create_directories(): remove some memcpy() and strchr() calls

Remove the call to memcpy() and strchr() for each path component
tested, and instead add each path component as we go forward inside
the while-loop.

Impact: small optimisation

Signed-off-by: Kjetil Barvik <barvik@broadpark.no>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

entry.c

@@ -2,15 +2,19 @@
 #include "blob.h"
 #include "dir.h"
 
-static void create_directories(const char *path, const struct checkout *state)
+static void create_directories(const char *path, int path_len,
+			       const struct checkout *state)
 {
-	int len = strlen(path);
-	char *buf = xmalloc(len + 1);
-	const char *slash = path;
-
-	while ((slash = strchr(slash+1, '/')) != NULL) {
-		len = slash - path;
-		memcpy(buf, path, len);
+	char *buf = xmalloc(path_len + 1);
+	int len = 0;
+
+	while (len < path_len) {
+		do {
+			buf[len] = path[len];
+			len++;
+		} while (len < path_len && path[len] != '/');
+		if (len >= path_len)
+			break;
 		buf[len] = 0;
 
 		/*
@@ -190,6 +194,7 @@ int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *t
 
 	memcpy(path, state->base_dir, len);
 	strcpy(path + len, ce->name);
+	len += ce_namelen(ce);
 
 	if (!lstat(path, &st)) {
 		unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID);
@@ -218,6 +223,6 @@ int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *t
 			return error("unable to unlink old '%s' (%s)", path, strerror(errno));
 	} else if (state->not_new)
 		return 0;
-	create_directories(path, state);
+	create_directories(path, len, state);
 	return write_entry(ce, path, state, 0);
 }