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Re: Default associative containers constructors/destructor/assignment
- From: François Dumont <frs dot dumont at gmail dot com>
- To: Jonathan Wakely <jwakely at redhat dot com>
- Cc: "libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Sun, 20 Nov 2016 19:14:04 +0100
- Subject: Re: Default associative containers constructors/destructor/assignment
- Authentication-results: sourceware.org; auth=none
- References: <87049605-cb4e-a451-01f7-4cf106dd0633@gmail.com> <20161117175241.GQ3145@redhat.com>
On 17/11/2016 18:52, Jonathan Wakely wrote:
On 28/10/16 21:42 +0200, François Dumont wrote:
+ template<typename _Key_compare>
+ struct _Rb_tree_key_compare
+ {
+ _Key_compare _M_key_compare;
+
+ _Rb_tree_key_compare()
+ _GLIBCXX_NOEXCEPT_IF(
+ is_nothrow_default_constructible<_Key_compare>::value)
+ : _M_key_compare()
+ { }
+
+ _Rb_tree_key_compare(const _Key_compare& __comp)
+ : _M_key_compare(__comp)
+ { }
+
+#if __cplusplus >= 201103L
+ _Rb_tree_key_compare(_Rb_tree_key_compare&& __x)
+ noexcept(is_nothrow_copy_constructible<_Key_compare>::value)
+ : _M_key_compare(__x._M_key_compare)
+ { }
+#endif
This constructor makes the type move-only (i.e. non-copyable) in
C++11 and later. It's copyable in C++98. Is that what you want?
I simply consider it was not a problem as, as you noticed, it is not used.
Adding defaulted copy operations would fix that. Even if we don't
actually need those copy operations, I'm uncomfortable with it being
copyable in C++98 and non-copyable otherwise.
Ok, I'll add a default copy constructor for consistency like this:
// Copy constructor added for consistency with C++98 mode.
_Rb_tree_key_compare(const _Rb_tree_compare&) = default;
+ void
+ _M_reset()
+ {
+ _M_initialize();
+ _M_node_count = 0;
+ }
This introduces a small change in behaviour, because _M_reset() now
does _M_header._M_color = _S_red, which it didn't do before. That
store is redundant. It could be avoided by just doing the three
assignments in _M_reset() instead of calling _M_initialize().
I thought it was ok to do this additional operation for the sake of
reusing _M_initialize(). I was compenciating it by avoiding default
initialization when there is something to move.
And we could remove _M_initialize() entirely, and remove the redundant
mem-initializers for _M_node_count (because it's set my _M_reset and
_M_move_data anyway):
_Rb_tree_header() _GLIBCXX_NOEXCEPT
{
_M_reset();
_M_header._M_color = _S_red;
}
#if __cplusplus >= 201103L
_Rb_tree_header(_Rb_tree_header&& __x) noexcept
{
if (__x._M_header._M_parent != nullptr)
_M_move_data(__x);
else
{
_M_reset();
_M_header._M_color = _S_red;
}
}
void
_M_move_data(_Rb_tree_header& __x)
{
_M_header._M_parent = __x._M_header._M_parent;
_M_header._M_left = __x._M_header._M_left;
_M_header._M_right = __x._M_header._M_right;
_M_header._M_parent->_M_parent = &_M_header;
_M_node_count = __x._M_node_count;
__x._M_reset();
}
#endif
void
_M_reset()
{
_M_header._M_parent = 0;
_M_header._M_left = &_M_header;
_M_header._M_right = &_M_header;
_M_node_count = 0;
}
Yes, looks nice, adopted.
Talking about _M_color I just realize that move semantic doesn't copy
_M_color. Shouldn't we capture it along with all the other _M_header
information ?
@@ -599,50 +674,31 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Unused _Is_pod_comparator is kept as it is part of mangled
name.
template<typename _Key_compare,
bool /* _Is_pod_comparator */ = __is_pod(_Key_compare)>
- struct _Rb_tree_impl : public _Node_allocator
+ struct _Rb_tree_impl
+ : public _Node_allocator
+ , public _Rb_tree_key_compare<_Key_compare>
+ , public _Rb_tree_header
Do these need to be base classes, rather than data members?
