1 files changed, 83 insertions, 0 deletions
diff --git a/Source/external/Box2D/Common/b2StackAllocator.cpp b/Source/external/Box2D/Common/b2StackAllocator.cpp
new file mode 100644
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+++ b/Source/external/Box2D/Common/b2StackAllocator.cpp
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+/*
+* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
+*
+* 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 = nullptr;
+}
+
+int32 b2StackAllocator::GetMaxAllocation() const
+{
+	return m_maxAllocation;
+}