QLatin1String: add at()/op[]/mid()/right()/left()

QLatin1String can be used as a string-view-like type.
When attempting to do so in uic, mid() and at() were
found to be missing. Added the others for completeness.

Use the new functions in uic, for which they were
originally conceived.

[ChangeLog][QtCore][QLatin1String] Added at(),
operator[](), mid(), right(), left().

Change-Id: I4cfe3e9ed1157dedee754b2012d9678fe72b161e
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

4 files changed, 116 insertions, 4 deletions

diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 24d43dad88..18435c3009 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -8328,6 +8328,78 @@ QString &QString::setRawData(const QChar *unicode, int size)
     Returns the size of the Latin-1 string stored in this object.
 */
 
+/*! \fn QLatin1Char QLatin1String::at(int pos) const
+    \since 5.8
+
+    Returns the character at position \a pos in this object.
+
+    \note This function performs no error checking.
+    The behavior is undefined when \a pos < 0 or \a pos ≥ size().
+
+    \sa operator[]()
+*/
+
+/*! \fn QLatin1Char QLatin1String::operator[](int pos) const
+    \since 5.8
+
+    Returns the character at position \a pos in this object.
+
+    \note This function performs no error checking.
+    The behavior is undefined when \a pos < 0 or \a pos ≥ size().
+
+    \sa at()
+*/
+
+/*! \fn QLatin1String QLatin1String::mid(int start) const
+    \since 5.8
+
+    Returns the substring starting at position \a start in this object,
+    and extending to the end of the string.
+
+    \note This function performs no error checking.
+    The behavior is undefined when \a start < 0 or \a start > size().
+
+    \sa left(), right()
+*/
+
+/*! \fn QLatin1String QLatin1String::mid(int start, int length) const
+    \since 5.8
+    \overload
+
+    Returns the substring of length \a length starting at position
+    \a start in this object.
+
+    \note This function performs no error checking.
+    The behavior is undefined when \a start < 0, \length < 0,
+    or \a start + \a length > size().
+
+    \sa left(), right()
+*/
+
+/*! \fn QLatin1String QLatin1String::left(int length) const
+    \since 5.8
+
+    Returns the substring of length \a length starting at position
+    0 in this object.
+
+    \note This function performs no error checking.
+    The behavior is undefined when \length < 0 or \a length > size().
+
+    \sa mid(), right()
+*/
+
+/*! \fn QLatin1String QLatin1String::right(int length) const
+    \since 5.8
+
+    Returns the substring of length \a length starting at position
+    size() - \a length in this object.
+
+    \note This function performs no error checking.
+    The behavior is undefined when \length < 0 or \a length > size().
+
+    \sa mid(), left()
+*/
+
 /*! \fn bool QLatin1String::operator==(const QString &other) const
 
     Returns \c true if this string is equal to string \a other;
diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h
index ddaab1f544..90a56828e2 100644
--- a/src/corelib/tools/qstring.h
+++ b/src/corelib/tools/qstring.h
@@ -99,6 +99,18 @@ public:
     Q_DECL_CONSTEXPR int size() const Q_DECL_NOTHROW { return m_size; }
     Q_DECL_CONSTEXPR const char *data() const Q_DECL_NOTHROW { return m_data; }
 
