generic-library/cxx
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Modest performance improvement for std::string's operator==.

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@180072 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Howard Hinnant 2013-04-22 23:55:13 +00:00
parent 5544f7e0c7
commit 08dd25303e
1 changed files with 28 additions and 7 deletions
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35
include/string
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@ -1462,6 +1462,11 @@ public:
int compare(size_type __pos1, size_type __n1, const_pointer __s, size_type __n2) const;
_LIBCPP_INLINE_VISIBILITY bool __invariants() const;
_LIBCPP_INLINE_VISIBILITY
bool __is_long() const _NOEXCEPT
{return bool(__r_.first().__s.__size_ & __short_mask);}
private:
_LIBCPP_INLINE_VISIBILITY
allocator_type& __alloc() _NOEXCEPT
@ -1470,10 +1475,6 @@ private:
const allocator_type& __alloc() const _NOEXCEPT
{return __r_.second();}
_LIBCPP_INLINE_VISIBILITY
bool __is_long() const _NOEXCEPT
{return bool(__r_.first().__s.__size_ & __short_mask);}
_LIBCPP_INLINE_VISIBILITY
void __set_short_size(size_type __s) _NOEXCEPT
#if _LIBCPP_BIG_ENDIAN
@ -3561,9 +3562,29 @@ bool
operator==(const basic_string<_CharT, _Traits, _Allocator>& __lhs,
const basic_string<_CharT, _Traits, _Allocator>& __rhs) _NOEXCEPT
{
return __lhs.size() == __rhs.size() && _Traits::compare(__lhs.data(),
__rhs.data(),
__lhs.size()) == 0;
size_t __lhs_sz = __lhs.size();
return __lhs_sz == __rhs.size() && _Traits::compare(__lhs.data(),
__rhs.data(),
__lhs_sz) == 0;
}
template<class _Allocator>
_LIBCPP_INLINE_VISIBILITY inline
bool
operator==(const basic_string<char, char_traits<char>, _Allocator>& __lhs,
const basic_string<char, char_traits<char>, _Allocator>& __rhs) _NOEXCEPT
{
size_t __lhs_sz = __lhs.size();
if (__lhs_sz != __rhs.size())
return false;
const char* __lp = __lhs.data();
const char* __rp = __rhs.data();
if (__lhs.__is_long())
return char_traits<char>::compare(__lp, __rp, __lhs_sz) == 0;
for (; __lhs_sz != 0; --__lhs_sz, ++__lp, ++__rp)
if (*__lp != *__rp)
return false;
return true;
}
template<class _CharT, class _Traits, class _Allocator>