Bullet Collision Detection & Physics Library
btStackAlloc.h
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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 StackAlloc extracted from GJK-EPA collision solver by Nathanael Presson
17 Nov.2006
18 */
19 
20 #ifndef BT_STACK_ALLOC
21 #define BT_STACK_ALLOC
22 
23 #include "btScalar.h" //for btAssert
24 #include "btAlignedAllocator.h"
25 
27 struct btBlock
28 {
30  unsigned char* address;
31 };
32 
35 {
36 public:
37  btStackAlloc(unsigned int size)
38  {
39  ctor();
40  create(size);
41  }
43 
44  inline void create(unsigned int size)
45  {
46  destroy();
47  data = (unsigned char*)btAlignedAlloc(size, 16);
48  totalsize = size;
49  }
50  inline void destroy()
51  {
52  btAssert(usedsize == 0);
53  //Raise(L"StackAlloc is still in use");
54 
55  if (usedsize == 0)
56  {
57  if (!ischild && data)
59 
60  data = 0;
61  usedsize = 0;
62  }
63  }
64 
65  int getAvailableMemory() const
66  {
67  return static_cast<int>(totalsize - usedsize);
68  }
69 
70  unsigned char* allocate(unsigned int size)
71  {
72  const unsigned int nus(usedsize + size);
73  if (nus < totalsize)
74  {
75  usedsize = nus;
76  return (data + (usedsize - size));
77  }
78  btAssert(0);
79  //&& (L"Not enough memory"));
80 
81  return (0);
82  }
84  {
85  btBlock* pb = (btBlock*)allocate(sizeof(btBlock));
86  pb->previous = current;
87  pb->address = data + usedsize;
88  current = pb;
89  return (pb);
90  }
92  {
93  btAssert(block == current);
94  //Raise(L"Unmatched blocks");
95  if (block == current)
96  {
97  current = block->previous;
98  usedsize = (unsigned int)((block->address - data) - sizeof(btBlock));
99  }
100  }
101 
102 private:
103  void ctor()
104  {
105  data = 0;
106  totalsize = 0;
107  usedsize = 0;
108  current = 0;
109  ischild = false;
110  }
111  unsigned char* data;
112  unsigned int totalsize;
113  unsigned int usedsize;
115  bool ischild;
116 };
117 
118 #endif //BT_STACK_ALLOC
btStackAlloc::create
void create(unsigned int size)
Definition: btStackAlloc.h:44
btAlignedFree
#define btAlignedFree(ptr)
Definition: btAlignedAllocator.h:47
btStackAlloc::beginBlock
btBlock * beginBlock()
Definition: btStackAlloc.h:83
btAlignedAlloc
#define btAlignedAlloc(size, alignment)
Definition: btAlignedAllocator.h:46
btBlock::previous
btBlock * previous
Definition: btStackAlloc.h:29
btStackAlloc::getAvailableMemory
int getAvailableMemory() const
Definition: btStackAlloc.h:65
btScalar.h
btStackAlloc::ctor
void ctor()
Definition: btStackAlloc.h:103
btBlock
The btBlock class is an internal structure for the btStackAlloc memory allocator.
Definition: btStackAlloc.h:27
btAssert
#define btAssert(x)
Definition: btScalar.h:153
btBlock::address
unsigned char * address
Definition: btStackAlloc.h:30
btAlignedAllocator.h
btStackAlloc::allocate
unsigned char * allocate(unsigned int size)
Definition: btStackAlloc.h:70
btStackAlloc
The StackAlloc class provides some fast stack-based memory allocator (LIFO last-in first-out)
Definition: btStackAlloc.h:34
btStackAlloc::~btStackAlloc
~btStackAlloc()
Definition: btStackAlloc.h:42
btStackAlloc::current
btBlock * current
Definition: btStackAlloc.h:114
SIMD_FORCE_INLINE
#define SIMD_FORCE_INLINE
Definition: btScalar.h:98
btStackAlloc::totalsize
unsigned int totalsize
Definition: btStackAlloc.h:112
btStackAlloc::btStackAlloc
btStackAlloc(unsigned int size)
Definition: btStackAlloc.h:37
btStackAlloc::destroy
void destroy()
Definition: btStackAlloc.h:50
btStackAlloc::usedsize
unsigned int usedsize
Definition: btStackAlloc.h:113
btStackAlloc::data
unsigned char * data
Definition: btStackAlloc.h:111
btStackAlloc::endBlock
void endBlock(btBlock *block)
Definition: btStackAlloc.h:91
size
static DBVT_INLINE btScalar size(const btDbvtVolume &a)
Definition: btDbvt.cpp:52
btStackAlloc::ischild
bool ischild
Definition: btStackAlloc.h:115