From 713b1ab118f4ded11a8435bbd4d81c117e7fe180 Mon Sep 17 00:00:00 2001
From: Andreas Eversberg <jolly@eversberg.eu>
Date: Thu, 5 Jan 2017 15:53:55 +0100
Subject: [PATCH] Rename functions and structure of biquad lowpass filter

---
 src/cnetz/scrambler.c   | 4 ++--
 src/cnetz/scrambler.h   | 2 +-
 src/common/filter.c     | 4 ++--
 src/common/filter.h     | 8 ++++----
 src/common/samplerate.c | 8 ++++----
 src/common/samplerate.h | 4 ++--
 6 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/src/cnetz/scrambler.c b/src/cnetz/scrambler.c
index 5b1af19..461fe76 100644
--- a/src/cnetz/scrambler.c
+++ b/src/cnetz/scrambler.c
@@ -48,7 +48,7 @@ void scrambler_init(void)
 
 void scrambler_setup(scrambler_t *scrambler, int samplerate)
 {
-	biquad_init(&scrambler->bq, CARRIER_HZ - FILTER_BELOW, samplerate);
+	filter_lowpass_init(&scrambler->lp, CARRIER_HZ - FILTER_BELOW, samplerate);
 	scrambler->carrier_phaseshift256 = 256.0 / ((double)samplerate / CARRIER_HZ);
 }
 
@@ -77,7 +77,7 @@ void scrambler(scrambler_t *scrambler, int16_t *samples, int length)
 	scrambler->carrier_phase256 = phase;
 
 	/* cut off carrier frequency and modulation above carrier frequency */
-	biquad_process(&scrambler->bq, spl, length, FILTER_TURNS);
+	filter_lowpass_process(&scrambler->lp, spl, length, FILTER_TURNS);
 
 	for (i = 0; i < length; i++) {
 		/* store result */
diff --git a/src/cnetz/scrambler.h b/src/cnetz/scrambler.h
index 7b5deff..757940b 100644
--- a/src/cnetz/scrambler.h
+++ b/src/cnetz/scrambler.h
@@ -3,7 +3,7 @@
 typedef struct scrambler {
 	double			carrier_phaseshift256;	/* carrier phase shift per sample */
 	double			carrier_phase256;	/* current phase of carrier frequency */
-	biquad_low_pass_t	bq;			/* filter to remove carrier frequency */
+	filter_lowpass_t	lp;			/* filter to remove carrier frequency */
 } scrambler_t;
 
 void scrambler_init(void);
diff --git a/src/common/filter.c b/src/common/filter.c
index 106ed7c..f568f1b 100644
--- a/src/common/filter.c
+++ b/src/common/filter.c
@@ -28,7 +28,7 @@
 
 //#define CASCADE
 
-void biquad_init(biquad_low_pass_t *bq, double frequency, int samplerate)
+void filter_lowpass_init(filter_lowpass_t *bq, double frequency, int samplerate)
 {
 	double Fc, Q, K, norm;
 
@@ -44,7 +44,7 @@ void biquad_init(biquad_low_pass_t *bq, double frequency, int samplerate)
 	bq->b2 = (1 - K / Q + K * K) * norm;
 }
 
-void biquad_process(biquad_low_pass_t *bq, double *samples, int length, int iterations)
+void filter_lowpass_process(filter_lowpass_t *bq, double *samples, int length, int iterations)
 {
 	double a0, a1, a2, b1, b2;
 	double *z1, *z2;
diff --git a/src/common/filter.h b/src/common/filter.h
index 6517731..09a379b 100644
--- a/src/common/filter.h
+++ b/src/common/filter.h
@@ -1,12 +1,12 @@
 #ifndef _FILTER_H
 #define _FILTER_H
 
-typedef struct biquad_low_pass {
+typedef struct filter_lowpass {
 	double a0, a1, a2, b1, b2;
 	double z1[10], z2[10];
-} biquad_low_pass_t;
+} filter_lowpass_t;
 
-void biquad_init(biquad_low_pass_t *bq, double frequency, int samplerate);
-void biquad_process(biquad_low_pass_t *bq, double *samples, int length, int iterations);
+void filter_lowpass_init(filter_lowpass_t *bq, double frequency, int samplerate);
+void filter_lowpass_process(filter_lowpass_t *bq, double *samples, int length, int iterations);
 
 #endif /* _FILTER_H */
diff --git a/src/common/samplerate.c b/src/common/samplerate.c
index 630ba5d..8113055 100644
--- a/src/common/samplerate.c
+++ b/src/common/samplerate.c
@@ -37,8 +37,8 @@ int init_samplerate(samplerate_t *state, double samplerate)
 	memset(state, 0, sizeof(*state));
 	state->factor = samplerate / 8000.0;
 
-	biquad_init(&state->up.bq, 4000.0, samplerate);
-	biquad_init(&state->down.bq, 4000.0, samplerate);
+	filter_lowpass_init(&state->up.lp, 4000.0, samplerate);
+	filter_lowpass_init(&state->down.lp, 4000.0, samplerate);
 
 	return 0;
 }
@@ -56,7 +56,7 @@ int samplerate_downsample(samplerate_t *state, int16_t *input, int input_num, in
 		spl[i] = *input++ / 32768.0;
 
 	/* filter down */
-	biquad_process(&state->down.bq, spl, input_num, 1);
+	filter_lowpass_process(&state->down.lp, spl, input_num, 1);
 
 	/* resample filtered result */
 	in_index = state->down.in_index;
@@ -125,7 +125,7 @@ int samplerate_upsample(samplerate_t *state, int16_t *input, int input_num, int1
 	state->up.in_index = in_index;
 
 	/* filter up */
-	biquad_process(&state->up.bq, spl, output_num, 1);
+	filter_lowpass_process(&state->up.lp, spl, output_num, 1);
 
 	/* convert double to samples */
 	for (i = 0; i < output_num; i++) {
diff --git a/src/common/samplerate.h b/src/common/samplerate.h
index 66e4912..27955de 100644
--- a/src/common/samplerate.h
+++ b/src/common/samplerate.h
@@ -3,11 +3,11 @@
 typedef struct samplerate {
 	double factor;
 	struct {
-		biquad_low_pass_t bq;
+		filter_lowpass_t lp;
 		double in_index;
 	} down;
 	struct {
-		biquad_low_pass_t bq;
+		filter_lowpass_t lp;
 		double in_index;
 	} up;
 } samplerate_t;