mirror of https://gitee.com/bigwinds/arangodb
525 lines
16 KiB
C++
525 lines
16 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// @brief associative array implementation
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///
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/// @file
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///
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/// DISCLAIMER
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///
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/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Dr. Frank Celler
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/// @author Martin Schoenert
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/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
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/// @author Copyright 2006-2013, triAGENS GmbH, Cologne, Germany
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////////////////////////////////////////////////////////////////////////////////
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#include "associative.h"
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#include "Basics/hashes.h"
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#include "Basics/tri-strings.h"
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// -----------------------------------------------------------------------------
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// --SECTION-- private defines
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initial number of elements in the array
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////////////////////////////////////////////////////////////////////////////////
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#define INITIAL_SIZE (11)
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// -----------------------------------------------------------------------------
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// --SECTION-- ASSOCIATIVE POINTERS
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// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
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// --SECTION-- private functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief adds a new element
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////////////////////////////////////////////////////////////////////////////////
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static void AddNewElementPointer (TRI_associative_pointer_t* array, void* element) {
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uint64_t hash;
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uint64_t i;
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// compute the hash
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hash = array->hashElement(array, element);
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// search the table
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i = hash % array->_nrAlloc;
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while (array->_table[i] != nullptr) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesR++;
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#endif
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}
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// add a new element to the associative array
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array->_table[i] = element;
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array->_nrUsed++;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief resizes the array
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////////////////////////////////////////////////////////////////////////////////
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static bool ResizeAssociativePointer (TRI_associative_pointer_t* array,
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uint32_t targetSize) {
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void** oldTable = array->_table;
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uint32_t oldAlloc = array->_nrAlloc;
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array->_nrAlloc = targetSize;
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#ifdef TRI_INTERNAL_STATS
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array->_nrResizes++;
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#endif
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array->_table = static_cast<void**>(TRI_Allocate(array->_memoryZone, (size_t) (array->_nrAlloc * sizeof(void*)), true));
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if (array->_table == nullptr) {
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array->_nrAlloc = oldAlloc;
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array->_table = oldTable;
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return false;
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}
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array->_nrUsed = 0;
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if (oldTable != nullptr) {
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// table is already cleared by allocate, copy old data
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for (uint32_t j = 0; j < oldAlloc; j++) {
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if (oldTable[j] != nullptr) {
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AddNewElementPointer(array, oldTable[j]);
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}
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}
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TRI_Free(array->_memoryZone, oldTable);
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}
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return true;
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors and destructors
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initializes an array
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////////////////////////////////////////////////////////////////////////////////
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int TRI_InitAssociativePointer (TRI_associative_pointer_t* array,
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TRI_memory_zone_t* zone,
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uint64_t (*hashKey) (TRI_associative_pointer_t*, void const*),
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uint64_t (*hashElement) (TRI_associative_pointer_t*, void const*),
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bool (*isEqualKeyElement) (TRI_associative_pointer_t*, void const*, void const*),
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bool (*isEqualElementElement) (TRI_associative_pointer_t*, void const*, void const*)) {
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array->hashKey = hashKey;
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array->hashElement = hashElement;
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array->isEqualKeyElement = isEqualKeyElement;
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array->isEqualElementElement = isEqualElementElement;
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array->_memoryZone = zone;
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array->_nrAlloc = 0;
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array->_nrUsed = 0;
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array->_table = nullptr;
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#ifdef TRI_INTERNAL_STATS
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array->_nrFinds = 0;
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array->_nrAdds = 0;
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array->_nrRems = 0;
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array->_nrResizes = 0;
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array->_nrProbesF = 0;
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array->_nrProbesA = 0;
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array->_nrProbesD = 0;
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array->_nrProbesR = 0;
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#endif
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if (nullptr == (array->_table = static_cast<void**>(TRI_Allocate(zone, sizeof(void*) * INITIAL_SIZE, true)))) {
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return TRI_ERROR_OUT_OF_MEMORY;
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}
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array->_nrAlloc = INITIAL_SIZE;
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return TRI_ERROR_NO_ERROR;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief destroys an array, but does not free the pointer
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////////////////////////////////////////////////////////////////////////////////
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void TRI_DestroyAssociativePointer (TRI_associative_pointer_t* array) {
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if (array->_table != nullptr) {
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TRI_Free(array->_memoryZone, array->_table);
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array->_table = nullptr;
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}
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- public functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief General hash function that can be used to hash a key
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////////////////////////////////////////////////////////////////////////////////
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uint64_t TRI_HashStringKeyAssociativePointer (TRI_associative_pointer_t* array,
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void const* key) {
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return TRI_FnvHashString((char const*) key);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief General function to determine equality of two string values
