1 files changed, 0 insertions, 99 deletions
diff --git a/src/common/filter.c b/src/common/filter.c
deleted file mode 100644
index 0a5c0dd..0000000
--- a/src/common/filter.c
+++ /dev/null
@@ -1,99 +0,0 @@
-/* cut-off filter (biquad) based on Nigel Redmon (www.earlevel.com)
- *
- * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
- * All Rights Reserved
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <stdio.h>
-#include <stdint.h>
-#include <string.h>
-#include <stdlib.h>
-#include <math.h>
-#include "sample.h"
-#include "filter.h"
-
-#define PI M_PI
-
-void filter_lowpass_init(filter_t *bq, double frequency, int samplerate, int iterations)
-{
-	double Fc, Q, K, norm;
-
-	if (iterations > 64) {
-		fprintf(stderr, "%s failed: too many iterations, please fix!\n", __func__);
-		abort();
-	}
-
-	memset(bq, 0, sizeof(*bq));
-	bq->iter = iterations;
-	Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
-	Fc = frequency / (double)samplerate;
-	K = tan(PI * Fc);
-	norm = 1 / (1 + K / Q + K * K);
-	bq->a0 = K * K * norm;
-	bq->a1 = 2 * bq->a0;
-	bq->a2 = bq->a0;
-	bq->b1 = 2 * (K * K - 1) * norm;
-	bq->b2 = (1 - K / Q + K * K) * norm;
-}
-
-void filter_highpass_init(filter_t *bq, double frequency, int samplerate, int iterations)
-{
-	double Fc, Q, K, norm;
-
-	memset(bq, 0, sizeof(*bq));
-	bq->iter = iterations;
-	Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
-	Fc = frequency / (double)samplerate;
-	K = tan(PI * Fc);
-	norm = 1 / (1 + K / Q + K * K);
-	bq->a0 = 1 * norm;
-	bq->a1 = -2 * bq->a0;
-	bq->a2 = bq->a0;
-	bq->b1 = 2 * (K * K - 1) * norm;
-	bq->b2 = (1 - K / Q + K * K) * norm;
-}
-
-void filter_process(filter_t *bq, sample_t *samples, int length)
-{
-	double a0, a1, a2, b1, b2;
-	double *z1, *z2;
-	double in, out;
-	int iterations = bq->iter;
-	int i, j;
-
-	/* get states */
-	a0 = bq->a0;
-	a1 = bq->a1;
-	a2 = bq->a2;
-	b1 = bq->b1;
-	b2 = bq->b2;
-
-	z1 = bq->z1;
-	z2 = bq->z2;
-
-	/* process filter */
-	for (i = 0; i < length; i++) {
-		in = *samples;
-		for (j = 0; j < iterations; j++) {
-			out = in * a0 + z1[j];
-			z1[j] = in * a1 + z2[j] - b1 * out;
-			z2[j] = in * a2 - b2 * out;
-			in = out;
-		}
-		*samples++ = in;
-	}
-}
-