We derive from the allocator to benefit from the empty base-class
optimization, but that isn't relevant for the _Rb_tree_key_compare and
_Rb_tree_header types. It *could* be relevant for the comparison
function, but would be an ABI change. We could do that ABI change
conditionally, for gnu-versioned-namespace builds, but that's still
possible using data members (e.g. have a data member that derives from
the comparison function and contains the header node and/or node count
members).
Making them data members would simply mean restoring the function
_Rb_tree_impl::_M_reset() and making it call reset on the member:
void
_M_reset() { _M_header._M_reset(); }
The minor convenience of inheriting this function from a base class
doesn't seem worth the stronger coupling that comes from using
inheritance.
Am I missing some other reason that inheritance is used here?
The purpose of this patch is to rely more on compiler especially in
regards to the noexcept qualifications. This is why I started isolating
each ressource in its own class in charge of its specificities. And I
leave to the compiler the work of combining those types. However I also
wanted to limit the impact of this patch on the _Rb_tree and still be
able to use things like this->_M_impl._M_node_count or
this->_M_impl._M_header. So the usage of inheritance.
- _Rb_tree_impl(const _Key_compare& __comp, const
_Node_allocator& __a)
- : _Node_allocator(__a), _M_key_compare(__comp), _M_header(),
- _M_node_count(0)
- { _M_initialize(); }
Please mention the removal of this constructor in the changelog.
@@ -1534,19 +1583,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
_M_move_data(_Rb_tree& __x, std::true_type)
- {
- _M_root() = __x._M_root();
- _M_leftmost() = __x._M_leftmost();
- _M_rightmost() = __x._M_rightmost();
- _M_root()->_M_parent = _M_end();
-
- __x._M_root() = 0;
- __x._M_leftmost() = __x._M_end();
- __x._M_rightmost() = __x._M_end();
-
- this->_M_impl._M_node_count = __x._M_impl._M_node_count;
- __x._M_impl._M_node_count = 0;
- }
+ { _M_impl._M_move_data(__x._M_impl); }
This function could be moved into the class body, or just have
'inline' added to its definition.
Ok, adopted in the attached new version of the patch.
Tested under x86_64 Linux, ok to commit ?
For info, I would like to propose another bunch of simplifications of
_Rb_tree, see other patch attached. Do you want me to propose it in
another mail ?
François
diff --git a/libstdc++-v3/include/bits/stl_map.h b/libstdc++-v3/include/bits/stl_map.h
index dea7d5b..bbd0a97 100644
--- a/libstdc++-v3/include/bits/stl_map.h
+++ b/libstdc++-v3/include/bits/stl_map.h
@@ -185,25 +185,22 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
/**
* @brief %Map copy constructor.
- * @param __x A %map of identical element and allocator types.
*
- * The newly-created %map uses a copy of the allocator object used
- * by @a __x (unless the allocator traits dictate a different object).
+ * Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
map(const map& __x)
: _M_t(__x._M_t) { }
+#else
+ map(const map&) = default;
-#if __cplusplus >= 201103L
/**
* @brief %Map move constructor.
- * @param __x A %map of identical element and allocator types.
*
- * The newly-created %map contains the exact contents of @a __x.
- * The contents of @a __x are a valid, but unspecified %map.
+ * The newly-created %map contains the exact contents of the moved
+ * instance. The moved instance is a valid, but unspecified, %map.
*/
- map(map&& __x)
- noexcept(is_nothrow_copy_constructible<_Compare>::value)
- : _M_t(std::move(__x._M_t)) { }
+ map(map&&) = default;
/**
* @brief Builds a %map from an initializer_list.
@@ -284,31 +281,31 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
: _M_t(__comp, _Pair_alloc_type(__a))
{ _M_t._M_insert_unique(__first, __last); }
- // FIXME There is no dtor declared, but we should have something
- // generated by Doxygen. I don't know what tags to add to this
- // paragraph to make that happen:
+#if __cplusplus >= 201103L
/**
* The dtor only erases the elements, and note that if the elements
* themselves are pointers, the pointed-to memory is not touched in any
* way. Managing the pointer is the user's responsibility.
