mirror of https://github.com/f4exb/sdrangel.git
134 lines
4.7 KiB
C++
134 lines
4.7 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2019 Edouard Griffiths, F4EXB //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// (at your option) any later version. //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#include "samplesourcefifo.h"
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const unsigned int SampleSourceFifo::m_rwDivisor = 2;
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const unsigned int SampleSourceFifo::m_guardDivisor = 10;
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SampleSourceFifo::SampleSourceFifo(QObject *parent) :
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QObject(parent)
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{}
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SampleSourceFifo::SampleSourceFifo(unsigned int size, QObject *parent) :
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QObject(parent)
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{
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resize(size);
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}
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void SampleSourceFifo::resize(unsigned int size)
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{
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QMutexLocker mutexLocker(&m_mutex);
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m_size = size;
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m_lowGuard = m_size / m_guardDivisor;
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m_highGuard = m_size - (m_size/m_guardDivisor);
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m_midPoint = m_size / m_rwDivisor;
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m_readCount = 0;
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m_readHead = 0;
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m_writeHead = m_midPoint;
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m_data.resize(size);
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}
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void SampleSourceFifo::reset()
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{
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QMutexLocker mutexLocker(&m_mutex);
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m_readCount = 0;
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m_readHead = 0;
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m_writeHead = m_midPoint;
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}
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SampleSourceFifo::~SampleSourceFifo()
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{}
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void SampleSourceFifo::read(
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unsigned int amount,
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unsigned int& ipart1Begin, unsigned int& ipart1End, // first part offsets where to read
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unsigned int& ipart2Begin, unsigned int& ipart2End // second part offsets
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)
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{
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QMutexLocker mutexLocker(&m_mutex);
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unsigned int spaceLeft = m_size - m_readHead;
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m_readCount = m_readCount + amount < m_size ? m_readCount + amount : m_size; // cannot exceed FIFO size
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if (amount <= spaceLeft)
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{
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ipart1Begin = m_readHead;
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ipart1End = m_readHead + amount;
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ipart2Begin = m_size;
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ipart2End = m_size;
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m_readHead += amount;
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}
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else
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{
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unsigned int remaining = (amount < m_size ? amount : m_size) - spaceLeft;
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ipart1Begin = m_readHead;
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ipart1End = m_size;
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ipart2Begin = 0;
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ipart2End = remaining;
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m_readHead = remaining;
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}
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emit dataRead();
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}
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void SampleSourceFifo::write(
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unsigned int amount,
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unsigned int& ipart1Begin, unsigned int& ipart1End, // first part offsets where to write
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unsigned int& ipart2Begin, unsigned int& ipart2End // second part offsets
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)
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{
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QMutexLocker mutexLocker(&m_mutex);
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unsigned int rwDelta = m_writeHead >= m_readHead ? m_writeHead - m_readHead : m_size - (m_readHead - m_writeHead);
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if (rwDelta < m_lowGuard)
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{
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qWarning("SampleSourceFifo::write: underrun (write too slow) using %d old samples", m_midPoint - m_lowGuard);
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m_writeHead = m_readHead + m_midPoint < m_size ? m_readHead + m_midPoint : m_readHead + m_midPoint - m_size;
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}
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else if (rwDelta > m_highGuard)
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{
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qWarning("SampleSourceFifo::write: overrun (read too slow) dropping %d samples", m_highGuard - m_midPoint);
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m_writeHead = m_readHead + m_midPoint < m_size ? m_readHead + m_midPoint : m_readHead + m_midPoint - m_size;
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}
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unsigned int spaceLeft = m_size - m_writeHead;
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if (amount <= spaceLeft)
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{
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ipart1Begin = m_writeHead;
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ipart1End = m_writeHead + amount;
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ipart2Begin = m_size;
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ipart2End = m_size;
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m_writeHead += amount;
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}
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else
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{
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unsigned int remaining = (amount < m_size ? amount : m_size) - spaceLeft;
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ipart1Begin = m_writeHead;
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ipart1End = m_size;
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ipart2Begin = 0;
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ipart2End = remaining;
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m_writeHead = remaining;
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}
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m_readCount = amount < m_readCount ? m_readCount - amount : 0; // cannot be less than 0
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}
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unsigned int SampleSourceFifo::getSizePolicy(unsigned int sampleRate)
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{
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return (sampleRate/100)*64; // .64s
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} |