/* This file is part of the KDE project
   Copyright (C) 2001 George Staikos <staikos@kde.org>
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
 
   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.
 
   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/


#include "cbc.h"
#include <string.h>



CipherBlockChain::CipherBlockChain(BlockCipher *cipher) : _cipher(cipher) {
	_next = 0L;
	_register = 0L;
	_len = -1;
	_reader = _writer = 0L;
	if (cipher) {
		_blksz = cipher->blockSize();
	}
}


CipherBlockChain::~CipherBlockChain() {
	delete[] (char *)_register;
	_register = 0L;
	delete[] (char *)_next;
	_next = 0L;
}


bool CipherBlockChain::setKey(void *key, int bitlength) {
	if (_cipher) {
		return _cipher->setKey(key, bitlength);
	}
	return false;
}


int CipherBlockChain::keyLen() const {
	if (_cipher) {
		return _cipher->keyLen();
	}
	return -1;
}


bool CipherBlockChain::variableKeyLen() const {
	if (_cipher) {
		return _cipher->variableKeyLen();
	}
	return false;
}


bool CipherBlockChain::readyToGo() const {
	if (_cipher) {
		return _cipher->readyToGo();
	}
	return false;
}


int CipherBlockChain::encrypt(void *block, int len) {
	if (_cipher && !_reader) {
		int rc;

		_writer |= 1;

		if (!_register) {
			_register = new unsigned char[len];
			_len = len;
			memset(_register, 0, len);
		} else if (len > _len) {
			return -1;
		}

		// This might be optimizable
		char *tb = (char *)block;
		for (int i = 0; i < len; i++) {
			tb[i] ^= ((char *)_register)[i];
		}

		rc = _cipher->encrypt(block, len);

		if (rc != -1) {
			memcpy(_register, block, len);
		}

		return rc;
	}
	return -1;
}


int CipherBlockChain::decrypt(void *block, int len) {
	if (_cipher && !_writer) {
		int rc;

		_reader |= 1;

		if (!_register) {
			_register = new unsigned char[len];
			_len = len;
			memset(_register, 0, len);
		} else if (len > _len) {
			return -1;
		} 

		if (!_next)
			_next = new unsigned char[_len];
		memcpy(_next, block, _len);

		rc = _cipher->decrypt(block, len);

		if (rc != -1) {
			// This might be optimizable
			char *tb = (char *)block;
			for (int i = 0; i < len; i++) {
				tb[i] ^= ((char *)_register)[i];
			}
		}

		void *temp;
		temp = _next;
		_next = _register;
		_register = temp;

		return rc;
	}
	return -1;
}