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hashtable_policy.h (_Hash_node_base): New, use it as base class of ...

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2012-01-13  François Dumont  <fdumont@gcc.gnu.org>

	* include/bits/hashtable_policy.h (_Hash_node_base): New, use it as
	base class of ...
	(_Hash_node<Value, true>, _Hash_node<Value, false>): ... those.
	* include/bits/hashtable.h (_Hashtable): Replace _M_begin_bucket_index
	by _M_before_begin. Review implementation so that we do not need to
	look for previous non-empty bucket when inserting nodes.

From-SVN: r183164
This commit is contained in:
François Dumont 2012-01-13 21:49:14 +00:00
parent d6430d9a0c
commit f86b266c7c
3 changed files with 231 additions and 324 deletions
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9
libstdc++-v3/ChangeLog
View File

@ -1,3 +1,12 @@
2012-01-13 François Dumont <fdumont@gcc.gnu.org>
* include/bits/hashtable_policy.h (_Hash_node_base): New, use it as
base class of ...
(_Hash_node<Value, true>, _Hash_node<Value, false>): ... those.
* include/bits/hashtable.h (_Hashtable): Replace _M_begin_bucket_index
by _M_before_begin. Review implementation so that we do not need to
look for previous non-empty bucket when inserting nodes.
2012-01-09 Kai Tietz <ktietz@redhat.com>
PR libstc++/51673 part 2

512
libstdc++-v3/include/bits/hashtable.h
View File

@ -93,13 +93,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// and unordered_multimap.
/**
* Here's _Hashtable data structure, each _Hashtable has:
* - _Bucket[] _M_buckets
* - size_type _M_bucket_count
* - size_type _M_begin_bucket_index
* - size_type _M_element_count
* - _Bucket[] _M_buckets
* - _Hash_node_base _M_before_begin
* - size_type _M_bucket_count
* - size_type _M_element_count
*
* with _Bucket being _Node* and _Node:
* - _Node* _M_next
* with _Bucket being _Hash_node* and _Hash_node constaining:
* - _Hash_node* _M_next
* - Tp _M_value
* - size_t _M_code if cache_hash_code is true
*
@ -107,36 +107,34 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* - std::forward_list<_Node> containing the elements
* - std::vector<std::forward_list<_Node>::iterator> representing the buckets
*
* The first non-empty bucket with index _M_begin_bucket_index contains the
* first container node which is also the first bucket node whereas other
* non-empty buckets contain the node before the first bucket node. This is so
* to implement something like a std::forward_list::erase_after on container
* erase calls.
* The non-empty buckets contain the node before the first bucket node. This
* design allow to implement something like a std::forward_list::insert_after
* on container insertion and std::forward_list::erase_after on container
* erase calls. _M_before_begin is equivalent to
* std::foward_list::before_begin. Empty buckets are containing nullptr.
* Note that one of the non-empty bucket contains &_M_before_begin which is
* not a derefenrenceable node so the node pointers in buckets shall never be
* derefenrenced, only its next node can be.
*
* Access to the bucket last element require a check on the hash code to see
* if the node is still in the bucket. Such a design impose a quite efficient
* hash functor and is one of the reasons it is highly advise to set
* Walk through a bucket nodes require a check on the hash code to see if the
* node is still in the bucket. Such a design impose a quite efficient hash
* functor and is one of the reasons it is highly advise to set
* __cache_hash_code to true.
*
* The container iterators are simply built from nodes. This way incrementing
* the iterator is perfectly efficient no matter how many empty buckets there
* are in the container.
* the iterator is perfectly efficient independent of how many empty buckets
* there are in the container.
*
* On insert we compute element hash code and thanks to it find the bucket
* index. If the element is the first one in the bucket we must find the
* previous non-empty bucket where the previous node rely. To keep this loop
* minimal it is important that the number of bucket is not too high compared
* to the number of elements. So the hash policy must be carefully design so
* that it computes a bucket count large enough to respect the user defined
* load factor but also not too large to limit impact on the insert operation.
* index. If the element must be inserted on an empty bucket we add it at the
* beginning of the singly linked list and make the bucket point to
* _M_before_begin. The bucket that used to point to _M_before_begin, if any,
* is updated to point to its new before begin node.
*
* On erase, the simple iterator design impose to use the hash functor to get
* the index of the bucket to update. For this reason, when __cache_hash_code
* is set to false, there is a static assertion that the hash functor cannot
* throw.
*
* _M_begin_bucket_index is used to offer contant time access to the container
* begin iterator.
