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-rw-r--r--string/strspn.c57
1 files changed, 42 insertions, 15 deletions
diff --git a/string/strspn.c b/string/strspn.c
index f0635c1..f98340b 100644
--- a/string/strspn.c
+++ b/string/strspn.c
@@ -16,32 +16,59 @@
<http://www.gnu.org/licenses/>. */
#include <string.h>
+#include <stdint.h>
#undef strspn
#ifndef STRSPN
-#define STRSPN strspn
+# define STRSPN strspn
#endif
/* Return the length of the maximum initial segment
of S which contains only characters in ACCEPT. */
size_t
-STRSPN (const char *s, const char *accept)
+STRSPN (const char *str, const char *accept)
{
- const char *p;
- const char *a;
- size_t count = 0;
-
- for (p = s; *p != '\0'; ++p)
+ if (accept[0] == '\0')
+ return 0;
+ if (__glibc_unlikely (accept[1] == '\0'))
{
- for (a = accept; *a != '\0'; ++a)
- if (*p == *a)
- break;
- if (*a == '\0')
- return count;
- else
- ++count;
+ const char *a = str;
+ for (; *str == *accept; str++);
+ return str - a;
}
- return count;
+ /* Use multiple small memsets to enable inlining on most targets. */
+ unsigned char table[256];
+ unsigned char *p = memset (table, 0, 64);
+ memset (p + 64, 0, 64);
+ memset (p + 128, 0, 64);
+ memset (p + 192, 0, 64);
+
+ unsigned char *s = (unsigned char*) accept;
+ /* Different from strcspn it does not add the NULL on the table
+ so can avoid check if str[i] is NULL, since table['\0'] will
+ be 0 and thus stopping the loop check. */
+ do
+ p[*s++] = 1;
+ while (*s);
+
+ s = (unsigned char*) str;
+ if (!p[s[0]]) return 0;
+ if (!p[s[1]]) return 1;
+ if (!p[s[2]]) return 2;
+ if (!p[s[3]]) return 3;
+
+ s = (unsigned char *) ((uintptr_t)(s) & ~3);
+ unsigned int c0, c1, c2, c3;
+ do {
+ s += 4;
+ c0 = p[s[0]];
+ c1 = p[s[1]];
+ c2 = p[s[2]];
+ c3 = p[s[3]];
+ } while ((c0 & c1 & c2 & c3) != 0);
+
+ size_t count = s - (unsigned char *) str;
+ return (c0 & c1) == 0 ? count + c0 : count + c2 + 2;
}
libc_hidden_builtin_def (strspn)