*/
+ ~map() = default;
+#endif
/**
* @brief %Map assignment operator.
- * @param __x A %map of identical element and allocator types.
- *
- * All the elements of @a __x are copied.
*
* Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
map&
operator=(const map& __x)
{
_M_t = __x._M_t;
return *this;
}
+#else
+ map&
+ operator=(const map&) = default;
-#if __cplusplus >= 201103L
/// Move assignment operator.
map&
operator=(map&&) = default;
diff --git a/libstdc++-v3/include/bits/stl_multimap.h b/libstdc++-v3/include/bits/stl_multimap.h
index 7e86b76..a5f775b 100644
--- a/libstdc++-v3/include/bits/stl_multimap.h
+++ b/libstdc++-v3/include/bits/stl_multimap.h
@@ -182,25 +182,23 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
/**
* @brief %Multimap copy constructor.
- * @param __x A %multimap of identical element and allocator types.
*
- * The newly-created %multimap uses a copy of the allocator object used
- * by @a __x (unless the allocator traits dictate a different object).
+ * Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
multimap(const multimap& __x)
: _M_t(__x._M_t) { }
+#else
+ multimap(const multimap&) = default;
-#if __cplusplus >= 201103L
/**
* @brief %Multimap move constructor.
- * @param __x A %multimap of identical element and allocator types.
*
- * The newly-created %multimap contains the exact contents of @a __x.
- * The contents of @a __x are a valid, but unspecified %multimap.
+ * The newly-created %multimap contains the exact contents of the
+ * moved instance. The moved instance is a valid, but unspecified
+ * %multimap.
*/
- multimap(multimap&& __x)
- noexcept(is_nothrow_copy_constructible<_Compare>::value)
- : _M_t(std::move(__x._M_t)) { }
+ multimap(multimap&&) = default;
/**
* @brief Builds a %multimap from an initializer_list.
@@ -278,31 +276,31 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
: _M_t(__comp, _Pair_alloc_type(__a))
{ _M_t._M_insert_equal(__first, __last); }
- // FIXME There is no dtor declared, but we should have something generated
- // by Doxygen. I don't know what tags to add to this paragraph to make
- // that happen:
+#if __cplusplus >= 201103L
/**
* The dtor only erases the elements, and note that if the elements
* themselves are pointers, the pointed-to memory is not touched in any
* way. Managing the pointer is the user's responsibility.
*/
+ ~multimap() = default;
+#endif
/**
* @brief %Multimap assignment operator.
- * @param __x A %multimap of identical element and allocator types.
- *
- * All the elements of @a __x are copied.
*
* Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
multimap&
operator=(const multimap& __x)
{
_M_t = __x._M_t;
return *this;
}
+#else
+ multimap&
+ operator=(const multimap&) = default;
-#if __cplusplus >= 201103L
/// Move assignment operator.
multimap&
operator=(multimap&&) = default;
diff --git a/libstdc++-v3/include/bits/stl_multiset.h b/libstdc++-v3/include/bits/stl_multiset.h
index 7fe2fbd..8a83b17 100644
--- a/libstdc++-v3/include/bits/stl_multiset.h
+++ b/libstdc++-v3/include/bits/stl_multiset.h
@@ -194,25 +194,23 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
/**
* @brief %Multiset copy constructor.
- * @param __x A %multiset of identical element and allocator types.
*
- * The newly-created %multiset uses a copy of the allocator object used
- * by @a __x (unless the allocator traits dictate a different object).
+ * Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
multiset(const multiset& __x)
: _M_t(__x._M_t) { }
+#else
+ multiset(const multiset&) = default;
-#if __cplusplus >= 201103L
/**
* @brief %Multiset move constructor.
- * @param __x A %multiset of identical element and allocator types.
*
- * The newly-created %multiset contains the exact contents of @a __x.
- * The contents of @a __x are a valid, but unspecified %multiset.
