From: Dan McGee <dpmcgee@gmail.com>
To: git@vger.kernel.org
Cc: Dan McGee <dpmcgee@gmail.com>
Subject: [PATCH 5/5] tree-walk: match_entry microoptimization
Date: Wed, 30 Mar 2011 20:38:01 -0500 [thread overview]
Message-ID: <1301535481-1085-5-git-send-email-dpmcgee@gmail.com> (raw)
In-Reply-To: <1301535481-1085-1-git-send-email-dpmcgee@gmail.com>
Before calling strncmp(), see if we can get away with checking only the
first character of the passed path components instead.
Signed-off-by: Dan McGee <dpmcgee@gmail.com>
---
tree-walk.c | 26 ++++++++++++++++++--------
1 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/tree-walk.c b/tree-walk.c
index 41383b0..083b951 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -488,9 +488,10 @@ static int match_entry(const struct name_entry *entry, int pathlen,
const char *match, int matchlen,
int *never_interesting)
{
- int m = -1; /* signals that we haven't called strncmp() */
+ int m = -1; /* signals that we haven't compared strings */
if (*never_interesting) {
+ const int maxlen = (matchlen < pathlen) ? matchlen : pathlen;
/*
* We have not seen any match that sorts later
* than the current path.
@@ -500,10 +501,13 @@ static int match_entry(const struct name_entry *entry, int pathlen,
* Does match sort strictly earlier than path
* with their common parts?
*/
- m = strncmp(match, entry->path,
- (matchlen < pathlen) ? matchlen : pathlen);
- if (m < 0)
- return 0;
+ if (maxlen && match[0] > entry->path[0]) {
+ /* no good for the shortcut here, match must be <= */
+ } else {
+ m = strncmp(match, entry->path, maxlen);
+ if(m < 0)
+ return 0;
+ }
/*
* If we come here even once, that means there is at
@@ -531,12 +535,17 @@ static int match_entry(const struct name_entry *entry, int pathlen,
return 0;
}
- if (m == -1)
+ if (m == -1) {
/*
- * we cheated and did not do strncmp(), so we do
+ * we cheated and did compare strings, so we do
* that here.
*/
- m = strncmp(match, entry->path, pathlen);
+ if (pathlen && match[0] == entry->path[0])
+ /* invariant: matchlen == pathlen */
+ m = strncmp(match, entry->path, pathlen);
+ else
+ m = 1;
+ }
/*
* If common part matched earlier then it is a hit,
@@ -552,6 +561,7 @@ static int match_entry(const struct name_entry *entry, int pathlen,
static int match_dir_prefix(const char *base,
const char *match, int matchlen)
{
+ /* invariant: baselen >= matchlen */
if (strncmp(base, match, matchlen))
return 0;
--
1.7.4.2
next prev parent reply other threads:[~2011-03-31 1:38 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-31 1:37 [PATCH 1/5] diff_tree_sha1: skip diff_tree if old == new Dan McGee
2011-03-31 1:37 ` [PATCH 2/5] tree-walk: drop unused parameter from match_dir_prefix Dan McGee
2011-08-30 18:55 ` Dan McGee
2011-03-31 1:37 ` [PATCH 3/5] tree-walk: micro-optimization in tree_entry_interesting Dan McGee
2011-04-03 4:01 ` Nguyen Thai Ngoc Duy
2011-04-03 18:55 ` Junio C Hamano
2011-04-05 0:22 ` Dan McGee
[not found] ` <CAEik5nOKrpFycZYVnSu4_5LYWxn0JS_hVXyiQH-80Bu-C4k8VQ@mail.gmail.com>
2011-08-30 19:51 ` Dan McGee
2011-08-30 20:40 ` Junio C Hamano
2011-09-09 2:02 ` [PATCH 1/2] tree-walk: drop unused parameter from match_dir_prefix Dan McGee
2011-09-09 2:02 ` [PATCH 2/2] tree-walk: micro-optimization in tree_entry_interesting Dan McGee
2011-04-04 14:46 ` [PATCH] tree_entry_interesting: inline strncmp() Nguyễn Thái Ngọc Duy
2011-03-31 1:38 ` [PATCH 4/5] tree-walk: unroll get_mode since loop boundaries are well-known Dan McGee
2011-04-02 9:28 ` Nguyen Thai Ngoc Duy
2011-04-02 17:28 ` Dan McGee
2011-04-03 4:07 ` Nguyen Thai Ngoc Duy
2011-04-04 10:29 ` Erik Faye-Lund
2011-04-04 12:30 ` Andreas Ericsson
2011-04-04 16:55 ` Junio C Hamano
2011-04-05 5:33 ` Dan McGee
2011-04-05 23:55 ` Antriksh Pany
2011-04-06 20:45 ` Dan McGee
2011-03-31 1:38 ` Dan McGee [this message]
2011-04-02 9:06 ` [PATCH 5/5] tree-walk: match_entry microoptimization Nguyen Thai Ngoc Duy
2011-04-02 17:54 ` Dan McGee
2011-03-31 12:58 ` [PATCH 1/5] diff_tree_sha1: skip diff_tree if old == new Nguyen Thai Ngoc Duy
2011-03-31 13:56 ` Dan McGee
2011-04-01 22:28 ` Junio C Hamano
[not found] ` <AANLkTinPSqDPdGi5nA3sH1D2wMSW1SQc+5gRqdLy++y0@mail.gmail.com>
2011-04-02 18:38 ` Fwd: " Dan McGee
2011-05-03 7:34 ` Nguyen Thai Ngoc Duy
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