From 5dfb2bbd8d2e2e48aa3ad6c6a8f437bbe5d2a7fb Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Mon, 24 Feb 2014 20:21:39 +0400 Subject: tree-diff: don't assume compare_tree_entry() returns -1,0,1 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 Signed-off-by: Junio C Hamano --- tree-diff.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/tree-diff.c b/tree-diff.c index 1af821903..6a677daa7 100644 --- a/tree-diff.c +++ b/tree-diff.c @@ -178,18 +178,24 @@ 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); -- cgit v1.2.1