It does, but we'll be reworking it in the next patch after it won't, and
besides it is better to stick to standard
strcmp/memcmp/base_name_compare/etc... convention, where comparison
function returns <0, =0, >0
Regarding performance, comparing for <0, =0, >0 should be a little bit
faster, than switch, because it is just 1 test-without-immediate
instruction and then up to 3 conditional branches, and in switch you
have up to 3 tests with immediate and up to 3 conditional branches.
No worry, that update_tree_entry(t2) is duplicated for =0 and >0 - it
will be good after we'll be adding support for multiparent walker and
will stay that way.
=0 case goes first, because it happens more often in real diffs - i.e.
paths are the same.
Signed-off-by: Kirill Smelkov <kirr@xxxxxxxxxx>
Signed-off-by: Junio C Hamano <gitster@xxxxxxxxx>
---
( re-posting without change )
tree-diff.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/tree-diff.c b/tree-diff.c
index a5b9ff9..5f7dbbf 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -179,18 +179,24 @@ int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
update_tree_entry(t1);
continue;
}
- switch (compare_tree_entry(t1, t2, &base, opt)) {
- case -1:
+
+ cmp = compare_tree_entry(t1, t2, &base, opt);
+
+ /* t1 = t2 */
+ if (cmp == 0) {
update_tree_entry(t1);
- continue;
- case 0:
+ update_tree_entry(t2);
+ }
+
+ /* t1 < t2 */
+ else if (cmp < 0) {
update_tree_entry(t1);
- /* Fallthrough */
- case 1:
+ }
+
+ /* t1 > t2 */
+ else {
update_tree_entry(t2);
- continue;
}
- die("git diff-tree: internal error");
}
strbuf_release(&base);
--
1.9.rc1.181.g641f458
--
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