I am trying to use the FFT filter in some c++ code and I'm having issues with seg faulting. The code below will work, but only because the output buffer is twice as large as the input buffer. It doesn't have to be twice as large, but it does have to be some number larger than the input buffer. Why is that? Also, how do I know what the output buffer size should be?
// Generate a set of zeroed out taps
std::vector<std::complex<float> > taps(512, std::complex<float>(0.0f, 0.0f));
// Number of random samples to generate
const int sampleSize = 30000;
// Create a vector of 32fc samples. Don't initialize it to anything, just let it have
// random data.
gr_complex * input = (gr_complex *)malloc(sizeof(gr_complex) * sampleSize);
// Place to store the output samples from the FFT
gr_complex * output = (gr_complex *)malloc(sizeof(gr_complex) * sampleSize);
// Create a filter to run the input samples through
gr::filter::kernel::fft_filter_ccc * filter = new gr::filter::kernel::fft_filter_ccc(1, taps, 1);
// Filter the input samples
filter->filter(sampleSize, input, output);
// Free up the malloc'd input and output storage