Function createSinglebyteDecoder

lib/internal/encoding/single-byte.js:108–149

(encoding, fatal)

const decodersFatal = new SafeMap();

function createSinglebyteDecoder(encoding, fatal) {
  const id = encoding === 'iso-8859-8-i' ? 'iso-8859-8' : encoding;
  const decoders = fatal ? decodersFatal : decodersLoose;
  const cached = decoders.get(id);
  if (cached) return cached;

  const map = getEncoding(id);
  const incomplete = TypedArrayPrototypeIncludes(map, r);

  // Expects type-checked Buffer input
  const decoder = (buf) => {
    if (buf.byteLength === 0) return '';
    if (isAscii(buf)) return buf.latin1Slice(); // .latin1Slice is faster than .asciiSlice
    const o = new Uint16Array(buf.length);
    TypedArrayPrototypeSet(o, buf); // Copy to modify in-place, also those are 16-bit now

    let i = 0;
    for (const end7 = o.length - 7; i < end7; i += 8) {
      o[i] = map[o[i]];
      o[i + 1] = map[o[i + 1]];
      o[i + 2] = map[o[i + 2]];
      o[i + 3] = map[o[i + 3]];
      o[i + 4] = map[o[i + 4]];
      o[i + 5] = map[o[i + 5]];
      o[i + 6] = map[o[i + 6]];
      o[i + 7] = map[o[i + 7]];
    }

    for (const end = o.length; i < end; i++) o[i] = map[o[i]];

    const b = new FastBuffer(o.buffer, o.byteOffset, o.byteLength);
    if (isBigEndian) b.swap16();
    const string = b.ucs2Slice();
    if (fatal && incomplete && StringPrototypeIncludes(string, '\uFFFD')) {
      throw new ERR_ENCODING_INVALID_ENCODED_DATA(encoding, undefined);
    }
    return string;
  };

  decoders.set(id, decoder);
  return decoder;
}

module.exports = {
  isSinglebyteEncoding,