/*

 * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved.

 *

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP

#define SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP

#include "gc/shenandoah/shenandoahHeapRegionSet.hpp"

#include "gc/shenandoah/shenandoahHeap.hpp"

class ShenandoahFreeSet : public CHeapObj<mtGC> {

private:

  ShenandoahHeap* const _heap;

  CHeapBitMap _mutator_free_bitmap;

  CHeapBitMap _collector_free_bitmap;

  size_t _max;

  // Left-most and right-most region indexes. There are no free regions outside

  // of [left-most; right-most] index intervals

  size_t _mutator_leftmost, _mutator_rightmost;

  size_t _collector_leftmost, _collector_rightmost;

  size_t _capacity;

  size_t _used;

  void assert_bounds() const NOT_DEBUG_RETURN;

  void assert_heaplock_owned_by_current_thread() const NOT_DEBUG_RETURN;

  void assert_heaplock_not_owned_by_current_thread() const NOT_DEBUG_RETURN;

  bool is_mutator_free(size_t idx) const;

  bool is_collector_free(size_t idx) const;

  HeapWord* try_allocate_in(ShenandoahHeapRegion* region, ShenandoahAllocRequest& req, bool& in_new_region);

  HeapWord* allocate_single(ShenandoahAllocRequest& req, bool& in_new_region);

  HeapWord* allocate_contiguous(ShenandoahAllocRequest& req);

  void flip_to_gc(ShenandoahHeapRegion* r);

  void recompute_bounds();

  void adjust_bounds();

  bool touches_bounds(size_t num) const;

  void increase_used(size_t amount);

  void clear_internal();

  size_t collector_count() const { return _collector_free_bitmap.count_one_bits(); }

  size_t mutator_count()   const { return _mutator_free_bitmap.count_one_bits();   }

  void try_recycle_trashed(ShenandoahHeapRegion *r);

  bool is_empty_or_trash(ShenandoahHeapRegion *r);

  size_t alloc_capacity(ShenandoahHeapRegion *r);

  bool has_no_alloc_capacity(ShenandoahHeapRegion *r);

public:

  ShenandoahFreeSet(ShenandoahHeap* heap, size_t max_regions);

  void clear();

  void rebuild();

  void recycle_trash();

  void log_status();

  size_t capacity()  const { return _capacity; }

  size_t used()      const { return _used;     }

  size_t available() const {

    assert(_used <= _capacity, "must use less than capacity");

    return _capacity - _used;

  }

  HeapWord* allocate(ShenandoahAllocRequest& req, bool& in_new_region);

  size_t unsafe_peek_free() const;

  void print_on(outputStream* out) const;

};

#endif // SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP