/*

 * Copyright (c) 2017, 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.

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#ifndef SHARE_JFR_RECORDER_STORAGE_JFRVIRTUALMEMORY_HPP

#define SHARE_JFR_RECORDER_STORAGE_JFRVIRTUALMEMORY_HPP

#include "jfr/utilities/jfrAllocation.hpp"

class JfrVirtualMemoryManager;

class JfrVirtualMemory : public JfrCHeapObj {

 private:

  JfrVirtualMemoryManager* _vmm;

  const u1* _reserved_low; // lowest address of reservation

  const u1* _reserved_high; // highest address of reservation

  u1* _top; // current allocation address

  const u1* _commit_point; // synch points for committing new memory

  size_t _physical_commit_size_request_words; // aligned to os::vm_allocation_granularity()

  size_t _aligned_datum_size_bytes; // datum alignment

  bool commit_memory_block();

  void* commit(size_t block_size_request_words);

  void* index_ptr(size_t index); // index to address map

 public:

  JfrVirtualMemory();

  ~JfrVirtualMemory();

  // initialization will do the reservation and return it

  void* initialize(size_t reservation_size_request_bytes, size_t block_size_request_bytes, size_t datum_size_bytes = 1);

  void* new_datum(); // datum oriented allocation

  void* get(size_t index); // direct access retrieval

  size_t aligned_datum_size_bytes() const;

  bool is_full() const; // limit of reservation committed and in use

  bool is_empty() const;

  size_t count() const; // how many

  size_t live_set() const; // how much resident memory (actually in use)

  size_t reserved_size() const; // size of reservation

  bool compact(size_t index);

};

#endif // SHARE_JFR_RECORDER_STORAGE_JFRVIRTUALMEMORY_HPP