Re: [PATCH] Speedup prefixcmp() common case

From: Marco Costalba <mcostalba@gmail.com>
Date: Dec 29, 2007, 20:43 UTC
Message-ID: <e5bfff550712291243x6f8d7b2k15055ff55379142e@mail.gmail.com>
In-Reply-To: <e5bfff550712291001q5f246ceah6700b98308fb96f1@mail.gmail.com>

In case the prefix string is a single char avoid a costly call to strlen() + strncmp()

With this patch git log with --pretty=format option is 10% faster

With suggestions by Junio C Hamano

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
---

 git-compat-util.h |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/git-compat-util.h b/git-compat-util.h
index 79eb10e..e26b684 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -398,6 +398,10 @@ static inline int sane_case

 static inline int prefixcmp(const char *str, const char *prefix)
 {
+       /* shortcut common case of a single char prefix */
+       if (prefix && !prefix[1] && str)
+               return *str - *prefix;
+
       return strncmp(str, prefix, strlen(prefix));
 }

--
1.5.4.rc2-dirty