CRC32Example

    // ------------------------------- //
    // -------- Start of File -------- //
    // ------------------------------- //
    // ----------------------------------------------------------- //
    // C++ Source Code File Name: testprog.cpp
    // Compiler Used: MSVC, BCC32, GCC, HPUX aCC, SOLARIS CC
    // Produced By: DataReel Software Development Team
    // File Creation Date: 08/17/1998
    // Date Last Modified: 06/17/2016
    // Copyright (c) 2001-2016 DataReel Software Development
    // ----------------------------------------------------------- //
    // ------------- Program description and details ------------- //
    // ----------------------------------------------------------- //
    /*
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
    USA

    The CRC32 functions (Cyclic Redundancy Check) are used to
    calculate a sophisticated checksum based on the algebra of
    polynomials. The Cyclic Redundancy Check, is a way to detect
    bit errors that occur during data storage or transmission.
    The CRC-32 algorithm operates on a block of data as a single
    large numerical value. The algorithm divides this large value
    by the CRC-32 polynomial or generator polynomial, leaving the
    remainder 32-bit, which is the checksum.
    */
    // ----------------------------------------------------------- //
    #include "gxdlcode.h"

    #if defined (__USE_ANSI_CPP__) // Use the ANSI Standard C++ library
    #include <iostream>
    #include <iomanip>
    using namespace std; // Use unqualified names for Standard C++ library
    #else // Use the old iostream library by default
    #include <iostream.h>
    #include <iomanip.h>
    #endif // __USE_ANSI_CPP__

    #include <string.h>
    #include <stdlib.h>
    #include "gxcrc32.h"

    char in_file[255]; // Input file

    void HelpMessage(const char *program_name)
    {
      cout << "\n";
      cout << "CRC-32 program." << "\n";
      cerr << "Displays 32-bit CRC for a specified file or string." << "\n";
      cout << "Usage: " << program_name << " [switches] infile" << "\n";
      cout << "Switches:  -?      = Display this help message." << "\n";
      cout << "           -sData  = Display 32-bit CRC for a specified string."
           << "\n";
      cout << "           -t      = Write a CRC-32 table to the standard output."
           << "\n";
      cout << "\n";
      exit(0);
    }

    void ProcessArgs(int argc, char *argv[])
    // Process the program's argument list
    {
      char *sbuf;
      int i;
      for(i = 1; i < argc; i++ ) {
        if(*argv[i] == '-') {
          char sw = *(argv[i] +1);
          switch(sw) {
    	case '?' :
    	  HelpMessage(argv[0]);
    	  break;

    	case 's': {
    	  sbuf = &argv[i][2];
    	  unsigned long crc;
    	  crc = calcCRC32(sbuf, strlen(sbuf));
    	  cout << sbuf << "\n";
    	  cout << "CRC-32 = ";
    	  cout.setf(ios::uppercase);
    	  cout << "0x" << setfill('0') << setw(8) << hex << crc << "\n";
    	  cout.unsetf(ios::uppercase);
    	  exit(0);
    	  break;
    	}

    	case 't':
    	  makeCRC32(cout);
    	  exit(0);
    	  break;

    	default:
    	  cerr << "\n";
    	  cerr << "Unknown switch " << argv[i] << "\n";
    	  cerr << "Exiting..." << "\n";
    	  cerr << "\n";
    	  exit(0);
    	  break;
          }
        }
        else {
          strcpy(in_file, argv[i]);
        }
      }
    }

    int main(int argc,char *argv[])
    {
      // If no argument is given print usage message to the screen
      if(argc < 2) {
        HelpMessage(argv[0]);
        return 0;
      }

      // Process the programs command line arguments
      ProcessArgs(argc, argv);

      if(in_file[0] == 0 ) {
        cout << "\n";
        cout << "You must specify a valid input file name." << "\n";
        cout << "\n";
        return 0;
      }

      DiskFileB infile(in_file);
      if(!infile) {
        cerr << "\n";
        cerr << "Cannot open file: " << in_file << "\n";
        cerr << "Exiting..." << "\n";
        cerr << "\n";
        return 1;
      }

      unsigned long crc = calcCRC32(infile);
      cout << in_file << "\n";
      cout << "CRC-32 = ";
      cout.setf(ios::uppercase);
      cout << "0x" << setfill('0') << setw(8) << hex << crc << "\n";
      cout.unsetf(ios::uppercase);
      infile.df_Close();
      return 0;
    }
    // ----------------------------------------------------------- //
    // ------------------------------- //
    // --------- End of File --------- //
    // ------------------------------- //