ols: Use a dynamic sample buffer

The number of samples to be received is pretty clear if no RLE is being used.
But if RLE is being used, the number of raw samples must be counted. For now,
read samples until we time out. This should work for RLE and non-RLE, but
may break if the device is connected via a high-latency network connection.

Author: v1ne

src/hardware/openbench-logic-sniffer/api.c

@@ -402,7 +402,7 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
 		return SR_ERR;
 
 	/* Reset all operational states. */
-	devc->rle_count = devc->num_transfers = 0;
+	devc->rle_count = devc->raw_sample_buf_size = 0;
 	devc->num_samples = devc->num_bytes = 0;
 	devc->cnt_bytes = devc->cnt_samples = devc->cnt_samples_rle = 0;
 	memset(devc->sample, 0, 4);

src/hardware/openbench-logic-sniffer/protocol.c

@@ -376,37 +376,23 @@ SR_PRIV int ols_receive_data(int fd, int revents, void *cb_data)
 	serial = sdi->conn;
 	devc = sdi->priv;
 
-	if (devc->num_transfers == 0 && revents == 0) {
+	if (devc->cnt_bytes == 0 && revents == 0) {
 		/* Ignore timeouts as long as we haven't received anything */
 		return TRUE;
 	}
 
-	if (devc->num_transfers++ == 0) {
-		devc->raw_sample_buf = g_try_malloc(devc->limit_samples * 4);
-		if (!devc->raw_sample_buf) {
-			sr_err("Sample buffer malloc failed.");
-			return FALSE;
-		}
-		/* fill with 1010... for debugging */
-		memset(devc->raw_sample_buf, 0x82, devc->limit_samples * 4);
-	}
-
 	num_changroups = 0;
 	for (i = 0x20; i > 0x02; i >>= 1) {
 		if ((devc->capture_flags & i) == 0) {
 			num_changroups++;
 		}
 	}
 
-	if (revents == G_IO_IN && devc->num_samples < devc->limit_samples) {
+	if (revents == G_IO_IN) {
 		if (serial_read_nonblocking(serial, &byte, 1) != 1)
 			return FALSE;
 		devc->cnt_bytes++;
 
-		/* Ignore it if we've read enough. */
-		if (devc->num_samples >= devc->limit_samples)
-			return TRUE;
-
 		devc->sample[devc->num_bytes++] = byte;
 		sr_spew("Received byte 0x%.2x.", byte);
 		if (devc->num_bytes == num_changroups) {
@@ -464,6 +450,22 @@ SR_PRIV int ols_receive_data(int fd, int revents, void *cb_data)
 			}
 
 			unsigned int samples_to_write = devc->rle_count + 1;
+			unsigned int new_sample_buf_size =
+				4 * MAX(devc->limit_samples, devc->num_samples + samples_to_write);
+			if (devc->raw_sample_buf_size < new_sample_buf_size) {
+				unsigned int old_size = devc->raw_sample_buf_size;
+				new_sample_buf_size *= 2;
+				devc->raw_sample_buf = g_try_realloc(devc->raw_sample_buf, new_sample_buf_size);
+				devc->raw_sample_buf_size = new_sample_buf_size;
+
+				if (!devc->raw_sample_buf) {
+					sr_err("Sample buffer malloc failed.");
+					return FALSE;
+				}
+				/* fill with 1010... for debugging */
+				memset(devc->raw_sample_buf + old_size, 0x82, new_sample_buf_size - old_size);
+			}
+
 			for (i = 0; i < samples_to_write; i++)
 				memcpy(devc->raw_sample_buf + (devc->num_samples + i) * 4, devc->sample, 4);
 
@@ -505,8 +507,7 @@ SR_PRIV int ols_receive_data(int fd, int revents, void *cb_data)
 				packet.payload = &logic;
 				logic.length = devc->trigger_at_smpl * 4;
 				logic.unitsize = 4;
-				logic.data = devc->raw_sample_buf +
-					(devc->limit_samples - devc->num_samples) * 4;
+				logic.data = devc->raw_sample_buf;
 				sr_session_send(sdi, &packet);
 			}
 
@@ -521,11 +522,11 @@ SR_PRIV int ols_receive_data(int fd, int revents, void *cb_data)
 		packet.payload = &logic;
 		logic.length = (devc->num_samples - num_pre_trigger_samples) * 4;
 		logic.unitsize = 4;
-		logic.data = devc->raw_sample_buf + (num_pre_trigger_samples +
-			devc->limit_samples - devc->num_samples) * 4;
+		logic.data = devc->raw_sample_buf + num_pre_trigger_samples *4;
 		sr_session_send(sdi, &packet);
 
 		g_free(devc->raw_sample_buf);
+		devc->raw_sample_buf = 0;
 
 		serial_flush(serial);
 		abort_acquisition(sdi);

src/hardware/openbench-logic-sniffer/protocol.h

@@ -114,7 +114,6 @@ struct dev_context {
 	int trigger_at_smpl;
 	uint16_t capture_flags;
 
-	unsigned int num_transfers;
 	unsigned int num_samples;
 	int num_bytes;
 	int cnt_bytes;
@@ -124,6 +123,7 @@ struct dev_context {
 	unsigned int rle_count;
 	unsigned char sample[4];
 	unsigned char *raw_sample_buf;
+	unsigned int raw_sample_buf_size;
 };
 
 SR_PRIV extern const char *ols_channel_names[];