parseBinaryData()

in packages/miew/src/gfx/FrameInfo.js [147:204]
57 lines of code
11 McCabe index (conditional complexity)

  parseBinaryData(arrayBuffer) {
    const dataView = new DataView(arrayBuffer);
    let offset = 0;
    const atomsCount = dataView.getUint32(offset, true);
    offset += 4;
    const framesCount = dataView.getUint32(offset, true);
    this._framesCount = framesCount;
    this._framesRange.end = this._framesRange.end > 0
      ? Math.min(this._framesRange.end, framesCount - 1) : framesCount - 1;
    offset += 4;
    this._atomsCount = atomsCount;
    const maxSize = 1024 * 1024; // 1 MB
    this._framesRequestLength = Math.ceil(maxSize / (atomsCount * 8));
    const chunkedFramesCount = this._framesRange.end - this._framesRange.start + 1;
    if (atomsCount !== this._complex._atoms.length
      || arrayBuffer.byteLength !== cDataOffset + chunkedFramesCount * atomsCount * 8) {
      throw new Error();
    }
    const complex = this._complex;
    let timeStep = dataView.getUint32(offset, true);
    let iName = 0;
    while (timeStep > 1000 && iName < cSecNames.length - 1) {
      timeStep /= 1000;
      ++iName;
    }

    this._timeStep = `${timeStep.toString()} ${cSecNames[iName]}`;
    offset += 4;
    const secondary = [];
    const posData = new Float32Array(chunkedFramesCount * atomsCount * 3);
    let coordIdx = 0;
    const secondaryArr = new Int8Array(atomsCount);
    for (let j = 0; j < chunkedFramesCount; ++j) {
      for (let i = 0; i < atomsCount; ++i) {
        const hiWord = dataView.getUint32(offset, true);
        offset += 4;
        const loWord = dataView.getUint32(offset, true);
        offset += 4;
        const str = (loWord & cStrMask) >>> cStrShift;
        const x = fromUInt20ToInt20(((loWord & cFirstMask) >>> cFirstShift) >> 0);
        const y = fromUInt20ToInt20((((loWord & cSecMask1) << cSecShift1)
          | ((hiWord & cSecMask2) >>> cSecShift2)) >> 0);
        const z = fromUInt20ToInt20((hiWord & cThirdMask) >> 0);
        secondaryArr[i] = 0;
        if (str > 0 && str < 4) {
          secondaryArr[i] = cHelixIdx;
        } else if (str === 4) {
          secondaryArr[i] = cSheetIdx;
        }
        posData[coordIdx++] = x / 100;
        posData[coordIdx++] = y / 100;
        posData[coordIdx++] = z / 100;
      }
      secondary.push(_createSecondary(secondaryArr, complex));
    }
    this._secondaryData = secondary;
    this._data = posData;
  }