/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file memoryHook.h
 * @author drose
 * @date 2007-06-28
 */

#ifndef MEMORYHOOK_H
#define MEMORYHOOK_H

#include "dtoolbase.h"
#include "numeric_types.h"
#include "atomicAdjust.h"
#include "mutexImpl.h"
#include <map>

#ifdef LINMATH_ALIGN
// We require 16-byte alignment of certain structures, to support SSE2.  We
// don't strictly have to align *everything*, but it's just easier to do so.
#ifdef __AVX__
#define MEMORY_HOOK_ALIGNMENT 32
#else
#define MEMORY_HOOK_ALIGNMENT 16
#endif
// Otherwise, align to two words.  This seems to be pretty standard to the
// point where some code may rely on this being the case.
#elif defined(IS_OSX) || NATIVE_WORDSIZE >= 64
#define MEMORY_HOOK_ALIGNMENT 16
#else
#define MEMORY_HOOK_ALIGNMENT 8
#endif

class DeletedBufferChain;

/**
 * This class provides a wrapper around the various possible malloc schemes
 * Panda might employ.  It also exists to allow the MemoryUsage class in Panda
 * to insert callback hooks to track the size of allocated pointers.
 *
 * The PANDA_MALLOC_* and PANDA_FREE_* macros are defined to vector through
 * through this class (except in production builds) to facilitate that.  Every
 * memory allocation call in Panda should therefore use these macros instead
 * of direct calls to malloc or free.  (C++ new and delete operators may be
 * employed for classes which inherit from MemoryBase; otherwise, use the
 * PANDA_MALLOC macros.)
 */
class EXPCL_DTOOL MemoryHook {
public:
  MemoryHook();
  MemoryHook(const MemoryHook &copy);
  virtual ~MemoryHook();

  virtual void *heap_alloc_single(size_t size);
  virtual void heap_free_single(void *ptr);

  virtual void *heap_alloc_array(size_t size);
  virtual void *heap_realloc_array(void *ptr, size_t size);
  virtual void heap_free_array(void *ptr);

  INLINE void inc_heap(size_t size);
  INLINE void dec_heap(size_t size);

  bool heap_trim(size_t pad);

  CONSTEXPR static size_t get_memory_alignment();

  virtual void *mmap_alloc(size_t size, bool allow_exec);
  virtual void mmap_free(void *ptr, size_t size);
  INLINE size_t get_page_size() const;
  INLINE size_t round_up_to_page_size(size_t size) const;

  virtual void mark_pointer(void *ptr, size_t orig_size, ReferenceCount *ref_ptr);

  DeletedBufferChain *get_deleted_chain(size_t buffer_size);

  virtual void alloc_fail(size_t attempted_size);

  INLINE static size_t get_ptr_size(void *ptr);

private:
  INLINE static size_t inflate_size(size_t size);
  INLINE static void *alloc_to_ptr(void *alloc, size_t size);
  INLINE static void *ptr_to_alloc(void *ptr, size_t &size);

#ifdef DO_MEMORY_USAGE
protected:
  TVOLATILE AtomicAdjust::Integer _total_heap_single_size;
  TVOLATILE AtomicAdjust::Integer _total_heap_array_size;
  TVOLATILE AtomicAdjust::Integer _requested_heap_size;
  TVOLATILE AtomicAdjust::Integer _total_mmap_size;

  // If the allocated heap size crosses this threshold, we call
  // overflow_heap_size().
  size_t _max_heap_size;

  virtual void overflow_heap_size();
#endif  // DO_MEMORY_USAGE

private:
  size_t _page_size;

  typedef map<size_t, DeletedBufferChain *> DeletedChains;
  DeletedChains _deleted_chains;

  MutexImpl _lock;
};

#include "memoryHook.I"

#endif