1  /* Duff's device is legal C; test to make sure the compiler
       2     doesn't complain about it.
       3  
       4     Jason Thorpe <thorpej@wasabisystems.com>
       5     Derived from the BSD Telnet Kerberos 4 checksum routine.
       6     See also PR 5230.  */
       7  
       8  /* { dg-do run } */
       9  /* { dg-options "-O2" } */
      10  
      11  extern void abort (void);
      12  extern void exit (int);
      13  
      14  #if __INT_MAX__ >= 2147483647
      15  /* At least 32-bit integers. */
      16  typedef int type32;
      17  #else
      18  typedef long type32;
      19  #endif
      20  
      21  type32
      22  cksum (const unsigned char *src, unsigned long size)
      23  {
      24    type32 ck = 0;
      25  
      26    switch (size & 3)
      27      {
      28      while (size > 0)
      29        {
      30      case 0:
      31  	ck ^= (type32)*src++ << 24;
      32  	--size;
      33      case 3:
      34  	ck ^= (type32)*src++ << 16;
      35  	--size;
      36      case 2:
      37  	ck ^= (type32)*src++ << 8;
      38  	--size;
      39      case 1:
      40  	ck ^= (type32)*src++;
      41  	--size;
      42        }
      43      }
      44  
      45    return ck;
      46  }
      47  
      48  const char testpat[] = "The quick brown fox jumped over the lazy dog.";
      49  
      50  int
      51  main()
      52  {
      53    type32 ck;
      54  
      55    ck = cksum ((const unsigned char *) testpat, sizeof (testpat));
      56    if (ck != 925902908)
      57      abort ();
      58  
      59    exit (0);
      60  }