[PATCH v3 4/4] commit: rewrite read_graft_line

[Patryk Obara <patryk.obara@gmail.com>]

Determine the number of object_id's to parse in a single graft line by
counting separators (whitespace characters) instead of dividing by
length of hash representation.

This way graft parsing code can support different sizes of hashes
without any further code adaptations.

Signed-off-by: Patryk Obara <patryk.obara@gmail.com>
---
 commit.c | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/commit.c b/commit.c
index 61528a5..46ee2db 100644
--- a/commit.c
+++ b/commit.c
@@ -137,29 +137,27 @@ int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 struct commit_graft *read_graft_line(struct strbuf *line)
 {
 	/* The format is just "Commit Parent1 Parent2 ...\n" */
-	int i, len;
-	char *buf = line->buf;
+	int i, n;
+	const char *tail = NULL;
 	struct commit_graft *graft = NULL;
-	const int entry_size = GIT_SHA1_HEXSZ + 1;
 
 	strbuf_rtrim(line);
 	if (line->buf[0] == '#' || line->len == 0)
 		return NULL;
-	len = line->len;
-	if ((len + 1) % entry_size)
-		goto bad_graft_data;
-	i = (len + 1) / entry_size - 1;
+	/* count number of blanks to determine size of array to allocate */
+	for (i = 0, n = 0; i < line->len; i++)
+		if (isspace(line->buf[i]))
+			n++;
 	graft = xmalloc(st_add(sizeof(*graft),
-	                       st_mult(sizeof(struct object_id), i)));
-	graft->nr_parent = i;
-	if (get_oid_hex(buf, &graft->oid))
+	                       st_mult(sizeof(struct object_id), n)));
+	graft->nr_parent = n;
+	if (parse_oid_hex(line->buf, &graft->oid, &tail))
 		goto bad_graft_data;
-	for (i = GIT_SHA1_HEXSZ; i < len; i += entry_size) {
-		if (buf[i] != ' ')
-			goto bad_graft_data;
-		if (get_sha1_hex(buf + i + 1, graft->parent[i/entry_size].hash))
+	for (i = 0; i < graft->nr_parent; i++)
+		if (!isspace(*tail++) || parse_oid_hex(tail, &graft->parent[i], &tail))
 			goto bad_graft_data;
-	}
+	if (tail[0] != '\0')
+		goto bad_graft_data;
 	return graft;
 
 bad_graft_data:
-- 
2.9.5