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test for strncpy


I've written a test for strncpy - using the strcpy one as a starting point.
Unfortunately, there are more variables to consider, so this test takes
1.7 seconds natively on a 1.4 GHz Athlon; 6 minutes 13 seconds to execute
it under the sh64-elf simulator on the same machine for the -O0 version.
The -O and -O2 versions takes 1 minute 16 seconds and 1 minute 13 seconds,
respectively.
So, should we run this test only when optimizing?

*** /dev/null	Thu Aug 30 21:30:55 2001
--- gcc/testsuite/gcc.c-torture/execute/strncpy-1.c	Thu Sep 25 17:56:49 2003
***************
*** 0 ****
--- 1,84 ----
+ /* Copyright (C) 2003  Free Software Foundation.
+ 
+    Test strncpy with various combinations of pointer alignments and lengths to
+    make sure any optimizations in the library are correct.  */
+ 
+ #include <string.h>
+ 
+ #ifndef MAX_OFFSET
+ #define MAX_OFFSET (sizeof (long long))
+ #endif
+ 
+ #ifndef MAX_COPY
+ #define MAX_COPY (10 * sizeof (long long))
+ #endif
+ 
+ #ifndef MAX_EXTRA
+ #define MAX_EXTRA (sizeof (long long))
+ #endif
+ 
+ #define MAX_LENGTH (MAX_OFFSET + MAX_COPY + 1 + 2 * MAX_OFFSET + MAX_EXTRA)
+ 
+ /* Use a sequence length that is not divisible by two, to make it more
+    likely to detect when words are mixed up.  */
+ #define SEQUENCE_LENGTH 31
+ 
+ static union {
+   char buf[MAX_LENGTH];
+   long long align_int;
+   long double align_fp;
+ } u1, u2;
+ 
+ main ()
+ {
+   int off1, off2, off3, len, max, capped_len, i;
+   char *p, *q, c;
+ 
+   for (off1 = 0; off1 < MAX_OFFSET; off1++)
+     for (off2 = 0; off2 < MAX_OFFSET; off2++)
+       for (off3 = 0; off3 < MAX_OFFSET; off3++)
+         for (len = 1; len < MAX_COPY; len++)
+           for (max = len - MAX_OFFSET; max <= len + 2 * (int) MAX_OFFSET; max++)
+             {
+               if (max < 0)
+                 max = 0;
+               for (i = 0, c = 'A'; i < MAX_LENGTH; i++, c++)
+                 {
+                   u1.buf[i] = 'a';
+                   if (c >= 'A' + SEQUENCE_LENGTH)
+                     c = 'A';
+                   u2.buf[i] = c;
+                 }
+               u2.buf[off2 + len] = '\0';
+               u2.buf[off2 + len + off3] = '\0';
+ 
+               p = strncpy (u1.buf + off1, u2.buf + off2, max);
+               if (p != u1.buf + off1)
+                 abort ();
+ 
+               q = u1.buf;
+               for (i = 0; i < off1; i++, q++)
+                 if (*q != 'a')
+                   abort ();
+               capped_len = len;
+               if (capped_len > max)
+                 capped_len = max;
+ 
+               for (i = 0, c = 'A' + off2; i < capped_len; i++, q++, c++)
+                 {
+                   if (c >= 'A' + SEQUENCE_LENGTH)
+                     c = 'A';
+                   if (*q != c)
+                     abort ();
+                 }
+ 
+               for (i = len; i < max; i++)
+                 if (*q++ != '\0')
+                   abort ();
+               for (i = 0; i < MAX_EXTRA; i++, q++)
+                 if (*q != 'a')
+                   abort ();
+             }
+ 
+   exit (0);
+ }


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