/*

 * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#ifndef SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP

#define SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP

#include "memory/allocation.hpp"

#include "memory/binaryTreeDictionary.hpp"

#include "memory/freeList.hpp"

#include "memory/metaspace/smallBlocks.hpp"

#include "memory/metaspace/metablock.hpp"

#include "utilities/globalDefinitions.hpp"

namespace metaspace {

typedef BinaryTreeDictionary<Metablock, FreeList<Metablock> > BlockTreeDictionary;

// Used to manage the free list of Metablocks (a block corresponds

// to the allocation of a quantum of metadata).

class BlockFreelist : public CHeapObj<mtClass> {

  BlockTreeDictionary* const _dictionary;

  SmallBlocks* _small_blocks;

  // Only allocate and split from freelist if the size of the allocation

  // is at least 1/4th the size of the available block.

  const static int WasteMultiplier = 4;

  // Accessors

  BlockTreeDictionary* dictionary() const { return _dictionary; }

  SmallBlocks* small_blocks() {

    if (_small_blocks == NULL) {

      _small_blocks = new SmallBlocks();

    }

    return _small_blocks;

  }

 public:

  BlockFreelist();

  ~BlockFreelist();

  // Get and return a block to the free list

  MetaWord* get_block(size_t word_size);

  void return_block(MetaWord* p, size_t word_size);

  // Returns the total size, in words, of all blocks kept in this structure.

  size_t total_size() const  {

    size_t result = dictionary()->total_size();

    if (_small_blocks != NULL) {

      result = result + _small_blocks->total_size();

    }

    return result;

  }

  // Returns the number of all blocks kept in this structure.

  uintx num_blocks() const {

    uintx result = dictionary()->total_free_blocks();

    if (_small_blocks != NULL) {

      result = result + _small_blocks->total_num_blocks();

    }

    return result;

  }

  static size_t min_dictionary_size()   { return TreeChunk<Metablock, FreeList<Metablock> >::min_size(); }

  void print_on(outputStream* st) const;

};

} // namespace metaspace

#endif // SHARE_MEMORY_METASPACE_BLOCKFREELIST_HPP