Example 3. Checking CRC Values: check_crc.c

#include <stdio.h>
#include "crc_tbl.h"

/****************************************************************************/
/* gen_crc() - computes the CRC value of data using the CRC algorithm ID    */
/*             specified.  Found in ref_crc.c                               */
/****************************************************************************/
unsigned long gen_crc(int id, const unsigned char *data, size_t len);

/****************************************************************************/
/* my_check_CRC() - verify the CRC values for all records stored in the     */
/*                  given CRC table.  Print diagnostic information also.    */
/****************************************************************************/
unsigned int my_check_CRC(CRC_TABLE *tp)
{
   int i;
   unsigned int ret_val = 1;
   uint32_t my_crc;

   printf("\n\tTABLE INFO: rec size=%d, num_rec=%d.",
          tp->rec_size, tp->num_recs);

   for (i = 0; i < tp->num_recs; i++)
   {
      CRC_RECORD crc_rec = tp->recs[i];

      /**************************************************/
      /* COMPUTE CRC OF DATA STARTING AT crc_rec.addr   */
      /* FOR crc_rec.size UNITS.  USE                   */
      /* crc_rec.crc_alg_ID to select algorithm.        */
      /* COMPARE COMPUTED VALUE TO crc_rec.crc_value.   */
      /**************************************************/
      my_crc = gen_crc(crc_rec.crc_alg_ID, (unsigned char *)crc_rec.addr, 
                       crc_rec.size);
      printf("\n\tCRC record: page=%x, alg=%x, addr = %lx, size=%lx, "
             "\n\t\tcrc=%lx, my_crc=%lx.",
             crc_rec.page_id, crc_rec.crc_alg_ID,
             crc_rec.addr, crc_rec.size, crc_rec.crc_value, my_crc);

      if (my_crc == crc_rec.crc_value)
         printf("\n\tCRCs match for record %d.\n", i);
      else
      {
         ret_val = 0;
         printf("\n\tCRCs DO NOT match for record %d.\n", i);
      }
   }
   return ret_val;
}