Engine/lib/bullet/src/LinearMath/btPoolAllocator.h

   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 #include "btThreads.h"
  22
  23 ///The btPoolAllocator class allows to efficiently allocate a large pool of objects, instead of dynamically allocating them separately.
  24 class btPoolAllocator
  25 {
  26         int                             m_elemSize;
  27         int                             m_maxElements;
  28         int                             m_freeCount;
  29         void*                   m_firstFree;
  30         unsigned char*  m_pool;
  31     btSpinMutex     m_mutex;  // only used if BT_THREADSAFE
  32
  33 public:
  34
  35         btPoolAllocator(int elemSize, int maxElements)
  36                 :m_elemSize(elemSize),
  37                 m_maxElements(maxElements)
  38         {
  39                 m_pool = (unsigned char*) btAlignedAlloc( static_cast<unsigned int>(m_elemSize*m_maxElements),16);
  40
  41                 unsigned char* p = m_pool;
  42         m_firstFree = p;
  43         m_freeCount = m_maxElements;
  44         int count = m_maxElements;
  45         while (--count) {
  46             *(void**)p = (p + m_elemSize);
  47             p += m_elemSize;
  48         }
  49         *(void**)p = 0;
  50     }
  51
  52         ~btPoolAllocator()
  53         {
  54                 btAlignedFree( m_pool);
  55         }
  56
  57         int     getFreeCount() const
  58         {
  59                 return m_freeCount;
  60         }
  61
  62         int getUsedCount() const
  63         {
  64                 return m_maxElements - m_freeCount;
  65         }
  66
  67         int getMaxCount() const
  68         {
  69                 return m_maxElements;
  70         }
  71
  72         void*   allocate(int size)
  73         {
  74                 // release mode fix
  75                 (void)size;
  76         btMutexLock(&m_mutex);
  77                 btAssert(!size || size<=m_elemSize);
  78                 //btAssert(m_freeCount>0);  // should return null if all full
  79         void* result = m_firstFree;
  80         if (NULL != m_firstFree)
  81         {
  82             m_firstFree = *(void**)m_firstFree;
  83             --m_freeCount;
  84         }
  85         btMutexUnlock(&m_mutex);
  86         return result;
  87         }
  88
  89         bool validPtr(void* ptr)
  90         {
  91                 if (ptr) {
  92                         if (((unsigned char*)ptr >= m_pool && (unsigned char*)ptr < m_pool + m_maxElements * m_elemSize))
  93                         {
  94                                 return true;
  95                         }
  96                 }
  97                 return false;
  98         }
  99
 100         void    freeMemory(void* ptr)
 101         {
 102                  if (ptr) {
 103             btAssert((unsigned char*)ptr >= m_pool && (unsigned char*)ptr < m_pool + m_maxElements * m_elemSize);
 104
 105             btMutexLock(&m_mutex);
 106             *(void**)ptr = m_firstFree;
 107             m_firstFree = ptr;
 108             ++m_freeCount;
 109             btMutexUnlock(&m_mutex);
 110         }
 111         }
 112
 113         int     getElementSize() const
 114         {
 115                 return m_elemSize;
 116         }
 117
 118         unsigned char*  getPoolAddress()
 119         {
 120                 return m_pool;
 121         }
 122
 123         const unsigned char*    getPoolAddress() const
 124         {
 125                 return m_pool;
 126         }
 127
 128 };
 129
 130 #endif //_BT_POOL_ALLOCATOR_H