CubicSDR/src/demod/DemodulatorWorkerThread.cpp

#include "DemodulatorWorkerThread.h"
#include "CubicSDRDefs.h"
#include <vector>

DemodulatorWorkerThread::DemodulatorWorkerThread(DemodulatorThreadWorkerCommandQueue* in, DemodulatorThreadWorkerResultQueue* out) :
        terminated(false), commandQueue(in), resultQueue(out) {

}

DemodulatorWorkerThread::~DemodulatorWorkerThread() {
}

void DemodulatorWorkerThread::threadMain() {

    std::cout << "Demodulator worker thread started.." << std::endl;

    while (!terminated) {
        bool filterChanged = false;
        DemodulatorWorkerThreadCommand filterCommand;
        DemodulatorWorkerThreadCommand command;

        bool done = false;
        while (!done) {
            commandQueue->pop(command);
            switch (command.cmd) {
            case DemodulatorWorkerThreadCommand::DEMOD_WORKER_THREAD_CMD_BUILD_FILTERS:
                filterChanged = true;
                filterCommand = command;
                break;
            }
            done = commandQueue->empty();
        }

        if (filterChanged) {
            DemodulatorWorkerThreadResult result(DemodulatorWorkerThreadResult::DEMOD_WORKER_THREAD_RESULT_FILTERS);

            result.resample_ratio = (float) (filterCommand.bandwidth) / (float) filterCommand.inputRate;
            result.audio_resample_ratio = (float) (filterCommand.audioSampleRate) / (float) filterCommand.bandwidth;

            float fc = 0.5 * ((double) filterCommand.bandwidth / (double) filterCommand.inputRate);         // filter cutoff frequency

            if (fc <= 0) {
                fc = 0;
            }

            if (fc >= 0.5) {
                fc = 0.5;
            }

            float ft = 0.05f;         // filter transition
            float As = 60.0f;         // stop-band attenuation [dB]
            float mu = 0.0f;         // fractional timing offset

            // estimate required filter length and generate filter
            unsigned int h_len = estimate_req_filter_len(ft, As);
            float h[h_len];
            liquid_firdes_kaiser(h_len, fc, As, mu, h);

            result.fir_filter = firfilt_crcf_create(h, h_len);
            result.resampler = msresamp_crcf_create(result.resample_ratio, As);
            result.audio_resampler = msresamp_crcf_create(result.audio_resample_ratio, As);

            result.audioSampleRate = filterCommand.audioSampleRate;
            result.bandwidth = filterCommand.bandwidth;
            result.inputRate = filterCommand.inputRate;

            resultQueue->push(result);
        }

    }

    std::cout << "Demodulator worker thread done." << std::endl;
}

void DemodulatorWorkerThread::terminate() {
    terminated = true;
    DemodulatorWorkerThreadCommand inp;    // push dummy to nudge queue
    commandQueue->push(inp);
}