Make QString("inf").toFloat() return inf instead of zero.

Currently, QString::toFloat() returns 0 (and sets ok to false) if you
try to convert "inf". This is because inf is greater than QT_MAX_FLOAT
and there is currently no check to handle inf.

Task-number: QTBUG-8629
Change-Id: I498daf4a7a6f880f928461fca628fcaf7d1d6d08
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index a5a7bad..a2d91c5 100644 (file)
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -48,6 +48,7 @@
 #endif
 #include <private/qutfcodec_p.h>
 #include "qsimd_p.h"
+#include <qnumeric.h>
 #include <qdatastream.h>
 #include <qlist.h>
 #include "qlocale.h"
@@ -6051,14 +6052,21 @@ float QString::toFloat(bool *ok) const
 {
     bool myOk;
     double d = toDouble(&myOk);
-    if (!myOk || d > QT_MAX_FLOAT || d < -QT_MAX_FLOAT) {
+    if (!myOk) {
+        if (ok != 0)
+            *ok = false;
+        return 0.0;
+    }
+    if (qIsInf(d))
+        return float(d);
+    if (d > QT_MAX_FLOAT || d < -QT_MAX_FLOAT) {
         if (ok != 0)
             *ok = false;
         return 0.0;
     }
     if (ok != 0)
         *ok = true;
-    return (float) d;
+    return float(d);
 }
 
 /*! \fn QString &QString::setNum(int n, int base)

diff --git a/tests/auto/corelib/tools/qstring/tst_qstring.cpp b/tests/auto/corelib/tools/qstring/tst_qstring.cpp
index a3c418c..8d96861 100644 (file)
--- a/tests/auto/corelib/tools/qstring/tst_qstring.cpp
+++ b/tests/auto/corelib/tools/qstring/tst_qstring.cpp
@@ -4850,6 +4850,21 @@ void tst_QString::nanAndInf()
 
     QString("0INF0").toLong(&ok, 36);
     QVERIFY(ok);
+
+    // Check that inf (float) => "inf" (QString) => inf (float).
+    float value = qInf();
+    QString valueAsString = QString::number(value);
+    QCOMPARE(valueAsString, QString::fromLatin1("inf"));
+    float valueFromString = valueAsString.toFloat();
+    QVERIFY(qIsInf(valueFromString));
+
+    // Check that -inf (float) => "-inf" (QString) => -inf (float).
+    value = -qInf();
+    valueAsString = QString::number(value);
+    QCOMPARE(valueAsString, QString::fromLatin1("-inf"));
+    valueFromString = valueAsString.toFloat();
+    QVERIFY(value == -qInf());
+    QVERIFY(qIsInf(valueFromString));
 }
 
 void tst_QString::arg_fillChar_data()