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authorgit perforce import user <a@b>2016-10-25 12:29:14 -0600
committerSheikh Dawood Abdul Ajees <Sheikh Dawood Abdul Ajees>2016-10-25 18:56:37 -0500
commit3dfe2108cfab31ba3ee5527e217d0d8e99a51162 (patch)
treefa6485c169e50d7415a651bf838f5bcd0fd3bfbd /PhysX_3.4/Source/LowLevelCloth/src/StackAllocator.h
downloadphysx-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')
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+// 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
+};