format_si_value(): Use the timestamp type in the calculation

[pulseview.git] / pv / util.cpp

diff --git a/pv/util.cpp b/pv/util.cpp
index 192a2e06ba1571766bbab637e1135d1980b5904a..78b32af7920c5de0caf354fe8a99c5066ed0ec24 100644 (file)
--- a/pv/util.cpp
+++ b/pv/util.cpp
@@ -25,6 +25,7 @@
 #include <assert.h>
 
 #include <algorithm>
+#include <sstream>
 
 #include <QTextStream>
 #include <QDebug>
@@ -34,49 +35,98 @@ using namespace Qt;
 namespace pv {
 namespace util {
 
-static const QString SIPrefixes[17] =
-       {"y", "z", "a", "f", "p", "n", QChar(0x03BC), "m", "", "k", "M", "G",
-       "T", "P", "E", "Z", "Y"};
-const int FirstSIPrefix = 8;
-const int FirstSIPrefixPower = -(FirstSIPrefix * 3);
+static const QString SIPrefixes[17] = {
+       "y", "z",
+       "a", "f", "p",
+       "n", QChar(0x03BC), "m",
+       "",
+       "k", "M", "G",
+       "T", "P", "E",
+       "Z", "Y"};
+const int EmptySIPrefix = 8;
+const int FirstSIPrefixPower = -(EmptySIPrefix * 3);
 const double MinTimeDelta = 1e-15; // Anything below 1 fs can be considered zero
 
-static QString format_si_value(double v, QString unit, int prefix,
+// Insert the timestamp value into the stream in fixed-point notation
+// (and honor the precision)
+static QTextStream& operator<<(QTextStream& stream, const Timestamp& t)
+{
+       // The multiprecision types already have a function and a stream insertion
+       // operator to convert them to a string, however these functions abuse a
+       // precision value of zero to print all available decimal places instead of
+       // none, and the boost authors refuse to fix this because they don't want
+       // to break buggy code that relies on this bug.
+       // (https://svn.boost.org/trac/boost/ticket/10103)
+       // Therefore we have to work around the case where precision is zero.
+
+       int precision = stream.realNumberPrecision();
+
+       std::ostringstream ss;
+       ss << std::fixed;
+
+       if (stream.numberFlags() & QTextStream::ForceSign) {
+               ss << std::showpos;
+       }
+
+       if (0 == precision) {
+               ss
+                       << std::setprecision(1)
+                       << round(t);
+       } else {
+               ss
+                       << std::setprecision(precision)
+                       << t;
+       }
+
+       std::string str(ss.str());
+       if (0 == precision) {
+               // remove the separator and the unwanted decimal place
+               str.resize(str.size() - 2);
+       }
+
+       return stream << QString::fromStdString(str);
+}
+
+QString format_si_value(const Timestamp& 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;
+               // No prefix given, calculate it
+
+               if (v.is_zero()) {
+                       prefix = EmptySIPrefix;
+               } else {
+                       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 < (int)countof(SIPrefixes));
 
-       const double multiplier = pow(10.0,
+       const Timestamp multiplier = pow(Timestamp(10),
                (int)- prefix * 3 - FirstSIPrefixPower);
 
        QString s;
        QTextStream ts(&s);
-       if (sign)
+       if (sign && !v.is_zero())
                ts << forcesign;
-       ts << fixed << qSetRealNumberPrecision(precision) <<
-               (v  * multiplier) << " " << SIPrefixes[prefix] << unit;
+       ts
+               << qSetRealNumberPrecision(precision)
+               << (v * multiplier)
+               << ' '
+               << SIPrefixes[prefix]
+               << unit;
 
        return s;
 }
 
-QString format_si_value(const Timestamp& v, QString unit, int prefix,
-       unsigned int precision, bool sign)
-{
-       return format_si_value(v.convert_to<double>(), unit, prefix, precision, sign);
-}
-
 static QString pad_number(unsigned int number, int length)
 {
        return QString("%1").arg(number, length, 10, QChar('0'));
@@ -156,7 +206,7 @@ static QString format_time_with_si(double t, QString unit, int prefix,
                -(prefix * 3 + pv::util::FirstSIPrefixPower);
 
        const unsigned int relative_prec =
-               (prefix >= pv::util::FirstSIPrefix) ? precision :
+               (prefix >= EmptySIPrefix) ? precision :
                std::max((int)(precision - prefix_order), 0);
 
        return format_si_value(t, unit, prefix, relative_prec);
@@ -189,7 +239,7 @@ QString format_time(const Timestamp& t, int prefix, TimeUnit unit, unsigned int
 
 QString format_second(const Timestamp& second)
 {
-       return format_si_value(second.convert_to<double>(), "s", -1, 0, false);
+       return format_si_value(second, "s", -1, 0, false);
 }
 
 } // namespace util