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////////////////////////////////////////////////////////////////////////////////
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bool TRI_EqualStringKeyAssociativePointer (TRI_associative_pointer_t* array,
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void const* key,
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void const* element) {
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return TRI_EqualString((char*) key, (char*) element);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief reserves space in the array for extra elements
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////////////////////////////////////////////////////////////////////////////////
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bool TRI_ReserveAssociativePointer (TRI_associative_pointer_t* array,
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int32_t nrElements) {
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uint32_t targetSize = array->_nrUsed + nrElements;
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if (array->_nrAlloc < 2 * targetSize) {
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// we must resize
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return ResizeAssociativePointer(array, (uint32_t) (2 * targetSize) + 1);
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}
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// no seed to resize
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return true;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief looks up an element given a key
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////////////////////////////////////////////////////////////////////////////////
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void* TRI_LookupByKeyAssociativePointer (TRI_associative_pointer_t* array,
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void const* key) {
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if (array->_nrUsed == 0) {
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return nullptr;
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}
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// compute the hash
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uint64_t hash = array->hashKey(array, key);
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uint64_t i = hash % array->_nrAlloc;
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#ifdef TRI_INTERNAL_STATS
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// update statistics
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array->_nrFinds++;
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#endif
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// search the table
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while (array->_table[i] != nullptr && ! array->isEqualKeyElement(array, key, array->_table[i])) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesF++;
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#endif
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}
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// return whatever we found
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return array->_table[i];
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief looks up an element given an element
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////////////////////////////////////////////////////////////////////////////////
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void* TRI_LookupByElementAssociativePointer (TRI_associative_pointer_t* array,
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void const* element) {
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// compute the hash
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uint64_t const hash = array->hashElement(array, element);
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uint64_t const n = array->_nrAlloc;
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uint64_t i, k;
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i = k = hash % n;
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#ifdef TRI_INTERNAL_STATS
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// update statistics
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array->_nrFinds++;
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#endif
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// search the table
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for (; i < n && array->_table[i] != nullptr && ! array->isEqualElementElement(array, element, array->_table[i]); ++i);
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if (i == n) {
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for (i = 0; i < k && array->_table[i] != nullptr && ! array->isEqualElementElement(array, element, array->_table[i]); ++i);
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}
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// return whatever we found
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return array->_table[i];
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief adds an element to the array
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////////////////////////////////////////////////////////////////////////////////
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void* TRI_InsertElementAssociativePointer (TRI_associative_pointer_t* array,
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void* element,
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bool overwrite) {
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uint64_t hash;
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uint64_t i;
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void* old;
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// check for out-of-memory
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if (array->_nrAlloc == array->_nrUsed) {
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TRI_set_errno(TRI_ERROR_OUT_OF_MEMORY);
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return nullptr;
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}
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// compute the hash
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hash = array->hashElement(array, element);
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i = hash % array->_nrAlloc;
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#ifdef TRI_INTERNAL_STATS
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// update statistics
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array->_nrAdds++;
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#endif
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// search the table
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while (array->_table[i] != nullptr && ! array->isEqualElementElement(array, element, array->_table[i])) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesA++;
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#endif
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}
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old = array->_table[i];
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// if we found an element, return
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if (old != nullptr) {
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if (overwrite) {
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array->_table[i] = element;
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}
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return old;
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}
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// add a new element to the associative array
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array->_table[i] = element;
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array->_nrUsed++;
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// if we were adding and the table is more than half full, extend it
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if (array->_nrAlloc < 2 * array->_nrUsed) {
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ResizeAssociativePointer(array, (uint32_t) (2 * array->_nrAlloc) + 1);
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}
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return nullptr;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief adds an key/element to the array
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////////////////////////////////////////////////////////////////////////////////
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void* TRI_InsertKeyAssociativePointer (TRI_associative_pointer_t* array,
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void const* key,
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void* element,
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bool overwrite) {
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uint64_t hash;
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uint64_t i;
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void* old;
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// check for out-of-memory
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if (array->_nrAlloc == array->_nrUsed) {
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TRI_set_errno(TRI_ERROR_OUT_OF_MEMORY);
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return nullptr;
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}
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// compute the hash
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hash = array->hashKey(array, key);
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i = hash % array->_nrAlloc;
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#ifdef TRI_INTERNAL_STATS
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// update statistics
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array->_nrAdds++;
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#endif
