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>;
34 #include "debugging/debugging.h"
36 namespace HashTableDetail
38 inline std::size_t next_power_of_two( std::size_t size ){
39 std::size_t result = 1;
40 while ( result < size )
53 inline void list_initialise( BucketNodeBase& self ){
54 self.next = self.prev = &self;
57 inline void list_swap( BucketNodeBase& self, BucketNodeBase& other ){
58 BucketNodeBase tmp( self );
59 if ( other.next == &other ) {
60 list_initialise( self );
65 self.next->prev = self.prev->next = &self;
67 if ( tmp.next == &self ) {
68 list_initialise( other );
73 other.next->prev = other.prev->next = &other;
77 inline void node_link( BucketNodeBase* node, BucketNodeBase* next ){
79 node->prev = next->prev;
81 node->prev->next = node;
83 inline void node_unlink( BucketNodeBase* node ){
84 node->prev->next = node->next;
85 node->next->prev = node->prev;
88 template<typename Key, typename Value>
94 KeyValue( const Key& key_, const Value& value_ )
95 : key( key_ ), value( value_ ){
99 template<typename Key, typename Value, typename Hash>
100 struct BucketNode : public BucketNodeBase
103 KeyValue<Key, Value> m_value;
105 BucketNode( Hash hash, const Key& key, const Value& value )
106 : m_hash( hash ), m_value( key, value ){
108 BucketNode* getNext() const {
109 return static_cast<BucketNode*>( next );
111 BucketNode* getPrev() const {
112 return static_cast<BucketNode*>( prev );
116 template<typename Key, typename Value, typename Hash>
119 typedef BucketNode<Key, Value, Hash> Node;
123 m_node = m_node->getNext();
127 typedef std::forward_iterator_tag iterator_category;
128 typedef std::ptrdiff_t difference_type;
129 typedef difference_type distance_type;
130 typedef KeyValue<Key, Value> value_type;
131 typedef value_type* pointer;
132 typedef value_type& reference;
134 BucketIterator( Node* node ) : m_node( node ){
141 bool operator==( const BucketIterator& other ) const {
142 return m_node == other.m_node;
144 bool operator!=( const BucketIterator& other ) const {
145 return !operator==( other );
147 BucketIterator& operator++(){
151 BucketIterator operator++( int ){
152 BucketIterator tmp = *this;
156 value_type& operator*() const {
157 return m_node->m_value;
159 value_type* operator->() const {
160 return &( operator*() );
166 /// A hash-table container which maps keys to values.
168 /// - Inserting or removing elements does not invalidate iterators.
169 /// - Inserting or retrieving an element for a given key takes O(1) time on average.
170 /// - Elements are stored in no particular order.
172 /// \param Key Uniquely identifies a value. Must provide a copy-constructor.
173 /// \param Value The value to be stored . Must provide a default-constructor and a copy-constructor.
174 /// \param Hasher Must provide 'std::size_t operator()(const Key&) const' which always returns the same result if the same argument is given.
175 /// \param KeyEqual Must provide 'bool operator==(const Key&, const Key&) const' which returns true only if both arguments are equal.
177 /// \dontinclude container/hashtable.cpp
178 /// \skipline HashTable example
179 /// \until end example
180 template<typename Key, typename Value, typename Hasher, typename KeyEqual = std::equal_to<Key> >
181 class HashTable : private KeyEqual, private Hasher
183 typedef typename Hasher::hash_type hash_type;
184 typedef HashTableDetail::KeyValue<Key, Value> KeyValue;
185 typedef HashTableDetail::BucketNode<Key, Value, hash_type> BucketNode;
187 inline BucketNode* node_create( hash_type hash, const Key& key, const Value& value ){
188 return new BucketNode( hash, key, value );
190 inline void node_destroy( BucketNode* node ){
194 typedef BucketNode* Bucket;
196 static Bucket* buckets_new( std::size_t count ){
197 Bucket* buckets = new Bucket[count];
198 std::uninitialized_fill( buckets, buckets + count, Bucket( 0 ) );
201 static void buckets_delete( Bucket* buckets ){
205 std::size_t m_bucketCount;
208 HashTableDetail::BucketNodeBase m_list;
210 BucketNode* getFirst(){
211 return static_cast<BucketNode*>( m_list.next );
213 BucketNode* getLast(){
214 return static_cast<BucketNode*>( &m_list );
219 typedef KeyValue value_type;
220 typedef HashTableDetail::BucketIterator<Key, Value, hash_type> iterator;
