/*

 * Copyright (C) 2012 David Anderson

 *

 * This file is part of JITCraft.

 *

 * JITCraft is free software: you can redistribute it and/or modify it under

 * the terms of the GNU General Public License as published by the Free

 * Software Foundation, either version 3 of the License, or (at your option)

 * any later version.

 * 

 * Foobar 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 for more details.

 *

 * You should have received a copy of the GNU General Public License along with

 * JITCraft. If not, see http://www.gnu.org/licenses/.

 */

#ifndef _include_jitcraft_platform_h_

#define _include_jitcraft_platform_h_

#include "Utility.h"

namespace jc {

namespace OS {

    enum Protection {

        Prot_ReadWrite,         // rw-, for the heap

        Prot_ReadExecute,       // r-x, for code

        Prot_ReadWriteExecute   // rwx, if disabling r-x for code.

    };

    enum MapMode {

        Map_Reserve,            // don't ask for actual pages yet

        Map_Commit              // ask for pages right away

    };

    Address MapMemory(size_t amount, MapMode mode, Protection prot);

    bool CommitMemory(Address address, size_t amount, Protection prot);

    void UnmapMemory(Address address, size_t size);

    class AlignableMapping {

        Address base_;

        Address aligned_;

        size_t size_;

      public:

        AlignableMapping(Address ptr, size_t alignment, size_t size)

          : base_(ptr),

            size_(size)

        {

            aligned_ = base_;

            if (!IsAligned(aligned_, alignment))

                aligned_ = AlignedBase(aligned_, alignment) + alignment;

        }

        AlignableMapping() : base_(NULL), aligned_(NULL), size_(0)

        {

        }

        Address base() const {

            return base_;

        }

        bool isValid() const {

            return !!base_;

        }

        size_t size() const {

            return size_;

        }

        Address aligned() const {

            return aligned_;

        }

    };

    AlignableMapping MapAlignedMemory(size_t amount, size_t alignment, MapMode mode);

    void UnmapAlignedMemory(Address address, size_t size);

    // The default alignment of memory returned via MapMemory().

    // :TODO: better ifdefs

#ifdef _MSC_VER

    static const size_t kMapAlignment = 64 * kKB;

#else

    static const size_t kMapAlignment = 4 * kKB;

#endif

    // Internal OS:: use only.

    Address MapMemoryAt(Address address, size_t amount, MapMode mode, Protection prot);

    AlignableMapping Shared_MapAlignableMemory(size_t amount, size_t alignment, MapMode mode);

}

}

#endif // _include_jitcraft_platform_h_