+ * The newly-created %multiset contains the exact contents of the
+ * moved instance. The moved instance is a valid, but unspecified
+ * %multiset.
*/
- multiset(multiset&& __x)
- noexcept(is_nothrow_copy_constructible<_Compare>::value)
- : _M_t(std::move(__x._M_t)) { }
+ multiset(multiset&&) = default;
/**
* @brief Builds a %multiset from an initializer_list.
@@ -256,24 +254,31 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
const allocator_type& __a)
: _M_t(_Compare(), _Key_alloc_type(__a))
{ _M_t._M_insert_equal(__first, __last); }
+
+ /**
+ * The dtor only erases the elements, and note that if the elements
+ * themselves are pointers, the pointed-to memory is not touched in any
+ * way. Managing the pointer is the user's responsibility.
+ */
+ ~multiset() = default;
#endif
/**
* @brief %Multiset assignment operator.
- * @param __x A %multiset of identical element and allocator types.
- *
- * All the elements of @a __x are copied.
*
* Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
multiset&
operator=(const multiset& __x)
{
_M_t = __x._M_t;
return *this;
}
+#else
+ multiset&
+ operator=(const multiset&) = default;
-#if __cplusplus >= 201103L
/// Move assignment operator.
multiset&
operator=(multiset&&) = default;
diff --git a/libstdc++-v3/include/bits/stl_set.h b/libstdc++-v3/include/bits/stl_set.h
index 5ed9672..db1e031 100644
--- a/libstdc++-v3/include/bits/stl_set.h
+++ b/libstdc++-v3/include/bits/stl_set.h
@@ -199,25 +199,22 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
/**
* @brief %Set copy constructor.
- * @param __x A %set of identical element and allocator types.
*
- * The newly-created %set uses a copy of the allocator object used
- * by @a __x (unless the allocator traits dictate a different object).
+ * Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
set(const set& __x)
: _M_t(__x._M_t) { }
+#else
+ set(const set&) = default;
-#if __cplusplus >= 201103L
/**
* @brief %Set move constructor
- * @param __x A %set of identical element and allocator types.
*
- * The newly-created %set contains the exact contents of @a x.
- * The contents of @a x are a valid, but unspecified %set.
+ * The newly-created %set contains the exact contents of the moved
+ * instance. The moved instance is a valid, but unspecified, %set.
*/
- set(set&& __x)
- noexcept(is_nothrow_copy_constructible<_Compare>::value)
- : _M_t(std::move(__x._M_t)) { }
+ set(set&&) = default;
/**
* @brief Builds a %set from an initializer_list.
@@ -261,24 +258,31 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
const allocator_type& __a)
: _M_t(_Compare(), _Key_alloc_type(__a))
{ _M_t._M_insert_unique(__first, __last); }
+
+ /**
+ * The dtor only erases the elements, and note that if the elements
+ * themselves are pointers, the pointed-to memory is not touched in any
+ * way. Managing the pointer is the user's responsibility.
+ */
+ ~set() = default;
#endif
/**
* @brief %Set assignment operator.
- * @param __x A %set of identical element and allocator types.
- *
- * All the elements of @a __x are copied.
*
* Whether the allocator is copied depends on the allocator traits.
*/
+#if __cplusplus < 201103L
set&
operator=(const set& __x)
{
_M_t = __x._M_t;
return *this;
}
+#else
+ set&
+ operator=(const set&) = default;
-#if __cplusplus >= 201103L
/// Move assignment operator.
set&
operator=(set&&) = default;
diff --git a/libstdc++-v3/include/bits/stl_tree.h b/libstdc++-v3/include/bits/stl_tree.h
index 0bc5f4b..8de5e31 100644
--- a/libstdc++-v3/include/bits/stl_tree.h
+++ b/libstdc++-v3/include/bits/stl_tree.h
@@ -137,6 +137,80 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
};
+ // Helper type offering value initialization guarantee on the compare functor.
