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/*
* Copyright 2003-2018 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef DYNAMIC_FIFO_BUFFER_HXX
#define DYNAMIC_FIFO_BUFFER_HXX
#include "ForeignFifoBuffer.hxx"
/**
* A first-in-first-out buffer: you can append data at the end, and
* read data from the beginning. This class automatically shifts the
* buffer as needed. It is not thread safe.
*/
template<typename T>
class DynamicFifoBuffer : protected ForeignFifoBuffer<T> {
public:
typedef typename ForeignFifoBuffer<T>::size_type size_type;
typedef typename ForeignFifoBuffer<T>::pointer_type pointer_type;
typedef typename ForeignFifoBuffer<T>::const_pointer_type const_pointer_type;
typedef typename ForeignFifoBuffer<T>::Range Range;
explicit DynamicFifoBuffer(size_type _capacity) noexcept
:ForeignFifoBuffer<T>(new T[_capacity], _capacity) {}
~DynamicFifoBuffer() noexcept {
delete[] GetBuffer();
}
DynamicFifoBuffer(const DynamicFifoBuffer &) = delete;
using ForeignFifoBuffer<T>::GetCapacity;
using ForeignFifoBuffer<T>::Clear;
using ForeignFifoBuffer<T>::empty;
using ForeignFifoBuffer<T>::IsFull;
using ForeignFifoBuffer<T>::GetAvailable;
using ForeignFifoBuffer<T>::Read;
using ForeignFifoBuffer<T>::Consume;
using ForeignFifoBuffer<T>::Write;
using ForeignFifoBuffer<T>::Append;
void Grow(size_type new_capacity) noexcept {
assert(new_capacity > GetCapacity());
T *old_data = GetBuffer();
T *new_data = new T[new_capacity];
ForeignFifoBuffer<T>::MoveBuffer(new_data, new_capacity);
delete[] old_data;
}
void WantWrite(size_type n) noexcept {
if (ForeignFifoBuffer<T>::WantWrite(n))
/* we already have enough space */
return;
const size_type in_use = GetAvailable();
const size_type required_capacity = in_use + n;
size_type new_capacity = GetCapacity();
do {
new_capacity <<= 1;
} while (new_capacity < required_capacity);
Grow(new_capacity);
}
/**
* Write data to the buffer, growing it as needed. Returns a
* writable pointer.
*/
pointer_type Write(size_type n) noexcept {
WantWrite(n);
return Write().data;
}
/**
* Append data to the buffer, growing it as needed.
*/
void Append(const_pointer_type p, size_type n) noexcept {
std::copy_n(p, n, Write(n));
Append(n);
}
protected:
using ForeignFifoBuffer<T>::GetBuffer;
};
#endif
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