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# Box2D/Box2D/Common/b2StackAllocator.h

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    00001 /*
    00002 * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
    00003 *
    00004 * This software is provided 'as-is', without any express or implied
    00005 * warranty.  In no event will the authors be held liable for any damages
    00006 * arising from the use of this software.
    00007 * Permission is granted to anyone to use this software for any purpose,
    00008 * including commercial applications, and to alter it and redistribute it
    00009 * freely, subject to the following restrictions:
    00010 * 1. The origin of this software must not be misrepresented; you must not
    00011 * claim that you wrote the original software. If you use this software
    00012 * in a product, an acknowledgment in the product documentation would be
    00013 * appreciated but is not required.
    00014 * 2. Altered source versions must be plainly marked as such, and must not be
    00015 * misrepresented as being the original software.
    00016 * 3. This notice may not be removed or altered from any source distribution.
    00017 */
    00018
    00019 #ifndef B2_STACK_ALLOCATOR_H
    00020 #define B2_STACK_ALLOCATOR_H
    00021
    00022 #include <Box2D/Common/b2Settings.h>
    00023
    00024 const int32 b2_stackSize = 100 * 1024;  // 100k
    00025 const int32 b2_maxStackEntries = 32;
    00026
    00027 struct b2StackEntry
    00028 {
    00029         char* data;
    00030         int32 size;
    00031         bool usedMalloc;
    00032 };
    00033
    00034 // This is a stack allocator used for fast per step allocations.
    00035 // You must nest allocate/free pairs. The code will assert
    00036 // if you try to interleave multiple allocate/free pairs.
    00037 class b2StackAllocator
    00038 {
    00039 public:
    00040         b2StackAllocator();
    00041         ~b2StackAllocator();
    00042
    00043         void* Allocate(int32 size);
    00044         void Free(void* p);
    00045
    00046         int32 GetMaxAllocation() const;
    00047
    00048 private:
    00049
    00050         char m_data[b2_stackSize];
    00051         int32 m_index;
    00052
    00053         int32 m_allocation;
    00054         int32 m_maxAllocation;
    00055
    00056         b2StackEntry m_entries[b2_maxStackEntries];
    00057         int32 m_entryCount;
    00058 };
    00059
    00060 #endif