Accessing an array with a pointer is not a very good idea.
audio_signal = new double [buffer_size];
signal_start = audio_signal;
signal_end = audio_signal; /* valid signal in [start, end) */
//
for (int i = 0; i < (int) (period_size * channels); i++) {
*signal_end++ = samples[i]; /* get new signal */
}
//
if(signal_end - signal_start >= nfft) { /* if there is enough for FFT */
for (int i = 0; i < nfft; i++) {
in_real[i] = *signal_start++ * audio_window[i];
}
}
//
auto p = signal_start;
auto q = audio_signal;
while(p < signal_end) {
*q++ = *p++;
}
signal_start = audio_signal;
signal_end = q;
The code is far from nice and simple.