2 Copyright (C) 2001-2006, William Joseph.
5 This file is part of GtkRadiant.
7 GtkRadiant is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 GtkRadiant is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GtkRadiant; if not, write to the Free Software
19 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 #if !defined( INCLUDED_CONTAINER_HASHTABLE_H )
23 #define INCLUDED_CONTAINER_HASHTABLE_H
25 #include <unordered_map>
27 template<typename Key, typename Value, typename Hasher, typename KeyEqual = std::equal_to<Key> >
28 using HashTable = std::unordered_map<Key, Value, Hasher, KeyEqual>;
35 #include "debugging/debugging.h"
37 namespace HashTableDetail
39 inline std::size_t next_power_of_two( std::size_t size ){
40 std::size_t result = 1;
41 while ( result < size )
54 inline void list_initialise( BucketNodeBase& self ){
55 self.next = self.prev = &self;
58 inline void list_swap( BucketNodeBase& self, BucketNodeBase& other ){
59 BucketNodeBase tmp( self );
60 if ( other.next == &other ) {
61 list_initialise( self );
66 self.next->prev = self.prev->next = &self;
68 if ( tmp.next == &self ) {
69 list_initialise( other );
74 other.next->prev = other.prev->next = &other;
78 inline void node_link( BucketNodeBase* node, BucketNodeBase* next ){
80 node->prev = next->prev;
82 node->prev->next = node;
84 inline void node_unlink( BucketNodeBase* node ){
85 node->prev->next = node->next;
86 node->next->prev = node->prev;
89 template<typename Key, typename Value>
95 KeyValue( const Key& key_, const Value& value_ )
96 : key( key_ ), value( value_ ){
100 template<typename Key, typename Value, typename Hash>
101 struct BucketNode : public BucketNodeBase
104 KeyValue<Key, Value> m_value;
106 BucketNode( Hash hash, const Key& key, const Value& value )
107 : m_hash( hash ), m_value( key, value ){
109 BucketNode* getNext() const {
110 return static_cast<BucketNode*>( next );
112 BucketNode* getPrev() const {
113 return static_cast<BucketNode*>( prev );
117 template<typename Key, typename Value, typename Hash>
120 typedef BucketNode<Key, Value, Hash> Node;
124 m_node = m_node->getNext();
128 typedef std::forward_iterator_tag iterator_category;
129 typedef std::ptrdiff_t difference_type;
130 typedef difference_type distance_type;
131 typedef KeyValue<Key, Value> value_type;
132 typedef value_type* pointer;
133 typedef value_type& reference;
135 BucketIterator( Node* node ) : m_node( node ){
142 bool operator==( const BucketIterator& other ) const {
143 return m_node == other.m_node;
145 bool operator!=( const BucketIterator& other ) const {
146 return !operator==( other );
148 BucketIterator& operator++(){
152 BucketIterator operator++( int ){
153 BucketIterator tmp = *this;
157 value_type& operator*() const {
158 return m_node->m_value;
160 value_type* operator->() const {
161 return &( operator*() );
167 /// A hash-table container which maps keys to values.
169 /// - Inserting or removing elements does not invalidate iterators.
170 /// - Inserting or retrieving an element for a given key takes O(1) time on average.
171 /// - Elements are stored in no particular order.
173 /// \param Key Uniquely identifies a value. Must provide a copy-constructor.
174 /// \param Value The value to be stored . Must provide a default-constructor and a copy-constructor.
175 /// \param Hasher Must provide 'std::size_t operator()(const Key&) const' which always returns the same result if the same argument is given.
176 /// \param KeyEqual Must provide 'bool operator==(const Key&, const Key&) const' which returns true only if both arguments are equal.
