Merge branch 'rs/memmem' into maint

* rs/memmem:
  optimize compat/ memmem()
  diffcore-pickaxe: use memmem()

Author: gitster

compat/memmem.c

@@ -5,6 +5,8 @@ void *gitmemmem(const void *haystack, size_t haystack_len,
 {
 	const char *begin = haystack;
 	const char *last_possible = begin + haystack_len - needle_len;
+	const char *tail = needle;
+	char point;
 
 	/*
 	 * The first occurrence of the empty string is deemed to occur at
@@ -20,8 +22,9 @@ void *gitmemmem(const void *haystack, size_t haystack_len,
 	if (haystack_len < needle_len)
 		return NULL;
 
+	point = *tail++;
 	for (; begin <= last_possible; begin++) {
-		if (!memcmp(begin, needle, needle_len))
+		if (*begin == point && !memcmp(begin + 1, tail, needle_len - 1))
 			return (void *)begin;
 	}
 

diffcore-pickaxe.c

@@ -10,7 +10,7 @@ static unsigned int contains(struct diff_filespec *one,
 			     regex_t *regexp)
 {
 	unsigned int cnt;
-	unsigned long offset, sz;
+	unsigned long sz;
 	const char *data;
 	if (diff_populate_filespec(one, 0))
 		return 0;
@@ -33,15 +33,13 @@ static unsigned int contains(struct diff_filespec *one,
 		}
 
 	} else { /* Classic exact string match */
-		/* Yes, I've heard of strstr(), but the thing is *data may
-		 * not be NUL terminated.  Sue me.
-		 */
-		for (offset = 0; offset + len <= sz; offset++) {
-			/* we count non-overlapping occurrences of needle */
-			if (!memcmp(needle, data + offset, len)) {
-				offset += len - 1;
-				cnt++;
-			}
+		while (sz) {
+			const char *found = memmem(data, sz, needle, len);
+			if (!found)
+				break;
+			sz -= found - data + len;
+			data = found + len;
+			cnt++;
 		}
 	}
 	diff_free_filespec_data(one);