output/wav: Initial module implementation.

src/output/wav.c

@@ -17,32 +17,317 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <string.h>
 #include "libsigrok.h"
 #include "libsigrok-internal.h"
 
 #define LOG_PREFIX "output/wav"
 
-static int init(struct sr_output *o, GHashTable *options)
+/* Minimum/maximum number of samples per channel to put in a data chunk */
+#define MIN_DATA_CHUNK_SAMPLES 10
+
+struct out_context {
+	gboolean header_done;
+	uint64_t samplerate;
+	int num_channels;
+	GSList *channels;
+	int chanbuf_size;
+	int *chanbuf_used;
+	uint8_t **chanbuf;
+};
+
+static int realloc_chanbufs(const struct sr_output *o, int size)
 {
-	(void)o;
+	struct out_context *outc;
-	(void)options;
+	int i;
+
+	outc = o->priv;
+	for (i = 0; i < outc->num_channels; i++) {
+		if (!(outc->chanbuf[i] = g_try_realloc(outc->chanbuf[i], sizeof(float) * size))) { 
+			sr_err("Unable to allocate enough output buffer memory.");
+			return SR_ERR;
+		}
+		outc->chanbuf_used[i] = 0;
+	}
+	outc->chanbuf_size = size;
 
 	return SR_OK;
 }
 
+static int flush_chanbufs(const struct sr_output *o, GString *out)
+{
+	struct out_context *outc;
+	int size, i, j;
+	char *buf, **bufp;
+
+	outc = o->priv;
+
+	/* Any one of them will do. */
+	size = outc->chanbuf_used[0];
+	if (!(buf = g_try_malloc(4 * size * outc->num_channels))) {
+		sr_err("Unable to allocate enough interleaved output buffer memory.");
+		return SR_ERR;
+	}
+	bufp = g_malloc(sizeof(char *) * outc->num_channels);
+	for (i = 0; i < outc->num_channels; i++)
+		bufp[i] = buf + i * 4;
+
+	for (i = 0; i < size * 4; i += 4) {
+		for (j = 0; j < outc->num_channels; j++) {
+			memcpy(bufp[j], outc->chanbuf[j] + i, 4);
+			bufp[j] += outc->num_channels * 4;
+		}
+	}
+	g_string_append_len(out, buf, 4 * size * outc->num_channels);
+	g_free(bufp);
+	g_free(buf);
+
+	for (i = 0; i < outc->num_channels; i++)
+		outc->chanbuf_used[i] = 0;
+
+	return SR_OK;
+}
+
+static int init(struct sr_output *o, GHashTable *options)
+{
+	struct out_context *outc;
+	struct sr_channel *ch;
+	GSList *l;
+
+	(void)options;
+
+	outc = g_malloc0(sizeof(struct out_context));
+	o->priv = outc;
+
+	for (l = o->sdi->channels; l; l = l->next) {
+		ch = l->data;
+		if (ch->type != SR_CHANNEL_ANALOG)
+			continue;
+		if (!ch->enabled)
+			continue;
+		outc->channels = g_slist_append(outc->channels, ch);
+		outc->num_channels++;
+	}
+
+	outc->chanbuf = g_malloc0(sizeof(float *) * outc->num_channels);
+	outc->chanbuf_used = g_malloc0(sizeof(int) * outc->num_channels);
+
+	/* Start off the interleaved buffer with 100 samples/channel. */
+	realloc_chanbufs(o, 100);
+
+	return SR_OK;
+}
+
+static void add_data_chunk(const struct sr_output *o, GString *gs)
+{
+	struct out_context *outc;
+	char tmp[4];
+
+	outc = o->priv;
+	g_string_append(gs, "fmt ");
+	/* Remaining chunk size */
+	WL32(tmp, 0x12);
+	g_string_append_len(gs, tmp, 4);
+	/* Format code 3 = IEEE float */
+	WL16(tmp, 0x0003);
+	g_string_append_len(gs, tmp, 2);
+	/* Number of channels */
+	WL16(tmp, outc->num_channels);
+	g_string_append_len(gs, tmp, 2);
+	/* Samplerate */
+	WL32(tmp, outc->samplerate);
+	g_string_append_len(gs, tmp, 4);
+	/* Byterate, using 32-bit floats. */
+	WL32(tmp, outc->samplerate * outc->num_channels * 4);
+	g_string_append_len(gs, tmp, 4);
+	/* Blockalign */
+	WL16(tmp, outc->num_channels * 4);
+	g_string_append_len(gs, tmp, 2);
+	/* Bits per sample */
+	WL16(tmp, 32);
+	g_string_append_len(gs, tmp, 2);
+	WL16(tmp, 0);
+	g_string_append_len(gs, tmp, 2);
+
+	g_string_append(gs, "data");
+	/* Data chunk size, max it out. */
+	WL32(tmp, 0xffffffff);
+	g_string_append_len(gs, tmp, 4);
+}
+
+static GString *gen_header(const struct sr_output *o)
+{
+	struct out_context *outc;
+	GVariant *gvar;
+	GString *header;
+	char tmp[4];
+
+	outc = o->priv;
+	if (outc->samplerate == 0) {
+		if (sr_config_get(o->sdi->driver, o->sdi, NULL, SR_CONF_SAMPLERATE,
+				&gvar) == SR_OK) {
+			outc->samplerate = g_variant_get_uint64(gvar);
+			g_variant_unref(gvar);
+		}
+	}
+
+	header = g_string_sized_new(512);
+	g_string_append(header, "RIFF");