*/
template<typename _Key, typename _Value, typename _Allocator,
@ -182,6 +180,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using __if_hash_code_not_cached
= __or_<integral_constant<bool, __cache_hash_code>, _Cond>;
// When hash codes are not cached the hash functor shall not throw
// because it is used in methods (erase, swap...) that shall not throw.
static_assert(__if_hash_code_not_cached<__detail::__is_noexcept_hash<_Key,
_H1>>::value,
"Cache the hash code or qualify your hash functor with noexcept");
@ -246,19 +246,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef __detail::_Hash_node<_Value, __cache_hash_code> _Node;
typedef typename _Allocator::template rebind<_Node>::other
_Node_allocator_type;
typedef _Node* _Bucket;
typedef __detail::_Hash_node_base _BaseNode;
typedef _BaseNode* _Bucket;
typedef typename _Allocator::template rebind<_Bucket>::other
_Bucket_allocator_type;
typedef typename _Allocator::template rebind<_Value>::other
_Value_allocator_type;
_Node_allocator_type _M_node_allocator;
_Bucket* _M_buckets;
size_type _M_bucket_count;
size_type _M_begin_bucket_index; // First non-empty bucket.
size_type _M_element_count;
_RehashPolicy _M_rehash_policy;
_Node_allocator_type _M_node_allocator;
_Bucket* _M_buckets;
size_type _M_bucket_count;
_BaseNode _M_before_begin;
size_type _M_element_count;
_RehashPolicy _M_rehash_policy;
template<typename... _Args>
_Node*
@ -277,15 +278,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_M_deallocate_buckets(_Bucket*, size_type __n);
// Gets bucket begin dealing with the difference between first non-empty
// bucket containing the first container node and the other non-empty
// buckets containing the node before the one belonging to the bucket.
// Gets bucket begin, deals with the fact that non-empty buckets contain
// their before begin node.
_Node*
_M_bucket_begin(size_type __bkt) const;
// Gets the bucket last node if any
_Node*
_M_bucket_end(size_type __bkt) const;
_M_begin() const
{ return static_cast<_Node*>(_M_before_begin._M_nxt); }
public:
// Constructor, destructor, assignment, swap
@ -330,11 +330,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Basic container operations
iterator
begin() noexcept
{ return iterator(_M_buckets[_M_begin_bucket_index]); }
{ return iterator(_M_begin()); }
const_iterator
begin() const noexcept
{ return const_iterator(_M_buckets[_M_begin_bucket_index]); }
{ return const_iterator(_M_begin()); }
iterator
end() noexcept
@ -346,7 +346,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const_iterator
cbegin() const noexcept
{ return const_iterator(_M_buckets[_M_begin_bucket_index]); }
{ return const_iterator(_M_begin()); }
const_iterator
cend() const noexcept
@ -454,6 +454,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
equal_range(const key_type& __k) const;
private:
// Bucket index computation helpers.
size_type
_M_bucket_index(_Node* __n) const
{ return _HCBase::_M_bucket_index(__n, _M_bucket_count); }
@ -464,26 +465,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ return _HCBase::_M_bucket_index(__k, __c, _M_bucket_count); }
// Find and insert helper functions and types
_Node*
_M_find_node(size_type, const key_type&,
typename _Hashtable::_Hash_code_type) const;
// Find the node before the one matching the criteria.
_BaseNode*
_M_find_before_node(size_type, const key_type&,
typename _Hashtable::_Hash_code_type) const;
// Insert a node in an empty bucket
_Node*
_M_find_node(size_type __bkt, const key_type& __key,
typename _Hashtable::_Hash_code_type __c) const
{
_BaseNode* __before_n = _M_find_before_node(__bkt, __key, __c);
if (__before_n)
return static_cast<_Node*>(__before_n->_M_nxt);
return nullptr;
}
// Insert a node at the beginning of a bucket.
