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
cksum(const unsigned char * src,unsigned long size)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
main()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 }
61