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| author | Jonathan Wakely <jwakely@redhat.com> | 2016-09-23 18:25:23 +0100 |
|---|---|---|
| committer | Jonathan Wakely <redi@gcc.gnu.org> | 2016-09-23 18:25:23 +0100 |
| commit | a922c5ff6f3872fc9ce1e484a0e92f288ff6c68d (patch) | |
| tree | 62231e54ad2ab9735e402dda27e441a3c84f50bb | |
| parent | b862552dff04fbd4c7debf07a7c82d361869a552 (diff) | |
| download | gcc-a922c5ff6f3872fc9ce1e484a0e92f288ff6c68d.zip gcc-a922c5ff6f3872fc9ce1e484a0e92f288ff6c68d.tar.gz gcc-a922c5ff6f3872fc9ce1e484a0e92f288ff6c68d.tar.bz2 | |
Optimize truncating a basic_string
* include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI]
(basic_string::erase(size_type, size_type)): Add fast path for
truncating the string, by calling _M_set_length directly.
(basic_string::erase(__const_iterator, __const_iterator)): Likewise.
* include/bits/basic_string.tcc [_GLIBCXX_USE_CXX11_ABI]
(basic_string::resize(size_type, _CharT)): Likewise.
From-SVN: r240446
| -rw-r--r-- | libstdc++-v3/ChangeLog | 9 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/basic_string.h | 12 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/basic_string.tcc | 2 |
3 files changed, 19 insertions, 4 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 69338c1..80bc018 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,12 @@ +2016-09-23 Jonathan Wakely <jwakely@redhat.com> + + * include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI] + (basic_string::erase(size_type, size_type)): Add fast path for + truncating the string, by calling _M_set_length directly. + (basic_string::erase(__const_iterator, __const_iterator)): Likewise. + * include/bits/basic_string.tcc [_GLIBCXX_USE_CXX11_ABI] + (basic_string::resize(size_type, _CharT)): Likewise. + 2016-09-22 Jason Merrill <jason@redhat.com> * configure.ac: Define HAVE_MEMALIGN for newlib. diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h index e823f13..2708cbc 100644 --- a/libstdc++-v3/include/bits/basic_string.h +++ b/libstdc++-v3/include/bits/basic_string.h @@ -1709,8 +1709,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11 basic_string& erase(size_type __pos = 0, size_type __n = npos) { - this->_M_erase(_M_check(__pos, "basic_string::erase"), - _M_limit(__pos, __n)); + _M_check(__pos, "basic_string::erase"); + if (__n == npos) + this->_M_set_length(__pos); + else if (__n != 0) + this->_M_erase(__pos, _M_limit(__pos, __n)); return *this; } @@ -1747,7 +1750,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11 _GLIBCXX_DEBUG_PEDASSERT(__first >= begin() && __first <= __last && __last <= end()); const size_type __pos = __first - begin(); - this->_M_erase(__pos, __last - __first); + if (__last == end()) + this->_M_set_length(__pos); + else + this->_M_erase(__pos, __last - __first); return iterator(this->_M_data() + __pos); } diff --git a/libstdc++-v3/include/bits/basic_string.tcc b/libstdc++-v3/include/bits/basic_string.tcc index 0080d2b..df1e8dd 100644 --- a/libstdc++-v3/include/bits/basic_string.tcc +++ b/libstdc++-v3/include/bits/basic_string.tcc @@ -351,7 +351,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION if (__size < __n) this->append(__n - __size, __c); else if (__n < __size) - this->_M_erase(__n, __size - __n); + this->_M_set_length(__n); } template<typename _CharT, typename _Traits, typename _Alloc> |