/* Test hash function to convert "abcdefABCDEF" to hexadecimal. */

#include<stdio.h>

int main(void)
{
   int correct, expected, actual, i, d;

   correct = 0;

   /* Input is already adjusted to match decimal digits, so the
      search range comes with a -48 adjustment.                 */
   for(i = 0; i < 256 - 48; i++)
   {
      expected = (i >= 'a' - 48 && i <= 'f' - 48) ||
                 (i >= 'A' - 48 && i <= 'F' - 48) ? (i & 15) + 9 : -1;

      d = i;

      #if 0
         actual = (d-- & ~39) - 16
            ? -1
            : (d &= 15) < 6 ? d + 10 : -1;
      #else
         actual = (d & ~39) - 16 || ~-d % 16 > 5
            ? -1
            : d % 16 + 9;
      #endif
      if( (expected < 0 && actual < 0) || (expected == actual) )
         correct++;
   }
   if( correct == 256 - 48 )
      puts("ok");

   return 0;
}