+    Q_DECL_CONSTEXPR QLatin1Char at(int i) const { return QLatin1Char(m_data[i]); }
+    Q_DECL_CONSTEXPR QLatin1Char operator[](int i) const { return at(i); }
+
+    Q_DECL_CONSTEXPR QLatin1String mid(int pos) const
+    { return QLatin1String(m_data + pos, m_size - pos); }
+    Q_DECL_CONSTEXPR QLatin1String mid(int pos, int n) const
+    { return QLatin1String(m_data + pos, n); }
+    Q_DECL_CONSTEXPR QLatin1String left(int n) const
+    { return QLatin1String(m_data, n); }
+    Q_DECL_CONSTEXPR QLatin1String right(int n) const
+    { return QLatin1String(m_data + m_size - n, n); }
+
     inline bool operator==(const QString &s) const Q_DECL_NOTHROW;
     inline bool operator!=(const QString &s) const Q_DECL_NOTHROW;
     inline bool operator>(const QString &s) const Q_DECL_NOTHROW;
diff --git a/src/tools/uic/cpp/cppwriteinitialization.cpp b/src/tools/uic/cpp/cppwriteinitialization.cpp
index 0886cf4c4a..ebb7f8691a 100644
--- a/src/tools/uic/cpp/cppwriteinitialization.cpp
+++ b/src/tools/uic/cpp/cppwriteinitialization.cpp
@@ -785,8 +785,7 @@ void WriteInitialization::acceptWidget(DomWidget *node)
         DomPropertyList headerProperties;
         for (auto realPropertyName : realPropertyNames) {
             const QString fakePropertyName = QLatin1String("header")
-                    + QChar(QLatin1Char(realPropertyName.data()[0])).toUpper()
-                    + QLatin1String(realPropertyName.data() + 1, realPropertyName.size() - 1);
+                    + QChar(realPropertyName.at(0)).toUpper() + realPropertyName.mid(1);
             if (DomProperty *fakeProperty = attributes.value(fakePropertyName)) {
                 fakeProperty->setAttributeName(realPropertyName);
                 headerProperties << fakeProperty;
@@ -807,8 +806,7 @@ void WriteInitialization::acceptWidget(DomWidget *node)
             DomPropertyList headerProperties;
             for (auto realPropertyName : realPropertyNames) {
                 const QString fakePropertyName = headerPrefix
-                        + QChar(QLatin1Char(realPropertyName.data()[0])).toUpper()
-                        + QLatin1String(realPropertyName.data() + 1, realPropertyName.size() - 1);
+                        + QChar(realPropertyName.at(0)).toUpper() + realPropertyName.mid(1);
                 if (DomProperty *fakeProperty = attributes.value(fakePropertyName)) {
                     fakeProperty->setAttributeName(realPropertyName);
                     headerProperties << fakeProperty;
diff --git a/tests/auto/corelib/tools/qlatin1string/tst_qlatin1string.cpp b/tests/auto/corelib/tools/qlatin1string/tst_qlatin1string.cpp
index 1295a36c1a..3c22770fba 100644
--- a/tests/auto/corelib/tools/qlatin1string/tst_qlatin1string.cpp
+++ b/tests/auto/corelib/tools/qlatin1string/tst_qlatin1string.cpp
@@ -35,10 +35,40 @@ class tst_QLatin1String : public QObject
     Q_OBJECT
 
 private Q_SLOTS:
+    void at();
+    void midLeftRight();
     void nullString();
     void emptyString();
 };
 
+
+void tst_QLatin1String::at()
+{
+    const QLatin1String l1("Hello World");
+    QCOMPARE(l1.at(0), QLatin1Char('H'));
+    QCOMPARE(l1.at(l1.size() - 1), QLatin1Char('d'));
+    QCOMPARE(l1[0], QLatin1Char('H'));
+    QCOMPARE(l1[l1.size() - 1], QLatin1Char('d'));
+}
+
+void tst_QLatin1String::midLeftRight()
+{
+    const QLatin1String l1("Hello World");
+    QCOMPARE(l1.mid(0),            l1);
+    QCOMPARE(l1.mid(0, l1.size()), l1);
+    QCOMPARE(l1.left(l1.size()),   l1);
+    QCOMPARE(l1.right(l1.size()),  l1);
+
+    QCOMPARE(l1.mid(6), QLatin1String("World"));
+    QCOMPARE(l1.mid(6, 5), QLatin1String("World"));
+    QCOMPARE(l1.right(5), QLatin1String("World"));
+
+    QCOMPARE(l1.mid(6, 1), QLatin1String("W"));
+    QCOMPARE(l1.right(5).left(1), QLatin1String("W"));
+
+    QCOMPARE(l1.left(5), QLatin1String("Hello"));
+}
+
 void tst_QLatin1String::nullString()
 {
     // default ctor