From 8ac435301605ddbda81c48ddbaaa59f82c59adcf Mon Sep 17 00:00:00 2001
From: Arne Goedeke <el@laramies.com>
Date: Fri, 30 May 2014 13:41:36 +0200
Subject: [PATCH] hashtable.c: do not rechain in lookup
Reordering the bucket list during lookup is very expensive. Removing it
makes cpp() about 10% faster on a file that only contains define and if
defined() statements.
Additionally, the const attribute on the hash table argument is correct now.
---
src/hashtable.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/src/hashtable.c b/src/hashtable.c
index f9b0d96d75..c7fc06a8b1 100644
--- a/src/hashtable.c
+++ b/src/hashtable.c
@@ -26,20 +26,14 @@ static size_t gobble(const struct pike_string *s)
struct hash_entry *hash_lookup(const struct hash_table *h,
const struct pike_string *s)
{
- struct hash_entry *e, **prev, **base;
+ struct hash_entry *e;
if(!h) return 0;
- base = prev = h->htable + (gobble(s) & h->mask);
- for( ;(e = *prev); prev= &e->next)
+ e = h->htable[gobble(s) & h->mask];
+ for( ; e; e = e->next)
{
if(s == e->s)
{
- /* Teleport entry to beginning of line */
- *prev = e->next;
- e->next = *base;
- *base = e;
- /* Entry arrives in a puff of smoke. */
-
return e;
}
}
--
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