117 lines
2.8 KiB
C++
117 lines
2.8 KiB
C++
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/*
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Copyright (c) 2003-2013 Gino van den Bergen / Erwin Coumans http://bulletphysics.org
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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/*
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StackAlloc extracted from GJK-EPA collision solver by Nathanael Presson
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Nov.2006
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*/
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#ifndef B3_STACK_ALLOC
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#define B3_STACK_ALLOC
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#include "b3Scalar.h" //for b3Assert
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#include "b3AlignedAllocator.h"
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///The b3Block class is an internal structure for the b3StackAlloc memory allocator.
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struct b3Block
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{
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b3Block* previous;
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unsigned char* address;
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};
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///The StackAlloc class provides some fast stack-based memory allocator (LIFO last-in first-out)
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class b3StackAlloc
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{
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public:
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b3StackAlloc(unsigned int size) { ctor();create(size); }
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~b3StackAlloc() { destroy(); }
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inline void create(unsigned int size)
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{
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destroy();
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data = (unsigned char*) b3AlignedAlloc(size,16);
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totalsize = size;
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}
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inline void destroy()
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{
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b3Assert(usedsize==0);
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//Raise(L"StackAlloc is still in use");
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if(usedsize==0)
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{
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if(!ischild && data)
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b3AlignedFree(data);
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data = 0;
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usedsize = 0;
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}
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}
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int getAvailableMemory() const
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{
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return static_cast<int>(totalsize - usedsize);
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}
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unsigned char* allocate(unsigned int size)
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{
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const unsigned int nus(usedsize+size);
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if(nus<totalsize)
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{
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usedsize=nus;
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return(data+(usedsize-size));
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}
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b3Assert(0);
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//&& (L"Not enough memory"));
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return(0);
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}
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B3_FORCE_INLINE b3Block* beginBlock()
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{
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b3Block* pb = (b3Block*)allocate(sizeof(b3Block));
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pb->previous = current;
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pb->address = data+usedsize;
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current = pb;
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return(pb);
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}
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B3_FORCE_INLINE void endBlock(b3Block* block)
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{
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b3Assert(block==current);
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//Raise(L"Unmatched blocks");
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if(block==current)
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{
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current = block->previous;
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usedsize = (unsigned int)((block->address-data)-sizeof(b3Block));
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}
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}
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private:
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void ctor()
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{
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data = 0;
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totalsize = 0;
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usedsize = 0;
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current = 0;
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ischild = false;
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}
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unsigned char* data;
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unsigned int totalsize;
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unsigned int usedsize;
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b3Block* current;
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bool ischild;
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};
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#endif //B3_STACK_ALLOC
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