output/gnuplot: Support getting samplerate from meta packets.

output/gnuplot.c

@@ -29,48 +29,32 @@
 
 struct context {
 	unsigned int num_enabled_channels;
+	uint64_t samplerate;
 	uint64_t samplecount;
-	GString *header;
+	gboolean header_done;
 	uint8_t *prevsample;
 	int *channel_index;
 };
 
 static const char *gnuplot_header = "\
-# Sample data in space-separated columns format usable by gnuplot\n\
+# Sample data in space-separated columns format usable by gnuplot.\n";
-#\n\
+static const char *gnuplot_header2 = "\
-# Generated by: %s on %s%s\
+#\n# Column\tChannel\n\
-# Period: %s\n\
+# -----------------------------------------------------------------------------\n\
-#\n\
+# 0\t\tSample counter (for internal gnuplot purposes)\n";
-# Column\tChannel\n\
-# -------------------------------------\
-----------------------------------------\n\
-# 0\t\tSample counter (for internal gnuplot purposes)\n%s\n";
 
-static const char *gnuplot_header_comment = "\
-# Comment: Acquisition with %d/%d channels at %s\n";
 
 static int init(struct sr_output *o)
 {
 	struct context *ctx;
 	struct sr_channel *ch;
 	GSList *l;
-	GVariant *gvar;
+	unsigned int i;
-	uint64_t samplerate;
-	unsigned int i, j;
-	int num_channels;
-	char *c, *frequency_s;
-	char wbuf[1000], comment[128];
-	time_t t;
 
-	if (!o)
+	if (!o || !o->sdi)
 		return SR_ERR_ARG;
 
-	if (!o->sdi)
+	ctx = g_malloc0(sizeof(struct context));
-		return SR_ERR_ARG;
-
-	if (!(ctx = g_malloc0(sizeof(struct context))))
-		return SR_ERR_MALLOC;
-
 	o->internal = ctx;
 	ctx->num_enabled_channels = 0;
 	for (l = o->sdi->channels; l; l = l->next) {
@@ -87,56 +71,72 @@ static int init(struct sr_output *o)
 	}
 	ctx->channel_index = g_malloc(sizeof(int) * ctx->num_enabled_channels);
 
-	num_channels = g_slist_length(o->sdi->channels);
+	/* Once more to map the enabled channels. */
-	comment[0] = '\0';
+	for (i = 0, l = o->sdi->channels; l; l = l->next) {
-	samplerate = 0;
-	if (sr_config_get(o->sdi->driver, o->sdi, NULL, SR_CONF_SAMPLERATE,
-			&gvar) == SR_OK) {
-		samplerate = g_variant_get_uint64(gvar);
-		g_variant_unref(gvar);
-		if (!(frequency_s = sr_samplerate_string(samplerate))) {
-			sr_err("%s: sr_samplerate_string failed", __func__);
-			g_free(ctx);
-			return SR_ERR;
-		}
-		snprintf(comment, 127, gnuplot_header_comment,
-			ctx->num_enabled_channels, num_channels, frequency_s);
-		g_free(frequency_s);
-	}
-
-	/* Columns / channels */
-	wbuf[0] = '\0';
-	for (i = 0, j = 0, l = o->sdi->channels; l; l = l->next, i++) {
 		ch = l->data;
 		if (ch->type != SR_CHANNEL_LOGIC)
 			continue;
 		if (!ch->enabled)
 			continue;
-		c = (char *)&wbuf + strlen((const char *)&wbuf);
+		ctx->channel_index[i++] = ch->index;
-		sprintf(c, "# %d\t\t%s\n", i + 1, ch->name);
-		/* Remember the enabled channel's index while we're at it. */
-		ctx->channel_index[j++] = i;
 	}
 
