4coder/non-source/test_data/lots_of_files/internal_concurrent_hash.h

1322 lines
47 KiB
C++

/***
* ==++==
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
* ==--==
* =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
*
* internal_concurrent_hash.h
*
* =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
****/
#pragma once
#include <utility>
#include "internal_split_ordered_list.h"
#include <concrt.h>
#pragma pack(push,_CRT_PACKING)
namespace Concurrency
{
namespace details
{
// Template class for hash compare
template<typename _Key_type, typename _Hasher, typename _Key_equality>
class _Hash_compare
{
public:
typedef _Hasher hasher;
_Hash_compare()
{
}
_Hash_compare(hasher _Hasharg) : _M_hash_object(_Hasharg)
{
}
_Hash_compare(hasher _Hasharg, _Key_equality _Keyeqarg) : _M_hash_object(_Hasharg), _M_key_compare_object(_Keyeqarg)
{
}
size_t operator()(const _Key_type& _Keyval) const
{
return ((size_t)_M_hash_object(_Keyval));
}
bool operator()(const _Key_type& _Keyval1, const _Key_type& _Keyval2) const
{
return (!_M_key_compare_object(_Keyval1, _Keyval2));
}
hasher _M_hash_object; // The hash object
_Key_equality _M_key_compare_object; // The equality comparator object
};
// An efficient implementation of the _Reverse function utilizes a 2^8 or 2^16 lookup table holding the
// bit-reversed values of [0..2^8 - 1] or [0..2^16 - 1] respectively. Those values can also be computed
// on the fly at a slightly higher cost.
extern _CRTIMP2 const unsigned char _Byte_reverse_table[];
// Given a byte, reverses it
inline unsigned char _Reverse_byte(unsigned char _Original_byte)
{
// return ((_Original_byte * 0x80200802ULL) & 0x0884422110ULL) * 0x0101010101ULL >> 32;
return _Byte_reverse_table[_Original_byte];
}
// Finds the most significant bit in a size_t
inline unsigned char _Get_msb(size_t _Mask)
{
unsigned long _Index = 0;
#if (defined (_M_IX86) || defined (_M_ARM))
_BitScanReverse(&_Index, _Mask);
#else /* (defined (_M_IX86) || defined (_M_ARM)) */
_BitScanReverse64(&_Index, _Mask);
#endif /* (defined (_M_IX86) || defined (_M_ARM)) */
return (unsigned char) _Index;
}
#pragma warning(push)
#pragma warning(disable: 4127) // Warning 4127 -- while (true) has a constant expression in it
template <typename _Traits>
class _Concurrent_hash : public _Traits
{
public:
// Type definitions
typedef _Concurrent_hash<_Traits> _Mytype;
typedef typename _Split_ordered_list<typename _Traits::value_type, typename _Traits::allocator_type> _Mylist;
typedef typename _Traits::_Key_compare _Key_compare;
typedef typename _Traits::_Value_compare _Value_compare;
typedef typename _Traits::value_type value_type;
typedef typename _Traits::key_type key_type;
typedef typename _Traits::allocator_type allocator_type;
typedef typename allocator_type::pointer pointer;
typedef typename allocator_type::const_pointer const_pointer;
typedef typename allocator_type::reference reference;
typedef typename allocator_type::const_reference const_reference;
typedef typename allocator_type::size_type size_type;
typedef typename allocator_type::difference_type difference_type;
typedef typename std::tr1::conditional<std::tr1::is_same<key_type, value_type>::value, typename _Mylist::const_iterator, typename _Mylist::iterator>::type iterator;
typedef typename _Mylist::const_iterator const_iterator;
typedef iterator local_iterator;
typedef const_iterator const_local_iterator;
typedef typename _Mylist::_Nodeptr _Nodeptr;
// Iterators that walk the entire split-order list, including dummy nodes
typedef typename _Mylist::_Full_iterator _Full_iterator;
typedef typename _Mylist::_Full_const_iterator _Full_const_iterator;
static const size_type _Initial_bucket_number = 8; // Initial number of buckets
static const size_type _Initial_bucket_load = 4; // Initial maximum number of elements per bucket
static size_type const _Pointers_per_table = sizeof(size_type) * 8; // One bucket segment per bit
// Constructors/Destructors
_Concurrent_hash(size_type _Number_of_buckets = _Initial_bucket_number, const _Key_compare& _Parg = _Key_compare(), const allocator_type& _Allocator = allocator_type())
: _Traits(_Parg), _M_number_of_buckets(_Number_of_buckets), _M_split_ordered_list(_Allocator), _M_allocator(_Allocator), _M_maximum_bucket_size((float) _Initial_bucket_load)
{
_Init();
}
_Concurrent_hash(const _Concurrent_hash& _Right, const allocator_type& _Allocator) : _Traits(_Right._M_comparator), _M_split_ordered_list(_Allocator), _M_allocator(_Allocator)
{
_Copy(_Right);
}
_Concurrent_hash(const _Concurrent_hash& _Right) : _Traits(_Right._M_comparator), _M_split_ordered_list(_Right.get_allocator()), _M_allocator(_Right.get_allocator())
{
_Init();
_Copy(_Right);
}
_Concurrent_hash(_Concurrent_hash&& _Right) : _Traits(_Right._M_comparator), _M_split_ordered_list(_Right.get_allocator()), _M_allocator(_Right.get_allocator()),
