176 lines
3.8 KiB
C++
176 lines
3.8 KiB
C++
#ifndef _DERINGBUFFER_HPP
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#define _DERINGBUFFER_HPP
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/*-------------------------------------------------------------------------
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* drawElements C++ Base Library
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* -----------------------------
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*
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* Copyright 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*//*!
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* \file
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* \brief Ring buffer template.
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*//*--------------------------------------------------------------------*/
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#include "deDefs.hpp"
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namespace de
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{
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void RingBuffer_selfTest (void);
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/** Ring buffer template. */
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template <typename T>
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class RingBuffer
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{
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public:
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RingBuffer (int size);
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~RingBuffer (void);
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void clear (void);
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void resize (int newSize);
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int getSize (void) const { return m_size; }
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int getNumElements (void) const { return m_numElements; }
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int getNumFree (void) const { return m_size - m_numElements; }
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void pushFront (const T& elem);
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void pushFront (const T* elemBuf, int count);
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void peekBack (T* elemBuf, int count) const;
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T peekBack (int offset) const;
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T popBack (void);
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void popBack (T* elemBuf, int count) { peekBack(elemBuf, count); popBack(count); }
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void popBack (int count);
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protected:
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int m_numElements;
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int m_front;
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int m_back;
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T* m_buffer;
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int m_size;
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};
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// RingBuffer implementation.
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template <typename T>
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RingBuffer<T>::RingBuffer (int size)
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: m_numElements (0)
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, m_front (0)
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, m_back (0)
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, m_size (size)
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{
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DE_ASSERT(size > 0);
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m_buffer = new T[m_size];
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}
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template <typename T>
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RingBuffer<T>::~RingBuffer ()
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{
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delete[] m_buffer;
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}
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template <typename T>
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void RingBuffer<T>::clear (void)
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{
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m_numElements = 0;
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m_front = 0;
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m_back = 0;
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}
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template <typename T>
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void RingBuffer<T>::resize (int newSize)
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{
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DE_ASSERT(newSize >= m_numElements);
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T* buf = new T[newSize];
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try
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{
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// Copy old elements.
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for (int ndx = 0; ndx < m_numElements; ndx++)
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buf[ndx] = m_buffer[(m_back + ndx) % m_size];
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// Reset pointers.
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m_front = m_numElements;
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m_back = 0;
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m_size = newSize;
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DE_SWAP(T*, buf, m_buffer);
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delete[] buf;
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}
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catch (...)
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{
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delete[] buf;
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throw;
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}
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}
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template <typename T>
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inline void RingBuffer<T>::pushFront (const T& elem)
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{
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DE_ASSERT(getNumFree() > 0);
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m_buffer[m_front] = elem;
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m_front = (m_front + 1) % m_size;
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m_numElements += 1;
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}
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template <typename T>
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void RingBuffer<T>::pushFront (const T* elemBuf, int count)
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{
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DE_ASSERT(de::inRange(count, 0, getNumFree()));
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for (int i = 0; i < count; i++)
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m_buffer[(m_front + i) % m_size] = elemBuf[i];
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m_front = (m_front + count) % m_size;
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m_numElements += count;
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}
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template <typename T>
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inline T RingBuffer<T>::popBack ()
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{
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DE_ASSERT(getNumElements() > 0);
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int ndx = m_back;
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m_back = (m_back + 1) % m_size;
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m_numElements -= 1;
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return m_buffer[ndx];
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}
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template <typename T>
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inline T RingBuffer<T>::peekBack (int offset) const
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{
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DE_ASSERT(de::inBounds(offset, 0, getNumElements()));
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return m_buffer[(m_back + offset) % m_size];
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}
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template <typename T>
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void RingBuffer<T>::peekBack (T* elemBuf, int count) const
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{
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DE_ASSERT(de::inRange(count, 0, getNumElements()));
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for (int i = 0; i < count; i++)
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elemBuf[i] = m_buffer[(m_back + i) % m_size];
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}
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template <typename T>
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void RingBuffer<T>::popBack (int count)
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{
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DE_ASSERT(de::inRange(count, 0, getNumElements()));
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m_back = (m_back + count) % m_size;
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m_numElements -= count;
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}
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} // de
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#endif // _DERINGBUFFER_HPP
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