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authorJeff King <peff@peff.net>2015-04-16 04:58:54 -0400
committerJunio C Hamano <gitster@pobox.com>2015-04-16 08:15:05 -0700
commitf80c153bea4e0ea86f5b6d32e77df0b69501ee18 (patch)
treecc4486dc531f676cf884dee2bb962092b840a4a4 /strbuf.c
parentfec501dae8bf6c8fdcd4124c94f37c4cbc26ba29 (diff)
downloadgit-f80c153bea4e0ea86f5b6d32e77df0b69501ee18.tar.gz
git-f80c153bea4e0ea86f5b6d32e77df0b69501ee18.tar.xz
strbuf_getwholeline: avoid calling strbuf_grow
As with the recent speedup to strbuf_addch, we can avoid calling strbuf_grow() in a tight loop of single-character adds by instead checking strbuf_avail. Note that we would instead call strbuf_addch directly here, but it does more work than necessary: it will NUL-terminate the result for each character read. Instead, in this loop we read the characters one by one and then add the terminator manually at the end. Running "git rev-parse refs/heads/does-not-exist" on a repo with an extremely large (1.6GB) packed-refs file went from (best-of-5): real 0m10.948s user 0m10.548s sys 0m0.412s to: real 0m8.601s user 0m8.084s sys 0m0.524s for a wall-clock speedup of 21%. Helped-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'strbuf.c')
-rw-r--r--strbuf.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/strbuf.c b/strbuf.c
index af2bad4b5..921619ea6 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -445,7 +445,8 @@ int strbuf_getwholeline(struct strbuf *sb, FILE *fp, int term)
strbuf_reset(sb);
flockfile(fp);
while ((ch = getc_unlocked(fp)) != EOF) {
- strbuf_grow(sb, 1);
+ if (!strbuf_avail(sb))
+ strbuf_grow(sb, 1);
sb->buf[sb->len++] = ch;
if (ch == term)
break;