export function getValidWindows()

in speech-commands/src/dataset.ts [875:944]

• 64 lines of code
• 16 McCabe index (conditional complexity)

export function getValidWindows(
    snippetLength: number, focusIndex: number, windowLength: number,
    windowHop: number): Array<[number, number]> {
  tf.util.assert(
      Number.isInteger(snippetLength) && snippetLength > 0,
      () =>
          `snippetLength must be a positive integer, but got ${snippetLength}`);
  if (focusIndex != null) {
    tf.util.assert(
        Number.isInteger(focusIndex) && focusIndex >= 0,
        () =>
            `focusIndex must be a non-negative integer, but got ${focusIndex}`);
  }
  tf.util.assert(
      Number.isInteger(windowLength) && windowLength > 0,
      () => `windowLength must be a positive integer, but got ${windowLength}`);
  tf.util.assert(
      Number.isInteger(windowHop) && windowHop > 0,
      () => `windowHop must be a positive integer, but got ${windowHop}`);
  tf.util.assert(
      windowLength <= snippetLength,
      () => `windowLength (${windowLength}) exceeds snippetLength ` +
          `(${snippetLength})`);
  tf.util.assert(
      focusIndex < snippetLength,
      () => `focusIndex (${focusIndex}) equals or exceeds snippetLength ` +
          `(${snippetLength})`);

  if (windowLength === snippetLength) {
    return [[0, snippetLength]];
  }

  const windows: Array<[number, number]> = [];

  if (focusIndex == null) {
    // Deal with the special case of no focus frame:
    // Output an array of evenly-spaced windows, starting from
    // the first possible location.
    let begin = 0;
    while (begin + windowLength <= snippetLength) {
      windows.push([begin, begin + windowLength]);
      begin += windowHop;
    }
    return windows;
  }

  const leftHalf = Math.floor(windowLength / 2);
  let left = focusIndex - leftHalf;
  if (left < 0) {
    left = 0;
  } else if (left + windowLength > snippetLength) {
    left = snippetLength - windowLength;
  }

  while (true) {
    if (left - windowHop < 0 || focusIndex >= left - windowHop + windowLength) {
      break;
    }
    left -= windowHop;
  }

  while (left + windowLength <= snippetLength) {
    if (focusIndex < left) {
      break;
    }
    windows.push([left, left + windowLength]);
    left += windowHop;
  }
  return windows;
}