void
_M_insert_bucket_begin(size_type, _Node*);
// Insert a node after an other one in a non-empty bucket
void
_M_insert_after(size_type, _Node*, _Node*);
// Remove the bucket first node
void
_M_remove_bucket_begin(size_type __bkt, _Node* __next_n,
size_type __next_bkt);
// Get the node before __n in the bucket __bkt
_Node*
_M_get_previous_node(size_type __bkt, _Node* __n);
_BaseNode*
_M_get_previous_node(size_type __bkt, _BaseNode* __n);
template<typename _Arg>
iterator
@ -645,7 +653,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
while (__n)
{
_Node* __tmp = __n;
__n = __n->_M_next;
__n = __n->_M_next();
_M_deallocate_node(__tmp);
}
}
@ -663,10 +671,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
_Bucket_allocator_type __alloc(_M_node_allocator);
// We allocate one extra bucket to have _M_begin_bucket_index
// point to it as long as container is empty
_Bucket* __p = __alloc.allocate(__n + 1);
__builtin_memset(__p, 0, (__n + 1) * sizeof(_Bucket));
_Bucket* __p = __alloc.allocate(__n);
__builtin_memset(__p, 0, __n * sizeof(_Bucket));
return __p;
}
@ -680,7 +686,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_deallocate_buckets(_Bucket* __p, size_type __n)
{
_Bucket_allocator_type __alloc(_M_node_allocator);
__alloc.deallocate(__p, __n + 1);
__alloc.deallocate(__p, __n);
}
template<typename _Key, typename _Value,
@ -694,29 +700,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
_M_bucket_begin(size_type __bkt) const
{
if (__bkt == _M_begin_bucket_index)
return _M_buckets[__bkt];
_Node* __n = _M_buckets[__bkt];
return __n ? __n->_M_next : nullptr;
}
template<typename _Key, typename _Value,
typename _Allocator, typename _ExtractKey, typename _Equal,
typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
bool __chc, bool __cit, bool __uk>
typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
_Equal, _H1, _H2, _Hash, _RehashPolicy,
__chc, __cit, __uk>::_Node*
_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
_M_bucket_end(size_type __bkt) const
{
_Node* __n = _M_bucket_begin(__bkt);
if (__n)
for (;; __n = __n->_M_next)
if (!__n->_M_next || _M_bucket_index(__n->_M_next) != __bkt)
break;
return __n;
_BaseNode* __n = _M_buckets[__bkt];
return __n ? static_cast<_Node*>(__n->_M_nxt) : nullptr;
}
template<typename _Key, typename _Value,
@ -744,7 +729,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// on the first insertion so we need to reset its previous resize level.
_M_rehash_policy._M_prev_resize = 0;
_M_buckets = _M_allocate_buckets(_M_bucket_count);
_M_begin_bucket_index = _M_bucket_count;
}
template<typename _Key, typename _Value,
@ -779,7 +763,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// level.
_M_rehash_policy._M_prev_resize = 0;
_M_buckets = _M_allocate_buckets(_M_bucket_count);
_M_begin_bucket_index = _M_bucket_count;
__try
{
for (; __f != __l; ++__f)
@ -806,48 +789,34 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__detail::_Map_base<_Key, _Value, _ExtractKey, __uk, _Hashtable>(__ht),
_M_node_allocator(__ht._M_node_allocator),
_M_bucket_count(__ht._M_bucket_count),
_M_begin_bucket_index(__ht._M_begin_bucket_index),
_M_element_count(__ht._M_element_count),
_M_rehash_policy(__ht._M_rehash_policy)
{
_M_buckets = _M_allocate_buckets(_M_bucket_count);
__try
{
const _Node* __ht_n = __ht._M_buckets[__ht._M_begin_bucket_index];
if (!__ht_n)
if (!__ht._M_before_begin._M_nxt)
return;
// Note that the copy constructor do not rely on hash code usage.
// First deal with the special first node that is directly store in
// the first non-empty bucket
// First deal with the special first node pointed to by
// _M_before_begin.
const _Node* __ht_n = __ht._M_begin();
_Node* __this_n = _M_allocate_node(__ht_n->_M_v);
this->_M_copy_code(__this_n, __ht_n);
_M_buckets[_M_begin_bucket_index] = __this_n;
__ht_n = __ht_n->_M_next;
// Second deal with following non-empty buckets containing previous
// nodes node.
for (size_type __i = __ht._M_begin_bucket_index + 1;
__i != __ht._M_bucket_count; ++__i)
{
if (!__ht._M_buckets[__i])
continue;
_M_before_begin._M_nxt = __this_n;
_M_buckets[_M_bucket_index(__this_n)] = &_M_before_begin;
for (; __ht_n != __ht._M_buckets[__i]->_M_next;
__ht_n = __ht_n->_M_next)
{
__this_n->_M_next = _M_allocate_node(__ht_n->_M_v);
this->_M_copy_code(__this_n->_M_next, __ht_n);
__this_n = __this_n->_M_next;
}
_M_buckets[__i] = __this_n;
}
// Last finalize copy of the nodes of the last non-empty bucket
for (; __ht_n; __ht_n = __ht_n->_M_next)
// Then deal with other nodes.