_M_number_of_buckets(_Initial_bucket_number), _M_maximum_bucket_size((float) _Initial_bucket_load)
{
_Init();
swap(_Right);
}
_Concurrent_hash& operator=(const _Concurrent_hash& _Right)
{
if (this != &_Right)
{
_Copy(_Right);
}
return (*this);
}
_Concurrent_hash& operator=(_Concurrent_hash&& _Right)
{
if (this != &_Right)
{
clear();
swap(_Right);
}
return (*this);
}
~_Concurrent_hash()
{
// Delete all node segments
for (size_type _Index = 0; _Index < _Pointers_per_table; _Index++)
{
if (_M_buckets[_Index] != NULL)
{
size_type _Seg_size = _Segment_size(_Index);
for (size_type _Index2 = 0; _Index2 < _Seg_size; _Index2++)
{
_M_allocator.destroy(&_M_buckets[_Index][_Index2]);
}
_M_allocator.deallocate(_M_buckets[_Index], _Seg_size);
}
}
}
static size_type __cdecl _Segment_index_of( size_type _Index )
{
return size_type( _Get_msb( _Index|1 ) );
}
static size_type _Segment_base( size_type _K )
{
return (size_type(1)<<_K & ~size_type(1));
}
static size_type _Segment_size( size_type _K )
{
return _K ? size_type(1)<<_K : 2;
}
/// <summary>
/// Returns the stored allocator object for this concurrent container. This method is concurrency safe.
/// </summary>
/// <returns>
/// The stored allocator object for this concurrent container.
/// </returns>
/**/
allocator_type get_allocator() const
{
return _M_split_ordered_list.get_allocator();
}
/// <summary>
/// Tests whether no elements are present. This method is concurrency safe.
/// </summary>
/// <remarks>
/// In the presence of concurrent inserts, whether or not the concurrent container is empty may change immediately
/// after calling this function, before the return value is even read.
/// </remarks>
/// <returns>
/// <c>true</c> if the concurrent container is empty, <c>false</c> otherwise.
/// </returns>
/**/
bool empty() const
{
return _M_split_ordered_list.empty();
}
/// <summary>
/// Returns the number of elements in this concurrent container. This method is concurrency safe.
/// </summary>
/// <remarks>
/// In the presence of concurrent inserts, the number of elements in the concurrent container may change immediately
/// after calling this function, before the return value is even read.
/// </remarks>
/// <returns>
/// The number of items in the container.
/// </returns>
/**/
size_type size() const
{
return _M_split_ordered_list.size();
}
/// <summary>
/// Returns the maximum size of the concurrent container, determined by the allocator. This method is concurrency safe.
/// </summary>
/// <remarks>
/// This upper bound value may actually be higher than what the container can actually hold.
/// </remarks>
/// <returns>
/// The maximum number of elements that can be inserted into this concurrent container.
/// </returns>
/**/
size_type max_size() const
{
return _M_split_ordered_list.max_size();
}
/// <summary>
/// Returns an iterator pointing to the first element in the concurrent container. This method is concurrency safe.
/// </summary>
/// <returns>
/// An iterator to the first element in the concurrent container.
/// </returns>
/**/
iterator begin()
{
return _M_split_ordered_list.begin();
}
/// <summary>
/// Returns an iterator pointing to the first element in the concurrent container. This method is concurrency safe.
/// </summary>
/// <returns>
/// An iterator to the first element in the concurrent container.
/// </returns>
/**/
const_iterator begin() const
{
return _M_split_ordered_list.begin();
}
/// <summary>
/// Returns an iterator pointing to the location succeeding the last element in the concurrent container.
/// This method is concurrency safe.
/// </summary>
/// <returns>
/// An iterator to the location succeeding the last element in the concurrent container.
/// </returns>
/**/
iterator end()
{
return _M_split_ordered_list.end();
}
/// <summary>
/// Returns a const_iterator pointing to the location succeeding the last element in the concurrent container.
/// This method is concurrency safe.
/// </summary>
/// <returns>
/// A const_iterator to the location succeeding the last element in the concurrent container.
/// </returns>
/**/
const_iterator end() const
{
return _M_split_ordered_list.end();
}
/// <summary>
/// Returns a const iterator pointing to the first element in the concurrent container. This method is concurrency safe.
/// </summary>
/// <returns>
/// A const iterator to the first element in the concurrent container.
/// </returns>
/**/
const_iterator cbegin() const
{
return _M_split_ordered_list.cbegin();
}
/// <summary>
/// Returns a const iterator pointing to the location succeeding the last element in the concurrent container. This method is concurrency safe.
/// </summary>
/// <returns>
/// A const iterator to the location succeeding the last element in the concurrent container.
