72 lines
3.7 KiB
C++
72 lines
3.7 KiB
C++
/********************************************************************************
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* ReactPhysics3D physics library, http://www.reactphysics3d.com *
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* Copyright (c) 2010-2022 Daniel Chappuis *
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*********************************************************************************
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* *
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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 *
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* use of this software. *
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* *
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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 *
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* freely, subject to the following restrictions: *
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* *
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* 1. The origin of this software must not be misrepresented; you must not claim *
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* that you wrote the original software. If you use this software in a *
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* product, an acknowledgment in the product documentation would be *
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* appreciated but is not required. *
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* *
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* 2. Altered source versions must be plainly marked as such, and must not be *
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* misrepresented as being the original software. *
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* *
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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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// Libraries
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#include <reactphysics3d/memory/MemoryAllocator.h>
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#include <cassert>
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using namespace reactphysics3d;
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/// Given a pointer to memory, this method returns the next aligned address
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/**
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* @param pointer Pointer to a memory location
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* @param alignment Desired alignment
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* @return Pointer to the next aligned memory location
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*/
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void* MemoryAllocator::alignAddress(void* pointer, std::uint8_t alignment) {
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ptrdiff_t alignmentOffset;
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return alignAddress(pointer, alignment, alignmentOffset);
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}
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/// Given a pointer to memory, this method returns the next aligned address and also output the alignment offset
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/**
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* @param pointer Pointer to a memory location
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* @param alignment Desired alignment
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* @param outAlignmentOffset Output alignment offset needed to align the initial pointer
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* @return Pointer to the next aligned memory location
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*/
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void* MemoryAllocator::alignAddress(void* pointer, std::uint8_t alignment, ptrdiff_t& outAlignmentOffset) {
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// Take care of alignment to make sure that we always return an address to the
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// enforce the global alignment of the library
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const uintptr_t currentAdress = reinterpret_cast<uintptr_t>(pointer);
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// Calculate the adjustment by masking off the lower bits of the address, to determine how "misaligned" it is.
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const size_t mask = alignment - 1;
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const uintptr_t misalignment = currentAdress & mask;
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outAlignmentOffset = alignment - misalignment;
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assert(outAlignmentOffset <= alignment);
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// Compute the aligned address
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const uintptr_t alignedAdress = currentAdress + outAlignmentOffset;
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void* alignedPointer = reinterpret_cast<void*>(alignedAdress);
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// Check that allocated memory is correctly aligned
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assert(reinterpret_cast<uintptr_t>(alignedPointer) % alignment == 0);
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return alignedPointer;
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}
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