/*

  * 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_