ' chunk of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readCueChunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('cue ');
    if (chunk) {
      this.head = chunk.chunkData.start;
      this.cue.chunkId = chunk.chunkId;
      this.cue.chunkSize = chunk.chunkSize;
      this.cue.dwCuePoints = this.readUInt32(buffer);
      for (let i = 0; i < this.cue.dwCuePoints; i++) {
        this.cue.points.push({
          dwName: this.readUInt32(buffer),
          dwPosition: this.readUInt32(buffer),
          fccChunk: this.readString(buffer, 4),
          dwChunkStart: this.readUInt32(buffer),
          dwBlockStart: this.readUInt32(buffer),
          dwSampleOffset: this.readUInt32(buffer),
        });
      }
    }
  }

  /**
   * Read the 'smpl' chunk of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readSmplChunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('smpl');
    if (chunk) {
      this.head = chunk.chunkData.start;
      this.smpl.chunkId = chunk.chunkId;
      this.smpl.chunkSize = chunk.chunkSize;
      this.smpl.dwManufacturer = this.readUInt32(buffer);
      this.smpl.dwProduct = this.readUInt32(buffer);
      this.smpl.dwSamplePeriod = this.readUInt32(buffer);
      this.smpl.dwMIDIUnityNote = this.readUInt32(buffer);
      this.smpl.dwMIDIPitchFraction = this.readUInt32(buffer);
      this.smpl.dwSMPTEFormat = this.readUInt32(buffer);
      this.smpl.dwSMPTEOffset = this.readUInt32(buffer);
      this.smpl.dwNumSampleLoops = this.readUInt32(buffer);
      this.smpl.dwSamplerData = this.readUInt32(buffer);
      for (let i = 0; i < this.smpl.dwNumSampleLoops; i++) {
        this.smpl.loops.push({
          dwName: this.readUInt32(buffer),
          dwType: this.readUInt32(buffer),
          dwStart: this.readUInt32(buffer),
          dwEnd: this.readUInt32(buffer),
          dwFraction: this.readUInt32(buffer),
          dwPlayCount: this.readUInt32(buffer),
        });
      }
    }
  }

  /**
   * Read the 'data' chunk of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @param {boolean} samples True if the samples should be loaded.
   * @throws {Error} If no 'data' chunk is found.
   * @private
   */
  readDataChunk_(buffer, samples) {
    /** @type {?Object} */
    let chunk = this.findChunk('data');
    if (chunk) {
      this.data.chunkId = 'data';
      this.data.chunkSize = chunk.chunkSize;
      if (samples) {
        this.data.samples = buffer.slice(
          chunk.chunkData.start,
          chunk.chunkData.end);
      }
    } else {
      throw Error('Could not find the "data" chunk');
    }
  }

  /**
   * Read the 'bext' chunk of a wav file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readBextChunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('bext');
    if (chunk) {
      this.head = chunk.chunkData.start;
      this.bext.chunkId = chunk.chunkId;
      this.bext.chunkSize = chunk.chunkSize;
      this.bext.description = this.readString(buffer, 256);
      this.bext.originator = this.readString(buffer, 32);
      this.bext.originatorReference = this.readString(buffer, 32);
      this.bext.originationDate = this.readString(buffer, 10);
      this.bext.originationTime = this.readString(buffer, 8);
      this.bext.timeReference = [
        this.readUInt32(buffer),
        this.readUInt32(buffer)];
      this.bext.version = this.readUInt16(buffer);
      this.bext.UMID = this.readString(buffer, 64);
      this.bext.loudnessValue = this.readUInt16(buffer);
      this.bext.loudnessRange = this.readUInt16(buffer);
      this.bext.maxTruePeakLevel = this.readUInt16(buffer);
      this.bext.maxMomentaryLoudness = this.readUInt16(buffer);
      this.bext.maxShortTermLoudness = this.readUInt16(buffer);
      this.bext.reserved = this.readString(buffer, 180);
      this.bext.codingHistory = this.readString(
        buffer, this.bext.chunkSize - 602);
    }
  }

