/*

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

// 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;

}