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Base mbfl_strpos on zend_memnstr

Browse source 
The same algorithm is also used by zend_memnstr, but it also has
a fast-path for short strings / needles, where a more naive
search performs better.
This commit is contained in:
Nikita Popov 2020-01-24 11:29:34 +01:00
parent 73b31302ed
commit d504ad5717
1 changed files with 18 additions and 45 deletions
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51
ext/mbstring/libmbfl/mbfl/mbfilter.c
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@ -83,6 +83,7 @@
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "zend_operators.h"
#include <stddef.h>
#include <string.h>
@ -898,54 +899,26 @@ mbfl_strpos(
goto out;
}
if (!reverse) {
const char *found_pos = zend_memnstr(
(const char *) offset_pointer,
(const char *) needle_u8->val, needle_u8->len,
(const char *) haystack_u8->val + haystack_u8->len);
if (found_pos) {
result = mbfl_pointer_to_offset_utf8(
haystack_u8->val, (const unsigned char *) found_pos);
}
} else {
if (needle_u8->len == 0) {
size_t haystack_length = mbfl_strlen(haystack_u8);
if (offset < 0) {
result = haystack_length + offset;
} else if (reverse) {
result = haystack_length;
} else {
result = (size_t) offset;
result = haystack_length;
}
goto out;
}
if (!reverse) {
size_t jtbl[1 << (sizeof(unsigned char) * 8)];
size_t needle_u8_len = needle_u8->len;
size_t i;
const unsigned char *p, *q, *e;
const unsigned char *haystack_u8_val = haystack_u8->val,
*needle_u8_val = needle_u8->val;
for (i = 0; i < sizeof(jtbl) / sizeof(*jtbl); ++i) {
jtbl[i] = needle_u8_len + 1;
}
for (i = 0; i < needle_u8_len - 1; ++i) {
jtbl[needle_u8_val[i]] = needle_u8_len - i;
}
e = haystack_u8_val + haystack_u8->len;
p = offset_pointer + needle_u8_len;
if (p > e) {
goto out;
}
while (p <= e) {
const unsigned char *pv = p;
q = needle_u8_val + needle_u8_len;
for (;;) {
if (q == needle_u8_val) {
result = mbfl_pointer_to_offset_utf8(haystack_u8_val, p);
goto out;
}
if (*--q != *--p) {
break;
}
}
p += jtbl[*p];
if (p <= pv) {
p = pv + 1;
}
}
} else {
size_t jtbl[1 << (sizeof(unsigned char) * 8)];
size_t needle_u8_len = needle_u8->len, needle_len = 0;
size_t i;