  /**
   * Read the 'ds64' chunk of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @throws {Error} If no 'ds64' chunk is found and the file is RF64.
   * @private
   */
  readDs64Chunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('ds64');
    if (chunk) {
      this.head = chunk.chunkData.start;
      this.ds64.chunkId = chunk.chunkId;
      this.ds64.chunkSize = chunk.chunkSize;
      this.ds64.riffSizeHigh = this.readUInt32(buffer);
      this.ds64.riffSizeLow = this.readUInt32(buffer);
      this.ds64.dataSizeHigh = this.readUInt32(buffer);
      this.ds64.dataSizeLow = this.readUInt32(buffer);
      this.ds64.originationTime = this.readUInt32(buffer);
      this.ds64.sampleCountHigh = this.readUInt32(buffer);
      this.ds64.sampleCountLow = this.readUInt32(buffer);
      //if (wav.ds64.chunkSize > 28) {
      //  wav.ds64.tableLength = unpack(
      //    chunkData.slice(28, 32), uInt32_);
      //  wav.ds64.table = chunkData.slice(
      //     32, 32 + wav.ds64.tableLength);
      //}
    } else {
      if (this.container == 'RF64') {
        throw Error('Could not find the "ds64" chunk');
      }
    }
  }

  /**
   * Read the 'LIST' chunks of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readLISTChunk_(buffer) {
    /** @type {?Object} */
    let listChunks = this.findChunk('LIST', true);
    if (listChunks !== null) {
      for (let j=0; j < listChunks.length; j++) {
        /** @type {!Object} */
        let subChunk = listChunks[j];
        this.LIST.push({
          chunkId: subChunk.chunkId,
          chunkSize: subChunk.chunkSize,
          format: subChunk.format,
          subChunks: []});
        for (let x=0; x<subChunk.subChunks.length; x++) {
          this.readLISTSubChunks_(subChunk.subChunks[x],
            subChunk.format, buffer);
        }
      }
    }
  }

  /**
   * Read the sub chunks of a 'LIST' chunk.
   * @param {!Object} subChunk The 'LIST' subchunks.
   * @param {string} format The 'LIST' format, 'adtl' or 'INFO'.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readLISTSubChunks_(subChunk, format, buffer) {
    if (format == 'adtl') {
      if (['labl', 'note','ltxt'].indexOf(subChunk.chunkId) > -1) {
        this.head = subChunk.chunkData.start;
        /** @type {!Object<string, string|number>} */
        let item = {
          chunkId: subChunk.chunkId,
          chunkSize: subChunk.chunkSize,
          dwName: this.readUInt32(buffer)
        };
        if (subChunk.chunkId == 'ltxt') {
          item.dwSampleLength = this.readUInt32(buffer);
          item.dwPurposeID = this.readUInt32(buffer);
          item.dwCountry = this.readUInt16(buffer);
          item.dwLanguage = this.readUInt16(buffer);
          item.dwDialect = this.readUInt16(buffer);
          item.dwCodePage = this.readUInt16(buffer);
        }
        item.value = this.readZSTR(buffer, this.head);
        this.LIST[this.LIST.length - 1].subChunks.push(item);
      }
    // RIFF INFO tags like ICRD, ISFT, ICMT
    } else if(format == 'INFO') {
      this.head = subChunk.chunkData.start;
      this.LIST[this.LIST.length - 1].subChunks.push({
        chunkId: subChunk.chunkId,
        chunkSize: subChunk.chunkSize,
        value: this.readZSTR(buffer, this.head)
      });
    }
  }

  /**
   * Read the 'junk' chunk of a wave file.
   * @param {!Uint8Array} buffer The wav file buffer.
   * @private
   */
  readJunkChunk_(buffer) {
    /** @type {?Object} */
    let chunk = this.findChunk('junk');
    if (chunk) {
      this.junk = {
        chunkId: chunk.chunkId,
        chunkSize: chunk.chunkSize,
        chunkData: [].slice.call(buffer.slice(
          chunk.chunkData.start,
          chunk.chunkData.end))
      };
    }
  }

  /**
   * Read bytes as a ZSTR string.
   * @param {!Uint8Array} bytes The bytes.
   * @param {number} index the index to start reading.
   * @return {string} The string.
   * @protected
   */
  readZSTR(bytes, index=0) {
    for (let i = index; i < bytes.length; i++) {
      this.head++;
      if (bytes[i] === 0) {
        break;
      }
    }
    return unpackString(bytes, index, this.head - 1);
  }

  /**
   * Read a number from a chunk.
   * @param {!Uint8Array} bytes The chunk bytes.
   * @return {number} The number.
   * @protected
   */
  readUInt16(bytes) {
    /** @type {number} */
    let value = unpack(bytes, this.uInt16, this.head);
    this.head += 2;
    return value;
  }
}

rochars / wavefile

Branch — wavefile-reader (73452d)

WaveFileReader.readBextChunk_ A

Complexity

Size

Duplication

Importance

Duplication Side-by-Side

Filter issues like
