diff options
| author | git perforce import user <a@b> | 2016-10-25 12:29:14 -0600 |
|---|---|---|
| committer | Sheikh Dawood Abdul Ajees <Sheikh Dawood Abdul Ajees> | 2016-10-25 18:56:37 -0500 |
| commit | 3dfe2108cfab31ba3ee5527e217d0d8e99a51162 (patch) | |
| tree | fa6485c169e50d7415a651bf838f5bcd0fd3bfbd /PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h | |
| download | physx-3.4-3dfe2108cfab31ba3ee5527e217d0d8e99a51162.tar.xz physx-3.4-3dfe2108cfab31ba3ee5527e217d0d8e99a51162.zip | |
Initial commit:
PhysX 3.4.0 Update @ 21294896
APEX 1.4.0 Update @ 21275617
[CL 21300167]
Diffstat (limited to 'PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h')
| -rw-r--r-- | PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h b/PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h new file mode 100644 index 00000000..eb8d8679 --- /dev/null +++ b/PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h @@ -0,0 +1,155 @@ +// This code contains NVIDIA Confidential Information and is disclosed to you +// under a form of NVIDIA software license agreement provided separately to you. +// +// Notice +// NVIDIA Corporation and its licensors retain all intellectual property and +// proprietary rights in and to this software and related documentation and +// any modifications thereto. Any use, reproduction, disclosure, or +// distribution of this software and related documentation without an express +// license agreement from NVIDIA Corporation is strictly prohibited. +// +// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES +// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO +// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT, +// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE. +// +// Information and code furnished is believed to be accurate and reliable. +// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such +// information or for any infringement of patents or other rights of third parties that may +// result from its use. No license is granted by implication or otherwise under any patent +// or patent rights of NVIDIA Corporation. Details are subject to change without notice. +// This code supersedes and replaces all information previously supplied. +// NVIDIA Corporation products are not authorized for use as critical +// components in life support devices or systems without express written approval of +// NVIDIA Corporation. +// +// Copyright (c) 2008-2016 NVIDIA Corporation. All rights reserved. +// Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved. +// Copyright (c) 2001-2004 NovodeX AG. All rights reserved. + +#pragma once + +#include "foundation/PxAssert.h" + +#if PX_LINUX_FAMILY +#include <stdint.h> // intptr_t +#endif + +template <size_t align> +class StackAllocator +{ + typedef unsigned char byte; + + // todo: switch to offsets so size is consistent on x64 + // mSize is just for book keeping so could be 4 bytes + struct Header + { + Header* mPrev; + size_t mSize : 31; + size_t mFree : 1; + }; + + StackAllocator(const StackAllocator&); + StackAllocator& operator=(const StackAllocator&); + + public: + StackAllocator(void* buffer, size_t bufferSize) + : mBuffer(reinterpret_cast<byte*>(buffer)), mBufferSize(bufferSize), mFreeStart(mBuffer), mTop(0) + { + } + + ~StackAllocator() + { + PX_ASSERT(userBytes() == 0); + } + + void* allocate(size_t numBytes) + { + // this is non-standard + if(!numBytes) + return 0; + + uintptr_t unalignedStart = uintptr_t(mFreeStart) + sizeof(Header); + + byte* allocStart = reinterpret_cast<byte*>((unalignedStart + (align - 1)) & ~(align - 1)); + byte* allocEnd = allocStart + numBytes; + + // ensure there is space for the alloc + PX_ASSERT(allocEnd <= mBuffer + mBufferSize); + + Header* h = getHeader(allocStart); + h->mPrev = mTop; + h->mSize = numBytes; + h->mFree = false; + + mTop = h; + mFreeStart = allocEnd; + + return allocStart; + } + + void deallocate(void* p) + { + if(!p) + return; + + Header* h = getHeader(p); + h->mFree = true; + + // unwind the stack to the next live alloc + while(mTop && mTop->mFree) + { + mFreeStart = reinterpret_cast<byte*>(mTop); + mTop = mTop->mPrev; + } + } + + private: + // return the header for an allocation + inline Header* getHeader(void* p) const + { + PX_ASSERT((reinterpret_cast<uintptr_t>(p) & (align - 1)) == 0); + PX_ASSERT(reinterpret_cast<byte*>(p) >= mBuffer + sizeof(Header)); + PX_ASSERT(reinterpret_cast<byte*>(p) < mBuffer + mBufferSize); + + return reinterpret_cast<Header*>(p) - 1; + } + + public: + // total user-allocated bytes not including any overhead + size_t userBytes() const + { + size_t total = 0; + Header* iter = mTop; + while(iter) + { + total += iter->mSize; + iter = iter->mPrev; + } + + return total; + } + + // total user-allocated bytes + overhead + size_t totalUsedBytes() const + { + return mFreeStart - mBuffer; + } + + size_t remainingBytes() const + { + return mBufferSize - totalUsedBytes(); + } + + size_t wastedBytes() const + { + return totalUsedBytes() - userBytes(); + } + + private: + byte* const mBuffer; + const size_t mBufferSize; + + byte* mFreeStart; // start of free space + Header* mTop; // top allocation header +}; |