1
0
mirror of https://github.com/f4exb/sdrangel.git synced 2024-12-23 18:15:45 -05:00
sdrangel/sdrbase/dsp/samplesourcefifo.cpp

134 lines
4.7 KiB
C++

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