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stl_list.h (_M_resize_pos(size_type&)): Declare.

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* include/bits/stl_list.h (_M_resize_pos(size_type&)): Declare.
	(operator==(const list&, const list&)): If size() is O(1) compare
	sizes before comparing each element.
	* include/bits/list.tcc (list::_M_resize_pos(size_type&)): Define.
	(list::resize): Use _M_resize_pos.

From-SVN: r223416
This commit is contained in:
Jonathan Wakely 2015-05-19 23:24:50 +01:00 committed by Jonathan Wakely
parent 4d6eb35a6d
commit 8e72571637
3 changed files with 76 additions and 22 deletions
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8
libstdc++-v3/ChangeLog
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@ -1,3 +1,11 @@
2015-05-19 Jonathan Wakely <jwakely@redhat.com>
* include/bits/stl_list.h (_M_resize_pos(size_type&)): Declare.
(operator==(const list&, const list&)): If size() is O(1) compare
sizes before comparing each element.
* include/bits/list.tcc (list::_M_resize_pos(size_type&)): Define.
(list::resize): Use _M_resize_pos.
2015-05-19 François Dumont <fdumont@gcc.gnu.org>
* testsuite/23_containers/unordered_map/cons/66055.cc: Add constructor

81
libstdc++-v3/include/bits/list.tcc
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@ -157,6 +157,52 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
return __ret;
}
// Return a const_iterator indicating the position to start inserting or
// erasing elements (depending whether the list is growing or shrinking),
// and set __new_size to the number of new elements that must be appended.
// Equivalent to the following, but performed optimally:
// if (__new_size < size()) {
// __new_size = 0;
// return std::next(begin(), __new_size);
// } else {
// __newsize -= size();
// return end();
// }
template<typename _Tp, typename _Alloc>
typename list<_Tp, _Alloc>::const_iterator
list<_Tp, _Alloc>::
_M_resize_pos(size_type& __new_size) const
{
const_iterator __i;
#if _GLIBCXX_USE_CXX11_ABI
const size_type __len = size();
if (__new_size < __len)
{
if (__new_size <= __len / 2)
{
__i = begin();
std::advance(__i, __new_size);
}
else
{
__i = end();
ptrdiff_t __num_erase = __len - __new_size;
std::advance(__i, -__num_erase);
}
__new_size = 0;
return __i;
}
else
__i = end();
#else
size_type __len = 0;
for (__i = begin(); __i != end() && __len < __new_size; ++__i, ++__len)
;
#endif
__new_size -= __len;
return __i;
}
#if __cplusplus >= 201103L
template<typename _Tp, typename _Alloc>
void
@ -182,14 +228,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
list<_Tp, _Alloc>::
resize(size_type __new_size)
{
iterator __i = begin();
size_type __len = 0;
for (; __i != end() && __len < __new_size; ++__i, ++__len)
;
if (__len == __new_size)
const_iterator __i = _M_resize_pos(__new_size);
if (__new_size)
_M_default_append(__new_size);
else
erase(__i, end());
else // __i == end()
_M_default_append(__new_size - __len);
}
template<typename _Tp, typename _Alloc>
@ -197,14 +240,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
list<_Tp, _Alloc>::
resize(size_type __new_size, const value_type& __x)
{
iterator __i = begin();
size_type __len = 0;
for (; __i != end() && __len < __new_size; ++__i, ++__len)
;
if (__len == __new_size)
const_iterator __i = _M_resize_pos(__new_size);
if (__new_size)
insert(end(), __new_size, __x);
else
erase(__i, end());
else // __i == end()
insert(end(), __new_size - __len, __x);
}
#else
template<typename _Tp, typename _Alloc>
@ -212,14 +252,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
list<_Tp, _Alloc>::
resize(size_type __new_size, value_type __x)
{
iterator __i = begin();
size_type __len = 0;
for (; __i != end() && __len < __new_size; ++__i, ++__len)
;
if (__len == __new_size)
erase(__i, end());
else // __i == end()
insert(end(), __new_size - __len, __x);
const_iterator __i = _M_resize_pos(__new_size);
if (__new_size)
insert(end(), __new_size, __x);
else
erase(__i._M_const_cast(), end());
}
#endif

9
libstdc++-v3/include/bits/stl_list.h
View File

@ -1789,6 +1789,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
_S_do_it(_M_get_Node_allocator(), __x._M_get_Node_allocator()))
__builtin_abort();
}
// Used to implement resize.
const_iterator
_M_resize_pos(size_type& __new_size) const;
};
_GLIBCXX_END_NAMESPACE_CXX11
@ -1806,6 +1810,11 @@ _GLIBCXX_END_NAMESPACE_CXX11
inline bool
operator==(const list<_Tp, _Alloc>& __x, const list<_Tp, _Alloc>& __y)
{
#if _GLIBCXX_USE_CXX11_ABI
if (__x.size() != __y.size())
return false;
#endif
typedef typename list<_Tp, _Alloc>::const_iterator const_iterator;
const_iterator __end1 = __x.end();
const_iterator __end2 = __y.end();