/*
 * 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.
 *
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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP

#include "memory/allocation.hpp"
#include "runtime/virtualspace.hpp"
#include "utilities/globalDefinitions.hpp"

class CardTableModRefBS;
class G1CollectedHeap;
class HeapRegion;

class G1CardCounts: public CHeapObj<mtGC> {
  // Table to track the number of times a card has been refined.
  // Once a card has been refined a certain number of times, it
  // is considered 'hot' and its refinement is delayed by inserting
  // the card into the hot card cache. The card will then be refined
  // when it is evicted from the hot card cache, or when the
  // hot card cache is 'drained' during the next evacuation pause.

  G1CollectedHeap* _g1h;

  // The table of counts
  jbyte* _card_counts;

  // Max capacity of the reserved space for the counts table
  size_t _reserved_max_card_num;

  // Max capacity of the committed space for the counts table
  size_t _committed_max_card_num;

  // Size of committed space for the counts table
  size_t _committed_size;

  // CardTable bottom.
  const jbyte* _ct_bot;

  // Barrier set
  CardTableModRefBS* _ct_bs;

  // The virtual memory backing the counts table
  VirtualSpace _card_counts_storage;

  void check_card_num(size_t card_num, const char* msg) {
    assert(card_num >= 0 && card_num < _committed_max_card_num, msg);
  }

  size_t ptr_2_card_num(jbyte* card_ptr) {
    size_t card_num = (size_t) (card_ptr - _ct_bot);
    check_card_num(card_num,
                   err_msg("card pointer out of range: "PTR_FORMAT, card_ptr));
    return card_num;
  }

  jbyte* card_num_2_ptr(size_t card_num) {
    check_card_num(card_num,
                   err_msg("card num out of range: "SIZE_FORMAT, card_num));
    return (jbyte*) (_ct_bot + card_num);
  }

  // Clear the counts table for the given (exclusive) index range.
  void clear_range(size_t from_card_num, size_t to_card_num);

  // Returns the count of this card after incrementing it.
  int add_card_count(jbyte* card_ptr);
  
 public:
  G1CardCounts(G1CollectedHeap* g1h);
  ~G1CardCounts();

  void initialize();

  // Resize the committed space for the card counts table in
  // response to a resize of the committed space for the heap.
  void resize(size_t heap_capacity);

  // Updates the refinment count for the given card.
  // Returns true if the card is considered 'hot'; false otherwise.
  bool is_hot(jbyte* card_ptr);

  // Clears the card counts for the cards spanned by the region
  void clear_region(HeapRegion* hr);

  // Clear the entire card counts table during GC.
  // Updates the policy stats with the duration.
  void clear_all();
};

#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP