From: Soeren Apel <redacted>
Date: Tue, 14 Aug 2018 08:03:35 +0000 (+0200)
Subject: std: Fix up non-zero FP value generation
X-Git-Url: http://sigrok.org/gitweb/?a=commitdiff_plain;h=653d087e15293c562409ef29ae231f8b16de39ea;p=libsigrok.git

std: Fix up non-zero FP value generation
---

diff --git a/src/std.c b/src/std.c
index 522606f8..47c3e534 100644
--- a/src/std.c
+++ b/src/std.c
@@ -712,15 +712,21 @@ SR_PRIV GVariant *std_gvar_min_max_step_array(const double a[3])
 
 SR_PRIV GVariant *std_gvar_min_max_step_thresholds(const double min, const double max, const double step)
 {
-	double d;
+	double d, v;
 	GVariant *gvar, *range[2];
 	GVariantBuilder gvb;
 
 	g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);
 
 	for (d = min; d <= max; d += step) {
-		range[0] = g_variant_new_double(d);
-		range[1] = g_variant_new_double(d);
+		/*
+		 * We will never see exactly 0.0 because of the error we're
+		 * accumulating, so catch the "zero" value and force it to be 0.
+		 */
+		v = ((d > (-step / 2)) && (d < (step / 2))) ? 0 : d;
+
+		range[0] = g_variant_new_double(v);
+		range[1] = g_variant_new_double(v);
 
 		gvar = g_variant_new_tuple(range, 2);
 		g_variant_builder_add_value(&gvb, gvar);