convert trivial cases to FLEX_ARRAY macros

Using FLEX_ARRAY macros reduces the amount of manual
computation size we have to do. It also ensures we don't
overflow size_t, and it makes sure we write the same number
of bytes that we allocated.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/builtin/mktree.c b/builtin/mktree.c
index a964d6be5..b0aab6535 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c
@@ -19,16 +19,17 @@ static int alloc, used;
 static void append_to_tree(unsigned mode, unsigned char *sha1, char *path)
 {
 	struct treeent *ent;
-	int len = strlen(path);
+	size_t len = strlen(path);
 	if (strchr(path, '/'))
 		die("path %s contains slash", path);
 
-	ALLOC_GROW(entries, used + 1, alloc);
-	ent = entries[used++] = xmalloc(sizeof(**entries) + len + 1);
+	FLEX_ALLOC_MEM(ent, name, path, len);
 	ent->mode = mode;
 	ent->len = len;
 	hashcpy(ent->sha1, sha1);
-	memcpy(ent->name, path, len+1);
+
+	ALLOC_GROW(entries, used + 1, alloc);
+	entries[used++] = ent;
 }
 
 static int ent_compare(const void *a_, const void *b_)