/*
 *  fhicl-sha1.h
 *
 *  Copyright (C) 1998, 2009
 *  Paul E. Jones <paulej@packetizer.com>
 *  All Rights Reserved.
 *
 *****************************************************************************
 *  $Id: fhicl-sha1.h 12 2009-06-22 19:34:25Z paulej $
 *****************************************************************************
 *
 *  Description:
 *      This class implements the Secure Hashing Standard as defined
 *      in FIPS PUB 180-1 published April 17, 1995.
 *
 *      Many of the variable names in this class, especially the single
 *      character names, were used because those were the names used
 *      in the publication.
 *
 *      Please read the file fhicl-sha1.cpp for more information.
 *
 */

#ifndef _SHA1_H_
#define _SHA1_H_

namespace fhicl {

class SHA1
{

	public:

		SHA1();
		virtual ~SHA1();

		/*
		 *  Re-initialize the class
		 */
		void Reset();

		/*
		 *  Returns the message digest
		 */
		bool Result(unsigned *message_digest_array);

		/*
		 *  Provide input to SHA1
		 */
		void Input( const unsigned char *message_array,
					unsigned            length);
		void Input( const char  *message_array,
					unsigned    length);
		void Input(unsigned char message_element);
		void Input(char message_element);
		SHA1& operator<<(const char *message_array);
		SHA1& operator<<(const unsigned char *message_array);
		SHA1& operator<<(const char message_element);
		SHA1& operator<<(const unsigned char message_element);

	private:

		/*
		 *  Process the next 512 bits of the message
		 */
		void ProcessMessageBlock();

		/*
		 *  Pads the current message block to 512 bits
		 */
		void PadMessage();

		/*
		 *  Performs a circular left shift operation
		 */
		inline unsigned CircularShift(int bits, unsigned word);

		unsigned H[5];                      // Message digest buffers

		unsigned Length_Low;                // Message length in bits
		unsigned Length_High;               // Message length in bits

		unsigned char Message_Block[64];    // 512-bit message blocks
		int Message_Block_Index;            // Index into message block array

		bool Computed;                      // Is the digest computed?
		bool Corrupted;                     // Is the message digest corruped?

};

} // end of namespace mf

#endif