178 /// \dontinclude container/hashtable.cpp
179 /// \skipline HashTable example
180 /// \until end example
181 template<typename Key, typename Value, typename Hasher, typename KeyEqual = std::equal_to<Key> >
182 class HashTable : private KeyEqual, private Hasher
184 typedef typename Hasher::hash_type hash_type;
185 typedef HashTableDetail::KeyValue<Key, Value> KeyValue;
186 typedef HashTableDetail::BucketNode<Key, Value, hash_type> BucketNode;
188 inline BucketNode* node_create( hash_type hash, const Key& key, const Value& value ){
189 return new BucketNode( hash, key, value );
191 inline void node_destroy( BucketNode* node ){
195 typedef BucketNode* Bucket;
197 static Bucket* buckets_new( std::size_t count ){
198 Bucket* buckets = new Bucket[count];
199 std::uninitialized_fill( buckets, buckets + count, Bucket( 0 ) );
202 static void buckets_delete( Bucket* buckets ){
206 std::size_t m_bucketCount;
209 HashTableDetail::BucketNodeBase m_list;
211 BucketNode* getFirst(){
212 return static_cast<BucketNode*>( m_list.next );
214 BucketNode* getLast(){
215 return static_cast<BucketNode*>( &m_list );
220 typedef KeyValue value_type;
221 typedef HashTableDetail::BucketIterator<Key, Value, hash_type> iterator;
226 list_initialise( m_list );
228 hash_type hashKey( const Key& key ){
229 return Hasher::operator()( key );
232 std::size_t getBucketId( hash_type hash ) const {
233 return hash & ( m_bucketCount - 1 );
235 Bucket& getBucket( hash_type hash ){
236 return m_buckets[getBucketId( hash )];
238 BucketNode* bucket_find( Bucket bucket, hash_type hash, const Key& key ){
239 std::size_t bucketId = getBucketId( hash );
240 for ( iterator i( bucket ); i != end(); ++i )
242 hash_type nodeHash = i.node()->m_hash;
244 if ( getBucketId( nodeHash ) != bucketId ) {
248 if ( nodeHash == hash && KeyEqual::operator()( ( *i ).first, key ) ) {
254 BucketNode* bucket_insert( Bucket& bucket, BucketNode* node ){
255 // link node into list
256 node_link( node, bucket_next( bucket ) );
260 BucketNode* bucket_next( Bucket& bucket ){
261 Bucket* end = m_buckets + m_bucketCount;
262 for ( Bucket* i = &bucket; i != end; ++i )
271 void buckets_resize( std::size_t count ){
272 BucketNode* first = getFirst();
273 BucketNode* last = getLast();
275 buckets_delete( m_buckets );
277 m_bucketCount = count;
279 m_buckets = buckets_new( m_bucketCount );
282 for ( BucketNode* i = first; i != last; )
284 BucketNode* node = i;
286 bucket_insert( getBucket( ( *node ).m_hash ), node );
289 void size_increment(){
290 if ( m_size == m_bucketCount ) {
291 buckets_resize( m_bucketCount == 0 ? 8 : m_bucketCount << 1 );
295 void size_decrement(){
299 HashTable( const HashTable& other );
300 HashTable& operator=( const HashTable& other );
302 HashTable() : m_bucketCount( 0 ), m_buckets( 0 ), m_size( 0 ){
305 HashTable( std::size_t bucketCount ) : m_bucketCount( HashTableDetail::next_power_of_two( bucketCount ) ), m_buckets( buckets_new( m_bucketCount ) ), m_size( 0 ){
309 for ( BucketNode* i = getFirst(); i != getLast(); )
311 BucketNode* node = i;
313 node_destroy( node );
315 buckets_delete( m_buckets );
319 return iterator( getFirst() );
322 return iterator( getLast() );
328 std::size_t size() const {
332 /// \brief Returns an iterator pointing to the value associated with \p key if it is contained by the hash-table, else \c end().
333 iterator find( const Key& key ){
334 hash_type hash = hashKey( key );
335 if ( m_bucketCount != 0 ) {
336 Bucket bucket = getBucket( hash );
338 BucketNode* node = bucket_find( bucket, hash, key );
340 return iterator( node );
347 /// \brief Adds \p value to the hash-table associated with \p key if it does not exist.
348 iterator insert( const Key& key, const Value& value ){
349 hash_type hash = hashKey( key );
350 if ( m_bucketCount != 0 ) {
351 Bucket& bucket = getBucket( hash );
353 BucketNode* node = bucket_find( bucket, hash, key );
355 return iterator( node );
361 return iterator( bucket_insert( getBucket( hash ), node_create( hash, key, value ) ) );
364 /// \brief Removes the value pointed to by \p i from the hash-table.
366 /// \p i must be a deferenceable iterator into the hash-table.
367 void erase( iterator i ){
368 Bucket& bucket = getBucket( i.node()->m_hash );
369 BucketNode* node = i.node();
371 // if this was the last node in the bucket
372 if ( bucket == node ) {
373 bucket = ( node->getNext() == getLast() || &getBucket( node->getNext()->m_hash ) != &bucket ) ? 0 : node->getNext();
377 ASSERT_MESSAGE( node != 0, "tried to erase a non-existent key/value" );
378 node_destroy( node );
383 /// \brief Returns the value identified by \p key if it is contained by the hash-table, else inserts and returns a new default-constructed value associated with \p key.
384 Value& operator[]( const Key& key ){
385 hash_type hash = hashKey( key );
386 if ( m_bucketCount != 0 ) {
387 Bucket& bucket = getBucket( hash );
389 BucketNode* node = bucket_find( bucket, hash, key );
391 return node->m_value.value;
396 return bucket_insert( getBucket( hash ), node_create( hash, key, Value() ) )->m_value.value;
398 /// \brief Removes the value associated with \p key from the hash-table.
399 void erase( const Key& key ){
400 erase( find( key ) );
402 /// \brief Swaps the contents of the hash-table with \p other.
403 void swap( HashTable& other ){
404 std::swap( m_buckets, other.m_buckets );
405 std::swap( m_bucketCount, other.m_bucketCount );
406 std::swap( m_size, other.m_size );
407 HashTableDetail::list_swap( m_list, other.m_list );
409 /// \brief Removes all values from the hash-table.