+ template<typename _Key_compare>
+ struct _Rb_tree_key_compare
+ {
+ _Key_compare _M_key_compare;
+
+ _Rb_tree_key_compare()
+ _GLIBCXX_NOEXCEPT_IF(
+ is_nothrow_default_constructible<_Key_compare>::value)
+ : _M_key_compare()
+ { }
+
+ _Rb_tree_key_compare(const _Key_compare& __comp)
+ : _M_key_compare(__comp)
+ { }
+
+#if __cplusplus >= 201103L
+ // Copy constructor added for consistency with C++98 mode.
+ _Rb_tree_key_compare(const _Rb_tree_key_compare&) = default;
+
+ _Rb_tree_key_compare(_Rb_tree_key_compare&& __x)
+ noexcept(is_nothrow_copy_constructible<_Key_compare>::value)
+ : _M_key_compare(__x._M_key_compare)
+ { }
+#endif
+ };
+
+ // Helper type to manage default initialization of node count and header.
+ struct _Rb_tree_header
+ {
+ _Rb_tree_node_base _M_header;
+ size_t _M_node_count; // Keeps track of size of tree.
+
+ _Rb_tree_header() _GLIBCXX_NOEXCEPT
+ {
+ _M_header._M_color = _S_red;
+ _M_reset();
+ }
+
+#if __cplusplus >= 201103L
+ _Rb_tree_header(_Rb_tree_header&& __x) noexcept
+ {
+ if (__x._M_header._M_parent != nullptr)
+ _M_move_data(__x);
+ else
+ {
+ _M_header._M_color = _S_red;
+ _M_reset();
+ }
+ }
+#endif
+
+ void
+ _M_move_data(_Rb_tree_header& __from)
+ {
+ _M_header._M_parent = __from._M_header._M_parent;
+ _M_header._M_left = __from._M_header._M_left;
+ _M_header._M_right = __from._M_header._M_right;
+ _M_header._M_parent->_M_parent = &_M_header;
+ _M_node_count = __from._M_node_count;
+
+ __from._M_reset();
+ }
+
+ void
+ _M_reset()
+ {
+ _M_header._M_parent = 0;
+ _M_header._M_left = &_M_header;
+ _M_header._M_right = &_M_header;
+ _M_node_count = 0;
+ }
+ };
+
template<typename _Val>
struct _Rb_tree_node : public _Rb_tree_node_base
{
@@ -599,50 +673,31 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Unused _Is_pod_comparator is kept as it is part of mangled name.
template<typename _Key_compare,
bool /* _Is_pod_comparator */ = __is_pod(_Key_compare)>
- struct _Rb_tree_impl : public _Node_allocator
+ struct _Rb_tree_impl
+ : public _Node_allocator
+ , public _Rb_tree_key_compare<_Key_compare>
+ , public _Rb_tree_header
{
- _Key_compare _M_key_compare;
- _Rb_tree_node_base _M_header;
- size_type _M_node_count; // Keeps track of size of tree.
+ typedef _Rb_tree_key_compare<_Key_compare> _Base_key_compare;
+#if __cplusplus < 201103L
_Rb_tree_impl()
- _GLIBCXX_NOEXCEPT_IF(
- is_nothrow_default_constructible<_Node_allocator>::value
- && is_nothrow_default_constructible<_Key_compare>::value)
- : _Node_allocator(), _M_key_compare(), _M_header(),
- _M_node_count(0)
- { _M_initialize(); }
+ { }
+#else
+ _Rb_tree_impl() = default;
+#endif
- _Rb_tree_impl(const _Key_compare& __comp, const _Node_allocator& __a)
- : _Node_allocator(__a), _M_key_compare(__comp), _M_header(),
- _M_node_count(0)
- { _M_initialize(); }
+ _Rb_tree_impl(const _Rb_tree_impl& __x)
+ : _Node_allocator(_Alloc_traits::_S_select_on_copy(__x))
+ , _Base_key_compare(__x._M_key_compare)
+ { }
#if __cplusplus >= 201103L
+ _Rb_tree_impl(_Rb_tree_impl&&) = default;
_Rb_tree_impl(const _Key_compare& __comp, _Node_allocator&& __a)
- : _Node_allocator(std::move(__a)), _M_key_compare(__comp),
- _M_header(), _M_node_count(0)
- { _M_initialize(); }