+	/* Total size. Max out the field. */
+	WL32(tmp, 0xffffffff);
+	g_string_append_len(header, tmp, 4);
+	g_string_append(header, "WAVE");
+	add_data_chunk(o, header);
+
+	return header;
+}
+
+/*
+ * Stores the float in little-endian BINARY32 IEEE-754 2008 format.
+ */
+static void float_to_le(uint8_t *buf, float value)
+{
+	char *old;
+
+	old = (char *)&value;
+#ifdef WORDS_BIGENDIAN
+	buf[0] = old[3];
+	buf[1] = old[2];
+	buf[2] = old[1];
+	buf[3] = old[0];
+#else
+	buf[0] = old[0];
+	buf[1] = old[1];
+	buf[2] = old[2];
+	buf[3] = old[3];
+#endif
+}
+
+/*
+ * Returns the number of samples used in the current channel buffers,
+ * or -1 if they're not all the same.
+ */
+static int check_chanbuf_size(const struct sr_output *o)
+{
+	struct out_context *outc;
+	int size, i;
+
+	outc = o->priv;
+	size = 0;
+	for (i = 0; i < outc->num_channels; i++) {
+		if (size == 0) {
+			if (outc->chanbuf_used[i] == 0) {
+				/* Nothing in all the buffers yet. */
+				size = -1;
+				break;
+			} else
+				/* New high water mark. */
+				size = outc->chanbuf_used[i];
+		} else if (outc->chanbuf_used[i] != size) {
+			/* All channel buffers are not equally full yet. */
+			size = -1;
+			break;
+		}
+	}
+
+	return size;
+}
 static int receive(const struct sr_output *o, const struct sr_datafeed_packet *packet,
 		GString **out)
 {
-	(void)o;
+	struct out_context *outc;
-	(void)packet;
+	const struct sr_datafeed_meta *meta;
-	(void)out;
+	const struct sr_datafeed_analog *analog;
+	const struct sr_config *src;
+	struct sr_channel *ch;
+	GSList *l;
+	int num_channels, size, *chan_idx, idx, i, j;
+	uint8_t *buf;
+
+	*out = NULL;
+	if (!o || !o->sdi || !(outc = o->priv))
+		return SR_ERR_ARG;
+
+	switch (packet->type) {
+	case SR_DF_META:
+		meta = packet->payload;
+		for (l = meta->config; l; l = l->next) {
+			src = l->data;
+			if (src->key != SR_CONF_SAMPLERATE)
+				continue;
+			outc->samplerate = g_variant_get_uint64(src->data);
+		}
+		break;
+	case SR_DF_ANALOG:
+		if (!outc->header_done) {
+			*out = gen_header(o);
+			outc->header_done = TRUE;
+		} else
+			*out = g_string_sized_new(512);
+
+		analog = packet->payload;
+		if (analog->num_samples == 0)
+			return SR_OK;
+
+		num_channels = g_slist_length(analog->channels);
+		if (num_channels > outc->num_channels) {
+			sr_err("Packet has %d channels, but only %d were enabled.",
+					num_channels, outc->num_channels);
+			return SR_ERR;
+		}
+
+		if (analog->num_samples > outc->chanbuf_size) {
+			if (realloc_chanbufs(o, analog->num_samples) != SR_OK)
+				return SR_ERR_MALLOC;
+		}
+
+		/* Index the channels in this packet, so we can interleave quicker. */
+		chan_idx = g_malloc(sizeof(int) * outc->num_channels);
+		for (i = 0; i < num_channels; i++) {
+			ch = g_slist_nth_data(analog->channels, i);
+			chan_idx[i] = g_slist_index(outc->channels, ch);
+		}
+
+		for (i = 0; i < analog->num_samples; i++) {
+			for (j = 0; j < num_channels; j++) {
+				idx = chan_idx[j];
+				buf = outc->chanbuf[idx] + outc->chanbuf_used[idx]++ * 4;
+				float_to_le(buf, analog->data[i + j]);
+			}
+		}
+		g_free(chan_idx);
+
+		size = check_chanbuf_size(o);
+		if (size > MIN_DATA_CHUNK_SAMPLES)
+			if (flush_chanbufs(o, *out) != SR_OK)
+				return SR_ERR;
+		break;
+	case SR_DF_END:
+		size = check_chanbuf_size(o);
+		if (size > 0) {
+			*out = g_string_sized_new(4 * size * outc->num_channels);
+			if (flush_chanbufs(o, *out) != SR_OK)
+				return SR_ERR;
+		}
+		break;
+	}
 
 	return SR_OK;
 }
 
 static int cleanup(struct sr_output *o)
 {
-	(void)o;
+	struct out_context *outc;
+	int i;
+
+	outc = o->priv;
+	g_slist_free(outc->channels);
+	for (i = 0; i < outc->num_channels; i++)
+		g_free(outc->chanbuf[i]);
+	g_free(outc->chanbuf_used);
+	g_free(outc->chanbuf);
+	g_free(outc);
+	o->priv = NULL;
 
 	return SR_OK;
 }
@@ -50,7 +335,7 @@ static int cleanup(struct sr_output *o)
 SR_PRIV struct sr_output_module output_wav = {
 	.id = "wav",
 	.name = "WAV",
-	.desc = "WAVE PCM sound module",
+	.desc = "WAVE file format",
 	.init = init,
 	.receive = receive,
 	.cleanup = cleanup,