[alsa-devel] [TINYCOMPRESS PATCH 2/2] crec: Add primitive exception handling

[Charles Keepax]

Add very primitive signal handling, we will not attempt to drain any
remaining data etc. simply save out what we have to a file.

Signed-off-by: Charles Keepax <ckeepax at opensource.wolfsonmicro.com>
---
 crec.c |   90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 files changed, 77 insertions(+), 13 deletions(-)

diff --git a/crec.c b/crec.c
index d2fd873..73b2630 100644
--- a/crec.c
+++ b/crec.c
@@ -74,6 +74,7 @@
 #include "tinycompress/tinycompress.h"
 
 static int verbose;
+static FILE *file;
 
 static const unsigned int DEFAULT_CHANNELS = 1;
 static const unsigned int DEFAULT_RATE = 44100;
@@ -183,6 +184,62 @@ static int print_time(struct compress *compress)
 	return 0;
 }
 
+static int finish_record()
+{
+	struct wave_header header;
+	int ret;
+	size_t read, written;
+
+	if (!file)
+		return -ENOENT;
+
+	/* Get amount of data written to file */
+	ret = fseek(file, 0, SEEK_END);
+	if (ret < 0)
+		goto seek_error;
+	ret = ftell(file);
+	if (ret < 0) {
+		fprintf(stderr, "Error reading file position: %s\n",
+			strerror(errno));
+		return errno;
+	}
+	written = ret;
+	if (written < sizeof(header)) {
+		fprintf(stderr, "No data recorded!\n");
+		return -ENOENT;
+	}
+	written -= sizeof(header);
+
+	/* Sync file header from file */
+	ret = fseek(file, 0, SEEK_SET);
+	if (ret < 0)
+		goto seek_error;
+	read = fread(&header, sizeof(header), 1, file);
+	if (read != 1) {
+		ret = ferror(file);
+		fprintf(stderr, "Error reading output file header: %d\n", ret);
+		return ret;
+	}
+
+	/* Update file header */
+	ret = fseek(file, 0, SEEK_SET);
+	if (ret < 0)
+		goto seek_error;
+	size_wave_header(&header, written);
+	written = fwrite(&header, sizeof(header), 1, file);
+	if (written != 1) {
+		ret = ferror(file);
+		fprintf(stderr, "Error updating output file header: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+
+seek_error:
+	fprintf(stderr, "Error seeking: %s\n", strerror(errno));
+	return errno;
+}
+
 void capture_samples(char *name, unsigned int card, unsigned int device,
 		     unsigned long buffer_size, unsigned int frag,
 		     unsigned int length, unsigned int rate,
@@ -192,7 +249,6 @@ void capture_samples(char *name, unsigned int card, unsigned int device,
 	struct snd_codec codec;
 	struct compress *compress;
 	struct wave_header header;
-	FILE *file;
 	char *buffer;
 	size_t written;
 	int read, ret;
@@ -318,25 +374,16 @@ void capture_samples(char *name, unsigned int card, unsigned int device,
 		fprintf(stderr, "ERR: %s\n", compress_get_error(compress));
 	}
 
-	/* Update file header now we know file size */
-	size_wave_header(&header, total_read);
-	ret = fseek(file, 0, SEEK_SET);
-	if (ret < 0) {
-		fprintf(stderr, "Error seeking: %s\n", stderror(errno));
+	ret = finish_record();
+	if (ret < 0)
 		goto buf_exit;
-	}
-	written = fwrite(&header, sizeof(header), 1, file);
-	if (written != 1) {
-		fprintf(stderr, "Error updating output file header: %d\n",
-			ferror(file));
-		goto buf_exit;
-	}
 
 	if (verbose)
 		printf("%s: exit success\n", __func__);
 
 	free(buffer);
 	fclose(file);
+	file = NULL;
 
 	compress_close(compress);
 
@@ -354,6 +401,18 @@ file_exit:
 	exit(EXIT_FAILURE);
 }
 
+static void sig_handler(int signum __attribute__ ((unused)))
+{
+	printf("Interrupted, saving what we have!\n");
+
+	finish_record();
+
+	if (file)
+		fclose(file);
+
+	_exit(EXIT_FAILURE);
+}
+
 int main(int argc, char **argv)
 {
 	char *file;
@@ -363,6 +422,11 @@ int main(int argc, char **argv)
 	unsigned int rate = DEFAULT_RATE, channels = DEFAULT_CHANNELS;
 	unsigned int format = DEFAULT_FORMAT;
 
+	if (signal(SIGINT, sig_handler) == SIG_ERR) {
+		fprintf(stderr, "Error registering signal handler\n");
+		exit(EXIT_FAILURE);
+	}
+
 	if (argc < 2)
 		usage();
 
-- 
1.7.2.5