/*

 * Copyright (c) 2019, SAP SE. All rights reserved.

 * Copyright (c) 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

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

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 */

#ifndef SHARE_MEMORY_METASPACE_LEFTOVERBINS_INLINE_HPP

#define SHARE_MEMORY_METASPACE_LEFTOVERBINS_INLINE_HPP

#include "memory/allocation.hpp"

#include "memory/metaspace/leftOverBins.hpp"

#include "utilities/debug.hpp"

#include "utilities/globalDefinitions.hpp"

#include "utilities/ostream.hpp"

namespace metaspace {

///////////////////////////////////////

// Take the topmost block from the large block reserve list

// and make it current.

inline void LeftOverManager::prime_current() {

  if (_large_block_reserve != NULL) {

    _current = (MetaWord*) _large_block_reserve;

    _current_size = _large_block_reserve->size;

    _large_block_reserve = _large_block_reserve->next;

  } else {

    _current = NULL;

    _current_size = 0;

  }

}

// Allocate from current block. Returns NULL if current block

// is too small.

inline MetaWord* LeftOverManager::alloc_from_current(size_t word_size) {

  if (_current_size >= word_size) {

    assert(_current != NULL, "Must be");

    MetaWord* p = _current;

    size_t remaining = _current_size - word_size;

    if (remaining >= _very_small_bins.minimal_word_size()) {

      _current = p + word_size;

      _current_size = remaining;

    } else {

      // completely used up old large block. Proceed to next.

      prime_current();

    }

    return p;

  }

  return NULL;

}

inline void LeftOverManager::add_block(MetaWord* p, size_t word_size) {

  if (word_size >= minimal_word_size()) {

    if (word_size < _very_small_bins.maximal_word_size()) {

      _very_small_bins.put(p, word_size);

    } else {

      if (_current == NULL) {

        assert(_large_block_reserve == NULL, "Should be primed.");

        _current = p;

        _current_size = word_size;

      } else {

        assert(sizeof(block_t) <= word_size * BytesPerWord, "must be");

        block_t* b = (block_t*)p;

        b->size = word_size;

        b->next = _large_block_reserve;

        _large_block_reserve = b;

      }

    }

    _total_word_size.increment_by(word_size);

  }

  DEBUG_ONLY(verify();)

}

inline MetaWord* LeftOverManager::get_block(size_t requested_word_size) {

  requested_word_size = MAX2(requested_word_size, minimal_word_size());

  // First attempt to take from current large block because that is cheap (pointer bump)

  // and efficient (no spread)

  MetaWord* p = alloc_from_current(requested_word_size);

  if (p == NULL && _current_size > 0) {

    // current large block is too small. If it is moth-eaten enough to be put

    // into the small remains bin, do so.

    if (_current_size < _very_small_bins.maximal_word_size()) {

      _very_small_bins.put(_current, _current_size);

      prime_current(); // proceed to next large block.

      // --- and re-attempt - but only once more. If that fails too, we give up.

      p = alloc_from_current(requested_word_size);

    }

  }

  if (p == NULL) {

    // Did not work. Check the small bins.

    if (requested_word_size < _very_small_bins.maximal_word_size()) {

      block_t* b = _very_small_bins.get(requested_word_size);

      if (b != NULL) {

        p = (MetaWord*)b;

        size_t remaining = b->size - requested_word_size;

        if (remaining >= _very_small_bins.minimal_word_size()) {

          MetaWord* q = p + requested_word_size;

          _very_small_bins.put(q, remaining);

        }

      }

    }

  }

  if (p != NULL) {

    _total_word_size.decrement_by(requested_word_size);

    DEBUG_ONLY(verify();)

  }

  return p;

}

} // namespace metaspace

#endif // SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP