On Tue, Jan 15, 2013 at 09:35:21PM -0800, Junio C Hamano wrote:
> >> Also the original only
> >> scanned the string from the beginning once (instead of letting
> >> strlen() to scan once and go back).
> >
> > But we do need to strlen() anyway in collect_all_attrs().
>
> That is exactly my point, isn't it?
OK I get your point now. Something like this?
-- 8< --
Subject: [PATCH] attr: avoid calling find_basename() twice per path
find_basename() is only used inside collect_all_attrs(), called once
in prepare_attr_stack, then again after prepare_attr_stack()
returns. Both calls return exact same value. Reorder the code to do
the same task once. Also avoid strlen() because we knows the length
after finding basename.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
attr.c | 45 ++++++++++++++++++---------------------------
1 file changed, 18 insertions(+), 27 deletions(-)
diff --git a/attr.c b/attr.c
index cfc6748..880f862 100644
--- a/attr.c
+++ b/attr.c
@@ -564,32 +564,12 @@ static void bootstrap_attr_stack(void)
attr_stack = elem;
}
-static const char *find_basename(const char *path)
-{
- const char *cp, *last_slash = NULL;
-
- for (cp = path; *cp; cp++) {
- if (*cp == '/' && cp[1])
- last_slash = cp;
- }
- return last_slash ? last_slash + 1 : path;
-}
-
-static void prepare_attr_stack(const char *path)
+static void prepare_attr_stack(const char *path, int dirlen)
{
struct attr_stack *elem, *info;
- int dirlen, len;
+ int len;
const char *cp;
- dirlen = find_basename(path) - path;
-
- /*
- * find_basename() includes the trailing slash, but we do
- * _not_ want it.
- */
- if (dirlen)
- dirlen--;
-
/*
* At the bottom of the attribute stack is the built-in
* set of attribute definitions, followed by the contents
@@ -769,15 +749,26 @@ static int macroexpand_one(int attr_nr, int rem)
static void collect_all_attrs(const char *path)
{
struct attr_stack *stk;
- int i, pathlen, rem;
- const char *basename;
+ int i, pathlen, rem, dirlen;
+ const char *basename, *cp, *last_slash = NULL;
+
+ for (cp = path; *cp; cp++) {
+ if (*cp == '/' && cp[1])
+ last_slash = cp;
+ }
+ pathlen = cp - path;
+ if (last_slash) {
+ basename = last_slash + 1;
+ dirlen = last_slash - path;
+ } else {
+ basename = path;
+ dirlen = 0;
+ }
- prepare_attr_stack(path);
+ prepare_attr_stack(path, dirlen);
for (i = 0; i < attr_nr; i++)
check_all_attr[i].value = ATTR__UNKNOWN;
- basename = find_basename(path);
- pathlen = strlen(path);
rem = attr_nr;
for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
rem = fill(path, pathlen, basename, stk, rem);
--
1.8.0.rc3.18.g0d9b108
-- 8< --
--
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