1 files changed, 100 insertions, 0 deletions
diff --git a/gfft.c b/gfft.c
new file mode 100644
index 0000000..fa21a11
--- /dev/null
+++ b/gfft.c
@@ -0,0 +1,100 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <ctype.h>
+
+#include "gfft.h"
+
+void window_hard(sample *in, double *out, size_t size, int ch, int nch)
+{
+	for (size_t i = 0; i < size; i++) {
+		sample val = in[i * nch + ch];
+		out[i] = (1./32768.) * val;
+	}
+}
+
+void window_hann(sample *in, double *out, size_t size, int ch, int nch)
+{
+	double cfac = 2. * M_PI / ((double) size - 1);
+	for (size_t i = 0; i < size; i++) {
+		sample val = in[i * nch + ch];
+		out[i] = (1./32768.) * val
+				* 0.5 * (1. - cos (cfac * (double)i));
+	}
+}
+
+static gpointer fftrun_threadf(gpointer param)
+{
+	struct fft_runner *fftr = param;
+	fftw_plan p;
+	double *in;
+	fftw_complex *out;
+	struct qe *qe;
+	struct fe *fe;
+	int stopped = 0;
+	sample *hist;
+	size_t span = fftr->span;
+	size_t pktsize = fftr->dev->pktsize;
+
+	hist = malloc(sizeof(sample) * pktsize * span * fftr->dev->chan);
+	in = fftw_malloc(sizeof(double) * pktsize * span);
+	out = fftw_malloc(sizeof(fftw_complex) * pktsize * span);
+	p = fftw_plan_dft_r2c_1d(pktsize * span, in, out,
+			FFTW_MEASURE | FFTW_DESTROY_INPUT);
+	free(out);
+
+	while (!stopped) {
+		qe = g_async_queue_pop(fftr->dev->queue);
+		fe = calloc(sizeof(struct fe), 1);
+
+		switch (qe->message) {
+		case QE_STOPPED:
+			fe->message = FE_STOPPED;
+			stopped = 1;
+			break;
+
+		case QE_ERROR:
+			fe->message = FE_DEV_ERROR;
+			fe->errcode = qe->errcode;
+			fe->errp = qe->errp;
+			break;
+
+		case QE_DATA:
+			memmove(hist, hist + pktsize,
+				pktsize * (span - 1) * fftr->dev->chan * sizeof(*hist));
+			memmove(hist + pktsize * (span - 1), qe->samples,
+				pktsize * fftr->dev->chan * sizeof(*hist));
+
+			fe->message = FE_DATA;
+			fe->data = fftw_malloc(sizeof(fftw_complex)
+					* pktsize * span);
+			fe->size = pktsize * span;
+			fftr->winf(hist, in, pktsize * span, 0, fftr->dev->chan);
+			fftw_execute_dft_r2c(p, in, fe->data);
+			break;
+		}
+		free(qe);
+
+		g_async_queue_push(fftr->queue, fe);
+	}
+
+	free(in);
+	fftw_destroy_plan(p);
+	return NULL;
+}
+
+struct fft_runner *fftrun_attach(struct device *device,
+		window_func *winf, size_t span)
+{
+	GError *error = NULL;
+	struct fft_runner *fftr;
+
+	fftr = malloc(sizeof(*fftr));
+	fftr->dev = device;
+	fftr->queue = g_async_queue_new();
+	fftr->thread = g_thread_create(fftrun_threadf, fftr, 0, &error);
+	fftr->winf = winf;
+	fftr->span = span;
+	return fftr;
+}
+