/*
 * Copyright (c) 2013, 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_IMPLEMENTATION_G1_PRESERVEMARKQUEUE_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_PRESERVEMARKQUEUE_HPP

#include "oops/oopsHierarchy.hpp"

struct G1PreserveMarkQueueEntry {
  oop obj;
  markOop mark;
};

class G1PreserveMarkChunk;

class G1PreserveMarkQueue {
  const size_t _initial_chunk_capacity;
  const size_t _max_chunk_capacity;
  size_t _current_capacity;
  G1PreserveMarkChunk* _current_write_chunk;
  G1PreserveMarkChunk* _current_read_chunk;

 public:
  G1PreserveMarkQueue(size_t initial_chunk_capacity, size_t max_chunk_capacity) :
    _initial_chunk_capacity(initial_chunk_capacity), _max_chunk_capacity(max_chunk_capacity),
    _current_write_chunk(NULL), _current_read_chunk(NULL) {
    assert(_initial_chunk_capacity <= _max_chunk_capacity, "initial must be <= max");
  }

  bool has_data();
  void append(const oop& obj, const markOop& mark);
  G1PreserveMarkQueueEntry remove_first();

  size_t new_chunk_capacity() {
    if (_current_write_chunk == NULL) {
      _current_capacity = _initial_chunk_capacity;
    } else if (_current_capacity == _max_chunk_capacity) {
      // do nothing. already at max capacity
    } else {
      // Grow with 50%, similar to java.util.ArrayList
      _current_capacity += _current_capacity >> 1;
      _current_capacity = MIN2(_current_capacity, _max_chunk_capacity);
    }

    assert(_current_capacity >= _initial_chunk_capacity, "too small capacity");
    assert(_current_capacity <= _max_chunk_capacity, "too large capacity");

    return _current_capacity;
  }

  NOT_PRODUCT(void verify_empty());
};

NOT_PRODUCT(void g1PreserveMarkChunkTests());
NOT_PRODUCT(void g1PreserveMarkQueueTests());

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_PRESERVEMARKQUEUE_HPP