QLocale: Accept trailing junk in qstrtod()

qstrtod() used to accept trailing junk until libdouble-conversion was
introduced and we need this behavior in order to implement EcmaScript's
parseFloat() correctly. The QString and QByteArray methods should not
accept trailing junk, though.

Task-number: QTBUG-50131
Change-Id: Ide922da0d65b2576be2c9f47f6053057eff77994
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

3 files changed, 78 insertions, 8 deletions

diff --git a/src/corelib/tools/qlocale_tools.cpp b/src/corelib/tools/qlocale_tools.cpp
index f766a301c5..44704b3575 100644
--- a/src/corelib/tools/qlocale_tools.cpp
+++ b/src/corelib/tools/qlocale_tools.cpp
@@ -271,7 +271,8 @@ void doubleToAscii(double d, QLocaleData::DoubleForm form, int precision, char *
         --length;
 }
 
-double asciiToDouble(const char *num, int numLen, bool &ok, int &processed)
+double asciiToDouble(const char *num, int numLen, bool &ok, int &processed,
+                     TrailingJunkMode trailingJunkMode)
 {
     if (*num == '\0') {
         ok = false;
@@ -308,7 +309,9 @@ double asciiToDouble(const char *num, int numLen, bool &ok, int &processed)
 
     double d = 0.0;
 #if !defined(QT_NO_DOUBLECONVERSION) && !defined(QT_BOOTSTRAPPED)
-    int conv_flags = double_conversion::StringToDoubleConverter::NO_FLAGS;
+    int conv_flags = (trailingJunkMode == TrailingJunkAllowed) ?
+                double_conversion::StringToDoubleConverter::ALLOW_TRAILING_JUNK :
+                double_conversion::StringToDoubleConverter::NO_FLAGS;
     double_conversion::StringToDoubleConverter conv(conv_flags, 0.0, qt_snan(), 0, 0);
     d = conv.StringToDouble(num, numLen, &processed);
 
@@ -327,7 +330,7 @@ double asciiToDouble(const char *num, int numLen, bool &ok, int &processed)
     if (qDoubleSscanf(num, QT_CLOCALE, "%lf%n", &d, &processed) < 1)
         processed = 0;
 
-    if (processed != numLen || qIsNaN(d)) {
+    if ((trailingJunkMode == TrailingJunkProhibited && processed != numLen) || qIsNaN(d)) {
         // Implementation defined nan symbol or garbage found. We don't accept it.
         processed = 0;
         ok = false;
@@ -339,7 +342,7 @@ double asciiToDouble(const char *num, int numLen, bool &ok, int &processed)
         // We assume that any infinity symbol has to contain a character that cannot be part of a
         // "normal" number (that is 0-9, ., -, +, e).
         ok = false;
-        for (int i = 0; i < numLen; ++i) {
+        for (int i = 0; i < processed; ++i) {
             char c = num[i];
             if ((c < '0' || c > '9') && c != '.' && c != '-' && c != '+' && c != 'e') {
                 // Garbage found
@@ -351,11 +354,12 @@ double asciiToDouble(const char *num, int numLen, bool &ok, int &processed)
     }
 #endif // !defined(QT_NO_DOUBLECONVERSION) && !defined(QT_BOOTSTRAPPED)
 
-    Q_ASSERT(processed == numLen); // Otherwise we would have gotten NaN or sorted it out above.
+    // Otherwise we would have gotten NaN or sorted it out above.
+    Q_ASSERT(trailingJunkMode == TrailingJunkAllowed || processed == numLen);
 
     // Check if underflow has occurred.
     if (isZero(d)) {
-        for (int i = 0; i < numLen; ++i) {
+        for (int i = 0; i < processed; ++i) {
             if (num[i] >= '1' && num[i] <= '9') {
                 // if a digit before any 'e' is not 0, then a non-zero number was intended.
                 ok = false;
@@ -529,7 +533,7 @@ double qstrtod(const char *s00, const char **se, bool *ok)
     bool nonNullOk = false;
     int len = static_cast<int>(strlen(s00));
     Q_ASSERT(len >= 0);
-    double d = asciiToDouble(s00, len, nonNullOk, processed);
+    double d = asciiToDouble(s00, len, nonNullOk, processed, TrailingJunkAllowed);
     if (se)
         *se = s00 + processed;
     if (ok)
diff --git a/src/corelib/tools/qlocale_tools_p.h b/src/corelib/tools/qlocale_tools_p.h
index 3a8036c642..f28b3dffcd 100644
--- a/src/corelib/tools/qlocale_tools_p.h
+++ b/src/corelib/tools/qlocale_tools_p.h
@@ -66,7 +66,13 @@
 
 QT_BEGIN_NAMESPACE
 
-double asciiToDouble(const char *num, int numLen, bool &ok, int &processed);
+enum TrailingJunkMode {
+    TrailingJunkProhibited,
+    TrailingJunkAllowed
+};
+
+double asciiToDouble(const char *num, int numLen, bool &ok, int &processed,
+                     TrailingJunkMode trailingJunkMode = TrailingJunkProhibited);
 void doubleToAscii(double d, QLocaleData::DoubleForm form, int precision, char *buf, int bufSize,
                    bool &sign, int &length, int &decpt);
 
diff --git a/tests/auto/corelib/tools/qlocale/tst_qlocale.cpp b/tests/auto/corelib/tools/qlocale/tst_qlocale.cpp
index ee45f95d83..51f691b1a4 100644
--- a/tests/auto/corelib/tools/qlocale/tst_qlocale.cpp
+++ b/tests/auto/corelib/tools/qlocale/tst_qlocale.cpp
@@ -46,6 +46,7 @@
 
