mirror of https://github.com/g4klx/MMDVM.git
105 lines
2.4 KiB
C++
105 lines
2.4 KiB
C++
/*
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* Copyright (C) 2020 by Jonathan Naylor G4KLX
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* Copyright (C) 2020 by Geoffrey Merck F4FXL - KC3FRA
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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; either version 2 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 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, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "Config.h"
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#if defined(MODE_FM)
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#include "FMUpSampler.h"
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const uint32_t FM_UPSAMPLE_MASK = 0x00000FFFU;
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CFMUpSampler::CFMUpSampler() :
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m_upSampleIndex(0),
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m_pack(0U),
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m_packPointer(NULL),
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m_samples(3600U), //300ms of 12 bit 8kHz audio
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m_running(false)
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{
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m_packPointer = (uint8_t*)&m_pack;
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}
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void CFMUpSampler::reset()
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{
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m_upSampleIndex = 0U;
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m_pack = 0U;
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m_samples.reset();
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m_running = false;
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}
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void CFMUpSampler::addData(const uint8_t* data, uint16_t length)
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{
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TSamplePairPack* packPointer = (TSamplePairPack*)data;
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TSamplePairPack* packPointerEnd = packPointer + (length / 3U);
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while(packPointer != packPointerEnd) {
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m_samples.put(*packPointer);
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packPointer++;
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}
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if(!m_running)
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m_running = m_samples.getData() > 300U;//75ms of audio
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}
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bool CFMUpSampler::getSample(q15_t& sample)
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{
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if(!m_running)
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return false;
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switch (m_upSampleIndex)
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{
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case 0: {
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TSamplePairPack pairPack;
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if(!m_samples.get(pairPack)) {
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m_running = false;
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return false;
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}
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m_pack = 0U;
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m_packPointer = (uint8_t*)&m_pack;
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m_packPointer[0U] = pairPack.byte0;
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m_packPointer[1U] = pairPack.byte1;
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m_packPointer[2U] = pairPack.byte2;
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sample = q15_t(m_pack >> 12) - 2048;
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break;
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}
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case 3:
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sample = q15_t(m_pack & FM_UPSAMPLE_MASK) - 2048;
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break;
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default:
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sample = 0;
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break;
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}
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m_upSampleIndex++;
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if(m_upSampleIndex >= 6U)
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m_upSampleIndex = 0U;
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return true;
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}
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uint16_t CFMUpSampler::getSpace() const
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{
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//return available space in bytes
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return m_samples.getSpace() * sizeof(TSamplePairPack);
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}
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#endif
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