/// </returns>
/**/
const_iterator cend() const
{
return _M_split_ordered_list.cend();
}
/// <summary>
/// Removes elements from the container at specified positions. This method is not concurrency-safe.
/// </summary>
/// <param name="_Where">
/// The iterator position to erase from.
/// </param>
/// <remarks>
/// The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
/// member function removes the elements in the range [<paramref name="_First"/>, <paramref name="_Last"/>).
/// <para>The third member function removes the elements in the range delimited by equal_range(<paramref name="_Keyval"/>)</see>. </para>
/// </remarks>
/// <returns>
/// The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
/// or end() if no such element exists. The third member function returns the number of elements it removes.
/// </returns>
/**/
iterator unsafe_erase(const_iterator _Where)
{
if (_Where == end())
{
return end();
}
return _Erase(_Where);
}
/// <summary>
/// Removes elements from the container at specified positions. This method is not concurrency-safe.
/// </summary>
/// <param name="_First">
/// The position of the first element in the range of elements to be erased.
/// </param>
/// <param name="_Last">
/// The position of the first element beyond the range of elements to be erased.
/// </param>
/// <remarks>
/// The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
/// member function removes the elements in the range [<paramref name="_First"/>, <paramref name="_Last"/>).
/// <para>The third member function removes the elements in the range delimited by equal_range(<paramref name="_Keyval"/>)</see>. </para>
/// </remarks>
/// <returns>
/// The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
/// or end() if no such element exists. The third member function returns the number of elements it removes.
/// </returns>
/**/
iterator unsafe_erase(const_iterator _First, const_iterator _Last)
{
while (_First != _Last)
{
unsafe_erase(_First++);
}
return _M_split_ordered_list._Get_iterator(_First);
}
/// <summary>
/// Removes elements from the container at specified positions. This method is not concurrency-safe.
/// </summary>
/// <param name="_Keyval">
/// The key value to erase.
/// </param>
/// <remarks>
/// The first member function removes the element of the controlled sequence pointed to by <paramref name="_Where"/>. The second
/// member function removes the elements in the range [<paramref name="_First"/>, <paramref name="_Last"/>).
/// <para>The third member function removes the elements in the range delimited by equal_range(<paramref name="_Keyval"/>)</see>. </para>
/// </remarks>
/// <returns>
/// The first two member functions return an iterator that designates the first element remaining beyond any elements removed,
/// or end() if no such element exists. The third member function returns the number of elements it removes.
/// </returns>
/**/
size_type unsafe_erase(const key_type& _Keyval)
{
std::pair<iterator, iterator> _Where = equal_range(_Keyval);
size_type _Count = _Distance(_Where.first, _Where.second);
unsafe_erase(_Where.first, _Where.second);
return _Count;
}
/// <summary>
/// Swaps the contents of two concurrent containers. This function is not concurrency safe.
/// </summary>
/// <param name="_Right">
/// The container to swap elements from.
/// </param>
/// <remarks>
/// The member function throws an <see cref="invalid_argument Class">invalid_argument</see> exception if the swap is being
/// performed on unequal allocators.
/// </remarks>
/**/
void swap(_Concurrent_hash& _Right)
{
if (this != &_Right)
{
std::_Swap_adl(_M_comparator, _Right._M_comparator);
_M_split_ordered_list.swap(_Right._M_split_ordered_list);
_Swap_buckets(_Right);
std::swap(_M_number_of_buckets, _Right._M_number_of_buckets);
std::swap(_M_maximum_bucket_size, _Right._M_maximum_bucket_size);
}
}
/// <summary>
/// Erases all the elements in the concurrent container. This function is not concurrency safe.
/// </summary>
/**/
void clear()
{
// Clear list
_M_split_ordered_list.clear();
// Clear buckets
for (size_type _Index = 0; _Index < _Pointers_per_table; _Index++)
{
if (_M_buckets[_Index] != NULL)
{
size_type _Seg_size = _Segment_size(_Index);
for (size_type _Index2 = 0; _Index2 < _Seg_size; _Index2++)
{
_M_allocator.destroy(&_M_buckets[_Index][_Index2]);
}
_M_allocator.deallocate(_M_buckets[_Index], _Seg_size);
}
}
// memset all the buckets to zero and initialize the dummy node 0
_Init();
}
/// <summary>
/// Finds an element that matches a specified key. This function is concurrency safe.
/// </summary>
/// <param name="_Keyval">
/// The key value to search for.
/// </param>
/// <returns>
/// An iterator pointing to the location of the the first element that matched the key provided,
/// or the iterator <c>end()</c> if no such element exists.
/// </returns>
/**/
iterator find(const key_type& _Keyval)
{
return _Find(_Keyval);
}
/// <summary>
/// Finds an element that matches a specified key. This function is concurrency safe.
/// </summary>
/// <param name="_Keyval">
/// The key value to search for.
/// </param>
/// <returns>
/// An iterator pointing to the location of the the first element that matched the key provided,
/// or the iterator <c>end()</c> if no such element exists.
