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 /*

  * Copyright (c) 2003, 2010, 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_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSVIRTUALSPACE_HPP

 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSVIRTUALSPACE_HPP

 #include "runtime/virtualspace.hpp"

 // VirtualSpace for the parallel scavenge collector.

 //

 // VirtualSpace is data structure for committing a previously reserved address

 // range in smaller chunks.

 class PSVirtualSpace : public CHeapObj {

   friend class VMStructs;

  protected:

   // The space is committed/uncommited in chunks of size _alignment.  The

   // ReservedSpace passed to initialize() must be aligned to this value.

   const size_t _alignment;

   // Reserved area

   char* _reserved_low_addr;

   char* _reserved_high_addr;

   // Committed area

   char* _committed_low_addr;

   char* _committed_high_addr;

   // The entire space has been committed and pinned in memory, no

   // os::commit_memory() or os::uncommit_memory().

   bool _special;

   // Convenience wrapper.

   inline static size_t pointer_delta(const char* left, const char* right);

  public:

   PSVirtualSpace(ReservedSpace rs, size_t alignment);

   PSVirtualSpace(ReservedSpace rs);

   ~PSVirtualSpace();

   // Eventually all instances should be created with the above 1- or 2-arg

   // constructors.  Then the 1st constructor below should become protected and

   // the 2nd ctor and initialize() removed.

   PSVirtualSpace(size_t alignment): _alignment(alignment) { }

   PSVirtualSpace();

   bool initialize(ReservedSpace rs, size_t commit_size);

   bool contains(void* p)      const;

   // Accessors (all sizes are bytes).

   size_t alignment()          const { return _alignment; }

   char* reserved_low_addr()   const { return _reserved_low_addr; }

   char* reserved_high_addr()  const { return _reserved_high_addr; }

   char* committed_low_addr()  const { return _committed_low_addr; }

   char* committed_high_addr() const { return _committed_high_addr; }

   bool  special()             const { return _special; }

   inline size_t committed_size()   const;

   inline size_t reserved_size()    const;

   inline size_t uncommitted_size() const;

   // Operations.

   inline  void   set_reserved(char* low_addr, char* high_addr, bool special);

   inline  void   set_reserved(ReservedSpace rs);

   inline  void   set_committed(char* low_addr, char* high_addr);

   virtual bool   expand_by(size_t bytes);

   virtual bool   shrink_by(size_t bytes);

   virtual size_t expand_into(PSVirtualSpace* space, size_t bytes);

   void           release();

 #ifndef PRODUCT

   // Debugging

   static  bool is_aligned(size_t val, size_t align);

           bool is_aligned(size_t val) const;

           bool is_aligned(char* val) const;

           void verify() const;

           void print() const;

   virtual bool grows_up() const   { return true; }

           bool grows_down() const { return !grows_up(); }

   // Helper class to verify a space when entering/leaving a block.

   class PSVirtualSpaceVerifier: public StackObj {

    private:

     const PSVirtualSpace* const _space;

    public:

     PSVirtualSpaceVerifier(PSVirtualSpace* space): _space(space) {

       _space->verify();

     }

     ~PSVirtualSpaceVerifier() { _space->verify(); }

   };

 #endif

   virtual void print_space_boundaries_on(outputStream* st) const;

  // Included for compatibility with the original VirtualSpace.

  public:

   // Committed area

   char* low()  const { return committed_low_addr(); }

   char* high() const { return committed_high_addr(); }

   // Reserved area

   char* low_boundary()  const { return reserved_low_addr(); }

   char* high_boundary() const { return reserved_high_addr(); }

 };

 // A virtual space that grows from high addresses to low addresses.

 class PSVirtualSpaceHighToLow : public PSVirtualSpace {

   friend class VMStructs;

  public:

   PSVirtualSpaceHighToLow(ReservedSpace rs, size_t alignment);

   PSVirtualSpaceHighToLow(ReservedSpace rs);

   virtual bool   expand_by(size_t bytes);

   virtual bool   shrink_by(size_t bytes);

   virtual size_t expand_into(PSVirtualSpace* space, size_t bytes);

   virtual void print_space_boundaries_on(outputStream* st) const;

 #ifndef PRODUCT

   // Debugging

   virtual bool grows_up() const   { return false; }

 #endif

 };

 //

 // PSVirtualSpace inlines.

 //

 inline size_t

 PSVirtualSpace::pointer_delta(const char* left, const char* right) {

   return ::pointer_delta((void *)left, (void*)right, sizeof(char));

 }

 inline size_t PSVirtualSpace::committed_size() const {

   return pointer_delta(committed_high_addr(), committed_low_addr());

 }

 inline size_t PSVirtualSpace::reserved_size() const {

   return pointer_delta(reserved_high_addr(), reserved_low_addr());

 }

 inline size_t PSVirtualSpace::uncommitted_size() const {

   return reserved_size() - committed_size();

 }

 inline void PSVirtualSpace::set_reserved(char* low_addr, char* high_addr, bool special) {

   _reserved_low_addr = low_addr;

   _reserved_high_addr = high_addr;

   _special = special;

 }

 inline void PSVirtualSpace::set_reserved(ReservedSpace rs) {

   set_reserved(rs.base(), rs.base() + rs.size(), rs.special());

 }

 inline void PSVirtualSpace::set_committed(char* low_addr, char* high_addr) {

   _committed_low_addr = low_addr;

   _committed_high_addr = high_addr;

 }

 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSVIRTUALSPACE_HPP