X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fsoft-trigger.c;h=245eb4fff8c94ed652233de2676a341961eeb691;hb=aff2094193c7ed0c040ff69d6e6de9c7f2b9d53e;hp=083b003a6cd6f297cd6f14f099b9a9eaab05d581;hpb=d52107a1592bd0a01ab89398a29e658e49a059f5;p=libsigrok.git

diff --git a/src/soft-trigger.c b/src/soft-trigger.c
index 083b003a..245eb4ff 100644
--- a/src/soft-trigger.c
+++ b/src/soft-trigger.c
@@ -26,6 +26,21 @@
 #define LOG_PREFIX "soft-trigger"
 /* @endcond */
 
+SR_PRIV int logic_channel_unitsize(GSList *channels)
+{
+	int number = 0;
+	struct sr_channel *channel;
+	GSList *l;
+
+	for (l = channels; l; l = l->next) {
+		channel = l->data;
+		if (channel->type == SR_CHANNEL_LOGIC)
+			number++;
+	}
+
+	return (number + 7) / 8;
+}
+
 SR_PRIV struct soft_trigger_logic *soft_trigger_logic_new(
 		const struct sr_dev_inst *sdi, struct sr_trigger *trigger,
 		int pre_trigger_samples)
@@ -35,11 +50,16 @@ SR_PRIV struct soft_trigger_logic *soft_trigger_logic_new(
 	stl = g_malloc0(sizeof(struct soft_trigger_logic));
 	stl->sdi = sdi;
 	stl->trigger = trigger;
-	stl->unitsize = (g_slist_length(sdi->channels) + 7) / 8;
+	stl->unitsize = logic_channel_unitsize(sdi->channels);
 	stl->prev_sample = g_malloc0(stl->unitsize);
 	stl->pre_trigger_size = stl->unitsize * pre_trigger_samples;
 	stl->pre_trigger_buffer = g_try_malloc(stl->pre_trigger_size);
-	if (!stl->pre_trigger_buffer) {
+	if (pre_trigger_samples > 0 && !stl->pre_trigger_buffer) {
+		/*
+		 * Error out if g_try_malloc() failed (or was invoked as
+		 * g_try_malloc(0)) *and* more than 0 pretrigger samples
+		 * were requested.
+		 */
 		soft_trigger_logic_free(stl);
 		return NULL;
 	}