viktorljung
99 lines
2.0 KiB
C++
99 lines
2.0 KiB
C++
/*
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* Copyright (c) 2013 Google, Inc.
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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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#ifndef B2_STACK_QUEUE
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#define B2_STACK_QUEUE
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#include <Box2D/Common/b2StackAllocator.h>
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template <typename T>
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class b2StackQueue
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{
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public:
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b2StackQueue(b2StackAllocator *allocator, int32 capacity)
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{
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m_allocator = allocator;
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m_buffer = (T*) m_allocator->Allocate(sizeof(T) * capacity);
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m_front = 0;
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m_back = 0;
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m_capacity = capacity;
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}
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~b2StackQueue()
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{
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m_allocator->Free(m_buffer);
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}
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void Push(const T &item)
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{
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if (m_back >= m_capacity)
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{
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for (int32 i = m_front; i < m_back; i++)
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{
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m_buffer[i - m_front] = m_buffer[i];
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}
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m_back -= m_front;
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m_front = 0;
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if (m_back >= m_capacity)
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{
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if (m_capacity > 0)
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{
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m_capacity *= 2;
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}
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else
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{
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m_capacity = 1;
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}
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m_buffer = (T*) m_allocator->Reallocate(m_buffer,
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sizeof(T) * m_capacity);
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}
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}
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m_buffer[m_back] = item;
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m_back++;
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}
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void Pop()
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{
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b2Assert(m_front < m_back);
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m_front++;
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}
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bool Empty() const
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{
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b2Assert(m_front <= m_back);
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return m_front == m_back;
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}
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const T &Front() const
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{
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return m_buffer[m_front];
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}
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private:
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b2StackAllocator *m_allocator;
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T* m_buffer;
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int32 m_front;
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int32 m_back;
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int32 m_capacity;
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};
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#endif
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