QString/QByteArray: add erase() for iterators

Otherwise they're not usable with iterator-based algorithms
that e.g. remove, partition and the like.

[ChangeLog][QtCore][QString] Added erase().

[ChangeLog][QtCore][QByteArray] Added erase().

Change-Id: I78829b1a5365dd53b6b6423ceedbc52edeafbc63
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>

src/corelib/text/qbytearray.cpp

@@ -1115,6 +1115,21 @@ QByteArray qUncompress(const uchar* data, qsizetype nbytes)
     squeeze().
 */
 
+/*!
+    \since 6.1
+
+    Removes from the byte array the characters in the half-open range
+    [ \a first , \a last ). Returns an iterator to the character
+    referred to by \a last before the erase.
+*/
+QByteArray::iterator QByteArray::erase(QByteArray::const_iterator first, QByteArray::const_iterator last)
+{
+    const auto start = std::distance(cbegin(), first);
+    const auto len = std::distance(first, last);
+    remove(start, len);
+    return begin() + start;
+}
+
 /*! \fn QByteArray::QByteArray(const QByteArray &other)
 
     Constructs a copy of \a other.

src/corelib/text/qbytearray.h

@@ -497,6 +497,7 @@ public:
     void push_front(QByteArrayView a)
     { prepend(a); }
     void shrink_to_fit() { squeeze(); }
+    iterator erase(const_iterator first, const_iterator last);
 
     static inline QByteArray fromStdString(const std::string &s);
     inline std::string toStdString() const;

src/corelib/text/qstring.cpp

@@ -8512,6 +8512,21 @@ bool QString::isRightToLeft() const
     Appends the given \a ch character onto the end of this string.
 */
 
+/*!
+    \since 6.1
+
+    Removes from the string the characters in the half-open range
+    [ \a first , \a last ). Returns an iterator to the character
+    referred to by \a last before the erase.
+*/
+QString::iterator QString::erase(QString::const_iterator first, QString::const_iterator last)
+{
+    const auto start = std::distance(cbegin(), first);
+    const auto len = std::distance(first, last);
+    remove(start, len);
+    return begin() + start;
+}
+
 /*! \fn void QString::shrink_to_fit()
     \since 5.10
 

src/corelib/text/qstring.h

@@ -1016,6 +1016,7 @@ public:
     inline void push_front(QChar c) { prepend(c); }
     inline void push_front(const QString &s) { prepend(s); }
     void shrink_to_fit() { squeeze(); }
+    iterator erase(const_iterator first, const_iterator last);
 
     static inline QString fromStdString(const std::string &s);
     inline std::string toStdString() const;