/// </returns>
/**/
const_iterator find(const key_type& _Keyval) const
{
return _Find(_Keyval);
}
/// <summary>
/// Counts the number of elements matching a specified key. This function is concurrency safe.
/// </summary>
/// <param name="_Keyval">
/// The key to search for.
/// </param>
/// <returns>
/// The number of times number of times the key appears in the container.
/// </returns>
/**/
size_type count(const key_type& _Keyval) const
{
size_type _Count = 0;
const_iterator _It = _Find(_Keyval);
for (;_It != end() && !_M_comparator(_Key_function(*_It), _Keyval); _It++)
{
_Count++;
}
return _Count;
}
/// <summary>
/// Finds a range that matches a specified key. This function is concurrency safe.
/// </summary>
/// <param name="_Keyval">
/// The key value to search for.
/// </param>
/// <returns>
/// A <see cref="pair Class">pair</see> where the first element is an iterator to the beginning and the second element
/// is an iterator to the end of the range.
/// </returns>
/// <remarks>
/// <para>It is possible for concurrent inserts to cause additional keys to be inserted after the begin iterator and
/// before the end iterator.</para>
/// </remarks>
/**/
std::pair<iterator, iterator> equal_range(const key_type& _Keyval)
{
return _Equal_range(_Keyval);
}
/// <summary>
/// Finds a range that matches a specified key. This function is concurrency safe.
/// </summary>
/// <param name="_Keyval">
/// The key value to search for.
/// </param>
/// <returns>
/// A <see cref="pair Class">pair</see> where the first element is an iterator to the beginning and the second element
/// is an iterator to the end of the range.
/// </returns>
/// <remarks>
/// <para>It is possible for concurrent inserts to cause additional keys to be inserted after the begin iterator and
/// before the end iterator.</para>
/// </remarks>
/**/
std::pair<const_iterator, const_iterator> equal_range(const key_type& _Keyval) const
{
return _Equal_range(_Keyval);
}
/// <summary>
/// Returns the current number of buckets in this container.
/// </summary>
/// <returns>
/// The current number of buckets in this container.
/// </returns>
/**/
size_type unsafe_bucket_count() const
{
return _M_number_of_buckets;
}
/// <summary>
/// Returns the maximum number of buckets in this container.
/// </summary>
/// <returns>
/// The maximum number of buckets in this container.
/// </returns>
/**/
size_type unsafe_max_bucket_count() const
{
return _Segment_size(_Pointers_per_table-1);
}
/// <summary>
/// Returns the number of items in a specific bucket of this container.
/// </summary>
/// <param name="_Bucket">
/// The bucket to search for.
/// </param>
/// <returns>
/// The current number of buckets in this container.
/// </returns>
/**/
size_type unsafe_bucket_size(size_type _Bucket)
{
size_type _Count = 0;
if (!_Is_initialized(_Bucket))
{
return _Count;
}
_Full_iterator _Iterator = _Get_bucket(_Bucket);
_Iterator++;
for (; _Iterator != _M_split_ordered_list._End() && !_Iterator._Mynode()->_Is_dummy(); _Iterator++)
{
_Count++;
}
return _Count;
}
/// <summary>
/// Returns the bucket index that a specific key maps to in this container.
/// </summary>
/// <param name="_Keyval">
/// The element key being searched for.
/// </param>
/// <returns>
/// The bucket index for the key in this container.
/// </returns>
/**/
size_type unsafe_bucket(const key_type& _Keyval) const
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Keyval);
size_type _Bucket = _Order_key % _M_number_of_buckets;
return _Bucket;
}
/// <summary>
/// Returns an iterator to the first element in this container for a specific bucket.
/// </summary>
/// <param name="_Bucket">
/// The bucket index.
/// </param>
/// <returns>
/// An iterator pointing to the beginning of the bucket.
/// </returns>
/**/
local_iterator unsafe_begin(size_type _Bucket)
{
// It is possible the bucket being searched for has not yet been initialized
if (!_Is_initialized(_Bucket))
{
_Initialize_bucket(_Bucket);
}
_Full_iterator _Iterator = _Get_bucket(_Bucket);
return _M_split_ordered_list._Get_first_real_iterator(_Iterator);
}
/// <summary>
/// Returns an iterator to the first element in this container for a specific bucket.
/// </summary>
/// <param name="_Bucket">
/// The bucket index.
/// </param>
/// <returns>
/// An iterator pointing to the beginning of the bucket.
/// </returns>
/**/
const_local_iterator unsafe_begin(size_type _Bucket) const
{
// It is possible the bucket being searched for has not yet been initialized
if (!_Is_initialized(_Bucket))
{
_Initialize_bucket(_Bucket);
}
_Full_const_iterator _Iterator = _Get_bucket(_Bucket);
return _M_split_ordered_list._Get_first_real_iterator(_Iterator);
}
/// <summary>
/// Returns an iterator to the last element in this container for a specific bucket.
/// </summary>
/// <param name="_Bucket">
/// The bucket index.
/// </param>
/// <returns>
/// An iterator pointing to the end of the bucket.
