From: Gerhard Sittig <redacted>
Date: Fri, 30 Dec 2016 12:16:04 +0000 (+0100)
Subject: scpi: Don't process received data of zero length
X-Git-Tag: libsigrok-0.5.0~154
X-Git-Url: https://sigrok.org/gitweb/?a=commitdiff_plain;h=904401e8fe8175252d68fcf6e0c0edae902c1c17;hp=d3de86f3ca50a55773c6974f0c336e942030b0bd;p=libsigrok.git

scpi: Don't process received data of zero length

When nothing was received in a read attempt, we need not adjust the
buffered data's read position nor the glib string object's size. Skip
any processing for empty input, just keep checking for timeouts.
---

diff --git a/src/scpi/scpi.c b/src/scpi/scpi.c
index 222201ce..efa839de 100644
--- a/src/scpi/scpi.c
+++ b/src/scpi/scpi.c
@@ -448,9 +448,9 @@ SR_PRIV int sr_scpi_get_data(struct sr_scpi_dev_inst *scpi,
 			return SR_ERR;
 		} else if (len > 0) {
 			laststart = g_get_monotonic_time();
+			offset += len;
+			g_string_set_size(response, offset);
 		}
-		offset += len;
-		g_string_set_size(response, offset);
 		elapsed_ms = (g_get_monotonic_time() - laststart) / 1000;
 		if (elapsed_ms >= scpi->read_timeout_ms) {
 			sr_err("Timed out waiting for SCPI response.");