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// search the table
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while (array->_table[i] != nullptr && ! array->isEqualKeyElement(array, key, array->_table[i])) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesA++;
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#endif
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}
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old = array->_table[i];
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// if we found an element, return
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if (old != nullptr) {
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if (overwrite) {
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array->_table[i] = element;
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}
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return old;
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}
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// add a new element to the associative array
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array->_table[i] = element;
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array->_nrUsed++;
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// if we were adding and the table is more than half full, extend it
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if (array->_nrAlloc < 2 * array->_nrUsed) {
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ResizeAssociativePointer(array, (uint32_t) (2 * array->_nrAlloc) + 1);
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}
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return nullptr;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief adds an key/element to the array
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/// returns a status code, and *found will contain the found element (if any)
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////////////////////////////////////////////////////////////////////////////////
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int TRI_InsertKeyAssociativePointer2 (TRI_associative_pointer_t* array,
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void const* key,
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void* element,
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void const** found) {
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uint64_t hash;
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uint64_t i;
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void* old;
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if (found != nullptr) {
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*found = nullptr;
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}
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// check for out-of-memory
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if (array->_nrAlloc == array->_nrUsed) {
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return TRI_ERROR_OUT_OF_MEMORY;
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}
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// compute the hash
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hash = array->hashKey(array, key);
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i = hash % array->_nrAlloc;
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#ifdef TRI_INTERNAL_STATS
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// update statistics
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array->_nrAdds++;
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#endif
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// search the table
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while (array->_table[i] != nullptr && ! array->isEqualKeyElement(array, key, array->_table[i])) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesA++;
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#endif
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}
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old = array->_table[i];
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// if we found an element, return
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if (old != nullptr) {
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if (found != nullptr) {
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*found = old;
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}
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return TRI_ERROR_NO_ERROR;
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}
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// if we were adding and the table is more than half full, extend it
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if (array->_nrAlloc < 2 * array->_nrUsed) {
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if (! ResizeAssociativePointer(array, (uint32_t) (2 * array->_nrAlloc) + 1)) {
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return TRI_ERROR_OUT_OF_MEMORY;
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}
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// now we need to recalc the position
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i = hash % array->_nrAlloc;
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// search the table
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while (array->_table[i] != nullptr && ! array->isEqualKeyElement(array, key, array->_table[i])) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesA++;
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#endif
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}
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}
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// add a new element to the associative array
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array->_table[i] = element;
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array->_nrUsed++;
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return TRI_ERROR_NO_ERROR;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief removes an key/element to the array
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////////////////////////////////////////////////////////////////////////////////
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void* TRI_RemoveKeyAssociativePointer (TRI_associative_pointer_t* array,
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void const* key) {
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uint64_t hash;
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uint64_t i;
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uint64_t k;
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void* old;
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hash = array->hashKey(array, key);
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i = hash % array->_nrAlloc;
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#ifdef TRI_INTERNAL_STATS
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// update statistics
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array->_nrRems++;
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#endif
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// search the table
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while (array->_table[i] != nullptr && ! array->isEqualKeyElement(array, key, array->_table[i])) {
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i = TRI_IncModU64(i, array->_nrAlloc);
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#ifdef TRI_INTERNAL_STATS
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array->_nrProbesD++;
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#endif
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}
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// if we did not find such an item return false
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if (array->_table[i] == nullptr) {
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return nullptr;
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}
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// remove item
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old = array->_table[i];
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array->_table[i] = nullptr;
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array->_nrUsed--;
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// and now check the following places for items to move here
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k = TRI_IncModU64(i, array->_nrAlloc);
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while (array->_table[k] != nullptr) {
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uint64_t j = array->hashElement(array, array->_table[k]) % array->_nrAlloc;
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if ((i < k && !(i < j && j <= k)) || (k < i && !(i < j || j <= k))) {
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array->_table[i] = array->_table[k];
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array->_table[k] = nullptr;
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i = k;
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}
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k = TRI_IncModU64(k, array->_nrAlloc);
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}
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// return success
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return old;
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- END-OF-FILE
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// -----------------------------------------------------------------------------
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// Local Variables:
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// mode: outline-minor
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// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}"
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// End:
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