/// </returns>
/**/
local_iterator unsafe_end(size_type _Bucket)
{
// If we've increased the number of buckets, there's a chance the intermediate dummy
// node marking the end of this bucket has not yet been lazily initialized.
// Inserting from _M_number_of_buckets/2 to _M_number_of_buckets will recursively
// initialize all the dummy nodes in the map.
for(size_type _Bucket_index = _M_number_of_buckets >> 1; _Bucket_index < _M_number_of_buckets; _Bucket_index++)
{
if (!_Is_initialized(_Bucket_index))
{
_Initialize_bucket(_Bucket_index);
}
}
_Full_iterator _Iterator = _Get_bucket(_Bucket);
// Find the end of the bucket, denoted by the dummy element
do
{
_Iterator++;
}
while(_Iterator != _M_split_ordered_list._End() && !_Iterator._Mynode()->_Is_dummy());
// Return the first real element past the end of the bucket
return _M_split_ordered_list._Get_first_real_iterator(_Iterator);
}
/// <summary>
/// Returns an iterator to the last element in this container for a specific bucket.
/// </summary>
/// <param name="_Bucket">
/// The bucket index.
/// </param>
/// <returns>
/// An iterator pointing to the end of the bucket.
/// </returns>
/**/
const_local_iterator unsafe_end(size_type _Bucket) const
{
// If we've increased the number of buckets, there's a chance the intermediate dummy
// node marking the end of this bucket has not yet been lazily initialized.
// Inserting from _M_number_of_buckets/2 to _M_number_of_buckets will recursively
// initialize all the dummy nodes in the map.
for(size_type _Bucket_index = _M_number_of_buckets >> 1; _Bucket_index < _M_number_of_buckets; _Bucket_index++)
{
if (!_Is_initialized(_Bucket_index))
{
_Initialize_bucket(_Bucket_index);
}
}
_Full_const_iterator _Iterator = _Get_bucket(_Bucket);
// Find the end of the bucket, denoted by the dummy element
do
{
_Iterator++;
}
while(_Iterator != _M_split_ordered_list._End() && !_Iterator._Mynode()->_Is_dummy());
// Return the first real element past the end of the bucket
return _M_split_ordered_list._Get_first_real_iterator(_Iterator);
}
/// <summary>
/// Returns an iterator to the first element in this container for a specific bucket.
/// </summary>
/// <param name="_Bucket">
/// The bucket index.
/// </param>
/// <returns>
/// An iterator pointing to the beginning of the bucket.
/// </returns>
/**/
const_local_iterator unsafe_cbegin(size_type) const
{
return ((const _Mytype *) this)->begin();
}
/// <summary>
/// Returns an iterator to the first element in this container for a specific bucket.
/// </summary>
/// <param name="_Bucket">
/// The bucket index.
/// </param>
/// <returns>
/// An iterator pointing to the beginning of the bucket.
/// </returns>
/**/
const_local_iterator unsafe_cend(size_type) const
{
return ((const _Mytype *) this)->end();
}
/// <summary>
/// Computes and returns the current load factor of the container. The load factor is the number of
/// elements in the container divided by the number of buckets.
/// </summary>
/// <returns>
/// The load factor for the container.
/// </returns>
/**/
float load_factor() const
{
return (float) size() / (float) unsafe_bucket_count();
}
/// <summary>
/// Gets or sets the maximum load factor of the container. The maximum load factor is the
/// largest number of elements than can be in any bucket before the container grows its
/// internal table.
/// </summary>
/// <returns>
/// The first member function returns the stored maximum load factor. The second member function does not return a value
/// but throws an <see cref="out_of_range Class">out_of_range</see> exception if the supplied load factor is invalid..
/// </returns>
/**/
float max_load_factor() const
{
return _M_maximum_bucket_size;
}
/// <summary>
/// Gets or sets the maximum load factor of the container. The maximum load factor is the
/// largest number of elements than can be in any bucket before the container grows its
/// internal table.
/// </summary>
/// <returns>
/// The first member function returns the stored maximum load factor. The second member function does not return a value
/// but throws an <see cref="out_of_range Class">out_of_range</see> exception if the supplied load factor is invalid..
/// </returns>
/**/
void max_load_factor(float _Newmax)
{
// The _Newmax != _Newmax is a check for NaN, because NaN is != to itself
if (_Newmax != _Newmax || _Newmax < 0)
{
throw std::out_of_range("invalid hash load factor");
}
_M_maximum_bucket_size = _Newmax;
}
// This function is a no op, because the underlying split-ordered list
// is already sorted, so an increase in the bucket number will be
// reflected next time this bucket is touched.
/// <summary>
/// Rebuilds the hash table.
/// </summary>
/// <param name="_Buckets">
/// The desired number of buckets.
/// </param>
/// <remarks>
/// The member function alters the number of buckets to be at least <paramref name="_Buckets"/> and rebuilds the hash
/// table as needed. The number of buckets must be a power of 2. If not a power of 2, it will be rounded up to
/// the next largest power of 2.