+ : _Node_allocator(std::move(__a)), _Base_key_compare(__comp)
+ { }
#endif
-
- void
- _M_reset()
- {
- this->_M_header._M_parent = 0;
- this->_M_header._M_left = &this->_M_header;
- this->_M_header._M_right = &this->_M_header;
- this->_M_node_count = 0;
- }
-
- private:
- void
- _M_initialize()
- {
- this->_M_header._M_color = _S_red;
- this->_M_header._M_parent = 0;
- this->_M_header._M_left = &this->_M_header;
- this->_M_header._M_right = &this->_M_header;
- }
};
_Rb_tree_impl<_Compare> _M_impl;
@@ -845,8 +900,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_impl(__comp, _Node_allocator(__a)) { }
_Rb_tree(const _Rb_tree& __x)
- : _M_impl(__x._M_impl._M_key_compare,
- _Alloc_traits::_S_select_on_copy(__x._M_get_Node_allocator()))
+ : _M_impl(__x._M_impl)
{
if (__x._M_root() != 0)
{
@@ -874,13 +928,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
}
- _Rb_tree(_Rb_tree&& __x)
- : _M_impl(__x._M_impl._M_key_compare,
- std::move(__x._M_get_Node_allocator()))
- {
- if (__x._M_root() != 0)
- _M_move_data(__x, std::true_type());
- }
+ _Rb_tree(_Rb_tree&&) = default;
_Rb_tree(_Rb_tree&& __x, const allocator_type& __a)
: _Rb_tree(std::move(__x), _Node_allocator(__a))
@@ -1278,7 +1326,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
private:
// Move elements from container with equal allocator.
void
- _M_move_data(_Rb_tree&, std::true_type);
+ _M_move_data(_Rb_tree& __x, std::true_type)
+ { _M_impl._M_move_data(__x._M_impl); }
// Move elements from container with possibly non-equal allocator,
// which might result in a copy not a move.
@@ -1533,25 +1582,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typename _Compare, typename _Alloc>
void
_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
- _M_move_data(_Rb_tree& __x, std::true_type)
- {
- _M_root() = __x._M_root();
- _M_leftmost() = __x._M_leftmost();
- _M_rightmost() = __x._M_rightmost();
- _M_root()->_M_parent = _M_end();
-
- __x._M_root() = 0;
- __x._M_leftmost() = __x._M_end();
- __x._M_rightmost() = __x._M_end();
-
- this->_M_impl._M_node_count = __x._M_impl._M_node_count;
- __x._M_impl._M_node_count = 0;
- }
-
- template<typename _Key, typename _Val, typename _KeyOfValue,
- typename _Compare, typename _Alloc>
- void
- _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::
_M_move_data(_Rb_tree& __x, std::false_type)
{
if (_M_get_Node_allocator() == __x._M_get_Node_allocator())
@@ -1966,26 +1996,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (_M_root() == 0)
{
if (__t._M_root() != 0)
- {
- _M_root() = __t._M_root();
- _M_leftmost() = __t._M_leftmost();
- _M_rightmost() = __t._M_rightmost();
- _M_root()->_M_parent = _M_end();
- _M_impl._M_node_count = __t._M_impl._M_node_count;
-
- __t._M_impl._M_reset();
- }
+ _M_impl._M_move_data(__t._M_impl);
}
else if (__t._M_root() == 0)
- {
- __t._M_root() = _M_root();
- __t._M_leftmost() = _M_leftmost();
- __t._M_rightmost() = _M_rightmost();
- __t._M_root()->_M_parent = __t._M_end();
- __t._M_impl._M_node_count = _M_impl._M_node_count;
-
- _M_impl._M_reset();
- }
+ __t._M_impl._M_move_data(_M_impl);
else
{
std::swap(_M_root(),__t._M_root());
diff --git a/libstdc++-v3/include/bits/stl_tree.h b/libstdc++-v3/include/bits/stl_tree.h
