/*
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/*
 * XSEC
 *
 * OpenSSLCryptoHashHMAC := OpenSSL Implementation of HMAC
 *
 * Author(s): Berin Lautenbach
 *
 * $Id: OpenSSLCryptoHashHMAC.cpp,v 1.4 2003/04/11 12:26:26 blautenb Exp $
 *
 */

#include <xsec/framework/XSECDefs.hpp>
#if defined (HAVE_OPENSSL)


#include <xsec/enc/OpenSSL/OpenSSLCryptoHashHMAC.hpp>
#include <xsec/enc/XSECCryptoException.hpp>
#include <xsec/enc/XSECCryptoKeyHMAC.hpp>

#include <memory.h>

// Constructors/Destructors

OpenSSLCryptoHashHMAC::OpenSSLCryptoHashHMAC(HashType alg) {

	// Initialise the digest

	switch (alg) {

	case (XSECCryptoHash::HASH_SHA1) :
	
		mp_md = EVP_get_digestbyname("SHA1");
		break;

	case (XSECCryptoHash::HASH_MD5) :
	
		mp_md = EVP_get_digestbyname("MD5");
		break;

	default :

		mp_md = NULL;

	}

	if(!mp_md) {

		throw XSECCryptoException(XSECCryptoException::MDError,
			"OpenSSL:HashHMAC - Error loading Message Digest"); 
	}

	m_initialised = false;
	m_hashType = alg;

}

void OpenSSLCryptoHashHMAC::setKey(XSECCryptoKey *key) {

	// Use this to initialise the HMAC Context

	if (key->getKeyType() != XSECCryptoKey::KEY_HMAC) {

		throw XSECCryptoException(XSECCryptoException::MDError,
			"OpenSSL:HashHMAC - Non HMAC Key passed to OpenSSLHashHMAC");

	}

	unsigned int m_keyLen = ((XSECCryptoKeyHMAC *) key)->getKey(m_keyBuf);


	HMAC_Init(&m_hctx, 
		m_keyBuf.rawBuffer(),
		m_keyLen,
		mp_md);

	m_initialised = true;

}

OpenSSLCryptoHashHMAC::~OpenSSLCryptoHashHMAC() {}



// Hashing Activities

void OpenSSLCryptoHashHMAC::reset(void) {


	if (m_initialised)
		HMAC_Init(&m_hctx, 
			m_keyBuf.rawBuffer(),
			m_keyLen,
			mp_md);

}

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

	if (!m_initialised)
		throw XSECCryptoException(XSECCryptoException::MDError,
			"OpenSSL:HashHMAC - hash called prior to setKey");


	HMAC_Update(&m_hctx, data, (int) length);

}

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

	unsigned int retLen;

	// Finish up and copy out hash, returning the length

	HMAC_Final(&m_hctx, m_mdValue, &m_mdLen);

	// Copy to output buffer
	
	retLen = (maxLength > m_mdLen ? m_mdLen : maxLength);
	memcpy(hash, m_mdValue, retLen);

	return retLen;

}

// Get information

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

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

}

#endif /* HAVE_OPENSSL */