225 list_initialise( m_list );
227 hash_type hashKey( const Key& key ){
228 return Hasher::operator()( key );
231 std::size_t getBucketId( hash_type hash ) const {
232 return hash & ( m_bucketCount - 1 );
234 Bucket& getBucket( hash_type hash ){
235 return m_buckets[getBucketId( hash )];
237 BucketNode* bucket_find( Bucket bucket, hash_type hash, const Key& key ){
238 std::size_t bucketId = getBucketId( hash );
239 for ( iterator i( bucket ); i != end(); ++i )
241 hash_type nodeHash = i.node()->m_hash;
243 if ( getBucketId( nodeHash ) != bucketId ) {
247 if ( nodeHash == hash && KeyEqual::operator()( ( *i ).first, key ) ) {
253 BucketNode* bucket_insert( Bucket& bucket, BucketNode* node ){
254 // link node into list
255 node_link( node, bucket_next( bucket ) );
259 BucketNode* bucket_next( Bucket& bucket ){
260 Bucket* end = m_buckets + m_bucketCount;
261 for ( Bucket* i = &bucket; i != end; ++i )
270 void buckets_resize( std::size_t count ){
271 BucketNode* first = getFirst();
272 BucketNode* last = getLast();
274 buckets_delete( m_buckets );
276 m_bucketCount = count;
278 m_buckets = buckets_new( m_bucketCount );
281 for ( BucketNode* i = first; i != last; )
283 BucketNode* node = i;
285 bucket_insert( getBucket( ( *node ).m_hash ), node );
288 void size_increment(){
289 if ( m_size == m_bucketCount ) {
290 buckets_resize( m_bucketCount == 0 ? 8 : m_bucketCount << 1 );
294 void size_decrement(){
298 HashTable( const HashTable& other );
299 HashTable& operator=( const HashTable& other );
301 HashTable() : m_bucketCount( 0 ), m_buckets( 0 ), m_size( 0 ){
304 HashTable( std::size_t bucketCount ) : m_bucketCount( HashTableDetail::next_power_of_two( bucketCount ) ), m_buckets( buckets_new( m_bucketCount ) ), m_size( 0 ){
308 for ( BucketNode* i = getFirst(); i != getLast(); )
310 BucketNode* node = i;
312 node_destroy( node );
314 buckets_delete( m_buckets );
318 return iterator( getFirst() );
321 return iterator( getLast() );
327 std::size_t size() const {
331 /// \brief Returns an iterator pointing to the value associated with \p key if it is contained by the hash-table, else \c end().
332 iterator find( const Key& key ){
333 hash_type hash = hashKey( key );
334 if ( m_bucketCount != 0 ) {
335 Bucket bucket = getBucket( hash );
337 BucketNode* node = bucket_find( bucket, hash, key );
339 return iterator( node );
346 /// \brief Adds \p value to the hash-table associated with \p key if it does not exist.
347 iterator insert( const Key& key, const Value& value ){
348 hash_type hash = hashKey( key );
349 if ( m_bucketCount != 0 ) {
350 Bucket& bucket = getBucket( hash );
352 BucketNode* node = bucket_find( bucket, hash, key );
354 return iterator( node );
360 return iterator( bucket_insert( getBucket( hash ), node_create( hash, key, value ) ) );
363 /// \brief Removes the value pointed to by \p i from the hash-table.
365 /// \p i must be a deferenceable iterator into the hash-table.
366 void erase( iterator i ){
367 Bucket& bucket = getBucket( i.node()->m_hash );
368 BucketNode* node = i.node();
370 // if this was the last node in the bucket
371 if ( bucket == node ) {
372 bucket = ( node->getNext() == getLast() || &getBucket( node->getNext()->m_hash ) != &bucket ) ? 0 : node->getNext();
376 ASSERT_MESSAGE( node != 0, "tried to erase a non-existent key/value" );
377 node_destroy( node );
382 /// \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.
383 Value& operator[]( const Key& key ){
384 hash_type hash = hashKey( key );
385 if ( m_bucketCount != 0 ) {
386 Bucket& bucket = getBucket( hash );
388 BucketNode* node = bucket_find( bucket, hash, key );
390 return node->m_value.value;
395 return bucket_insert( getBucket( hash ), node_create( hash, key, Value() ) )->m_value.value;
397 /// \brief Removes the value associated with \p key from the hash-table.
398 void erase( const Key& key ){
399 erase( find( key ) );
401 /// \brief Swaps the contents of the hash-table with \p other.
402 void swap( HashTable& other ){
403 std::swap( m_buckets, other.m_buckets );
404 std::swap( m_bucketCount, other.m_bucketCount );
405 std::swap( m_size, other.m_size );
406 HashTableDetail::list_swap( m_list, other.m_list );
408 /// \brief Removes all values from the hash-table.