Function createSampleRanges

src/pkg/utils/encoding.ts:75–108

(
  data: Uint8Array,
  rangeSize = CHECK_SIZE,
  maxRanges = MAX_UTF8_SAMPLE_RANGES
)

};

const createSampleRanges = (
  data: Uint8Array,
  rangeSize = CHECK_SIZE,
  maxRanges = MAX_UTF8_SAMPLE_RANGES
): ByteRange[] => {
  const n = data.length;
  if (n <= rangeSize) return [[0, n]];

  const ranges: ByteRange[] = [];
  const dk = n >>> 1;
  const rk = rangeSize >>> 1;
  addSampleRange(ranges, data, 0, rangeSize);
  addSampleRange(ranges, data, Math.max(0, dk - rk), Math.min(n, dk + rk));
  addSampleRange(ranges, data, Math.max(0, n - rangeSize), n);

  let nextHighByteSearchStart = rangeSize;
  while (ranges.length < maxRanges && nextHighByteSearchStart < n) {
    let highByteIndex = -1;
    for (let i = nextHighByteSearchStart; i < n; i++) {
      if (data[i] >= 0x80) {
        highByteIndex = i;
        break;
      }
    }
    if (highByteIndex < 0) break;

    const start = Math.max(0, highByteIndex - rk);
    const end = Math.min(data.length, start + rangeSize);
    addSampleRange(ranges, data, start, end);
    nextHighByteSearchStart = Math.max(highByteIndex + rangeSize, end);
  }

  return ranges.sort((a, b) => a[0] - b[0]);
};

const createLegacyDetectionSample = (data: Uint8Array): Uint8Array => {
  const n = data.length;