_BaseNode* __prev_n = __this_n;
for (__ht_n = __ht_n->_M_next(); __ht_n; __ht_n = __ht_n->_M_next())
{
__this_n->_M_next = _M_allocate_node(__ht_n->_M_v);
this->_M_copy_code(__this_n->_M_next, __ht_n);
__this_n = __this_n->_M_next;
__this_n = _M_allocate_node(__ht_n->_M_v);
__prev_n->_M_nxt = __this_n;
this->_M_copy_code(__this_n, __ht_n);
size_type __bkt = _M_bucket_index(__this_n);
if (!_M_buckets[__bkt])
_M_buckets[__bkt] = __prev_n;
__prev_n = __this_n;
}
}
__catch(...)
@ -872,14 +841,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_node_allocator(std::move(__ht._M_node_allocator)),
_M_buckets(__ht._M_buckets),
_M_bucket_count(__ht._M_bucket_count),
_M_begin_bucket_index(__ht._M_begin_bucket_index),
_M_before_begin(__ht._M_before_begin._M_nxt),
_M_element_count(__ht._M_element_count),
_M_rehash_policy(__ht._M_rehash_policy)
{
// Update, if necessary, bucket pointing to before begin that hasn't move.
if (_M_begin())
_M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
__ht._M_rehash_policy = _RehashPolicy();
__ht._M_bucket_count = __ht._M_rehash_policy._M_next_bkt(0);
__ht._M_buckets = __ht._M_allocate_buckets(__ht._M_bucket_count);
__ht._M_begin_bucket_index = __ht._M_bucket_count;
__ht._M_before_begin._M_nxt = nullptr;
__ht._M_element_count = 0;
}
@ -917,8 +889,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
std::swap(_M_rehash_policy, __x._M_rehash_policy);
std::swap(_M_buckets, __x._M_buckets);
std::swap(_M_bucket_count, __x._M_bucket_count);
std::swap(_M_begin_bucket_index, __x._M_begin_bucket_index);
std::swap(_M_before_begin._M_nxt, __x._M_before_begin._M_nxt);
std::swap(_M_element_count, __x._M_element_count);
// Fix buckets containing the _M_before_begin pointers that can't be
// swapped.
if (_M_begin())
_M_buckets[_M_bucket_index(_M_begin())] = &_M_before_begin;
if (__x._M_begin())
__x._M_buckets[__x._M_bucket_index(__x._M_begin())]
= &(__x._M_before_begin);
}
template<typename _Key, typename _Value,
@ -988,7 +967,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return 0;
std::size_t __result = 0;
for (;; __p = __p->_M_next)
for (;; __p = __p->_M_next())
{
if (this->_M_equals(__k, __code, __p))
++__result;
@ -997,7 +976,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// equivalent value after an equivalent one it means that we won't
// find anymore an equivalent value.
break;
if (!__p->_M_next || _M_bucket_index(__p->_M_next) != __n)
if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
break;
}
return __result;
@ -1025,10 +1004,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__p)
{
_Node* __p1 = __p->_M_next;
_Node* __p1 = __p->_M_next();
while (__p1 && _M_bucket_index(__p1) == __n
&& this->_M_equals(__k, __code, __p1))
__p1 = __p1->_M_next;
__p1 = __p1->_M_next();
return std::make_pair(iterator(__p), iterator(__p1));
}
@ -1058,10 +1037,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__p)
{
_Node* __p1 = __p->_M_next;
_Node* __p1 = __p->_M_next();
while (__p1 && _M_bucket_index(__p1) == __n
&& this->_M_equals(__k, __code, __p1))
__p1 = __p1->_M_next;
__p1 = __p1->_M_next();
return std::make_pair(const_iterator(__p), const_iterator(__p1));
}
@ -1077,21 +1056,23 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
bool __chc, bool __cit, bool __uk>
typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
_Equal, _H1, _H2, _Hash, _RehashPolicy,
__chc, __cit, __uk>::_Node*
__chc, __cit, __uk>::_BaseNode*
_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
_M_find_node(size_type __n, const key_type& __k,
typename _Hashtable::_Hash_code_type __code) const
_M_find_before_node(size_type __n, const key_type& __k,
typename _Hashtable::_Hash_code_type __code) const
{
_Node* __p = _M_bucket_begin(__n);
if (!__p)
_BaseNode* __prev_p = _M_buckets[__n];
if (!__prev_p)
return nullptr;
for (;; __p = __p->_M_next)
_Node* __p = static_cast<_Node*>(__prev_p->_M_nxt);
for (;; __p = __p->_M_next())
{
if (this->_M_equals(__k, __code, __p))
return __p;
if (!(__p->_M_next) || _M_bucket_index(__p->_M_next) != __n)
return __prev_p;
if (!(__p->_M_nxt) || _M_bucket_index(__p->_M_next()) != __n)
break;
__prev_p = __p;
}
return nullptr;
}
@ -1105,53 +1086,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
_M_insert_bucket_begin(size_type __bkt, _Node* __new_node)
{
_Node* __prev_n;
if (__bkt < _M_begin_bucket_index)
if (_M_buckets[__bkt])
{
if (_M_begin_bucket_index != _M_bucket_count)
{
__new_node->_M_next = _M_buckets[_M_begin_bucket_index];
_M_buckets[_M_begin_bucket_index] = __new_node;
}
__prev_n = __new_node;
_M_begin_bucket_index = __bkt;
// Bucket is not empty, we just need to insert the new node after the
// bucket before begin.