/// <para>It throws an <see cref="out_of_range Class">out_of_range</see> exception if the number of buckets
/// is invalid (either 0 or greater than the maximum number of buckets).</para>
/// </remarks>
/**/
void rehash(size_type _Buckets)
{
size_type _Current_buckets = _M_number_of_buckets;
if (_Current_buckets > _Buckets)
{
return;
}
else if (_Buckets <= 0 || _Buckets > unsafe_max_bucket_count())
{
throw std::out_of_range("invalid number of buckets");
}
// Round up the number of buckets to the next largest power of 2
_M_number_of_buckets = ((size_type) 1) << _Get_msb(_Buckets*2-1);
}
protected:
// Insert an element in the hash given its value
template<typename _ValTy>
std::pair<iterator, bool> _Insert(_ValTy&& _Value)
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Key_function(_Value));
size_type _Bucket = _Order_key % _M_number_of_buckets;
// If bucket is empty, initialize it first
if (!_Is_initialized(_Bucket))
{
_Initialize_bucket(_Bucket);
}
long _New_count;
_Order_key = _Split_order_regular_key(_Order_key);
_Full_iterator _Iterator = _Get_bucket(_Bucket);
_Full_iterator _Last = _M_split_ordered_list._End();
_Full_iterator _Where = _Iterator;
_Nodeptr _New_node = _M_split_ordered_list._Buynode(_Order_key, std::forward<_ValTy>(_Value));
_ASSERT_EXPR(_Where != _Last, L"Invalid head node");
// First node is a dummy node
_Where++;
for (;;)
{
if (_Where == _Last || _Mylist::_Get_key(_Where) > _Order_key)
{
// Try to insert it in the right place
std::pair<iterator, bool> _Result = _M_split_ordered_list._Insert(_Iterator, _Where, _New_node, &_New_count);
if (_Result.second)
{
// Insertion succeeded, adjust the table size, if needed
_Adjust_table_size(_New_count, _M_number_of_buckets);
return _Result;
}
else
{
// Insertion failed: either the same node was inserted by another thread, or
// another element was inserted at exactly the same place as this node.
// Proceed with the search from the previous location where order key was
// known to be larger (note: this is legal only because there is no safe
// concurrent erase operation supported).
_Where = _Iterator;
_Where++;
continue;
}
}
else if (!_M_allow_multimapping && _Mylist::_Get_key(_Where) == _Order_key &&
_M_comparator(_Key_function(*_Where), _Key_function(_New_node->_M_element)) == 0)
{
// If the insert failed (element already there), then delete the new one
_M_split_ordered_list._Erase(_New_node);
// Element already in the list, return it
return std::pair<iterator, bool>(_M_split_ordered_list._Get_iterator(_Where), false);
}
// Move the iterator forward
_Iterator = _Where;
_Where++;
}
}
template<class _Iterator>
void _Insert(_Iterator _First, _Iterator _Last)
{
for (_Iterator _I = _First; _I != _Last; _I++)
{
_Insert(*_I);
}
}
private:
// Initialize the hash and keep the first bucket open
void _Init()
{
// Allocate an array of segment pointers
memset(_M_buckets, 0, _Pointers_per_table * sizeof(void *));
// Insert the first element in the split-ordered list
_Full_iterator _Dummy_node = _M_split_ordered_list._Begin();
_Set_bucket(0, _Dummy_node);
}
void _Copy(const _Mytype& _Right)
{
clear();
_M_maximum_bucket_size = _Right._M_maximum_bucket_size;
_M_number_of_buckets = _Right._M_number_of_buckets;
try
{
_Insert(_Right.begin(), _Right.end());
_M_comparator = _Right._M_comparator;
}
catch(...)
{
_M_split_ordered_list.clear();
throw;
}
}
void _Swap_buckets(_Concurrent_hash& _Right)
{
if (_M_allocator == _Right._M_allocator)
{
// Swap all node segments
for (size_type _Index = 0; _Index < _Pointers_per_table; _Index++)
{
_Full_iterator * _Iterator_pointer = _M_buckets[_Index];
_M_buckets[_Index] = _Right._M_buckets[_Index];
_Right._M_buckets[_Index] = _Iterator_pointer;
}
}
else
{
throw std::invalid_argument("swap is invalid on non-equal allocators");
}
}
// Hash APIs
size_type _Distance(const_iterator _First, const_iterator _Last) const
{
size_type _Num = 0;
for (const_iterator _Iterator = _First; _Iterator != _Last; _Iterator++)
{
_Num++;
}
return _Num;
}
// Find the element in the split-ordered list
iterator _Find(const key_type& _Keyval)
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Keyval);
size_type _Bucket = _Order_key % _M_number_of_buckets;
// If _Bucket is empty, initialize it first
if (!_Is_initialized(_Bucket))
{
_Initialize_bucket(_Bucket);
}
_Order_key = _Split_order_regular_key(_Order_key);
_Full_iterator _Last = _M_split_ordered_list._End();
for (_Full_iterator _Iterator = _Get_bucket(_Bucket); _Iterator != _Last; _Iterator++)
{
if (_Mylist::_Get_key(_Iterator) > _Order_key)
{
// If the order key is smaller than the current order key, the element
// is not in the hash.
return end();
}
else if (_Mylist::_Get_key(_Iterator) == _Order_key)
{
// The fact that order keys match does not mean that the element is found.