 #include <qlocale.h>
 #include <private/qlocale_p.h>
+#include <private/qlocale_tools_p.h>
 #include <qnumeric.h>
 
 #if defined(Q_OS_LINUX) && !defined(__UCLIBC__)
@@ -99,6 +100,8 @@ private slots:
     void stringToDouble();
     void doubleToString_data();
     void doubleToString();
+    void strtod_data();
+    void strtod();
     void long_long_conversion_data();
     void long_long_conversion();
     void long_long_conversion_extra();
@@ -879,6 +882,63 @@ void tst_QLocale::doubleToString()
     setlocale(LC_ALL, currentLocale);
 }
 
+void tst_QLocale::strtod_data()
+{
+    QTest::addColumn<QString>("num_str");
+    QTest::addColumn<double>("num");
+    QTest::addColumn<int>("processed");
+    QTest::addColumn<bool>("ok");
+
+    QTest::newRow("3.4")             << QString("3.4")             << 3.4           << 3  << true;
+    QTest::newRow("0.035003945")     << QString("0.035003945")     << 0.035003945   << 11 << true;
+    QTest::newRow("3.5003945e-2")    << QString("3.5003945e-2")    << 0.035003945   << 12 << true;
+    QTest::newRow("0.000003945")     << QString("0.000003945")     << 0.000003945   << 11 << true;
+    QTest::newRow("3.945e-6")        << QString("3.945e-6")        << 0.000003945   << 8  << true;
+    QTest::newRow("12456789012")     << QString("12456789012")     << 12456789012.0 << 11 << true;
+    QTest::newRow("1.2456789012e10") << QString("1.2456789012e10") << 12456789012.0 << 15 << true;
+
+    QTest::newRow("a3.4")             << QString("a3.4")             << 0.0 << 0 << false;
+    QTest::newRow("b0.035003945")     << QString("b0.035003945")     << 0.0 << 0 << false;
+    QTest::newRow("c3.5003945e-2")    << QString("c3.5003945e-2")    << 0.0 << 0 << false;
+    QTest::newRow("d0.000003945")     << QString("d0.000003945")     << 0.0 << 0 << false;
+    QTest::newRow("e3.945e-6")        << QString("e3.945e-6")        << 0.0 << 0 << false;
+    QTest::newRow("f12456789012")     << QString("f12456789012")     << 0.0 << 0 << false;
+    QTest::newRow("g1.2456789012e10") << QString("g1.2456789012e10") << 0.0 << 0 << false;
+
+    QTest::newRow("3.4a")             << QString("3.4a")             << 3.4           << 3  << true;
+    QTest::newRow("0.035003945b")     << QString("0.035003945b")     << 0.035003945   << 11 << true;
+    QTest::newRow("3.5003945e-2c")    << QString("3.5003945e-2c")    << 0.035003945   << 12 << true;
+    QTest::newRow("0.000003945d")     << QString("0.000003945d")     << 0.000003945   << 11 << true;
+    QTest::newRow("3.945e-6e")        << QString("3.945e-6e")        << 0.000003945   << 8  << true;
+    QTest::newRow("12456789012f")     << QString("12456789012f")     << 12456789012.0 << 11 << true;
+    QTest::newRow("1.2456789012e10g") << QString("1.2456789012e10g") << 12456789012.0 << 15 << true;
+
+    QTest::newRow("0x3.4")             << QString("0x3.4")             << 0.0 << 1 << true;
+    QTest::newRow("0x0.035003945")     << QString("0x0.035003945")     << 0.0 << 1 << true;
+    QTest::newRow("0x3.5003945e-2")    << QString("0x3.5003945e-2")    << 0.0 << 1 << true;
+    QTest::newRow("0x0.000003945")     << QString("0x0.000003945")     << 0.0 << 1 << true;
+    QTest::newRow("0x3.945e-6")        << QString("0x3.945e-6")        << 0.0 << 1 << true;
+    QTest::newRow("0x12456789012")     << QString("0x12456789012")     << 0.0 << 1 << true;
+    QTest::newRow("0x1.2456789012e10") << QString("0x1.2456789012e10") << 0.0 << 1 << true;
+}
+
+void tst_QLocale::strtod()
+{
+    QFETCH(QString, num_str);
+    QFETCH(double, num);
+    QFETCH(int, processed);
+    QFETCH(bool, ok);
+
+    QByteArray numData = num_str.toLatin1();
+    const char *end = 0;
+    bool actualOk = false;
+    double result = qstrtod(numData.constData(), &end, &actualOk);
+
+    QCOMPARE(result, num);
+    QCOMPARE(actualOk, ok);
+    QCOMPARE(static_cast<int>(end - numData.constData()), processed);
+}
+
 void tst_QLocale::long_long_conversion_data()
 {
     QTest::addColumn<QString>("locale_name");