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| author | Christopher Jefferson <caj@cs.york.ac.uk> | 2004-10-05 10:28:17 +0000 |
|---|---|---|
| committer | Paolo Carlini <paolo@gcc.gnu.org> | 2004-10-05 10:28:17 +0000 |
| commit | 575665ff649eb2aac87bad3904b795c988077f30 (patch) | |
| tree | 529c9760906ca57e7255036f5b9e86c9f2fb7bed | |
| parent | 88a6ecb6f2950f8e6644bddc508b2e7ccaf53b06 (diff) | |
| download | gcc-575665ff649eb2aac87bad3904b795c988077f30.zip gcc-575665ff649eb2aac87bad3904b795c988077f30.tar.gz gcc-575665ff649eb2aac87bad3904b795c988077f30.tar.bz2 | |
stl_algobase.h (iter_swap): delegate to swap via __iter_swap when iterator's value_types are equal.
2004-10-05 Christopher Jefferson <caj@cs.york.ac.uk>
* include/bits/stl_algobase.h (iter_swap): delegate to swap via
__iter_swap when iterator's value_types are equal.
(struct __iter_swap): New.
From-SVN: r88549
| -rw-r--r-- | libstdc++-v3/ChangeLog | 6 | ||||
| -rw-r--r-- | libstdc++-v3/include/bits/stl_algobase.h | 78 |
2 files changed, 59 insertions, 25 deletions
diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog index 834f0b1..7dd6e7e 100644 --- a/libstdc++-v3/ChangeLog +++ b/libstdc++-v3/ChangeLog @@ -1,3 +1,9 @@ +2004-10-05 Christopher Jefferson <caj@cs.york.ac.uk> + + * include/bits/stl_algobase.h (iter_swap): delegate to swap via + __iter_swap when iterator's value_types are equal. + (struct __iter_swap): New. + 2004-10-04 Benjamin Kosnik <bkoz@redhat.com> * configure.ac (libtool_VERSION): To 6:3:0. diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h index f3f20e6..6257890 100644 --- a/libstdc++-v3/include/bits/stl_algobase.h +++ b/libstdc++-v3/include/bits/stl_algobase.h @@ -77,6 +77,57 @@ namespace std { + + /** + * @brief Swaps two values. + * @param a A thing of arbitrary type. + * @param b Another thing of arbitrary type. + * @return Nothing. + * + * This is the simple classic generic implementation. It will work on + * any type which has a copy constructor and an assignment operator. + */ + template<typename _Tp> + inline void + swap(_Tp& __a, _Tp& __b) + { + // concept requirements + __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) + + const _Tp __tmp = __a; + __a = __b; + __b = __tmp; + } + + // See http://gcc.gnu.org/ml/libstdc++/2004-08/msg00167.html: in a + // nutshell, we are partially implementing the resolution of DR 187, + // when it's safe, i.e., the value_types are equal. + template<bool _BoolType> + struct __iter_swap + { + template<typename _ForwardIterator1, typename _ForwardIterator2> + static void + iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b) + { + typedef typename iterator_traits<_ForwardIterator1>::value_type + _ValueType1; + const _ValueType1 __tmp = *__a; + *__a = *__b; + *__b = __tmp; + } + }; + + template<> + struct __iter_swap<true> + { + template<typename _ForwardIterator1, typename _ForwardIterator2> + static void + iter_swap(_ForwardIterator1 __a, _ForwardIterator2 __b) + { + swap(*__a, *__b); + } + }; + /** * @brief Swaps the contents of two iterators. * @param a An iterator. @@ -104,31 +155,8 @@ namespace std _ValueType2>) __glibcxx_function_requires(_ConvertibleConcept<_ValueType2, _ValueType1>) - - const _ValueType1 __tmp = *__a; - *__a = *__b; - *__b = __tmp; - } - - /** - * @brief Swaps two values. - * @param a A thing of arbitrary type. - * @param b Another thing of arbitrary type. - * @return Nothing. - * - * This is the simple classic generic implementation. It will work on - * any type which has a copy constructor and an assignment operator. - */ - template<typename _Tp> - inline void - swap(_Tp& __a, _Tp& __b) - { - // concept requirements - __glibcxx_function_requires(_SGIAssignableConcept<_Tp>) - - const _Tp __tmp = __a; - __a = __b; - __b = __tmp; + std::__iter_swap<__are_same<_ValueType1, _ValueType2>::_M_type>:: + iter_swap(__a, __b); } #undef min |