-	if (!(frequency_s = sr_period_string(samplerate))) {
+	return SR_OK;
-		sr_err("%s: sr_period_string failed", __func__);
+}
-		g_free(ctx);
+
-		return SR_ERR;
+static GString *gen_header(struct sr_output *o)
+{
+	struct context *ctx;
+	struct sr_channel *ch;
+	GVariant *gvar;
+	GString *header;
+	time_t t;
+	unsigned int num_channels, i;
+	char *samplerate_s;
+
+	ctx = o->internal;
+	if (ctx->samplerate == 0) {
+		if (sr_config_get(o->sdi->driver, o->sdi, NULL, SR_CONF_SAMPLERATE,
+				&gvar) == SR_OK) {
+			ctx->samplerate = g_variant_get_uint64(gvar);
+			g_variant_unref(gvar);
+		}
 	}
 
 	t = time(NULL);
-	ctx->header = g_string_sized_new(512);
+	header = g_string_sized_new(512);
-	g_string_printf(ctx->header, gnuplot_header, PACKAGE_STRING,
+	g_string_printf(header, "%s", gnuplot_header);
-			ctime(&t), comment, frequency_s, (char *)&wbuf);
+	g_string_append_printf(header, "# Generated by %s on %s",
-	g_free(frequency_s);
+			PACKAGE_STRING, ctime(&t));
 
-	return 0;
+	num_channels = g_slist_length(o->sdi->channels);
+	g_string_append_printf(header, "# Acquisition with %d/%d channels",
+			ctx->num_enabled_channels, num_channels);
+	if (ctx->samplerate != 0) {
+		samplerate_s = sr_samplerate_string(ctx->samplerate);
+		g_string_append_printf(header, " at %s", samplerate_s);
+		g_free(samplerate_s);
+	}
+	g_string_append_printf(header, "\n");
+
+	g_string_append_printf(header, "%s", gnuplot_header2);
+
+	/* Columns / channels */
+	for (i = 0; i < ctx->num_enabled_channels; i++) {
+		ch = g_slist_nth_data(o->sdi->channels, ctx->channel_index[i]);
+		g_string_append_printf(header, "# %d\t\t%s\n", i + 1, ch->name);
+	}
+
+	return header;
 }
 
 static int receive(struct sr_output *o, const struct sr_datafeed_packet *packet,
 		GString **out)
 {
+	const struct sr_datafeed_meta *meta;
 	const struct sr_datafeed_logic *logic;
+	const struct sr_config *src;
+	GSList *l;
 	struct context *ctx;
 	const uint8_t *sample;
 	unsigned int curbit, p, idx, i;
@@ -146,24 +146,28 @@ static int receive(struct sr_output *o, const struct sr_datafeed_packet *packet,
 		return SR_ERR_BUG;
 	ctx = o->internal;
 
+	if (packet->type == SR_DF_META) {
+		meta = packet->payload;
+		for (l = meta->config; l; l = l->next) {
+			src = l->data;
+			if (src->key != SR_CONF_SAMPLERATE)
+				continue;
+			ctx->samplerate = g_variant_get_uint64(src->data);
+		}
+	}
+
 	if (packet->type != SR_DF_LOGIC)
 		return SR_OK;
 	logic = packet->payload;
 
 	if (!ctx->prevsample) {
 		/* Can't allocate this until we know the stream's unitsize. */
-		if (!(ctx->prevsample = g_malloc0(logic->unitsize))) {
+		ctx->prevsample = g_malloc0(logic->unitsize);
-			g_free(ctx);
-			sr_err("%s: ctx->prevsample malloc failed", __func__);
-			return SR_ERR_MALLOC;
-		}
 	}
 
-	if (ctx->header) {
+	if (!ctx->header_done) {
-		/* The header is still here, this must be the first packet. */
+		*out = gen_header(o);
-		*out = ctx->header;
+		ctx->header_done = TRUE;
-		ctx->header = NULL;
-		ctx->samplecount = 0;
 	} else {
 		*out = g_string_sized_new(512);
 	}
@@ -206,8 +210,6 @@ static int cleanup(struct sr_output *o)
 	ctx = o->internal;
 	g_free(ctx->channel_index);
 	g_free(ctx->prevsample);
-	if (ctx->header)
-		g_string_free(ctx->header, TRUE);
 	g_free(ctx);
 
 	return SR_OK;