118 lines
2.8 KiB
C++
118 lines
2.8 KiB
C++
/*
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Copyright (c) 2003-2006 Gino van den Bergen / Erwin Coumans https://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 BT_STACK_ALLOC
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#define BT_STACK_ALLOC
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#include "btScalar.h" //for btAssert
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#include "btAlignedAllocator.h"
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///The btBlock class is an internal structure for the btStackAlloc memory allocator.
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struct btBlock
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{
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btBlock* 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 btStackAlloc
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{
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public:
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btStackAlloc(unsigned int size)
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{
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ctor();
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create(size);
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}
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~btStackAlloc() { 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*)btAlignedAlloc(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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btAssert(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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btAlignedFree(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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btAssert(0);
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//&& (L"Not enough memory"));
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return (0);
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}
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SIMD_FORCE_INLINE btBlock* beginBlock()
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{
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btBlock* pb = (btBlock*)allocate(sizeof(btBlock));
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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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SIMD_FORCE_INLINE void endBlock(btBlock* block)
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{
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btAssert(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(btBlock));
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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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btBlock* current;
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bool ischild;
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};
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#endif //BT_STACK_ALLOC
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