__new_node->_M_nxt = _M_buckets[__bkt]->_M_nxt;
_M_buckets[__bkt]->_M_nxt = __new_node;
}
else
{
// We need to find previous non-empty bucket to link the new node.
// There are several ways to find this previous bucket:
// 1. Move backward until we find it (the current method)
// 2. Start from the begin bucket index and move forward until we
// cross __n position.
// 3. Move forward until we find a non-empty bucket that will
// contain the previous node.
size_type __prev_bkt;
for (__prev_bkt = __bkt; __prev_bkt-- != 0;)
if (_M_buckets[__prev_bkt])
break;
__prev_n = _M_bucket_end(__prev_bkt);
_M_insert_after(__prev_bkt, __prev_n, __new_node);
// The bucket is empty, the new node is inserted at the beginning of
// the singly linked list and the bucket will contain _M_before_begin
// pointer.
__new_node->_M_nxt = _M_before_begin._M_nxt;
_M_before_begin._M_nxt = __new_node;
if (__new_node->_M_nxt)
// We must update former begin bucket that is pointing to
// _M_before_begin.
_M_buckets[_M_bucket_index(__new_node->_M_next())] = __new_node;
_M_buckets[__bkt] = &_M_before_begin;
}
_M_buckets[__bkt] = __prev_n;
}
template<typename _Key, typename _Value,
typename _Allocator, typename _ExtractKey, typename _Equal,
typename _H1, typename _H2, typename _Hash, typename _RehashPolicy,
bool __chc, bool __cit, bool __uk>
void
_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
_M_insert_after(size_type __bkt, _Node* __prev_n, _Node* __new_n)
{
if (__prev_n->_M_next)
{
size_type __next_bkt = _M_bucket_index(__prev_n->_M_next);
if (__next_bkt != __bkt)
_M_buckets[__next_bkt] = __new_n;
}
__new_n->_M_next = __prev_n->_M_next;
__prev_n->_M_next = __new_n;
}
template<typename _Key, typename _Value,
@ -1166,22 +1120,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (!__next || __next_bkt != __bkt)
{
// Bucket is now empty
if (__next && __next_bkt != __bkt)
// Update next non-empty bucket before begin node
// First update next bucket if any
if (__next)
_M_buckets[__next_bkt] = _M_buckets[__bkt];
// Second update before begin node if necessary
if (&_M_before_begin == _M_buckets[__bkt])
_M_before_begin._M_nxt = __next;
_M_buckets[__bkt] = nullptr;
if (__bkt == _M_begin_bucket_index)
// We need to update begin bucket index
if (__next)
{
_M_begin_bucket_index = __next_bkt;
_M_buckets[_M_begin_bucket_index] = __next;
}
else
_M_begin_bucket_index = _M_bucket_count;
}
else if (__bkt == _M_begin_bucket_index)
_M_buckets[__bkt] = __next;
}
template<typename _Key, typename _Value,
@ -1190,18 +1136,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
bool __chc, bool __cit, bool __uk>
typename _Hashtable<_Key, _Value, _Allocator, _ExtractKey,
_Equal, _H1, _H2, _Hash, _RehashPolicy,
__chc, __cit, __uk>::_Node*
__chc, __cit, __uk>::_BaseNode*
_Hashtable<_Key, _Value, _Allocator, _ExtractKey, _Equal,
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
_M_get_previous_node(size_type __bkt, _Node* __n)
_M_get_previous_node(size_type __bkt, _BaseNode* __n)
{
_Node* __prev_n = nullptr;
if (__bkt != _M_begin_bucket_index || __n != _M_buckets[__bkt])
{
__prev_n = _M_buckets[__bkt];
while (__prev_n->_M_next != __n)
__prev_n = __prev_n->_M_next;
}
_BaseNode* __prev_n = _M_buckets[__bkt];
while (__prev_n->_M_nxt != __n)
__prev_n = __prev_n->_M_nxt;
return __prev_n;
}
@ -1248,10 +1190,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__bkt = _M_bucket_index(__k, __code);
}
if (_M_buckets[__bkt])
_M_insert_after(__bkt, _M_buckets[__bkt], __new_node);
else
_M_insert_bucket_begin(__bkt, __new_node);
_M_insert_bucket_begin(__bkt, __new_node);
++_M_element_count;
return std::make_pair(iterator(__new_node), true);
}
@ -1279,7 +1218,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
= _M_rehash_policy._M_need_rehash(_M_bucket_count,
_M_element_count, 1);
// First build the node to get its hash code
// First build the node to get its hash code.
