diff options
Diffstat (limited to 'string/str-two-way.h')
| -rw-r--r-- | string/str-two-way.h | 65 |
1 files changed, 33 insertions, 32 deletions
diff --git a/string/str-two-way.h b/string/str-two-way.h index 599c867ffd..30aca30c40 100644 --- a/string/str-two-way.h +++ b/string/str-two-way.h @@ -221,7 +221,7 @@ critical_factorization (const unsigned char *needle, size_t needle_len, most 2 * HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching. If AVAILABLE modifies HAYSTACK_LEN (as in strstr), then at most 3 * HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching. */ -static RETURN_TYPE +static inline RETURN_TYPE two_way_short_needle (const unsigned char *haystack, size_t haystack_len, const unsigned char *needle, size_t needle_len) { @@ -281,50 +281,50 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len, } else { - const unsigned char *phaystack = &haystack[suffix]; + const unsigned char *phaystack; /* The comparison always starts from needle[suffix], so cache it and use an optimized first-character loop. */ unsigned char needle_suffix = CANON_ELEMENT (needle[suffix]); -#if CHECK_EOL - /* We start matching from the SUFFIX'th element, so make sure we - don't hit '\0' before that. */ - if (haystack_len < suffix + 1 - && !AVAILABLE (haystack, haystack_len, 0, suffix + 1)) - return NULL; -#endif - /* The two halves of needle are distinct; no extra memory is required, and any mismatch results in a maximal shift. */ period = MAX (suffix, needle_len - suffix) + 1; j = 0; - while (1 -#if !CHECK_EOL - && AVAILABLE (haystack, haystack_len, j, needle_len) -#endif - ) + while (AVAILABLE (haystack, haystack_len, j, needle_len)) { unsigned char haystack_char; const unsigned char *pneedle; - /* TODO: The first-character loop can be sped up by adapting - longword-at-a-time implementation of memchr/strchr. */ - if (needle_suffix + phaystack = &haystack[suffix + j]; + +#ifdef FASTSEARCH + if (*phaystack++ != needle_suffix) + { + phaystack = FASTSEARCH (phaystack, needle_suffix, + haystack_len - needle_len - j); + if (phaystack == NULL) + goto ret0; + j = phaystack - &haystack[suffix]; + phaystack++; + } +#else + while (needle_suffix != (haystack_char = CANON_ELEMENT (*phaystack++))) { RET0_IF_0 (haystack_char); -#if !CHECK_EOL +# if !CHECK_EOL ++j; -#endif - continue; + if (!AVAILABLE (haystack, haystack_len, j, needle_len)) + goto ret0; +# endif } -#if CHECK_EOL +# if CHECK_EOL /* Calculate J if it wasn't kept up-to-date in the first-character loop. */ j = phaystack - &haystack[suffix] - 1; +# endif #endif - /* Scan for matches in right half. */ i = suffix + 1; pneedle = &needle[i]; @@ -338,6 +338,11 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len, } ++i; } +#if CHECK_EOL + /* Update minimal length of haystack. */ + if (phaystack > haystack + haystack_len) + haystack_len = phaystack - haystack; +#endif if (needle_len <= i) { /* Scan for matches in left half. */ @@ -360,13 +365,6 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len, } else j += i - suffix + 1; - -#if CHECK_EOL - if (!AVAILABLE (haystack, haystack_len, j, needle_len)) - break; -#endif - - phaystack = &haystack[suffix + j]; } } ret0: __attribute__ ((unused)) @@ -384,8 +382,11 @@ two_way_short_needle (const unsigned char *haystack, size_t haystack_len, and sublinear performance O(HAYSTACK_LEN / NEEDLE_LEN) is possible. If AVAILABLE modifies HAYSTACK_LEN (as in strstr), then at most 3 * HAYSTACK_LEN - NEEDLE_LEN comparisons occur in searching, and - sublinear performance is not possible. */ -static RETURN_TYPE + sublinear performance is not possible. + + Since this function is large and complex, block inlining to avoid + slowing down the common case of small needles. */ +__attribute__((noinline)) static RETURN_TYPE two_way_long_needle (const unsigned char *haystack, size_t haystack_len, const unsigned char *needle, size_t needle_len) { |