Method Update

src/cryptopp/cmac.cpp:58–101

}

void CMAC_Base::Update(const byte *input, size_t length)
{
	CRYPTOPP_ASSERT((input && length) || !(input || length));
	if (!length)
		return;

	BlockCipher &cipher = AccessCipher();
	unsigned int blockSize = cipher.BlockSize();

	if (m_counter > 0)
	{
		const unsigned int len = UnsignedMin(blockSize - m_counter, length);
		if (len)
		{
			xorbuf(m_reg+m_counter, input, len);
			length -= len;
			input += len;
			m_counter += len;
		}

		if (m_counter == blockSize && length > 0)
		{
			cipher.ProcessBlock(m_reg);
			m_counter = 0;
		}
	}

	if (length > blockSize)
	{
		CRYPTOPP_ASSERT(m_counter == 0);
		size_t leftOver = 1 + cipher.AdvancedProcessBlocks(m_reg, input, m_reg, length-1, BlockTransformation::BT_DontIncrementInOutPointers|BlockTransformation::BT_XorInput);
		input += (length - leftOver);
		length = leftOver;
	}

	if (length > 0)
	{
		CRYPTOPP_ASSERT(m_counter + length <= blockSize);
		xorbuf(m_reg+m_counter, input, length);
		m_counter += (unsigned int)length;
	}

	CRYPTOPP_ASSERT(m_counter > 0);
}

void CMAC_Base::TruncatedFinal(byte *mac, size_t size)
{