/*
 * Copyright 2002-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * XSEC
 *
 * WinCAPICryptoHash := Windows CAPI Implementation of Message digests
 *
 * Author(s): Berin Lautenbach
 *
 * $Id$
 *
 */

#include <xsec/enc/WinCAPI/WinCAPICryptoHash.hpp>
#include <xsec/enc/XSECCryptoException.hpp>
#include <xsec/enc/WinCAPI/WinCAPICryptoProvider.hpp>

#if defined (HAVE_WINCAPI)

#include <memory.h>

// Constructors/Destructors

WinCAPICryptoHash::WinCAPICryptoHash(HCRYPTPROV prov, HashType alg) {

	m_p = prov;
	m_hashType = alg;
	m_h = 0;

	reset();
}


WinCAPICryptoHash::~WinCAPICryptoHash() {

	if (m_h != 0)
		CryptDestroyHash(m_h);

}


// Hashing Activities
void WinCAPICryptoHash::reset(void) {

	if (m_h != 0)
		CryptDestroyHash(m_h);

	m_h = 0;
	
	BOOL fResult;
	ALG_ID alg_id;

	switch (m_hashType) {

	case (XSECCryptoHash::HASH_SHA1) :
	
		alg_id = CALG_SHA;
		break;

	case (XSECCryptoHash::HASH_MD5) :
	
		alg_id = CALG_MD5;
		break;

	default :

		alg_id = 0;

	}

	if(alg_id == 0) {

		throw XSECCryptoException(XSECCryptoException::MDError,
			"WinCAPI:Hash - Unknown algorithm (NOTE SHA512 and SHA256 not supported"); 
	}

	fResult = CryptCreateHash(
		m_p,
		alg_id,
		0,
		0,
		&m_h);

	if (fResult == 0 || m_h == 0) {
		throw XSECCryptoException(XSECCryptoException::MDError,
			"WinCAPI:Hash - Error creating hash object"); 
	}

}

void WinCAPICryptoHash::hash(unsigned char * data, 
								 unsigned int length) {

	BOOL fResult = CryptHashData(
		m_h,
		data,
		length,
		0);

	if (fResult == 0) {
		throw XSECCryptoException(XSECCryptoException::MDError,
			"WinCAPI:Hash - Error Hashing Data"); 
	}

}

unsigned int WinCAPICryptoHash::finish(unsigned char * hash,
									   unsigned int maxLength) {

	DWORD retLen;
	BOOL fResult;

	retLen = WINCAPI_MAX_HASH_SIZE;

	fResult = CryptGetHashParam(
		m_h,
		HP_HASHVAL,
		m_mdValue,
		&retLen,
		0);

	if (fResult == 0) {
		throw XSECCryptoException(XSECCryptoException::MDError,
			"WinCAPI:Hash - Error getting hash value"); 
	}

	m_mdLen = retLen;
	retLen = (maxLength > m_mdLen ? m_mdLen : maxLength);
	memcpy(hash, m_mdValue, retLen);

	return (unsigned int) retLen;

}

// Get information

XSECCryptoHash::HashType WinCAPICryptoHash::getHashType(void) {

	return m_hashType;			// This could be any kind of hash

}

#endif /* HAVE_WINCAPI */