From 4e808c82ef5ed0ee261d20b86cb2f861982f049d Mon Sep 17 00:00:00 2001
From: Per Hedbor <ph@opera.com>
Date: Sun, 1 May 2011 05:20:50 +0200
Subject: [PATCH] Check strings for magnitude in the forward, not backward,
direction.
This saves a few % of CPU for short (<1Kb) strings, but not for long ones
(I guess the hardware prefetcher catches on rather quickly)
---
src/stralloc.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/src/stralloc.c b/src/stralloc.c
index 34b798e4f7..a09c56bba8 100644
--- a/src/stralloc.c
+++ b/src/stralloc.c
@@ -102,7 +102,7 @@ PMOD_EXPORT struct pike_string *empty_pike_string = 0;
#define StrHash(s,len) low_do_hash(s,len,0)
-static INLINE size_t low_do_hash(const void *s,
+static size_t low_do_hash(const void *s,
ptrdiff_t len__,
int size_shift)
{
@@ -119,23 +119,25 @@ static INLINE size_t do_hash(struct pike_string *s)
static INLINE int find_magnitude1(const p_wchar1 *s, ptrdiff_t len)
{
- while(--len>=0)
- if(s[len]>=256)
+ const p_wchar1 *e=s+len;
+ while(s<e)
+ if(*s++>=256)
return 1;
return 0;
}
static INLINE int find_magnitude2(const p_wchar2 *s, ptrdiff_t len)
{
- while(--len>=0)
+ const p_wchar2 *e=s+len;
+ while(s<e)
{
- if((unsigned INT32)s[len]>=256)
+ if((unsigned INT32)*s++>=256)
{
do
{
- if((unsigned INT32)s[len]>=65536)
+ if((unsigned INT32)*s++>=65536)
return 2;
- }while(--len>=0);
+ }while(s<e);
return 1;
}
}
--
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