/* verifycd - compare cd image to iso file on disk
**   keithl@keithl.com   January 7, 2004
**
**   compile with:   cc -o verifycd verifycd.c
*/

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define PROG      "verifycd"
#define BUFSIZE   512
#define BUFPERMEG 2048

#define DEBUG    1

int    bufcnt  ;
int    megcnt  ;
int    size_cd ;
int    size_hd ;
char   cdbuf[ BUFSIZE ];
char   hdbuf[ BUFSIZE ];
char  *cdptr;
char  *hdptr;
char  *bufend;
int    cd;
int    hd;

int main(int argc, char *argv[] )
{

   // check arguments

   if( argc != 3 )
   {
      fprintf( stderr, "usage: verifycd </dev/cdrom> <isofile>\n" );
      return 2;
   }

   // open cdrom and hd files
   
   if( ( cd = open( argv[1] , O_RDONLY , 0 ) ) < 0 )
   {
      fprintf( stderr, "%s: cannot open cdrom drive %s\n", PROG, argv[1] );
      return 2;
   }

   if( ( hd = open( argv[2] , O_RDONLY , 0 ) ) < 0 )
   {
      fprintf( stderr, "%s: cannot open file %s\n", PROG, argv[2] );
      return 2;
   }

   // buffer loop

   bufcnt = 0;
   megcnt = 0;

   do
   {
      size_cd = read( cd, cdbuf , BUFSIZE );
      size_hd = read( hd, hdbuf , BUFSIZE );


      // check for short CD

      if ( (size_hd > 0 ) && ( size_hd > size_cd ) )
      {
         close( cd );
         close( hd );
         fprintf( stderr, "hd=%03d cd=%03d\n", size_hd, size_cd );
         fprintf( stderr, "%s FAILED - CD image too short\n", PROG );
         return 1;
      }

      cdptr  = cdbuf ;
      hdptr  = hdbuf ;
      bufend = cdbuf + size_cd ;


      // byte loop - compare buffered data

      while ( cdptr < bufend ) 
      {
         if ( *(cdptr++) != *(hdptr++) )
         {
            close( cd );
            close( hd );
	    fprintf( stderr, "%s FAILED - images differ\n", PROG );
            return 1;
         }
      }

      // progress counter

      if( ++bufcnt >= BUFPERMEG )
      {
         fprintf( stdout, "%4d MB\r", ++megcnt );
         fflush( stdout );
         bufcnt = 0 ;
      }

   }
   while ( size_cd == BUFSIZE );


   // end of buffer loop, end of files

   close( cd );
   close( hd );
   fprintf( stderr, "%s SUCCEEDED - images OK\n", PROG );
   return 0;
}