From ba0b4e0db50c3f04e0b96dcc44ac8ed75679c945 Mon Sep 17 00:00:00 2001
From: Reiner Herrmann <reiner@reiner-h.de>
Date: Sat, 8 Apr 2017 20:59:09 +0200
Subject: Add capturing skeleton for new tuner program

---
 Makefile    | 16 +++++++----
 metronome.c |  2 +-
 tuner.c     | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+), 6 deletions(-)
 create mode 100644 tuner.c

diff --git a/Makefile b/Makefile
index 9fe729c..19fe7e6 100644
--- a/Makefile
+++ b/Makefile
@@ -1,12 +1,18 @@
 CFLAGS = -Wall -Wextra -Werror -ggdb3 -O3
 LDFLAGS = -lasound -lm -lrt
 
-OBJS = metronome.o
-BIN = metronome
+METRONOME_OBJS = metronome.o
+METRONOME_BIN = metronome
+TUNER_OBJS = tuner.o
+TUNER_BIN = tuner
 
-$(BIN): $(OBJS)
+OBJS = $(METRONOME_OBJS) $(TUNER_OBJS)
+BINS = $(METRONOME_BIN) $(TUNER_BIN)
 
-all: $(BIN)
+all: $(BINS)
+
+$(METRONOME_BIN): $(METRONOME_OBJS)
+$(TUNER_BIN): $(TUNER_OBJS)
 
 clean:
-	rm -f $(OBJS) $(BIN)
+	rm -f $(OBJS) $(BINS)
diff --git a/metronome.c b/metronome.c
index 79d2fc2..adbae9d 100644
--- a/metronome.c
+++ b/metronome.c
@@ -69,7 +69,7 @@ static int set_alsa_params(snd_pcm_t *pcm_handle)
 		return -1;
 	}
 	if (snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, &bufsize) < 0) {
-		fprintf(stderr, "Failed setting sample rate\n");
+		fprintf(stderr, "Failed setting buffer size\n");
 		return -1;
 	}
 	if (snd_pcm_hw_params_set_channels(pcm_handle, hwparams, 1) < 0) {
diff --git a/tuner.c b/tuner.c
new file mode 100644
index 0000000..0747f3f
--- /dev/null
+++ b/tuner.c
@@ -0,0 +1,94 @@
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <signal.h>
+#include <alsa/asoundlib.h>
+
+#define SAMPLE_RATE 8000
+#define BUFFER_SIZE 4096
+
+static int capturing = 1;
+
+static void handle_signals(int signum __attribute__((unused)))
+{
+	capturing = 0;
+}
+
+static int set_alsa_params(snd_pcm_t *pcm_handle)
+{
+	snd_pcm_hw_params_t *hwparams;
+	unsigned int rate = SAMPLE_RATE;
+	snd_pcm_uframes_t bufsize = BUFFER_SIZE;
+
+	snd_pcm_hw_params_alloca(&hwparams);
+
+	if (snd_pcm_hw_params_any(pcm_handle, hwparams) < 0) {
+		fprintf(stderr, "Failed configuring device\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED) < 0) {
+		fprintf(stderr, "Failed setting access mode\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_format(pcm_handle, hwparams, SND_PCM_FORMAT_S16_LE) < 0) {
+		fprintf(stderr, "Failed setting format\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, &rate, 0) < 0) {
+		fprintf(stderr, "Failed setting sample rate\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_buffer_size_near(pcm_handle, hwparams, &bufsize) < 0) {
+		fprintf(stderr, "Failed setting buffer size\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_channels(pcm_handle, hwparams, 1) < 0) {
+		fprintf(stderr, "Failed setting channel number\n");
+		return -1;
+	}
+	if (snd_pcm_hw_params(pcm_handle, hwparams) < 0) {
+		fprintf(stderr, "Failed applying hardware parameters\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+static void capture(snd_pcm_t *pcm_handle)
+{
+	char tonebuf[BUFFER_SIZE];
+	int n_frames = 0;
+	FILE* f = fopen("capture.raw", "w");
+
+	while(capturing) {
+		while ((n_frames = snd_pcm_readi(pcm_handle, tonebuf, sizeof(tonebuf) / 2)) < 0) {
+			snd_pcm_prepare(pcm_handle);
+			printf("overrun\n");
+		}
+		fwrite(tonebuf, n_frames*2, 1, f);
+	}
+	fclose(f);
+}
+
+int main()
+{
+	snd_pcm_t *pcm_handle;
+
+	if (snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_CAPTURE, 0) < 0) {
+		fprintf(stderr, "Failed opening device for capturing\n");
+		return 1;
+	}
+
+	if (set_alsa_params(pcm_handle) < 0) {
+		return 1;
+	}
+
+	signal(SIGINT, handle_signals);
+	signal(SIGTERM, handle_signals);
+
+	capture(pcm_handle);
+
+	snd_pcm_close(pcm_handle);
+
+	return 0;
+}
-- 
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