sha1.h

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/*
 *  sha1.h
 *
 *  Copyright (C) 1998, 2009
 *  Paul E. Jones <paulej@packetizer.com>
 *  All Rights Reserved.
 *
 *****************************************************************************
 *  $Id: 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 sha1.cpp for more information.
 *
 */

#ifndef cetlib_test_sha1_h
#define cetlib_test_sha1_h

namespace fhicl {

  class SHA1 {

  public:
    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 /* cetlib_test_sha1_h */

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