// Key function comparison has to be performed to check whether this is the
// right element. If not, keep searching while order key is the same.
if (!_M_comparator(_Key_function(*_Iterator), _Keyval))
{
return _M_split_ordered_list._Get_iterator(_Iterator);
}
}
}
return end();
}
// Find the element in the split-ordered list
const_iterator _Find(const key_type& _Keyval) const
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Keyval);
size_type _Bucket = _Order_key % _M_number_of_buckets;
// If _Bucket has not been initialized, keep searching up for a parent bucket
// that has been initialized. Worst case is the entire map will be read.
while (!_Is_initialized(_Bucket))
{
_Bucket = _Get_parent(_Bucket);
}
_Order_key = _Split_order_regular_key(_Order_key);
_Full_const_iterator _Last = _M_split_ordered_list._End();
for (_Full_const_iterator _Iterator = _Get_bucket(_Bucket); _Iterator != _Last; _Iterator++)
{
if (_Mylist::_Get_key(_Iterator) > _Order_key)
{
// If the order key is smaller than the current order key, the element
// is not in the hash.
return end();
}
else if (_Mylist::_Get_key(_Iterator) == _Order_key)
{
// The fact that order keys match does not mean that the element is found.
// Key function comparison has to be performed to check whether this is the
// right element. If not, keep searching while order key is the same.
if (!_M_comparator(_Key_function(*_Iterator), _Keyval))
{
return _M_split_ordered_list._Get_iterator(_Iterator);
}
}
}
return end();
}
// Erase an element from the list. This is not a concurrency safe function.
iterator _Erase(const_iterator _Iterator)
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Key_function(*_Iterator));
size_type _Bucket = _Order_key % _M_number_of_buckets;
// If bucket is empty, initialize it first
if (!_Is_initialized(_Bucket))
{
_Initialize_bucket(_Bucket);
}
_Order_key = _Split_order_regular_key(_Order_key);
_Full_iterator _Previous = _Get_bucket(_Bucket);
_Full_iterator _Last = _M_split_ordered_list._End();
_Full_iterator _Where = _Previous;
_ASSERT_EXPR(_Where != _Last, L"Invalid head node");
// First node is a dummy node
_Where++;
for (;;)
{
if (_Where == _Last)
{
return end();
}
else if (_M_split_ordered_list._Get_iterator(_Where) == _Iterator)
{
return _M_split_ordered_list._Erase(_Previous, _Iterator);
}
// Move the iterator forward
_Previous = _Where;
_Where++;
}
}
// Return the [begin, end] pair of iterators with the same key values.
// This operation makes sense only if mapping is many-to-one.
std::pair<iterator, iterator> _Equal_range(const key_type& _Keyval)
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Keyval);
size_type _Bucket = _Order_key % _M_number_of_buckets;
// If _Bucket is empty, initialize it first
if (!_Is_initialized(_Bucket))
{
_Initialize_bucket(_Bucket);
}
_Order_key = _Split_order_regular_key(_Order_key);
_Full_iterator _Last = _M_split_ordered_list._End();
for (_Full_iterator _Iterator = _Get_bucket(_Bucket); _Iterator != _Last; _Iterator++)
{
if (_Mylist::_Get_key(_Iterator) > _Order_key)
{
// There is no element with the given key
return std::pair<iterator, iterator>(end(), end());
}
else if (_Mylist::_Get_key(_Iterator) == _Order_key && !_M_comparator(_Key_function(*_Iterator), _Keyval))
{
iterator _Begin = _M_split_ordered_list._Get_iterator(_Iterator);
iterator _End= _Begin;
for (;_End != end() && !_M_comparator(_Key_function(*_End), _Keyval); _End++)
{
}
return std::pair<iterator, iterator>(_Begin, _End);
}
}
return std::pair<iterator, iterator>(end(), end());
}
// Return the [begin, end] pair of const iterators with the same key values.
// This operation makes sense only if mapping is many-to-one.
std::pair<const_iterator, const_iterator> _Equal_range(const key_type& _Keyval) const
{
_Split_order_key _Order_key = (_Split_order_key) _M_comparator(_Keyval);
size_type _Bucket = _Order_key % _M_number_of_buckets;
// If _Bucket has not been initialized, keep searching up for a parent bucket
// that has been initialized. Worst case is the entire map will be read.
