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// unordered_fast_key_table_internal.h
/* Copyright 2012 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
namespace mongo {
template< typename K_L, typename K_S, typename V, typename H, typename E, typename C, typename C_LS >
inline UnorderedFastKeyTable<K_L, K_S, V, H, E, C, C_LS>::Area::Area(unsigned capacity,
double maxProbeRatio)
: _capacity( capacity ),
_maxProbe( static_cast<unsigned>( capacity * maxProbeRatio ) ),
_entries( new Entry[_capacity] ) {
}
template< typename K_L, typename K_S, typename V, typename H, typename E, typename C, typename C_LS >
inline int UnorderedFastKeyTable<K_L, K_S, V, H, E, C, C_LS>::Area::find(
const K_L& key,
size_t hash,
int* firstEmpty,
const UnorderedFastKeyTable& sm ) const {
if ( firstEmpty )
*firstEmpty = -1;
for ( unsigned probe = 0; probe < _maxProbe; probe++ ) {
unsigned pos = (hash + probe) % _capacity;
if ( ! _entries[pos].used ) {
// space is empty
if ( firstEmpty && *firstEmpty == -1 )
*firstEmpty = pos;
if ( ! _entries[pos].everUsed )
return -1;
continue;
}
if ( _entries[pos].curHash != hash ) {
// space has something else
continue;
}
if ( ! sm._equals(key, sm._convertor( _entries[pos].data.first ) ) ) {
// hashes match
// strings are not equals
continue;
}
// hashes and strings are equal
// yay!
return pos;
}
return -1;
}
template< typename K_L, typename K_S, typename V, typename H, typename E, typename C, typename C_LS >
inline void UnorderedFastKeyTable<K_L, K_S, V, H, E, C, C_LS>::Area::transfer(
Area* newArea,
const UnorderedFastKeyTable& sm) const {
for ( unsigned i = 0; i < _capacity; i++ ) {
if ( ! _entries[i].used )
continue;
int firstEmpty = -1;
int loc = newArea->find( sm._convertor( _entries[i].data.first ),
_entries[i].curHash,
&firstEmpty,
sm );
verify( loc == -1 );
verify( firstEmpty >= 0 );
newArea->_entries[firstEmpty] = _entries[i];
}
}
template< typename K_L, typename K_S, typename V, typename H, typename E, typename C, typename C_LS >
inline UnorderedFastKeyTable<K_L, K_S, V, H, E, C, C_LS>::UnorderedFastKeyTable(
unsigned startingCapacity,
double maxProbeRatio)
: _maxProbeRatio( maxProbeRatio ), _area( startingCapacity, maxProbeRatio ) {
_size = 0;
}
template< typename K_L, typename K_S, typename V, typename H, typename E, typename C, typename C_LS >
inline V& UnorderedFastKeyTable<K_L, K_S, V, H, E, C, C_LS>::get( const K_L& key ) {
const size_t hash = _hash( key );
for ( int numGrowTries = 0; numGrowTries < 10; numGrowTries++ ) {
int firstEmpty = -1;
int pos = _area.find( key, hash, &firstEmpty, *this );
if ( pos >= 0 )
return _area._entries[pos].data.second;
// key not in map
// need to add
if ( firstEmpty >= 0 ) {
_size++;
_area._entries[firstEmpty].used = true;
_area._entries[firstEmpty].everUsed = true;
_area._entries[firstEmpty].curHash = hash;
_area._entries[firstEmpty].data.first = _convertorOther(key);
return _area._entries[firstEmpty].data.second;
}
// no space left in map
_grow();
}
msgasserted( 16471, "UnorderedFastKeyTable couldn't add entry after growing many times" );
}
template< typename K_L, typename K_S, typename V, typename H, typename E, typename C, typename C_LS >
inline void UnorderedFastKeyTable<K_L, K_S, V, H, E, C, C_LS>::_grow() {
Area newArea( _area._capacity * 2, _maxProbeRatio );
_area.transfer( &newArea, *this );
_area.swap( &newArea );
}
}
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