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Micro-optimize critical path of strstr, strcase and memmem.

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Maxim Kuvyrkov 2012-05-28 22:46:07 -07:00
parent 99677e5755
commit bcca089526
4 changed files with 18 additions and 1 deletions
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6
ChangeLog
View file

@ -1,3 +1,9 @@
2012-08-21 Maxim Kuvyrkov <maxim@codesourcery.com>
* string/str-two-way.h (AVAILABLE1_USES_J): New macro, define default.
(two_way_short_needle): Use it.
* string/{strstr.c, strcasestr.c} (AVAILABLE1_USES_J): Define.
2012-08-21 Maxim Kuvyrkov <maxim@codesourcery.com>
* string/str-two-way.h (two_way_short_needle): Use pointers instead of

11
string/str-two-way.h
View file

@ -84,6 +84,9 @@
#ifndef RET0_IF_0
# define RET0_IF_0(a) /* nothing */
#endif
#ifndef AVAILABLE1_USES_J
# define AVAILABLE1_USES_J (1)
#endif
/* Perform a critical factorization of NEEDLE, of length NEEDLE_LEN.
Return the index of the first byte in the right half, and set
@ -295,12 +298,17 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len,
!= (haystack_char = CANON_ELEMENT (*phaystack++)))
{
RET0_IF_0 (haystack_char);
#if AVAILABLE1_USES_J
++j;
#endif
continue;
}
/* Calculate J. */
#if !AVAILABLE1_USES_J
/* Calculate J if it wasn't kept up-to-date in the first-character
loop. */
j = phaystack - &haystack[suffix] - 1;
#endif
/* Scan for matches in right half. */
i = suffix + 1;
@ -497,6 +505,7 @@ two_way_long_needle (const unsigned char *haystack, size_t haystack_len,
#undef AVAILABLE
#undef AVAILABLE1
#undef AVAILABLE2
#undef AVAILABLE1_USES_J
#undef CANON_ELEMENT
#undef CMP_FUNC
#undef RET0_IF_0

1
string/strcasestr.c
View file

@ -46,6 +46,7 @@
#define AVAILABLE1(h, h_l, j, n_l) (true)
#define AVAILABLE2(h, h_l, j, n_l) AVAILABLE (h, h_l, j, n_l)
#define RET0_IF_0(a) if (!a) goto ret0
#define AVAILABLE1_USES_J (0)
#define CANON_ELEMENT(c) TOLOWER (c)
#define CMP_FUNC(p1, p2, l) \
__strncasecmp ((const char *) (p1), (const char *) (p2), l)

1
string/strstr.c
View file

@ -38,6 +38,7 @@
#define AVAILABLE1(h, h_l, j, n_l) (true)
#define AVAILABLE2(h, h_l, j, n_l) AVAILABLE (h, h_l, j, n_l)
#define RET0_IF_0(a) if (!a) goto ret0
#define AVAILABLE1_USES_J (0)
#include "str-two-way.h"
#undef strstr