/*

 * Copyright (c) 2003, 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

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#ifndef SHARE_SERVICES_MEMORYUSAGE_HPP

#define SHARE_SERVICES_MEMORYUSAGE_HPP

#include "utilities/globalDefinitions.hpp"

// A memory usage contains the following attributes about memory usage:

//  initSize - represents the initial amount of memory (in bytes) that

//     the Java virtual machine requests from the operating system

//     for memory management.  The Java virtual machine may request

//     additional memory from the operating system later when appropriate.

//     Its value may be undefined.

//  used      - represents the amount of memory currently used (in bytes).

//  committed - represents the amount of memory (in bytes) that is

//     guaranteed to be available for use by the Java virtual machine.

//     The amount of committed memory may change over time (increase

//     or decrease).  It is guaranteed to be greater than or equal

//     to initSize.

//  maxSize   - represents the maximum amount of memory (in bytes)

//     that can be used for memory management. The maximum amount of

//     memory for memory management could be less than the amount of

//     committed memory.  Its value may be undefined.

class MemoryUsage {

private:

  size_t _initSize;

  size_t _used;

  size_t _committed;

  size_t _maxSize;

public:

  // Constructors

  MemoryUsage(size_t i, size_t u, size_t c, size_t m) :

    _initSize(i), _used(u), _committed(c), _maxSize(m) {};

  MemoryUsage() :

    _initSize(0), _used(0), _committed(0), _maxSize(0) {};

  size_t init_size() const { return _initSize; }

  size_t used()      const { return _used; }

  size_t committed() const { return _committed; }

  size_t max_size()  const { return _maxSize; }

  static size_t undefined_size() { return (size_t) -1; }

  inline static jlong convert_to_jlong(size_t val) {

    // In the 64-bit vm, a size_t can overflow a jlong (which is signed).

    jlong ret;

    if (val == undefined_size()) {

      ret = -1L;

    } else {

      NOT_LP64(ret = val;)

      LP64_ONLY(ret = MIN2(val, (size_t)max_jlong);)

    }

    return ret;

  }

  jlong init_size_as_jlong() const { return convert_to_jlong(_initSize); }

  jlong used_as_jlong()      const { return convert_to_jlong(_used); }

  jlong committed_as_jlong() const { return convert_to_jlong(_committed); }

  jlong max_size_as_jlong()  const { return convert_to_jlong(_maxSize); }

};

#endif // SHARE_SERVICES_MEMORYUSAGE_HPP