reactphysics3d/src/memory/SingleFrameAllocator.cpp
2019-11-27 22:41:38 +01:00

136 lines
5.4 KiB
C++

/********************************************************************************
* ReactPhysics3D physics library, http://www.reactphysics3d.com *
* Copyright (c) 2010-2018 Daniel Chappuis *
*********************************************************************************
* *
* This software is provided 'as-is', without any express or implied warranty. *
* In no event will the authors be held liable for any damages arising from the *
* use of this software. *
* *
* Permission is granted to anyone to use this software for any purpose, *
* including commercial applications, and to alter it and redistribute it *
* freely, subject to the following restrictions: *
* *
* 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. *
* *
* 2. Altered source versions must be plainly marked as such, and must not be *
* misrepresented as being the original software. *
* *
* 3. This notice may not be removed or altered from any source distribution. *
* *
********************************************************************************/
// Libraries
#include "SingleFrameAllocator.h"
#include "MemoryManager.h"
#include <cstdlib>
#include <cassert>
using namespace reactphysics3d;
// Constructor
SingleFrameAllocator::SingleFrameAllocator()
: mTotalSizeBytes(INIT_SINGLE_FRAME_ALLOCATOR_NB_BYTES),
mCurrentOffset(0), mNbFramesTooMuchAllocated(0), mNeedToAllocatedMore(false) {
// Allocate a whole block of memory at the beginning
mMemoryBufferStart = static_cast<char*>(MemoryManager::getBaseAllocator().allocate(mTotalSizeBytes));
assert(mMemoryBufferStart != nullptr);
}
// Destructor
SingleFrameAllocator::~SingleFrameAllocator() {
// Release the memory allocated at the beginning
MemoryManager::getBaseAllocator().release(mMemoryBufferStart, mTotalSizeBytes);
}
// Allocate memory of a given size (in bytes) and return a pointer to the
// allocated memory.
void* SingleFrameAllocator::allocate(size_t size) {
// Check that there is enough remaining memory in the buffer
if (mCurrentOffset + size > mTotalSizeBytes) {
// We need to allocate more memory next time reset() is called
mNeedToAllocatedMore = true;
// Return default memory allocation
return MemoryManager::getBaseAllocator().allocate(size);
}
// Next available memory location
void* nextAvailableMemory = mMemoryBufferStart + mCurrentOffset;
// Increment the offset
mCurrentOffset += size;
// Return the next available memory location
return nextAvailableMemory;
}
// Release previously allocated memory.
void SingleFrameAllocator::release(void* pointer, size_t size) {
// If allocated memory is not within the single frame allocation range
char* p = static_cast<char*>(pointer);
if (p < mMemoryBufferStart || p > mMemoryBufferStart + mTotalSizeBytes) {
// Use default deallocation
MemoryManager::getBaseAllocator().release(pointer, size);
}
}
// Reset the marker of the current allocated memory
void SingleFrameAllocator::reset() {
// If too much memory is allocated
if (mCurrentOffset < mTotalSizeBytes / 2) {
mNbFramesTooMuchAllocated++;
if (mNbFramesTooMuchAllocated > NB_FRAMES_UNTIL_SHRINK) {
// Release the memory allocated at the beginning
MemoryManager::getBaseAllocator().release(mMemoryBufferStart, mTotalSizeBytes);
// Divide the total memory to allocate by two
mTotalSizeBytes /= 2;
if (mTotalSizeBytes == 0) mTotalSizeBytes = 1;
// Allocate a whole block of memory at the beginning
mMemoryBufferStart = static_cast<char*>(MemoryManager::getBaseAllocator().allocate(mTotalSizeBytes));
assert(mMemoryBufferStart != nullptr);
mNbFramesTooMuchAllocated = 0;
}
}
else {
mNbFramesTooMuchAllocated = 0;
}
// If we need to allocate more memory
if (mNeedToAllocatedMore) {
// Release the memory allocated at the beginning
MemoryManager::getBaseAllocator().release(mMemoryBufferStart, mTotalSizeBytes);
// Multiply the total memory to allocate by two
mTotalSizeBytes *= 2;
// Allocate a whole block of memory at the beginning
mMemoryBufferStart = static_cast<char*>(MemoryManager::getBaseAllocator().allocate(mTotalSizeBytes));
assert(mMemoryBufferStart != nullptr);
mNeedToAllocatedMore = false;
mNbFramesTooMuchAllocated = 0;
}
// Reset the current offset at the beginning of the block
mCurrentOffset = 0;
}