gapk: Implement optional looping/rewinding of input files

Together with the recently-added throttling, this can be useful to
generate a continuous stream of RTP data from an input file.

Change-Id: I2d552695dfb4cc96039838e79e0f5ae25a6737c8

include/osmocom/gapk/procqueue.h

@@ -20,6 +20,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 #include <stdio.h> /* for FILE */
 
 #include <osmocom/core/linuxlist.h>
@@ -85,7 +86,7 @@ char *osmo_gapk_pq_describe(struct osmo_gapk_pq *pq);
 struct osmo_gapk_pq_item *osmo_gapk_pq_add_item(struct osmo_gapk_pq *pq);
 
 /* File */
-int osmo_gapk_pq_queue_file_input(struct osmo_gapk_pq *pq, FILE *src, unsigned int block_len);
+int osmo_gapk_pq_queue_file_input(struct osmo_gapk_pq *pq, FILE *src, unsigned int block_len, bool loop);
 int osmo_gapk_pq_queue_file_output(struct osmo_gapk_pq *pq, FILE *dst, unsigned int block_len);
 
 /* RTP */

src/app_osmo_gapk.c

@@ -68,6 +68,7 @@ struct gapk_options
 	/* RTP payload type */
 	uint8_t rtp_pt_in, rtp_pt_out;
 
+	bool loop_input;
 	int throttle;
 	int benchmark;
 	int verbose;
@@ -144,6 +145,7 @@ print_help(char *progname)
 	fprintf(stdout, "  -P  --rtp-pt-out=TYPE\t\tRTP payload type for outgoing frames\n");
 	fprintf(stdout, "  -b, --enable-benchmark\tEnable codec benchmarking\n");
 	fprintf(stdout, "  -t, --throttle\tEnable throttling (one codec frame every 20ms)\n");
+	fprintf(stdout, "  -l, --loop-input\tEnable looping of the input file\n");
 	fprintf(stdout, "  -v, --verbose\t\t\tEnable debug messages\n");
 	fprintf(stdout, "\n");
 
@@ -217,10 +219,11 @@ parse_options(struct gapk_state *state, int argc, char *argv[])
 		{"rtp-pt-out", 1, 0, 'P'},
 		{"enable-benchmark", 0, 0, 'b'},
 		{"throttle", 0, 0, 't'},
+		{"loop-input", 0, 0, 'l'},
 		{"verbose", 0, 0, 'v'},
 		{"help", 0, 0, 'h'},
 	};
-	const char *short_options = "i:o:I:O:f:g:p:P:btvh"
+	const char *short_options = "i:o:I:O:f:g:p:P:btlvh"
 #ifdef HAVE_ALSA
 		"a:A:"
 #endif
@@ -322,6 +325,10 @@ parse_options(struct gapk_state *state, int argc, char *argv[])
 			opt->throttle = 1;
 			break;
 
+		case 'l':
+			opt->loop_input = true;
+			break;
+
 		case 'v':
 			log_parse_category_mask(osmo_stderr_target, "DAPP");
 			opt->verbose = 1;
@@ -577,7 +584,7 @@ make_processing_chain(struct gapk_state *gs)
 
 	/* File read */
 	if (gs->in.file.fh)
-		osmo_gapk_pq_queue_file_input(gs->pq, gs->in.file.fh, fmt_in->frame_len);
+		osmo_gapk_pq_queue_file_input(gs->pq, gs->in.file.fh, fmt_in->frame_len, gs->opts.loop_input);
 	else if (gs->in.rtp.fd != -1)
 		osmo_gapk_pq_queue_rtp_input(gs->pq, gs->in.rtp.fd,
 			fmt_in->frame_len, gs->opts.rtp_pt_in);

src/pq_file.c

@@ -19,6 +19,7 @@
 
 #include <errno.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <talloc.h>
 
 #include <osmocom/gapk/logging.h>
@@ -30,6 +31,7 @@
 struct pq_state_file {
 	FILE *fh;
 	unsigned int blk_len;
+	bool loop_input;
 };
 
 
@@ -39,6 +41,14 @@ pq_cb_file_input(void *_state, uint8_t *out, const uint8_t *in, unsigned int in_
 	struct pq_state_file *state = _state;
 	int rv;
 	rv = fread(out, state->blk_len, 1, state->fh);
+	if (rv == 0 && state->loop_input && feof(state->fh)) {
+		/* FIXME: this only works for files without a header
+		 * (e.g. .gsm files) but not for those with header (like
+		 * .amr files). gs->opts.fmt_in->header is not
+		 * accessible here :/ */
+		fseek(state->fh, 0, SEEK_SET);
+		rv = fread(out, state->blk_len, 1, state->fh);
+	}
 	if (rv <= 0)
 		return -1;
 	return rv * state->blk_len;
@@ -60,7 +70,7 @@ pq_cb_file_exit(void *_state)
 }
 
 static int
-pq_queue_file_op(struct osmo_gapk_pq *pq, FILE *fh, unsigned int blk_len, int in_out_n)
+pq_queue_file_op(struct osmo_gapk_pq *pq, FILE *fh, unsigned int blk_len, int in_out_n, bool loop_input)
 {
 	struct osmo_gapk_pq_item *item;
 	struct pq_state_file *state;
@@ -71,6 +81,7 @@ pq_queue_file_op(struct osmo_gapk_pq *pq, FILE *fh, unsigned int blk_len, int in
 
 	state->fh = fh;
 	state->blk_len = blk_len;
+	state->loop_input = loop_input;
 
 	item = osmo_gapk_pq_add_item(pq);
 	if (!item) {
@@ -105,11 +116,11 @@ pq_queue_file_op(struct osmo_gapk_pq *pq, FILE *fh, unsigned int blk_len, int in
  *  \param[in] blk_len block length to be read from file
  *  \returns 0 on success; negative on error */
 int
-osmo_gapk_pq_queue_file_input(struct osmo_gapk_pq *pq, FILE *src, unsigned int blk_len)
+osmo_gapk_pq_queue_file_input(struct osmo_gapk_pq *pq, FILE *src, unsigned int blk_len, bool loop)
 {
 	LOGPGAPK(LOGL_DEBUG, "PQ '%s': Adding file input (blk_len=%u)\n",
 		pq->name, blk_len);
-	return pq_queue_file_op(pq, src, blk_len, 1);
+	return pq_queue_file_op(pq, src, blk_len, 1, loop);
 }
 
 /*! Add file output to given processing queue
@@ -123,5 +134,5 @@ osmo_gapk_pq_queue_file_output(struct osmo_gapk_pq *pq, FILE *dst, unsigned int
 {
 	LOGPGAPK(LOGL_DEBUG, "PQ '%s': Adding file output (blk_len=%u)\n",
 		pq->name, blk_len);
-	return pq_queue_file_op(pq, dst, blk_len, 0);
+	return pq_queue_file_op(pq, dst, blk_len, 0, false);
 }

tests/io/pq_file_test.c

@@ -81,7 +81,7 @@ static int pq_file_check(FILE *src_file, unsigned int blk_len)
 	assert(pq != NULL);
 
 	/* Add a file sink */
-	rc = osmo_gapk_pq_queue_file_input(pq, src_file, blk_len);
+	rc = osmo_gapk_pq_queue_file_input(pq, src_file, blk_len, false);
 	assert(rc == 0);
 
 	/* Add a processing item */