protected override def decodeOneUnicodeChar()

in daffodil-io/src/main/scala/org/apache/daffodil/io/processors/charset/UTF8.scala [31:106]

• 66 lines of code
• 10 McCabe index (conditional complexity)

  protected override def decodeOneUnicodeChar(
    dis: InputSourceDataInputStream,
    finfo: FormatInfo
  ): Char = {
    val byte1 = getByte(dis, 0)
    if ((byte1 & 0x80) == 0) {
      // 1 byte
      byte1.toChar
    } else if ((byte1 & 0xe0) == 0xc0) {
      // 2 bytes
      val byte2 = getByte(dis, 8)
      checkContinuationByte(dis, byte2, 16)
      checkOverlong(byte1, 0x1f, 0, 0, 16)
      val cp = ((byte1 & 0x1f) << 6) | (byte2 & 0x3f)
      cp.toChar
    } else if ((byte1 & 0xf0) == 0xe0) {
      // 3 bytes
      val byte2 = getByte(dis, 8)
      checkContinuationByte(dis, byte2, 16)
      val byte3 = getByte(dis, 16)
      checkContinuationByte(dis, byte3, 24)
      checkOverlong(byte1, 0x0f, byte2, 0x20, 24)
      val cp = ((byte1 & 0x0f) << 12) | ((byte2 & 0x3f) << 6) | (byte3 & 0x3f)
      if (cp >= 0xd800 && cp <= 0xdfff) {
        // out of valid range of Unicode (reserved for surrogate)
        throw new BitsCharsetDecoderMalformedException(24)
      }
      cp.toChar
    } else if ((byte1 & 0xf8) == 0xf0) {
      // 4 bytes
      val byte2 = getByte(dis, 8)
      checkContinuationByte(dis, byte2, 16)
      val byte3 = getByte(dis, 16)
      checkContinuationByte(dis, byte3, 24)
      val byte4 = getByte(dis, 24)
      checkContinuationByte(dis, byte4, 32)
      checkOverlong(byte1, 0x07, byte2, 0x30, 32)
      val cp =
        ((byte1 & 0x0f) << 18) | ((byte2 & 0x3f) << 12) | ((byte3 & 0x3f) << 6) | (byte4 & 0x3f)
      if (cp > 0x10ffff) {
        // out of valid range of Unicode
        throw new BitsCharsetDecoderMalformedException(32)
      }
      val high = Character.highSurrogate(cp)
      setLowSurrogate(Character.lowSurrogate(cp))
      high
    } else if ((byte1 & 0xfc) == 0xf8) {
      // 5 bytes, invalid, but we still need to read any continuation bits and
      // mark them as all malformed
      val byte2 = getByte(dis, 8)
      checkContinuationByte(dis, byte2, 16)
      val byte3 = getByte(dis, 16)
      checkContinuationByte(dis, byte3, 24)
      val byte4 = getByte(dis, 24)
      checkContinuationByte(dis, byte4, 32)
      val byte5 = getByte(dis, 32)
      checkContinuationByte(dis, byte5, 40)
      throw new BitsCharsetDecoderMalformedException(40)
    } else if ((byte1 & 0xfe) == 0xfc) {
      // 6 bytes, invalid, but we still need to read any continuation bits and
      // mark them as all malformed
      val byte2 = getByte(dis, 8)
      checkContinuationByte(dis, byte2, 16)
      val byte3 = getByte(dis, 16)
      checkContinuationByte(dis, byte3, 24)
      val byte4 = getByte(dis, 24)
      checkContinuationByte(dis, byte4, 32)
      val byte5 = getByte(dis, 32)
      checkContinuationByte(dis, byte5, 40)
      val byte6 = getByte(dis, 40)
      checkContinuationByte(dis, byte6, 48)
      throw new BitsCharsetDecoderMalformedException(48)
    } else {
      throw new BitsCharsetDecoderMalformedException(8)
    }
  }