unsigned long framesPerBuffer,

const PaStreamCallbackTimeInfo *timeInfo,

PaStreamCallbackFlags statusFlags, void *userData) {

SAMPLE* out = (SAMPLE *)outputBuffer;

const SAMPLE *in = (const SAMPLE *)inputBuffer;

(void)timeInfo; /* Prevent unused variable warnings. */

(void)statusFlags;

(void)userData;

Buffer *buffer = reinterpret_cast<Buffer *>(userData);

size_t timeIndex = (timeInfo->currentTime /* in seconds */ * SAMPLE_RATE) /

FRAMES_PER_BUFFER * FRAMES_PER_BUFFER;

int scale = 1;

size_t reverseIndex = buffer->size - scale * timeIndex;

if (inputBuffer == NULL) {

for (int i = 0; i < framesPerBuffer; i++) {

*out++ = sigmoid(0);

*out++ = sigmoid(0);

}

gNumNoInputs += 1;

} else {

for (int i = 0; i < framesPerBuffer; i++) {

size_t playHead0 = (timeIndex + i) % buffer->size;

size_t playHead1 = (reverseIndex - scale * i ) % buffer->size; // reverse playhead

SAMPLE sample = *in++; /* MONO input */

float value = sigmoid(0.5 * sample + 0.5 * buffer->buffer[playHead1]);

*out++ = value; /* LEFT */

*out++ = value; /* RIGHT */

buffer->buffer[playHead0] = sample;

printf("\033[H\033[H\n\nTime = %f\nplayHead0 = %zu\nplayHead1 (reverse) "

"index=%zu\noutput value=%.2f\ninput value=%.2f\nplayhead1 value =%.2f\n",

timeInfo->currentTime, playHead0, playHead1, value,

sample,

buffer->buffer[playHead1]);

}

}

return paContinue;

if (!condition) {

fprintf(stderr, "%s\n", message);

Pa_Terminate();

exit(1);

}

PaStreamParameters inputParameters, outputParameters;

PaStream *stream;

PaError err;

printf("\033[H\033[J");

printf("Turn down volume before starting.\nPress Enter to start.");

getchar();

printf("\033[H\033[J");

err = Pa_Initialize();

check(err == paNoError, "Error: Pa_Initialize failed.");

// Setup device

inputParameters = {

.device = Pa_GetDefaultInputDevice(),

.channelCount = 1,

.sampleFormat = PA_SAMPLE_TYPE,

.suggestedLatency =

Pa_GetDeviceInfo(Pa_GetDefaultInputDevice())->defaultLowInputLatency,

.hostApiSpecificStreamInfo = NULL};

check(inputParameters.device != paNoDevice,

"Error: No default input device.");

outputParameters = {.device = Pa_GetDefaultOutputDevice(),

.channelCount = 2,

.sampleFormat = PA_SAMPLE_TYPE,

.suggestedLatency =

Pa_GetDeviceInfo(Pa_GetDefaultOutputDevice())

->defaultLowOutputLatency,

.hostApiSpecificStreamInfo = NULL};

if (outputParameters.device == paNoDevice) {

fprintf(stderr, "Error: No default output device.\n");

exit(1);

}

constexpr size_t kBufferTime = 4; // seconds

std::array<float, SAMPLE_RATE * kBufferTime> bufferAlloc;

// zero

for (size_t i = 0; i < bufferAlloc.size(); i++) {

bufferAlloc[i] = 0;

}

Buffer buffer = {bufferAlloc.data(), bufferAlloc.size()};

err = Pa_OpenStream(&stream, &inputParameters, &outputParameters, SAMPLE_RATE,

FRAMES_PER_BUFFER, 0,

/* paClipOff, */ /* we won't output out of range samples

callback, reinterpret_cast<void *>(&buffer));

check(err == paNoError, "Error: Pa_OpenStream failed.");

err = Pa_StartStream(stream);

check(err == paNoError, "Error: Pa_StartStream failed.");

printf("Hit Enter to stop program.\n");

getchar();

err = Pa_CloseStream(stream);

check(err == paNoError, "Error: Pa_CloseStream failed.");

printf("Finished. gNumNoInputs = %d\n", gNumNoInputs);

Pa_Terminate();

return 0;