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Use a 'register only' str[c]spn() on 64 bit systems.

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This commit is contained in:
dsl 2009-07-30 21:42:06 +00:00
parent f0a25cf095
commit 027bacee22
2 changed files with 95 additions and 4 deletions
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10
lib/libc/string/strcspn.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: strcspn.c,v 1.16 2008/07/30 16:13:59 joerg Exp $ */
/* $NetBSD: strcspn.c,v 1.17 2009/07/30 21:42:06 dsl Exp $ */
/*-
* Copyright (c) 2008 Joerg Sonnenberger
@ -26,12 +26,16 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: strcspn.c,v 1.16 2008/07/30 16:13:59 joerg Exp $");
__RCSID("$NetBSD: strcspn.c,v 1.17 2009/07/30 21:42:06 dsl Exp $");
#include <assert.h>
#include <inttypes.h>
#include <limits.h>
#include <string.h>
/* 64bit version is in strspn.c */
#if ULONG_MAX != 0xffffffffffffffffull
size_t
strcspn(const char *s, const char *charset)
{
@ -62,3 +66,5 @@ strcspn(const char *s, const char *charset)
break;
return t - s;
}
#endif

89
lib/libc/string/strspn.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: strspn.c,v 1.16 2008/07/30 16:13:59 joerg Exp $ */
/* $NetBSD: strspn.c,v 1.17 2009/07/30 21:42:06 dsl Exp $ */
/*-
* Copyright (c) 2008 Joerg Sonnenberger
@ -26,13 +26,15 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: strspn.c,v 1.16 2008/07/30 16:13:59 joerg Exp $");
__RCSID("$NetBSD: strspn.c,v 1.17 2009/07/30 21:42:06 dsl Exp $");
#include <assert.h>
#include <inttypes.h>
#include <limits.h>
#include <string.h>
#if ULONG_MAX != 0xffffffffffffffffull
size_t
strspn(const char *s, const char *charset)
{
@ -64,3 +66,86 @@ strspn(const char *s, const char *charset)
break;
return t - s;
}
#else
/* 64 bit system, use four 64 bits registers for bitmask */
static size_t
strspn_x(const char *s_s, const char *charset_s, unsigned long invert)
{
const unsigned char *s = (const unsigned char *)s_s;
const unsigned char *charset = (const unsigned char *)charset_s;
unsigned long m_0, m_4, m_8, m_c;
unsigned char ch, next_ch;
unsigned long bit;
unsigned long check;
size_t count;
/* Four 64bit registers have one bit for each character value */
m_0 = 0;
m_4 = 0;
m_8 = 0;
m_c = 0;
for (ch = *charset; ch != 0; ch = next_ch) {
next_ch = *++charset;
bit = 1ul << (ch & 0x3f);
if (__predict_true(ch < 0x80)) {
if (ch < 0x40)
m_0 |= bit;
else
m_4 |= bit;
} else {
if (ch < 0xc0)
m_8 |= bit;
else
m_c |= bit;
}
}
/* For strcspn() we just invert the validity set */
m_0 ^= invert;
m_4 ^= invert;
m_8 ^= invert;
m_c ^= invert;
/*
* We could do remove the lsb from m_0 to terminate at the
* end of the input string.
* However prefetching the next char is benifitial and we must
* not read the byte after the \0 - as it might fault!
* So we take the 'hit' of the compare against 0.
*/
ch = *s++;
for (count = 0; ch != 0; ch = next_ch) {
next_ch = s[count];
if (__predict_true(ch < 0x80)) {
check = m_0;
if (ch >= 0x40)
check = m_4;
} else {
check = m_8;
if (ch >= 0xc0)
check = m_c;
}
if (!((check >> (ch & 0x3f)) & 1))
break;
count++;
}
return count;
}
size_t
strspn(const char *s, const char *charset)
{
return strspn_x(s, charset, 0);
}
size_t
strcspn(const char *s, const char *charset)
{
return strspn_x(s, charset, ~0ul);
}
#endif