_Node* __new_node = _M_allocate_node(std::forward<_Args>(__args)...);
__try
{
@ -1287,33 +1226,25 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typename _Hashtable::_Hash_code_type __code
= this->_M_hash_code(__k);
this->_M_store_code(__new_node, __code);
size_type __bkt = _M_bucket_index(__k, __code);
// Second find the node, avoid rehash if compare throws.
_Node* __prev = _M_find_node(__bkt, __k, __code);
// Second, do rehash if necessary.
if (__do_rehash.first)
{
_M_rehash(__do_rehash.second, __saved_state);
__bkt = _M_bucket_index(__k, __code);
// __prev is still valid because rehash do not invalidate nodes
}
// Third, find the node before an equivalent one.
size_type __bkt = _M_bucket_index(__k, __code);
_BaseNode* __prev = _M_find_before_node(__bkt, __k, __code);
if (__prev)
// Insert after the previous equivalent node
_M_insert_after(__bkt, __prev, __new_node);
else if (_M_buckets[__bkt])
// Bucket is not empty and the inserted node has no equivalent in
// the hashtable. We must insert the new node at the beginning or
// end of the bucket to preserve equivalent elements relative
// positions.
if (__bkt != _M_begin_bucket_index)
// We insert the new node at the beginning
_M_insert_after(__bkt, _M_buckets[__bkt], __new_node);
else
// We insert the new node at the end
_M_insert_after(__bkt, _M_bucket_end(__bkt), __new_node);
{
// Insert after the node before the equivalent one.
__new_node->_M_nxt = __prev->_M_nxt;
__prev->_M_nxt = __new_node;
}
else
// The inserted node has no equivalent in the hashtable. We must
// insert the new node at the beginning of the bucket to preserve
// equivalent elements relative positions.
_M_insert_bucket_begin(__bkt, __new_node);
++_M_element_count;
return iterator(__new_node);
@ -1360,10 +1291,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__do_rehash.first)
_M_rehash(__do_rehash.second, __saved_state);
if (_M_buckets[__n])
_M_insert_after(__n, _M_buckets[__n], __new_node);
else
_M_insert_bucket_begin(__n, __new_node);
_M_insert_bucket_begin(__n, __new_node);
++_M_element_count;
return iterator(__new_node);
}
@ -1421,38 +1349,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
const key_type& __k = this->_M_extract()(__v);
typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
size_type __n = _M_bucket_index(__k, __code);
// First find the node, avoid leaking new_node if compare throws.
_Node* __prev = _M_find_node(__n, __k, __code);
_Node* __new_node = nullptr;
__try
{
// Second allocate new node so that we don't rehash if it throws
// First allocate new node so that we don't rehash if it throws.
__new_node = _M_allocate_node(std::forward<_Arg>(__v));
this->_M_store_code(__new_node, __code);
if (__do_rehash.first)
{
_M_rehash(__do_rehash.second, __saved_state);
__n = _M_bucket_index(__k, __code);
// __prev is still valid because rehash do not invalidate nodes
}
// Second, find the node before an equivalent one.
size_type __n = _M_bucket_index(__k, __code);
_BaseNode* __prev = _M_find_before_node(__n, __k, __code);
if (__prev)
// Insert after the previous equivalent node
_M_insert_after(__n, __prev, __new_node);
else if (_M_buckets[__n])
// Bucket is not empty and the inserted node has no equivalent in
// the hashtable. We must insert the new node at the beginning or
// end of the bucket to preserve equivalent elements relative
// positions.
if (__n != _M_begin_bucket_index)
// We insert the new node at the beginning
_M_insert_after(__n, _M_buckets[__n], __new_node);
else
// We insert the new node at the end
_M_insert_after(__n, _M_bucket_end(__n), __new_node);
{
// Insert after the node before the equivalent one.
__new_node->_M_nxt = __prev->_M_nxt;
__prev->_M_nxt = __new_node;
}
else
// The inserted node has no equivalent in the hashtable. We must
// insert the new node at the beginning of the bucket to preserve
// equivalent elements relative positions.
