ByteTools_browser_export.js

/**
 * ByteTools.js: Browser
 * Copyright (c) 2020 PROPHESSOR
 *
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

export default class ByteTools {
  /**
   *
   * @param {DataView} view - DataView (new DataView(ArrayBuffer))
   */
  constructor(view) {
    this.buffer = view;
    this.offset = 0;
  }

  // basics
  get length() {
    return this.buffer.byteLength;
  }
  
  tell() {
    return this.offset;
  }

  /**
   *
   * @param {number} offset
   * @param {'START'|'CUR'} mode
   */
  seek(offset, mode = 'START') {
    switch (mode) {
      case 'CUR':
        return this.offset += offset;
      case 'START':
      default:
        return this.offset = offset;
    }
  }

  // read

  readString(length = Infinity, trimZeroEnding = true) {
    let string = '';

    for (let i = 0; i < length; i++) {
      const char = this.readUInt8();

      if (length === Infinity && char === 0) return string;

      string += String.fromCharCode(char);
    }

    if (trimZeroEnding) return string.replace(/\x00/g, '');

    return string;
  }

  // int8

  readInt8() {
    const tmp = this.buffer.getInt8(this.offset);

    this.offset += 1;

    return tmp;
  }

  readUInt8() {
    const tmp = this.buffer.getUint8(this.offset);

    this.offset += 1;

    return tmp;
  }


  // int16

  readInt16() {
    const tmp = this.buffer.getInt16(this.offset, true);

    this.offset += 2;

    return tmp;
  }

  readUInt16() {
    const tmp = this.buffer.getUint16(this.offset, true);

    this.offset += 2;

    return tmp;
  }

  // int32

  readInt32() {
    const tmp = this.buffer.getInt32(this.offset, true);

    this.offset += 4;

    return tmp;
  }

  readUInt32() {
    const tmp = this.buffer.getUint32(this.offset, true);

    this.offset += 4;

    return tmp;
  }

  // seek

  // int8

  seekInt8() {
    return this.buffer.getInt8(this.offset);
  }

  seekUInt8() {
    return this.buffer.getUint8(this.offset);
  }


  // int16

  seekInt16() {
    return this.buffer.getInt16(this.offset, true);
  }

  seekUInt16() {
    return this.buffer.getUint16(this.offset, true);
  }

  // int32

  seekInt32() {
    return this.buffer.getInt32(this.offset, true);
  }

  seekUInt32() {
    return this.buffer.getUint32(this.offset, true);
  }

  // skip

  // int8

  skipInt8() {
    return this.offset += 1;
  }


  // int16

  skipInt16() {
    return this.offset += 2;
  }

  // int32

  skipInt32() {
    return this.offset += 4;
  }
}