X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Foutput%2Fwavedrom.c;h=65324bdc45f0a9c60d8c06456253ccdd756a9853;hb=f5c697bfe6d80c95051eaa1f52e1fefb54effa97;hp=67f33b60da8b6f1c10f9baf8abbdfd3315779a6e;hpb=dd5735c998264699d586a52b6ed5b4bf64397ee0;p=libsigrok.git

diff --git a/src/output/wavedrom.c b/src/output/wavedrom.c
index 67f33b60..65324bdc 100644
--- a/src/output/wavedrom.c
+++ b/src/output/wavedrom.c
@@ -69,6 +69,79 @@ static GString *wavedrom_render(const struct context *ctx)
 	return output;
 }
 
+static void process_logic(const struct context *ctx,
+	const struct sr_datafeed_logic *logic)
+{
+	size_t sample_count, ch, i;
+	uint8_t *sample, bit;
+	GString *accu;
+
+	if (!ctx->channel_count)
+		return;
+
+	/*
+	 * Extract the logic bits for each channel and store them
+	 * as wavedrom letters (1/0) in each channel's text string.
+	 * This transforms the input which consists of sample sets
+	 * that span multiple channels into output stripes per logic
+	 * channel which consist of bits for that individual channel.
+	 *
+	 * TODO Reduce memory consumption during accumulation of
+	 * output data.
+	 *
+	 * Ideally we'd accumulate binary chunks, and defer conversion
+	 * to the text format. Analog data already won't get here, only
+	 * logic data does. When the per-channel transformation also
+	 * gets deferred until later, then the only overhead would be
+	 * for disabled logic channels. Which may be acceptable or even
+	 * negligable.
+	 *
+	 * An optional addition to the above mentioned accumulation of
+	 * binary data is RLE compression. Mark both the position in the
+	 * accumulated data as well as a repetition counter, instead of
+	 * repeatedly storing the same sample set. The efficiency of
+	 * this approach of course depends on the change rate of input
+	 * data. But the approach perfectly matches the WaveDrom syntax
+	 * for repeated bit patterns, and thus is easily handled in the
+	 * text rendering stage of the output module.
+	 */
+	sample_count = logic->length / logic->unitsize;
+	for (i = 0; i < sample_count; i++) {
+		sample = logic->data + i * logic->unitsize;
+		for (ch = 0; ch < ctx->channel_count; ch++) {
+			accu = ctx->channel_outputs[ch];
+			if (!accu)
+				continue;
+			bit = sample[ch / 8] & (1 << (ch % 8));
+			g_string_append_c(accu, bit ? '1' : '0');
+		}
+	}
+}
+
+static int receive(const struct sr_output *o,
+	const struct sr_datafeed_packet *packet, GString **out)
+{
+	struct context *ctx;
+
+	*out = NULL;
+
+	if (!o || !o->sdi || !o->priv)
+		return SR_ERR_ARG;
+
+	ctx = o->priv;
+
+	switch (packet->type) {
+	case SR_DF_LOGIC:
+		process_logic(ctx, packet->payload);
+		break;
+	case SR_DF_END:
+		*out = wavedrom_render(ctx);
+		break;
+	}
+
+	return SR_OK;
+}
+
 static int init(struct sr_output *o, GHashTable *options)
 {
 	struct context *ctx;
@@ -125,56 +198,6 @@ static int cleanup(struct sr_output *o)
 	return SR_OK;
 }
 
-static void process_logic(const struct context *ctx,
-	const struct sr_datafeed_logic *logic)
-{
-	size_t sample_count, ch, i;
-	uint8_t *sample;
-
-	sample_count = logic->length / logic->unitsize;
-
-	/*
-	 * Extract the logic bits for each channel and store them
-	 * as wavedrom letters (1/0) in each channel's text string.
-	 */
-	for (ch = 0; ch < ctx->channel_count; ch++) {
-		if (ctx->channels[ch]) {
-			for (i = 0; i < sample_count; i++) {
-				sample = logic->data + i * logic->unitsize;
-
-				if (ctx->channel_outputs[ch]) {
-					g_string_append_c(ctx->channel_outputs[ch],
-						sample[ch / 8] & (1 << (ch % 8)) ? '1' : '0');
-				}
-			}
-		}
-	}
-}
-
-static int receive(const struct sr_output *o,
-	const struct sr_datafeed_packet *packet, GString **out)
-{
-	struct context *ctx;
-
-	*out = NULL;
-
-	if (!o || !o->sdi || !o->priv)
-		return SR_ERR_ARG;
-
-	ctx = o->priv;
-
-	switch (packet->type) {
-	case SR_DF_LOGIC:
-		process_logic(ctx, packet->payload);
-		break;
-	case SR_DF_END:
-		*out = wavedrom_render(ctx);
-		break;
-	}
-
-	return SR_OK;
-}
-
 SR_PRIV struct sr_output_module output_wavedrom = {
 	.id = "wavedrom",
 	.name = "WaveDrom",