_M_insert_bucket_begin(__n, __new_node);
++_M_element_count;
return iterator(__new_node);
@ -1504,22 +1423,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
std::size_t __bkt = _M_bucket_index(__n);
// Look for previous node to unlink it from the erased one, this is why
// we need buckets to contain the before begin node of the bucket to make
// this research fast.
_Node* __prev_n = _M_get_previous_node(__bkt, __n);
// we need buckets to contain the before begin to make this research fast.
_BaseNode* __prev_n = _M_get_previous_node(__bkt, __n);
if (__n == _M_bucket_begin(__bkt))
_M_remove_bucket_begin(__bkt, __n->_M_next,
__n->_M_next ? _M_bucket_index(__n->_M_next) : 0);
else if (__n->_M_next)
_M_remove_bucket_begin(__bkt, __n->_M_next(),
__n->_M_nxt ? _M_bucket_index(__n->_M_next()) : 0);
else if (__n->_M_nxt)
{
size_type __next_bkt = _M_bucket_index(__n->_M_next);
size_type __next_bkt = _M_bucket_index(__n->_M_next());
if (__next_bkt != __bkt)
_M_buckets[__next_bkt] = __prev_n;
}
if (__prev_n)
__prev_n->_M_next = __n->_M_next;
iterator __result(__n->_M_next);
__prev_n->_M_nxt = __n->_M_nxt;
iterator __result(__n->_M_next());
_M_deallocate_node(__n);
--_M_element_count;
@ -1539,26 +1456,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename _Hashtable::_Hash_code_type __code = this->_M_hash_code(__k);
std::size_t __bkt = _M_bucket_index(__k, __code);
// Look for the first matching node with its previous node at the same
// time
_Node* __n = _M_buckets[__bkt];
if (!__n)
// Look for the node before the first matching node.
_BaseNode* __prev_n = _M_find_before_node(__bkt, __k, __code);
if (!__prev_n)
return 0;
_Node* __prev_n = nullptr;
if (__bkt != _M_begin_bucket_index)
{
__prev_n = __n;
__n = __n->_M_next;
}
bool __is_bucket_begin = true;
for (;; __prev_n = __n, __n = __n->_M_next)
{
if (this->_M_equals(__k, __code, __n))
break;
if (!(__n->_M_next) || _M_bucket_index(__n->_M_next) != __bkt)
return 0;
__is_bucket_begin = false;
}
_Node* __n = static_cast<_Node*>(__prev_n->_M_nxt);
bool __is_bucket_begin = _M_buckets[__bkt] == __prev_n;
// We found a matching node, start deallocation loop from it
std::size_t __next_bkt = __bkt;
@ -1568,7 +1471,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
do
{
_Node* __p = __next_n;
__next_n = __p->_M_next;
__next_n = __p->_M_next();
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 526. Is it undefined if a function in the standard changes
// in parameters?
@ -1592,7 +1495,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
else if (__next_n && __next_bkt != __bkt)
_M_buckets[__next_bkt] = __prev_n;
if (__prev_n)
__prev_n->_M_next = __next_n;
__prev_n->_M_nxt = __next_n;
return __result;
}
@ -1614,7 +1517,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
std::size_t __bkt = _M_bucket_index(__n);
_Node* __prev_n = _M_get_previous_node(__bkt, __n);
_BaseNode* __prev_n = _M_get_previous_node(__bkt, __n);
bool __is_bucket_begin = __n == _M_bucket_begin(__bkt);
std::size_t __n_bkt = __bkt;
for (;;)
@ -1622,7 +1525,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
do
{
_Node* __tmp = __n;
__n = __n->_M_next;
__n = __n->_M_next();
_M_deallocate_node(__tmp);
--_M_element_count;
if (!__n)
@ -1640,8 +1543,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__n && __n_bkt != __bkt)
_M_buckets[__n_bkt] = __prev_n;
if (__prev_n)
__prev_n->_M_next = __n;
__prev_n->_M_nxt = __n;
return iterator(__n);
}
@ -1654,10 +1556,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_H1, _H2, _Hash, _RehashPolicy, __chc, __cit, __uk>::
clear() noexcept
{
_M_deallocate_nodes(_M_buckets[_M_begin_bucket_index]);
_M_deallocate_nodes(_M_begin());
__builtin_memset(_M_buckets, 0, _M_bucket_count * sizeof(_Bucket));
_M_element_count = 0;
_M_begin_bucket_index = _M_bucket_count;
_M_before_begin._M_nxt = nullptr;
}
template<typename _Key, typename _Value,
@ -1688,45 +1590,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__try
{
_Bucket* __new_buckets = _M_allocate_buckets(__n);
_Node* __p = _M_buckets[_M_begin_bucket_index];
// First loop to store each node in its new bucket
_Node* __p = _M_begin();
_M_before_begin._M_nxt = nullptr;
std::size_t __cur_bbegin_bkt;
while (__p)
{
_Node* __next = __p->_M_next;
_Node* __next = __p->_M_next();
std::size_t __new_index = _HCBase::_M_bucket_index(__p, __n);
if (!__new_buckets[__new_index])
// Store temporarily bucket end node in _M_buckets if possible.
