axmol/thirdparty/box2d-optimized/include/box2d/b2_free_list.h

114 lines
3.2 KiB
C++

/*
* Copyright (c) 2014 Google, Inc.
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#ifndef B2_FREE_LIST_H
#define B2_FREE_LIST_H
#include "b2_intrusive_list.h"
#include "b2_settings.h"
/// When B2_FREE_LIST_CHECK_ALLOCATED_ON_FREE is 1, b2FreeList::Free() will
/// check that the deallocated node was allocated from the freelist.
#ifndef B2_FREE_LIST_CHECK_ALLOCATED_ON_FREE
#define B2_FREE_LIST_CHECK_ALLOCATED_ON_FREE 0
#endif // B2_FREE_LIST_CHECK_ALLOCATED_ON_FREE
/// Fast - O(1) - list based allocator for items that can be inserted into
/// b2IntrusiveListNode lists.
class b2FreeList
{
public:
/// Construct the free list.
b2FreeList() { }
/// Destroy the free list.
~b2FreeList() { }
/// Allocate an item from the freelist.
b2IntrusiveListNode* Allocate();
/// Free an item from the freelist.
void Free(b2IntrusiveListNode* node);
/// Add an item to the freelist so that it can be allocated using
/// b2FreeList::Allocate().
void AddToFreeList(b2IntrusiveListNode* node);
/// Remove all items (allocated and free) from the freelist.
void RemoveAll();
/// Get the list which tracks allocated items.
const b2IntrusiveListNode& GetAllocatedList() const {
return m_allocated;
}
/// Get the list which tracks free items.
const b2IntrusiveListNode& GetFreeList() const {
return m_free;
}
protected:
/// List of allocated items.
b2IntrusiveListNode m_allocated;
/// List of free items.
b2IntrusiveListNode m_free;
};
/// Typed b2FreeList which manages items of type T assuming T implements
/// the GetInstanceFromListNode() and GetListNode() methods.
template<typename T>
class b2TypedFreeList {
public:
/// Construct the free list.
b2TypedFreeList() { }
/// Destroy the free list.
~b2TypedFreeList() { }
/// Allocate an item from the free list.
T* Allocate() {
b2IntrusiveListNode* const node = m_freeList.Allocate();
if (!node) return NULL;
return T::GetInstanceFromListNode(node);
}
/// Free an item.
void Free(T* instance) {
b2Assert(instance);
m_freeList.Free(instance->GetListNode());
}
/// Add an item to the freelist so that it can be allocated with
/// b2TypedFreeList::Allocate().
void AddToFreeList(T* instance)
{
b2Assert(instance);
m_freeList.AddToFreeList(instance->GetListNode());
}
// Get the underlying b2FreeList.
b2FreeList* GetFreeList() { return &m_freeList; }
const b2FreeList* GetFreeList() const { return &m_freeList; }
protected:
b2FreeList m_freeList;
};
#endif // B2_FREE_LIST_H