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Bug 1371215 part 2 - Remove FirstCharMatcher16bit as it's not used much and has some perf issues. r=luke

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Jan de Mooij 2017-06-09 09:18:30 +02:00
parent 20be2e7edb
commit 29ea196af6
1 changed files with 1 additions and 49 deletions
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50
js/src/jsstr.cpp
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@ -1633,52 +1633,6 @@ FirstCharMatcher8bit(const char* text, uint32_t n, const char pat)
return reinterpret_cast<const char*>(memchr(text, pat, n));
}
static const char16_t*
FirstCharMatcher16bit(const char16_t* text, uint32_t n, const char16_t pat)
{
#if defined(XP_DARWIN) || defined(XP_WIN)
/*
* Performance of memchr is horrible in OSX. Windows is better,
* but it is still better to use UnrolledMatcher.
*/
return FirstCharMatcherUnrolled<char16_t, char16_t>(text, n, pat);
#else
/*
* For linux the best performance is obtained by slightly hacking memchr.
* memchr works only on 8bit char but char16_t is 16bit. So we treat char16_t
* in blocks of 8bit and use memchr.
*/
const char* text8 = (const char*) text;
const char* pat8 = reinterpret_cast<const char*>(&pat);
MOZ_ASSERT(n < UINT32_MAX/2);
n *= 2;
uint32_t i = 0;
while (i < n) {
/* Find the first 8 bits of 16bit character in text. */
const char* pos8 = FirstCharMatcher8bit(text8 + i, n - i, pat8[0]);
if (pos8 == nullptr)
return nullptr;
i = static_cast<uint32_t>(pos8 - text8);
/* Incorrect match if it matches the last 8 bits of 16bit char. */
if (i % 2 != 0) {
i++;
continue;
}
/* Test if last 8 bits match last 8 bits of 16bit char. */
if (pat8[1] == text8[i + 1])
return (text + (i/2));
i += 2;
}
return nullptr;
#endif
}
template <class InnerMatch, typename TextChar, typename PatChar>
static int
Matcher(const TextChar* text, uint32_t textlen, const PatChar* pat, uint32_t patlen)
@ -1690,9 +1644,7 @@ Matcher(const TextChar* text, uint32_t textlen, const PatChar* pat, uint32_t pat
while (i < n) {
const TextChar* pos;
if (sizeof(TextChar) == 2 && sizeof(PatChar) == 2)
pos = (TextChar*) FirstCharMatcher16bit((char16_t*)text + i, n - i, pat[0]);
else if (sizeof(TextChar) == 1 && sizeof(PatChar) == 1)
if (sizeof(TextChar) == 1 && sizeof(PatChar) == 1)
pos = (TextChar*) FirstCharMatcher8bit((char*) text + i, n - i, pat[0]);
else
pos = (TextChar*) FirstCharMatcherUnrolled<TextChar, PatChar>(text + i, n - i, pat[0]);