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//
// Copyright 2021 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// CircularBuffer.h:
// An array class with an index that loops through the elements.
//
#ifndef COMMON_CIRCULARBUFFER_H_
#define COMMON_CIRCULARBUFFER_H_
#include "common/debug.h"
#include <algorithm>
#include <array>
namespace angle
{
template <class T, size_t N, class Storage = std::array<T, N>>
class CircularBuffer final
{
public:
using value_type = typename Storage::value_type;
using size_type = typename Storage::size_type;
using reference = typename Storage::reference;
using const_reference = typename Storage::const_reference;
using pointer = typename Storage::pointer;
using const_pointer = typename Storage::const_pointer;
using iterator = typename Storage::iterator;
using const_iterator = typename Storage::const_iterator;
CircularBuffer();
CircularBuffer(const value_type &value);
CircularBuffer(const CircularBuffer<T, N, Storage> &other);
CircularBuffer(CircularBuffer<T, N, Storage> &&other);
CircularBuffer<T, N, Storage> &operator=(const CircularBuffer<T, N, Storage> &other);
CircularBuffer<T, N, Storage> &operator=(CircularBuffer<T, N, Storage> &&other);
~CircularBuffer();
// begin() and end() are used to iterate over all elements regardless of the current position of
// the front of the buffer. Useful for initialization and clean up, as otherwise only the front
// element is expected to be accessed.
iterator begin();
const_iterator begin() const;
iterator end();
const_iterator end() const;
size_type size() const;
reference front();
const_reference front() const;
void swap(CircularBuffer<T, N, Storage> &other);
// Move the front forward to the next index, looping back to the beginning if the end of the
// array is reached.
void next();
private:
Storage mData;
size_type mFrontIndex;
};
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage>::CircularBuffer() : mFrontIndex(0)
{}
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage>::CircularBuffer(const value_type &value) : CircularBuffer()
{
std::fill(begin(), end(), value);
}
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage>::CircularBuffer(const CircularBuffer<T, N, Storage> &other)
{
*this = other;
}
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage>::CircularBuffer(CircularBuffer<T, N, Storage> &&other)
: CircularBuffer()
{
swap(other);
}
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage> &CircularBuffer<T, N, Storage>::operator=(
const CircularBuffer<T, N, Storage> &other)
{
std::copy(other.begin(), other.end(), begin());
mFrontIndex = other.mFrontIndex;
return *this;
}
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage> &CircularBuffer<T, N, Storage>::operator=(
CircularBuffer<T, N, Storage> &&other)
{
swap(other);
return *this;
}
template <class T, size_t N, class Storage>
CircularBuffer<T, N, Storage>::~CircularBuffer() = default;
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::iterator CircularBuffer<T, N, Storage>::begin()
{
return mData.begin();
}
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::const_iterator
CircularBuffer<T, N, Storage>::begin() const
{
return mData.begin();
}
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::iterator CircularBuffer<T, N, Storage>::end()
{
return mData.end();
}
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::const_iterator
CircularBuffer<T, N, Storage>::end() const
{
return mData.end();
}
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::size_type CircularBuffer<T, N, Storage>::size()
const
{
return N;
}
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::reference
CircularBuffer<T, N, Storage>::front()
{
ASSERT(mFrontIndex < size());
return mData[mFrontIndex];
}
template <class T, size_t N, class Storage>
ANGLE_INLINE typename CircularBuffer<T, N, Storage>::const_reference
CircularBuffer<T, N, Storage>::front() const
{
ASSERT(mFrontIndex < size());
return mData[mFrontIndex];
}
template <class T, size_t N, class Storage>
void CircularBuffer<T, N, Storage>::swap(CircularBuffer<T, N, Storage> &other)
{
std::swap(mData, other.mData);
std::swap(mFrontIndex, other.mFrontIndex);
}
template <class T, size_t N, class Storage>
void CircularBuffer<T, N, Storage>::next()
{
mFrontIndex = (mFrontIndex + 1) % size();
}
} // namespace angle
#endif // COMMON_CIRCULARBUFFER_H_