b2StackAllocator.cpp
上传用户:gb3593
上传日期:2022-01-07
资源大小:3028k
文件大小:2k
- /*
- * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
- *
- * 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.
- */
- #include <Box2D/Common/b2StackAllocator.h>
- #include <Box2D/Common/b2Math.h>
- b2StackAllocator::b2StackAllocator()
- {
- m_index = 0;
- m_allocation = 0;
- m_maxAllocation = 0;
- m_entryCount = 0;
- }
- b2StackAllocator::~b2StackAllocator()
- {
- b2Assert(m_index == 0);
- b2Assert(m_entryCount == 0);
- }
- void* b2StackAllocator::Allocate(int32 size)
- {
- b2Assert(m_entryCount < b2_maxStackEntries);
- b2StackEntry* entry = m_entries + m_entryCount;
- entry->size = size;
- if (m_index + size > b2_stackSize)
- {
- entry->data = (char*)b2Alloc(size);
- entry->usedMalloc = true;
- }
- else
- {
- entry->data = m_data + m_index;
- entry->usedMalloc = false;
- m_index += size;
- }
- m_allocation += size;
- m_maxAllocation = b2Max(m_maxAllocation, m_allocation);
- ++m_entryCount;
- return entry->data;
- }
- void b2StackAllocator::Free(void* p)
- {
- b2Assert(m_entryCount > 0);
- b2StackEntry* entry = m_entries + m_entryCount - 1;
- b2Assert(p == entry->data);
- if (entry->usedMalloc)
- {
- b2Free(p);
- }
- else
- {
- m_index -= entry->size;
- }
- m_allocation -= entry->size;
- --m_entryCount;
- p = NULL;
- }
- int32 b2StackAllocator::GetMaxAllocation() const
- {
- return m_maxAllocation;
- }