On Wed, Jan 16, 2013 at 08:08:03AM +0700, Duy Nguyen wrote:
> Actually I'd like to remove that function.
This is what I had in mind:
-- 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 it
once.
While at it, make use of "pathlen" to stop searching early if
possible.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
attr.c | 46 +++++++++++++++++++---------------------------
1 file changed, 19 insertions(+), 27 deletions(-)
diff --git a/attr.c b/attr.c
index cfc6748..04cb9a0 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 +749,27 @@ 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 = 0;
+ const char *basename = path, *cp;
- prepare_attr_stack(path);
+ pathlen = strlen(path);
+
+ /*
+ * This loop is similar to strrchr(path, '/') except that the
+ * trailing slash is skipped.
+ */
+ for (cp = path + pathlen - 2; cp >= path; cp--) {
+ if (*cp == '/') {
+ basename = cp + 1;
+ dirlen = cp - path;
+ break;
+ }
+ }
+
+ 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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