X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=pv%2Futil.cpp;h=237ca7f059f1e589dac4dd9e6f6bc29120a6e3c5;hb=ef85cfa4599d3741e7007921e39a44490e97cfaf;hp=6424a9b1b5893b13d212ad1deef61221bea30aef;hpb=3083cda853bd12d73b741c3bc97b70f5d395a15a;p=pulseview.git

diff --git a/pv/util.cpp b/pv/util.cpp
index 6424a9b1..237ca7f0 100644
--- a/pv/util.cpp
+++ b/pv/util.cpp
@@ -138,8 +138,44 @@ QString format_time_si(const Timestamp& v, SIPrefix prefix,
 	QTextStream ts(&s);
 	if (sign && !v.is_zero())
 		ts << forcesign;
-	ts << qSetRealNumberPrecision(precision) << (v * multiplier) << ' '
-		<< prefix << unit;
+	ts << qSetRealNumberPrecision(precision) << (v * multiplier);
+	if (!unit.isNull())
+		ts << ' ' << prefix << unit;
+
+	return s;
+}
+
+QString format_value_si(double v, SIPrefix prefix, unsigned precision,
+	QString unit, bool sign)
+{
+	if (prefix == SIPrefix::unspecified) {
+		// No prefix given, calculate it
+
+		if (v == 0) {
+			prefix = SIPrefix::none;
+		} else {
+			int exp = exponent(SIPrefix::yotta);
+			prefix = SIPrefix::yocto;
+			while ((fabs(v) * pow(Timestamp(10), exp)) > 999 &&
+					prefix < SIPrefix::yotta) {
+				prefix = successor(prefix);
+				exp -= 3;
+			}
+		}
+	}
+
+	assert(prefix >= SIPrefix::yocto);
+	assert(prefix <= SIPrefix::yotta);
+
+	const double multiplier = pow(10.0, -exponent(prefix));
+
+	QString s;
+	QTextStream ts(&s);
+	if (sign && (v != 0))
+		ts << forcesign;
+	ts.setRealNumberNotation(QTextStream::FixedNotation);
+	ts.setRealNumberPrecision(precision);
+	ts << (v * multiplier) << ' ' << prefix << unit;
 
 	return s;
 }