From: Joel Holdsworth <redacted>
Date: Tue, 30 Dec 2014 09:56:49 +0000 (+0000)
Subject: util: Added format_si_value
X-Git-Tag: pulseview-0.3.0~290
X-Git-Url: https://sigrok.org/gitweb/?p=pulseview.git;a=commitdiff_plain;h=4bc10a910593fda2d378d62a57448cec4b2166bf

util: Added format_si_value
---

diff --git a/pv/util.cpp b/pv/util.cpp
index 62f0ee1f..2a04aaec 100644
--- a/pv/util.cpp
+++ b/pv/util.cpp
@@ -36,9 +36,21 @@ static const QString SIPrefixes[9] =
 	{"f", "p", "n", QChar(0x03BC), "m", "", "k", "M", "G"};
 const int FirstSIPrefixPower = -15;
 
-QString format_time(double t, unsigned int prefix,
+QString format_si_value(double v, QString unit, int prefix,
 	unsigned int precision, bool sign)
 {
+	if (prefix < 0) {
+		int exp = -FirstSIPrefixPower;
+
+		prefix = 0;
+		while ((fabs(v) * pow(10.0, exp)) > 999.0 &&
+			prefix < (int)(countof(SIPrefixes) - 1)) {
+			prefix++;
+			exp -= 3;
+		}
+	}
+
+	assert(prefix >= 0);
 	assert(prefix < countof(SIPrefixes));
 
 	const double multiplier = pow(10.0,
@@ -46,26 +58,23 @@ QString format_time(double t, unsigned int prefix,
 
 	QString s;
 	QTextStream ts(&s);
-	if (sign) {
+	if (sign)
 		ts << forcesign;
-	}
 	ts << fixed << qSetRealNumberPrecision(precision)
-		<< (t  * multiplier) << SIPrefixes[prefix] << "s";
+		<< (v  * multiplier) << SIPrefixes[prefix] << unit;
 
 	return s;
 }
 
-QString format_second(double second)
+QString format_time(double t, int prefix,
+	unsigned int precision, bool sign)
 {
-	unsigned int i = 0;
-	int exp = - FirstSIPrefixPower;
-
-	while ((second * pow(10.0, exp)) > 999.0 && i < countof(SIPrefixes) - 1) {
-		i++;
-		exp -= 3;
-	}
+	return format_si_value(t, "s", prefix, precision, sign);
+}
 
-	return format_time(second, i, 0, false);
+QString format_second(double second)
+{
+	return format_si_value(second, "s", -1, 0, false);
 }
 
 } // namespace util
diff --git a/pv/util.hpp b/pv/util.hpp
index 572bed31..5d656940 100644
--- a/pv/util.hpp
+++ b/pv/util.hpp
@@ -31,18 +31,33 @@ namespace util {
 extern const int FirstSIPrefixPower;
 
 /**
- * Formats a given time value with the specified SI prefix.
+ * Formats a given value with the specified SI prefix.
+ * @param v The value to format.
+ * @param unit The unit of quantity.
+ * @param prefix The number of the prefix, from 0 for 'femto' up to
+ *   8 for 'giga'. If prefix is set to -1, the prefix will be calculated.
+ * @param precision The number of digits after the decimal separator.
+ * @param sign Whether or not to add a sign also for positive numbers.
+ *
+ * @return The formated value.
+ */
+QString format_si_value(
+	double v, QString unit, int prefix = -1,
+	unsigned precision = 0, bool sign = true);
+
+/**
+ * Formats a given time with the specified SI prefix.
  * @param t The time value in seconds to format.
  * @param prefix The number of the prefix, from 0 for 'femto' up to
- *               8 for 'giga'.
- * @parma precision The number of digits after the decimal separator.
+ *   8 for 'giga'. If prefix is set to -1, the prefix will be calculated.
+ * @param unit The unit of quantity.
+ * @param precision The number of digits after the decimal separator.
  * @param sign Whether or not to add a sign also for positive numbers.
  *
  * @return The formated value.
  */
 QString format_time(
-	double t, unsigned int prefix,
-	unsigned precision = 0, bool sign = true);
+	double t, int prefix = -1, unsigned precision = 0, bool sign = true);
 
 /**
  * Formats a given time value with a SI prefix so that the