We do in fact support 'F' format for floating-point values

Update docs and add tests.

[ChangeLog][QtCore] Documented existing support for 'F' format when
converting floating-point numbers to strings in QLocale::toString(),
hence equally for QString's floating-point formatting. Previously it
was supported but the documentation neglected to mention it; it only
differs from 'f' for infinities and NaN.

Change-Id: Ic946c0f7b9e86fdf512daa3124bea57fc664b34b
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

2 files changed, 102 insertions, 1 deletions

diff --git a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
index a7eb29d2d1..09f034cb0e 100644
--- a/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
+++ b/tests/auto/corelib/text/qlocale/tst_qlocale.cpp
@@ -90,6 +90,7 @@ private slots:
     void long_long_conversion_data();
     void long_long_conversion();
     void long_long_conversion_extra();
+    void infNaN();
     void fpExceptions();
     void negativeZero_data();
     void negativeZero();
@@ -1408,6 +1409,101 @@ void tst_QLocale::long_long_conversion_extra()
     QCOMPARE(l.toString((qulonglong)12345), QString("12,345"));
 }
 
+void tst_QLocale::infNaN()
+{
+    // TODO: QTBUG-95460 -- could support localized forms of inf/NaN
+    const QLocale c(QLocale::C);
+    QCOMPARE(c.toString(qQNaN()), u"nan");
+    QCOMPARE(c.toString(qQNaN(), 'e'), u"nan");
+    QCOMPARE(c.toString(qQNaN(), 'f'), u"nan");
+    QCOMPARE(c.toString(qQNaN(), 'g'), u"nan");
+    QCOMPARE(c.toString(qQNaN(), 'E'), u"NAN");
+    QCOMPARE(c.toString(qQNaN(), 'F'), u"NAN");
+    QCOMPARE(c.toString(qQNaN(), 'G'), u"NAN");
+
+    QCOMPARE(c.toString(qInf()), u"inf");
+    QCOMPARE(c.toString(qInf(), 'e'), u"inf");
+    QCOMPARE(c.toString(qInf(), 'f'), u"inf");
+    QCOMPARE(c.toString(qInf(), 'g'), u"inf");
+    QCOMPARE(c.toString(qInf(), 'E'), u"INF");
+    QCOMPARE(c.toString(qInf(), 'F'), u"INF");
+    QCOMPARE(c.toString(qInf(), 'G'), u"INF");
+
+    // Precision is ignored for inf and NaN:
+    QCOMPARE(c.toString(qQNaN(), 'g', 42), u"nan");
+    QCOMPARE(c.toString(qQNaN(), 'G', 42), u"NAN");
+    QCOMPARE(c.toString(qInf(), 'g', 42), u"inf");
+    QCOMPARE(c.toString(qInf(), 'G', 42), u"INF");
+
+    // Case is ignored when parsing inf and NaN:
+    bool ok = false;
+    QCOMPARE(c.toDouble("inf", &ok), qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("INF", &ok), qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("Inf", &ok), qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("+inf", &ok), qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("+INF", &ok), qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("+inF", &ok), qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("-inf", &ok), -qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("-INF", &ok), -qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("-iNf", &ok), -qInf());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("nan", &ok), qQNaN());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("NaN", &ok), qQNaN());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("NAN", &ok), qQNaN());
+    QVERIFY(ok);
+    QCOMPARE(c.toDouble("nAn", &ok), qQNaN());
+    QVERIFY(ok);
+    // Sign is invalid for NaN:
+    QCOMPARE(c.toDouble("-nan", &ok), 0.0);
+    QVERIFY(!ok);
+    QCOMPARE(c.toDouble("+nan", &ok), 0.0);
+    QVERIFY(!ok);
+
+
+    // Case is ignored when parsing inf and NaN:
+    QCOMPARE(c.toFloat("inf", &ok), float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("INF", &ok), float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("Inf", &ok), float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("+inf", &ok), float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("+INF", &ok), float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("+inF", &ok), float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("-inf", &ok), -float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("-INF", &ok), -float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("-iNf", &ok), -float(qInf()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("nan", &ok), float(qQNaN()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("NaN", &ok), float(qQNaN()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("NAN", &ok), float(qQNaN()));
+    QVERIFY(ok);
+    QCOMPARE(c.toFloat("nAn", &ok), float(qQNaN()));
+    QVERIFY(ok);
+    // Sign is invalid for NaN:
+    QCOMPARE(c.toFloat("-nan", &ok), 0.0f);
+    QVERIFY(!ok);
+    QCOMPARE(c.toFloat("+nan", &ok), 0.0f);
+    QVERIFY(!ok);
+}
+
 void tst_QLocale::fpExceptions()
 {
     // Check that double-to-string conversion doesn't throw floating point
diff --git a/tests/auto/corelib/text/qstring/tst_qstring.cpp b/tests/auto/corelib/text/qstring/tst_qstring.cpp
index 7743c13dc0..e42ca7d199 100644
--- a/tests/auto/corelib/text/qstring/tst_qstring.cpp
+++ b/tests/auto/corelib/text/qstring/tst_qstring.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2021 The Qt Company Ltd.
+** Copyright (C) 2022 The Qt Company Ltd.
 ** Copyright (C) 2020 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
@@ -6430,6 +6430,11 @@ void tst_QString::nanAndInf()
     QCOMPARE(form.arg(-qInf(), 6, 'f', 3, '0'), u"00-inf");
     QCOMPARE(form.arg(-qInf(), -6, 'f', 3, '0'), u"-inf00");
     QCOMPARE(form.arg(qQNaN(), -5, 'f', 3, '0'), u"nan00");
+    QCOMPARE(form.arg(qInf(), 5, 'F', 3, '0'), u"00INF");
+    QCOMPARE(form.arg(qInf(), -5, 'F', 3, '0'), u"INF00");
+    QCOMPARE(form.arg(-qInf(), 6, 'F', 3, '0'), u"00-INF");
+    QCOMPARE(form.arg(-qInf(), -6, 'F', 3, '0'), u"-INF00");
+    QCOMPARE(form.arg(qQNaN(), -5, 'F', 3, '0'), u"NAN00");
     QCOMPARE(form.arg(qInf(), 5, 'e', 3, '0'), u"00inf");
     QCOMPARE(form.arg(qInf(), -5, 'e', 3, '0'), u"inf00");
     QCOMPARE(form.arg(-qInf(), 6, 'e', 3, '0'), u"00-inf");