void decode()

in src/main/java/org/apache/commons/codec/binary/Base16.java [151:200]
34 lines of code
11 McCabe index (conditional complexity)

    void decode(final byte[] data, int offset, final int length, final Context context) {
        if (context.eof || length < 0) {
            context.eof = true;
            if (context.ibitWorkArea != 0) {
                validateTrailingCharacter();
            }
            return;
        }

        final int dataLen = Math.min(data.length - offset, length);
        final int availableChars = (context.ibitWorkArea != 0 ? 1 : 0) + dataLen;

        // small optimisation to short-cut the rest of this method when it is fed byte-by-byte
        if (availableChars == 1 && availableChars == dataLen) {
            // store 1/2 byte for next invocation of decode, we offset by +1 as empty-value is 0
            context.ibitWorkArea = decodeOctet(data[offset]) + 1;
            return;
        }

        // we must have an even number of chars to decode
        final int charsToProcess = availableChars % BYTES_PER_ENCODED_BLOCK == 0 ? availableChars : availableChars - 1;
        final int end = offset + dataLen;

        final byte[] buffer = ensureBufferSize(charsToProcess / BYTES_PER_ENCODED_BLOCK, context);

        int result;
        if (dataLen < availableChars) {
            // we have 1/2 byte from previous invocation to decode
            result = (context.ibitWorkArea - 1) << BITS_PER_ENCODED_BYTE;
            result |= decodeOctet(data[offset++]);

            buffer[context.pos++] = (byte)result;

            // reset to empty-value for next invocation!
            context.ibitWorkArea = 0;
        }

        final int loopEnd = end - 1;
        while (offset < loopEnd) {
            result = decodeOctet(data[offset++]) << BITS_PER_ENCODED_BYTE;
            result |= decodeOctet(data[offset++]);
            buffer[context.pos++] = (byte)result;
        }

        // we have one char of a hex-pair left over
        if (offset < end) {
            // store 1/2 byte for next invocation of decode, we offset by +1 as empty-value is 0
            context.ibitWorkArea = decodeOctet(data[offset]) + 1;
        }
    }