index 8de5e31..1bfbfa7 100644
--- a/libstdc++-v3/include/bits/stl_tree.h
+++ b/libstdc++-v3/include/bits/stl_tree.h
@@ -861,11 +861,22 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Link_type
_M_copy(_Const_Link_type __x, _Base_ptr __p, _NodeGen&);
+ template<typename _NodeGen>
+ _Link_type
+ _M_copy(const _Rb_tree& __x, _NodeGen& __gen)
+ {
+ _Link_type __root = _M_copy(__x._M_begin(), _M_end(), __gen);
+ _M_leftmost() = _S_minimum(__root);
+ _M_rightmost() = _S_maximum(__root);
+ _M_impl._M_node_count = __x._M_impl._M_node_count;
+ return __root;
+ }
+
_Link_type
- _M_copy(_Const_Link_type __x, _Base_ptr __p)
+ _M_copy(const _Rb_tree& __x)
{
_Alloc_node __an(*this);
- return _M_copy(__x, __p, __an);
+ return _M_copy(__x, __an);
}
void
@@ -903,12 +914,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_impl(__x._M_impl)
{
if (__x._M_root() != 0)
- {
- _M_root() = _M_copy(__x._M_begin(), _M_end());
- _M_leftmost() = _S_minimum(_M_root());
- _M_rightmost() = _S_maximum(_M_root());
- _M_impl._M_node_count = __x._M_impl._M_node_count;
- }
+ _M_root() = _M_copy(__x);
}
#if __cplusplus >= 201103L
@@ -920,12 +926,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: _M_impl(__x._M_impl._M_key_compare, _Node_allocator(__a))
{
if (__x._M_root() != nullptr)
- {
- _M_root() = _M_copy(__x._M_begin(), _M_end());
- _M_leftmost() = _S_minimum(_M_root());
- _M_rightmost() = _S_maximum(_M_root());
- _M_impl._M_node_count = __x._M_impl._M_node_count;
- }
+ _M_root() = _M_copy(__x);
}
_Rb_tree(_Rb_tree&&) = default;
@@ -1595,10 +1596,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
auto& __val = const_cast<value_type&>(__cval);
return __an(std::move_if_noexcept(__val));
};
- _M_root() = _M_copy(__x._M_begin(), _M_end(), __lbd);
- _M_leftmost() = _S_minimum(_M_root());
- _M_rightmost() = _S_maximum(_M_root());
- _M_impl._M_node_count = __x._M_impl._M_node_count;
+ _M_root() = _M_copy(__x, __lbd);
}
}
@@ -1636,10 +1634,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
auto& __val = const_cast<value_type&>(__cval);
return __roan(std::move_if_noexcept(__val));
};
- _M_root() = _M_copy(__x._M_begin(), _M_end(), __lbd);
- _M_leftmost() = _S_minimum(_M_root());
- _M_rightmost() = _S_maximum(_M_root());
- _M_impl._M_node_count = __x._M_impl._M_node_count;
+ _M_root() = _M_copy(__x, __lbd);
__x.clear();
}
}
@@ -1653,10 +1648,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
&& is_nothrow_move_assignable<_Compare>::value)
{
_M_impl._M_key_compare = std::move(__x._M_impl._M_key_compare);
- constexpr bool __move_storage =
- _Alloc_traits::_S_propagate_on_move_assign()
- || _Alloc_traits::_S_always_equal();
- _M_move_assign(__x, __bool_constant<__move_storage>());
+ _M_move_assign(__x, __bool_constant<_Alloc_traits::_S_nothrow_move()>());
return *this;
}
@@ -1716,12 +1708,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_impl._M_reset();
_M_impl._M_key_compare = __x._M_impl._M_key_compare;
if (__x._M_root() != 0)
- {
- _M_root() = _M_copy(__x._M_begin(), _M_end(), __roan);
- _M_leftmost() = _S_minimum(_M_root());
- _M_rightmost() = _S_maximum(_M_root());
- _M_impl._M_node_count = __x._M_impl._M_node_count;
- }
+ _M_root() = _M_copy(__x, __roan);
}
return *this;