- for (j = 0; j < 256; j++)
- input[i + j] = j;
- for (j = 0; j < 256; j++)
- {
- ASSERT (MEMCHR (input + i, j, 256) == input + i + j);
- }
+ for (j = 0; j < 256; j++)
+ input[i + j] = j;
+ for (j = 0; j < 256; j++)
+ {
+ ASSERT (MEMCHR (input + i, j, 256) == input + i + j);
+ }
+ }
+ }
+
+ /* Check that memchr() does not read past the first occurrence of the
+ byte being searched. See the Austin Group's clarification
+ <http://www.opengroup.org/austin/docs/austin_454.txt>.
+ Test both '\0' and something else, since some implementations
+ special-case searching for NUL.
+ */
+ {
+ char *page_boundary = (char *) zerosize_ptr ();
+ /* Too small, and we miss cache line boundary tests; too large,
+ and the test takes cubically longer to complete. */
+ int limit = 257;
+
+ if (page_boundary != NULL)
+ {
+ for (n = 1; n <= limit; n++)
+ {
+ char *mem = page_boundary - n;
+ memset (mem, 'X', n);
+ ASSERT (MEMCHR (mem, 'U', n) == NULL);
+ ASSERT (MEMCHR (mem, 0, n) == NULL);
+
+ {
+ size_t i;
+ size_t k;
+
+ for (i = 0; i < n; i++)
+ {
+ mem[i] = 'U';
+ for (k = i + 1; k < n + limit; k++)
+ ASSERT (MEMCHR (mem, 'U', k) == mem + i);
+ mem[i] = 0;
+ for (k = i + 1; k < n + limit; k++)
+ ASSERT (MEMCHR (mem, 0, k) == mem + i);
+ mem[i] = 'X';
+ }
+ }
+ }