/*

 * Copyright (c) 2015, 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_VM_GC_G1_YOUNGLIST_HPP

#define SHARE_VM_GC_G1_YOUNGLIST_HPP

#include "memory/allocation.hpp"

#include "runtime/globals.hpp"

class YoungList : public CHeapObj<mtGC> {

private:

  G1CollectedHeap* _g1h;

  HeapRegion* _head;

  uint        _length;

  void         empty_list(HeapRegion* list);

public:

  YoungList(G1CollectedHeap* g1h);

  void         push_region(HeapRegion* hr);

  void         add_survivor_region(HeapRegion* hr);

  void         empty_list();

  bool         is_empty() { return _length == 0; }

  uint         length() { return _length; }

  uint         eden_length() { return length() - survivor_length(); }

  // Currently we do not keep track of the used byte sum for the

  // young list and the survivors and it'd be quite a lot of work to

  // do so. When we'll eventually replace the young list with

  // instances of HeapRegionLinkedList we'll get that for free. So,

  // we'll report the more accurate information then.

  size_t       eden_used_bytes() {

    assert(length() >= survivor_length(), "invariant");

    return (size_t) eden_length() * HeapRegion::GrainBytes;

  }

  size_t       survivor_used_bytes() {

    return (size_t) survivor_length() * HeapRegion::GrainBytes;

  }

  // for development purposes

  void reset_auxilary_lists();

  void clear() { _head = NULL; _length = 0; }

  void clear_survivors() {

  }

  HeapRegion* first_region() { return _head; }

  // debugging

  bool          check_list_well_formed();

  bool          check_list_empty();

  void          print();

};

#endif // SHARE_VM_GC_G1_YOUNGLIST_HPP