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 26 ///The btBlock class is an internal structure for the btStackAlloc memory allocator. 27 struct btBlock 28 { 29 btBlock* previous; 30 unsigned char* address; 31 }; 32 33 ///The StackAlloc class provides some fast stack-based memory allocator (LIFO last-in first-out) 34 class btStackAlloc 35 { 36 public: 37 btStackAlloc(unsigned int size)38 btStackAlloc(unsigned int size) { ctor();create(size); } ~btStackAlloc()39 ~btStackAlloc() { destroy(); } 40 create(unsigned int size)41 inline void create(unsigned int size) 42 { 43 destroy(); 44 data = (unsigned char*) btAlignedAlloc(size,16); 45 totalsize = size; 46 } destroy()47 inline void destroy() 48 { 49 btAssert(usedsize==0); 50 //Raise(L"StackAlloc is still in use"); 51 52 if(usedsize==0) 53 { 54 if(!ischild && data) 55 btAlignedFree(data); 56 57 data = 0; 58 usedsize = 0; 59 } 60 61 } 62 getAvailableMemory()63 int getAvailableMemory() const 64 { 65 return static_cast<int>(totalsize - usedsize); 66 } 67 allocate(unsigned int size)68 unsigned char* allocate(unsigned int size) 69 { 70 const unsigned int nus(usedsize+size); 71 if(nus<totalsize) 72 { 73 usedsize=nus; 74 return(data+(usedsize-size)); 75 } 76 btAssert(0); 77 //&& (L"Not enough memory")); 78 79 return(0); 80 } beginBlock()81 SIMD_FORCE_INLINE btBlock* beginBlock() 82 { 83 btBlock* pb = (btBlock*)allocate(sizeof(btBlock)); 84 pb->previous = current; 85 pb->address = data+usedsize; 86 current = pb; 87 return(pb); 88 } endBlock(btBlock * block)89 SIMD_FORCE_INLINE void endBlock(btBlock* block) 90 { 91 btAssert(block==current); 92 //Raise(L"Unmatched blocks"); 93 if(block==current) 94 { 95 current = block->previous; 96 usedsize = (unsigned int)((block->address-data)-sizeof(btBlock)); 97 } 98 } 99 100 private: ctor()101 void ctor() 102 { 103 data = 0; 104 totalsize = 0; 105 usedsize = 0; 106 current = 0; 107 ischild = false; 108 } 109 unsigned char* data; 110 unsigned int totalsize; 111 unsigned int usedsize; 112 btBlock* current; 113 bool ischild; 114 }; 115 116 #endif //BT_STACK_ALLOC 117