////////////////////////////////////////////////////////////////////////////////
/// @brief Aql, item block manager
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2012-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

#include "AqlItemBlockManager.h"
#include "Aql/AqlItemBlock.h"

using namespace triagens::aql;

// -----------------------------------------------------------------------------
// --SECTION--                                        constructors / destructors
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief create the manager
////////////////////////////////////////////////////////////////////////////////

AqlItemBlockManager::AqlItemBlockManager ()
  : _last(nullptr) {

}

////////////////////////////////////////////////////////////////////////////////
/// @brief destroy the manager
////////////////////////////////////////////////////////////////////////////////

AqlItemBlockManager::~AqlItemBlockManager () {
  delete _last;
}

// -----------------------------------------------------------------------------
// --SECTION--                                                    public methods
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief request a block with the specified size
////////////////////////////////////////////////////////////////////////////////

AqlItemBlock* AqlItemBlockManager::requestBlock (size_t nrItems, 
                                                 RegisterId nrRegs) {
  if (_last != nullptr &&
      _last->size() == nrItems &&
      _last->getNrRegs() == nrRegs) {
    auto block = _last;
    _last = nullptr;
    return block;
  }

  return new AqlItemBlock(nrItems, nrRegs);
}

////////////////////////////////////////////////////////////////////////////////
/// @brief return a block to the manager
////////////////////////////////////////////////////////////////////////////////

void AqlItemBlockManager::returnBlock (AqlItemBlock*& block) {
  TRI_ASSERT(block != nullptr);
  block->destroy();

  delete _last;
  _last = block;
  block = nullptr;
}

// -----------------------------------------------------------------------------
// --SECTION--                                                       END-OF-FILE
// -----------------------------------------------------------------------------

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