Revision control
++ // Copyright (c) 2001-2004 NovodeX AG. All rights reserved.
++ // Copyright (c) 2004-2008 AGEIA Technologies, Inc. All rights reserved.
++ // SPDX-FileCopyrightText: Copyright (c) 2008-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
++ // SPDX-License-Identifier: Apache-2.0
++
++ #ifndef PXC_SCRATCH_ALLOCATOR_H
++ #define PXC_SCRATCH_ALLOCATOR_H
++
++ #include "foundation/PxAssert.h"
++ #include "PxPhysXConfig.h"
++ #include "foundation/PxMutex.h"
++ #include "foundation/PxArray.h"
++ #include "foundation/PxAllocator.h"
++ #include "foundation/PxUserAllocated.h"
++
++ namespace physx
++ {
++ class PxcScratchAllocator : public PxUserAllocated
++ {
++ PX_NOCOPY(PxcScratchAllocator)
++ public:
++ PxcScratchAllocator() : mStack("PxcScratchAllocator"), mStart(NULL), mSize(0)
++ {
++ mStack.reserve(64);
++ mStack.pushBack(0);
++ }
++
++ void setBlock(void* addr, PxU32 size)
++ {
++ PX_ASSERT(!(size&15));
++
++ // if the stack is not empty then some scratch memory was not freed on the previous frame. That's
++ // likely indicative of a problem, because when the scratch block is too small the memory will have
++ // come from the heap
++
++ PX_ASSERT(mStack.size()==1);
++ mStack.popBack();
++
++ mStart = reinterpret_cast<PxU8*>(addr);
++ mSize = size;
++ mStack.pushBack(mStart + size);
++ }
++
++ void* allocAll(PxU32& size)
++ {
++ PxMutex::ScopedLock lock(mLock);
++ PX_ASSERT(mStack.size()>0);
++ size = PxU32(mStack.back()-mStart);
++
++ if(size==0)
++ return NULL;
++
++ mStack.pushBack(mStart);
++ return mStart;
++ }
++
++ void* alloc(PxU32 requestedSize, bool fallBackToHeap = false)
++ {
++ requestedSize = (requestedSize+15)&~15;
++
++ PxMutex::ScopedLock lock(mLock);
++ PX_ASSERT(mStack.size()>=1);
++
++ PxU8* top = mStack.back();
++
++ if(top - mStart >= ptrdiff_t(requestedSize))
++ {
++ PxU8* addr = top - requestedSize;
++ mStack.pushBack(addr);
++ return addr;
++ }
++
++ if(!fallBackToHeap)
++ return NULL;
++
++ return PX_ALLOC(requestedSize, "Scratch Block Fallback");
++ }
++
++ void free(void* addr)
++ {
++ PX_ASSERT(addr!=NULL);
++ if(!isScratchAddr(addr))
++ {
++ PX_FREE(addr);
++ return;
++ }
++
++ PxMutex::ScopedLock lock(mLock);
++ PX_ASSERT(mStack.size()>1);
++
++ PxU32 i=mStack.size()-1;
++ while(mStack[i]<addr)
++ i--;
++
++ PX_ASSERT(mStack[i]==addr);
++ mStack.remove(i);
++ }
++
++ bool isScratchAddr(void* addr) const
++ {
++ PxU8* a = reinterpret_cast<PxU8*>(addr);
++ return a>= mStart && a<mStart+mSize;
++ }
++
++ private:
++ PxMutex mLock;
++ PxArray<PxU8*> mStack;
++ PxU8* mStart;
++ PxU32 mSize;
++ };
++
++ }
++
++ #endif