pack-objects: use strcspn(3) in name_cmp_len()

Call strcspn(3) to find the length of a string terminated by NUL, NL or
slash instead of open-coding it.  Adopt its return type, size_t, to
support strings of arbitrary length.  Use that type in callers as well
for variables and function parameters that receive the return value.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pack-objects.c

@@ -1708,17 +1708,14 @@ static void pbase_tree_put(struct pbase_tree_cache *cache)
 	free(cache);
 }
 
-static int name_cmp_len(const char *name)
+static size_t name_cmp_len(const char *name)
 {
-	int i;
-	for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
-		;
-	return i;
+	return strcspn(name, "\n/");
 }
 
 static void add_pbase_object(struct tree_desc *tree,
 			     const char *name,
-			     int cmplen,
+			     size_t cmplen,
 			     const char *fullname)
 {
 	struct name_entry entry;
@@ -1743,7 +1740,7 @@ static void add_pbase_object(struct tree_desc *tree,
 			struct tree_desc sub;
 			struct pbase_tree_cache *tree;
 			const char *down = name+cmplen+1;
-			int downlen = name_cmp_len(down);
+			size_t downlen = name_cmp_len(down);
 
 			tree = pbase_tree_get(&entry.oid);
 			if (!tree)
@@ -1795,7 +1792,7 @@ static int check_pbase_path(unsigned hash)
 static void add_preferred_base_object(const char *name)
 {
 	struct pbase_tree *it;
-	int cmplen;
+	size_t cmplen;
 	unsigned hash = pack_name_hash(name);
 
 	if (!num_preferred_base || check_pbase_path(hash))