1 /*
2 Copyright (c) 2003-2006 Gino van den Bergen / Erwin Coumans  http://continuousphysics.com/Bullet/
3 
4 This software is provided 'as-is', without any express or implied warranty.
5 In no event will the authors be held liable for any damages arising from the use of this software.
6 Permission is granted to anyone to use this software for any purpose,
7 including commercial applications, and to alter it and redistribute it freely,
8 subject to the following restrictions:
9 
10 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.
11 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
12 3. This notice may not be removed or altered from any source distribution.
13 */
14 
15 
16 #ifndef _BT_POOL_ALLOCATOR_H
17 #define _BT_POOL_ALLOCATOR_H
18 
19 #include "btScalar.h"
20 #include "btAlignedAllocator.h"
21 
22 ///The btPoolAllocator class allows to efficiently allocate a large pool of objects, instead of dynamically allocating them separately.
23 class btPoolAllocator
24 {
25 	int				m_elemSize;
26 	int				m_maxElements;
27 	int				m_freeCount;
28 	void*			m_firstFree;
29 	unsigned char*	m_pool;
30 
31 public:
32 
btPoolAllocator(int elemSize,int maxElements)33 	btPoolAllocator(int elemSize, int maxElements)
34 		:m_elemSize(elemSize),
35 		m_maxElements(maxElements)
36 	{
37 		m_pool = (unsigned char*) btAlignedAlloc( static_cast<unsigned int>(m_elemSize*m_maxElements),16);
38 
39 		unsigned char* p = m_pool;
40         m_firstFree = p;
41         m_freeCount = m_maxElements;
42         int count = m_maxElements;
43         while (--count) {
44             *(void**)p = (p + m_elemSize);
45             p += m_elemSize;
46         }
47         *(void**)p = 0;
48     }
49 
~btPoolAllocator()50 	~btPoolAllocator()
51 	{
52 		btAlignedFree( m_pool);
53 	}
54 
getFreeCount()55 	int	getFreeCount() const
56 	{
57 		return m_freeCount;
58 	}
59 
getUsedCount()60 	int getUsedCount() const
61 	{
62 		return m_maxElements - m_freeCount;
63 	}
64 
getMaxCount()65 	int getMaxCount() const
66 	{
67 		return m_maxElements;
68 	}
69 
allocate(int size)70 	void*	allocate(int size)
71 	{
72 		// release mode fix
73 		(void)size;
74 		btAssert(!size || size<=m_elemSize);
75 		btAssert(m_freeCount>0);
76         void* result = m_firstFree;
77         m_firstFree = *(void**)m_firstFree;
78         --m_freeCount;
79         return result;
80 	}
81 
validPtr(void * ptr)82 	bool validPtr(void* ptr)
83 	{
84 		if (ptr) {
85 			if (((unsigned char*)ptr >= m_pool && (unsigned char*)ptr < m_pool + m_maxElements * m_elemSize))
86 			{
87 				return true;
88 			}
89 		}
90 		return false;
91 	}
92 
freeMemory(void * ptr)93 	void	freeMemory(void* ptr)
94 	{
95 		 if (ptr) {
96             btAssert((unsigned char*)ptr >= m_pool && (unsigned char*)ptr < m_pool + m_maxElements * m_elemSize);
97 
98             *(void**)ptr = m_firstFree;
99             m_firstFree = ptr;
100             ++m_freeCount;
101         }
102 	}
103 
getElementSize()104 	int	getElementSize() const
105 	{
106 		return m_elemSize;
107 	}
108 
getPoolAddress()109 	unsigned char*	getPoolAddress()
110 	{
111 		return m_pool;
112 	}
113 
getPoolAddress()114 	const unsigned char*	getPoolAddress() const
115 	{
116 		return m_pool;
117 	}
118 
119 };
120 
121 #endif //_BT_POOL_ALLOCATOR_H
122