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rtl_sdr: add -n parameter (only read n samples)

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Signed-off-by: Steve Markgraf <steve@steve-m.de>
This commit is contained in:
Steve Markgraf 2012-10-20 19:43:13 +02:00
parent 25789493c6
commit cf66e3aa8b
1 changed files with 26 additions and 1 deletions
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27
src/rtl_sdr.c
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@ -38,6 +38,7 @@
#define MAXIMAL_BUF_LENGTH (256 * 16384) #define MAXIMAL_BUF_LENGTH (256 * 16384)
static int do_exit = 0; static int do_exit = 0;
static uint32_t bytes_to_read = 0;
static rtlsdr_dev_t *dev = NULL; static rtlsdr_dev_t *dev = NULL;
void usage(void) void usage(void)
@ -49,6 +50,7 @@ void usage(void)
"\t[-d device_index (default: 0)]\n" "\t[-d device_index (default: 0)]\n"
"\t[-g gain (default: 0 for auto)]\n" "\t[-g gain (default: 0 for auto)]\n"
"\t[-b output_block_size (default: 16 * 16384)]\n" "\t[-b output_block_size (default: 16 * 16384)]\n"
"\t[-n number of samples to read (default: 0, infinite)]\n"
"\t[-S force sync output (default: async)]\n" "\t[-S force sync output (default: async)]\n"
"\tfilename (a '-' dumps samples to stdout)\n\n"); "\tfilename (a '-' dumps samples to stdout)\n\n");
exit(1); exit(1);
@ -78,10 +80,22 @@ static void sighandler(int signum)
static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx) static void rtlsdr_callback(unsigned char *buf, uint32_t len, void *ctx)
{ {
if (ctx) { if (ctx) {
if (do_exit)
return;
if ((bytes_to_read > 0) && (bytes_to_read < len)) {
len = bytes_to_read;
do_exit = 1;
rtlsdr_cancel_async(dev);
}
if (fwrite(buf, 1, len, (FILE*)ctx) != len) { if (fwrite(buf, 1, len, (FILE*)ctx) != len) {
fprintf(stderr, "Short write, samples lost, exiting!\n"); fprintf(stderr, "Short write, samples lost, exiting!\n");
rtlsdr_cancel_async(dev); rtlsdr_cancel_async(dev);
} }
if (bytes_to_read > 0)
bytes_to_read -= len;
} }
} }
@ -104,7 +118,7 @@ int main(int argc, char **argv)
int device_count; int device_count;
char vendor[256], product[256], serial[256]; char vendor[256], product[256], serial[256];
while ((opt = getopt(argc, argv, "d:f:g:s:b:S::")) != -1) { while ((opt = getopt(argc, argv, "d:f:g:s:b:n:S::")) != -1) {
switch (opt) { switch (opt) {
case 'd': case 'd':
dev_index = atoi(optarg); dev_index = atoi(optarg);
@ -121,6 +135,9 @@ int main(int argc, char **argv)
case 'b': case 'b':
out_block_size = (uint32_t)atof(optarg); out_block_size = (uint32_t)atof(optarg);
break; break;
case 'n':
bytes_to_read = (uint32_t)atof(optarg) * 2;
break;
case 'S': case 'S':
sync_mode = 1; sync_mode = 1;
break; break;
@ -236,6 +253,11 @@ int main(int argc, char **argv)
break; break;
} }
if ((bytes_to_read > 0) && (bytes_to_read < (uint32_t)n_read)) {
n_read = bytes_to_read;
do_exit = 1;
}
if (fwrite(buffer, 1, n_read, file) != (size_t)n_read) { if (fwrite(buffer, 1, n_read, file) != (size_t)n_read) {
fprintf(stderr, "Short write, samples lost, exiting!\n"); fprintf(stderr, "Short write, samples lost, exiting!\n");
break; break;
@ -245,6 +267,9 @@ int main(int argc, char **argv)
fprintf(stderr, "Short read, samples lost, exiting!\n"); fprintf(stderr, "Short read, samples lost, exiting!\n");
break; break;
} }
if (bytes_to_read > 0)
bytes_to_read -= n_read;
} }
} else { } else {
fprintf(stderr, "Reading samples in async mode...\n"); fprintf(stderr, "Reading samples in async mode...\n");