sS decompressMozillaJSONLZ4File(File f) {
  byte[] data = loadBinaryFile(f);
  if (empty(data)) null;
  
  int lDecompressed = intFromBytes_littleEndian(data, 8);

  // our very own LZ4 decompressor!
  int i = 12, n = l(data), iOut = 0;
  byte[] out = new byte[lDecompressed];
  while (i < n) {
    int lLiteral = (data[i] >> 4) & 0x0F;
    int lMatches = (data[i] & 0x0F)+4;
    i++;
    if (lLiteral == 15) {
      int more;
      do {
        more = data[i++] & 0xFF;
        lLiteral += more;
      } while (more == 255);
    }
    arraycopy(data, i, out, iOut, lLiteral);
    iOut += lLiteral;
    i += lLiteral;
    if (i >= n) break;
    int offset = data[i] & 0xFF | (data[i+1] & 0xFF) << 8;
    i += 2;
    if (offset == 0) fail("bad offset");
    if (lMatches == 19) {
      int more;
      do {
        more = data[i++] & 0xFF;
        lMatches += more;
      } while (more == 255);
    }
    int j = lMatches;
    while (j-- > 0) {
      out[iOut] = out[iOut-offset];
      iOut++;
    }
  }
  ret fromUtf8(out);
}