viktorljung
121 lines
2.9 KiB
C++
121 lines
2.9 KiB
C++
/*
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* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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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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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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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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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#include <Box2D/Common/b2StackAllocator.h>
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#include <Box2D/Common/b2Math.h>
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#include <string.h>
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b2StackAllocator::b2StackAllocator()
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{
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m_index = 0;
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m_allocation = 0;
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m_maxAllocation = 0;
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m_entryCount = 0;
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}
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b2StackAllocator::~b2StackAllocator()
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{
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b2Assert(m_index == 0);
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b2Assert(m_entryCount == 0);
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}
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void* b2StackAllocator::Allocate(int32 size)
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{
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b2Assert(m_entryCount < b2_maxStackEntries);
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const int32 roundedSize = (size + ALIGN_MASK) & ~ALIGN_MASK;
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b2StackEntry* entry = m_entries + m_entryCount;
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entry->size = roundedSize;
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if (m_index + roundedSize > b2_stackSize)
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{
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entry->data = (char*)b2Alloc(roundedSize);
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entry->usedMalloc = true;
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}
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else
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{
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entry->data = m_data + m_index;
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entry->usedMalloc = false;
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m_index += roundedSize;
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}
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m_allocation += roundedSize;
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m_maxAllocation = b2Max(m_maxAllocation, m_allocation);
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++m_entryCount;
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return entry->data;
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}
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void* b2StackAllocator::Reallocate(void* p, int32 size)
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{
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b2Assert(m_entryCount > 0);
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b2StackEntry* entry = m_entries + m_entryCount - 1;
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b2Assert(p == entry->data);
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B2_NOT_USED(p);
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int32 incrementSize = size - entry->size;
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if (incrementSize > 0)
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{
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if (entry->usedMalloc)
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{
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void* data = b2Alloc(size);
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memcpy(data, entry->data, entry->size);
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b2Free(entry->data);
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entry->data = (char*)data;
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}
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else if (m_index + incrementSize > b2_stackSize)
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{
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void* data = b2Alloc(size);
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memcpy(data, entry->data, entry->size);
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m_index -= entry->size;
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entry->data = (char*)data;
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entry->usedMalloc = true;
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}
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else
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{
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m_index += incrementSize;
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m_allocation += incrementSize;
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m_maxAllocation = b2Max(m_maxAllocation, m_allocation);
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}
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entry->size = size;
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}
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return entry->data;
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}
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void b2StackAllocator::Free(void* p)
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{
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b2Assert(m_entryCount > 0);
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b2StackEntry* entry = m_entries + m_entryCount - 1;
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b2Assert(p == entry->data);
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if (entry->usedMalloc)
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{
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b2Free(p);
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}
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else
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{
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m_index -= entry->size;
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}
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m_allocation -= entry->size;
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--m_entryCount;
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p = NULL;
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}
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int32 b2StackAllocator::GetMaxAllocation() const
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{
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return m_maxAllocation;
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}
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