// This will boost second loop where we need to access bucket
// end node quickly.
if (__new_index < _M_bucket_count)
_M_buckets[__new_index] = __p;
__p->_M_next = __new_buckets[__new_index];
__new_buckets[__new_index] = __p;
{
__p->_M_nxt = _M_before_begin._M_nxt;
_M_before_begin._M_nxt = __p;
__new_buckets[__new_index] = &_M_before_begin;
if (__p->_M_nxt)
__new_buckets[__cur_bbegin_bkt] = __p;
__cur_bbegin_bkt = __new_index;
}
else
{
__p->_M_nxt = __new_buckets[__new_index]->_M_nxt;
__new_buckets[__new_index]->_M_nxt = __p;
}
__p = __next;
}
_M_begin_bucket_index = __n;
_Node* __prev_node = nullptr;
// Second loop to link all nodes together and to fix bucket values so
// that they contain the before begin node of the bucket.
for (size_type __i = 0; __i != __n; ++__i)
if (__new_buckets[__i])
{
if (__prev_node)
{
__prev_node->_M_next = __new_buckets[__i];
__new_buckets[__i] = __prev_node;
}
else
_M_begin_bucket_index = __i;
if (__i < _M_bucket_count)
__prev_node = _M_buckets[__i];
else
{
__prev_node = __new_buckets[__i];
while (__prev_node->_M_next)
__prev_node = __prev_node->_M_next;
}
}
_M_deallocate_buckets(_M_buckets, _M_bucket_count);
_M_bucket_count = __n;
_M_buckets = __new_buckets;

34
libstdc++-v3/include/bits/hashtable_policy.h
View File

@ -73,32 +73,44 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// template parameter of class template _Hashtable controls whether
// nodes also store a hash code. In some cases (e.g. strings) this
// may be a performance win.
struct _Hash_node_base
{
_Hash_node_base* _M_nxt;
_Hash_node_base()
: _M_nxt() { }
_Hash_node_base(_Hash_node_base* __next)
: _M_nxt(__next) { }
};
template<typename _Value, bool __cache_hash_code>
struct _Hash_node;
template<typename _Value>
struct _Hash_node<_Value, true>
struct _Hash_node<_Value, true> : _Hash_node_base
{
_Value _M_v;
std::size_t _M_hash_code;
_Hash_node* _M_next;
template<typename... _Args>
_Hash_node(_Args&&... __args)
: _M_v(std::forward<_Args>(__args)...),
_M_hash_code(), _M_next() { }
: _M_v(std::forward<_Args>(__args)...), _M_hash_code() { }
_Hash_node* _M_next() const
{ return static_cast<_Hash_node*>(_M_nxt); }
};
template<typename _Value>
struct _Hash_node<_Value, false>
struct _Hash_node<_Value, false> : _Hash_node_base
{
_Value _M_v;
_Hash_node* _M_next;
template<typename... _Args>
_Hash_node(_Args&&... __args)
: _M_v(std::forward<_Args>(__args)...),
_M_next() { }
: _M_v(std::forward<_Args>(__args)...) { }
_Hash_node* _M_next() const
{ return static_cast<_Hash_node*>(_M_nxt); }
};
// Node iterators, used to iterate through all the hashtable.
@ -110,7 +122,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_M_incr()
{ _M_cur = _M_cur->_M_next; }
{ _M_cur = _M_cur->_M_next(); }
_Hash_node<_Value, __cache>* _M_cur;
};
@ -904,7 +916,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_M_incr()
{
_M_cur = _M_cur->_M_next;
_M_cur = _M_cur->_M_next();
if (_M_cur)
{
std::size_t __bkt = _M_h2()(_M_cur->_M_hash_code, _M_bucket_count);
@ -936,7 +948,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
void
_M_incr()
{
_M_cur = _M_cur->_M_next;
_M_cur = _M_cur->_M_next();
if (_M_cur)
{
std::size_t __bkt = this->_M_bucket_index(_M_cur, _M_bucket_count);