while (!_Is_initialized(_Bucket))
{
_Bucket = _Get_parent(_Bucket);
}
_Order_key = _Split_order_regular_key(_Order_key);
_Full_const_iterator _Last = _M_split_ordered_list._End();
for (_Full_const_iterator _Iterator = _Get_bucket(_Bucket); _Iterator != _Last; _Iterator++)
{
if (_Mylist::_Get_key(_Iterator) > _Order_key)
{
// There is no element with the given key
return std::pair<const_iterator, const_iterator>(end(), end());
}
else if (_Mylist::_Get_key(_Iterator) == _Order_key && !_M_comparator(_Key_function(*_Iterator), _Keyval))
{
const_iterator _Begin = _M_split_ordered_list._Get_iterator(_Iterator);
const_iterator _End = _Begin;
for (; _End != end() && !_M_comparator(_Key_function(*_End), _Keyval); _End++)
{
}
return std::pair<const_iterator, const_iterator>(_Begin, _End);
}
}
return std::pair<const_iterator, const_iterator>(end(), end());
}
// Bucket APIs
void _Initialize_bucket(size_type _Bucket)
{
// Bucket 0 has no parent. Initialize it and return.
if (_Bucket == 0)
{
_Init();
return;
}
size_type _Parent_bucket = _Get_parent(_Bucket);
// All _Parent_bucket buckets have to be initialized before this bucket is
if (!_Is_initialized(_Parent_bucket))
{
_Initialize_bucket(_Parent_bucket);
}
_Full_iterator _Parent = _Get_bucket(_Parent_bucket);
// Create a dummy first node in this bucket
_Full_iterator _Dummy_node = _M_split_ordered_list._Insert_dummy(_Parent, _Split_order_dummy_key(_Bucket));
_Set_bucket(_Bucket, _Dummy_node);
}
void _Adjust_table_size(size_type _Total_elements, size_type _Current_size)
{
// Grow the table by a factor of 2 if possible and needed
if (((float) _Total_elements / (float) _Current_size) > _M_maximum_bucket_size)
{
// Double the size of the hash only if size has not changed inbetween loads
_InterlockedCompareExchangeSizeT(&_M_number_of_buckets, 2 * _Current_size, _Current_size);
}
}
size_type _Get_parent(size_type _Bucket) const
{
// Unsets bucket's most significant turned-on bit
unsigned char _Msb = _Get_msb(_Bucket);
return _Bucket & ~(1 << _Msb);
}
// Dynamic sized array (segments)
_Full_iterator _Get_bucket(size_type _Bucket) const
{
size_type _Segment = _Segment_index_of(_Bucket);
_Bucket -= _Segment_base(_Segment);
return _M_buckets[_Segment][_Bucket];
}
void _Set_bucket(size_type _Bucket, _Full_iterator _Dummy_head)
{
size_type _Segment = _Segment_index_of(_Bucket);
_Bucket -= _Segment_base(_Segment);
if (_M_buckets[_Segment] == NULL)
{
size_type _Seg_size = _Segment_size(_Segment);
_Full_iterator * _New_segment = _M_allocator.allocate(_Seg_size);
std::_Wrap_alloc<decltype(_M_allocator)> _Wrapped_allocator(_M_allocator);
std::_Uninitialized_default_fill_n(_New_segment, _Seg_size, _Wrapped_allocator);
if (_InterlockedCompareExchangePointer((void * volatile *) &_M_buckets[_Segment], _New_segment, NULL) != NULL)
{
_M_allocator.deallocate(_New_segment, _Seg_size);
}
}
_M_buckets[_Segment][_Bucket] = _Dummy_head;
}
bool _Is_initialized(size_type _Bucket) const
{
size_type _Segment = _Segment_index_of(_Bucket);
_Bucket -= _Segment_base(_Segment);
if (_M_buckets[_Segment] == NULL)
{
return false;
}
_Full_iterator _Iterator = _M_buckets[_Segment][_Bucket];
return (_Iterator._Mynode() != NULL);
}
// Utilities for keys
_Split_order_key _Reverse(_Map_key _Order_key) const
{
_Split_order_key _Reversed_order_key;
unsigned char * _Original = (unsigned char *) &_Order_key;
unsigned char * _Reversed = (unsigned char *) &_Reversed_order_key;
int _Size = sizeof(_Map_key);
for (int _Index = 0; _Index < _Size; _Index++)
{
_Reversed[_Size - _Index - 1] = _Reverse_byte(_Original[_Index]);
}
return _Reversed_order_key;
}
// A regular order key has its original hash value reversed and the last bit set
_Split_order_key _Split_order_regular_key(_Map_key _Order_key) const
{
return _Reverse(_Order_key) | 0x1;
}
// A dummy order key has its original hash value reversed and the last bit unset
_Split_order_key _Split_order_dummy_key(_Map_key _Order_key) const
{
return _Reverse(_Order_key) & ~(0x1);
}
// Shared variables
_Full_iterator * _M_buckets[_Pointers_per_table]; // The segment table
_Mylist _M_split_ordered_list; // List where all the elements are kept
typename allocator_type::template rebind<_Full_iterator>::other _M_allocator; // Allocator object for segments
size_type _M_number_of_buckets; // Current table size
float _M_maximum_bucket_size; // Maximum size of the bucket
};
#pragma warning(pop) // Warning 4127 -- while (true) has a constant expression in it
} // namespace details;
} // namespace Concurrency
namespace concurrency = Concurrency;
#pragma pack(pop)