QByteArrayView: Add mid/left/right

Because they are too convenient to leave out.

Change-Id: I844cfb794ce0f575c2c65075d9051b0b878a434f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/text/qbytearrayview.h

@@ -5,6 +5,7 @@
 
 #include <QtCore/qbytearrayalgorithms.h>
 #include <QtCore/qstringfwd.h>
+#include <QtCore/qarraydata.h>
 
 #include <string>
 
@@ -198,6 +199,18 @@ public:
     [[nodiscard]] constexpr QByteArrayView chopped(qsizetype len) const
     { Q_ASSERT(len >= 0); Q_ASSERT(len <= size()); return first(size() - len); }
 
+    [[nodiscard]] constexpr QByteArrayView left(qsizetype n) const
+    { if (n < 0 || n > size()) n = size(); return QByteArrayView(data(), n); }
+    [[nodiscard]] constexpr QByteArrayView right(qsizetype n) const
+    { if (n < 0 || n > size()) n = size(); if (n < 0) n = 0; return QByteArrayView(data() + size() - n, n); }
+    [[nodiscard]] constexpr QByteArrayView mid(qsizetype pos, qsizetype n = -1) const
+    {
+        using namespace QtPrivate;
+        auto result = QContainerImplHelper::mid(size(), &pos, &n);
+        return result == QContainerImplHelper::Null ? QByteArrayView()
+                                                    : QByteArrayView(m_data + pos, n);
+    }
+
     constexpr void truncate(qsizetype n)
     { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size = n; }
     constexpr void chop(qsizetype n)

src/corelib/text/qbytearrayview.qdoc

@@ -617,6 +617,54 @@
     \sa sliced(), first(), last(), chopped(), truncate()
 */
 
+/*!
+    \fn QByteArrayView QByteArrayView::mid(qsizetype start, qsizetype length) const
+    \since 6.5
+
+    \deprecated Use sliced() instead in new code.
+
+    Returns the subarray of length \a length starting at position
+    \a start in this object.
+
+    Returns an empty byte array view if \a start exceeds the
+    length of the byte array view. If there are less than \a length characters
+    available in the byte array view starting at \a start, or if
+    \a length is negative (default), the function returns all characters that
+    are available from \a start.
+
+    \sa first(), last(), sliced(), chopped(), chop(), truncate()
+*/
+
+/*!
+    \fn QByteArrayView QByteArrayView::left(qsizetype length) const
+    \since 6.5
+
+    \deprecated Use first() instead in new code.
+
+    Returns the subarray of length \a length starting at position
+    0 in this object.
+
+    The entire byte array view is returned if \a length is greater than or equal
+    to size(), or less than zero.
+
+    \sa first(), last(), sliced(), startsWith(), chopped(), chop(), truncate()
+*/
+
+/*!
+    \fn QByteArrayView QByteArrayView::right(qsizetype length) const
+    \since 6.5
+
+    \deprecated Use last() instead in new code.
+
+    Returns the subarray of length \a length starting at position
+    size() - \a length in this object.
+
+    The entire byte array view is returned if \a length is greater than or equal
+    to size(), or less than zero.
+
+    \sa first(), last(), sliced(), endsWith(), chopped(), chop(), truncate()
+*/
+
 /*!
     \fn QByteArrayView QByteArrayView::trimmed() const noexcept
     \since 6.3

tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp

@@ -730,6 +730,8 @@ private Q_SLOTS:
     void mid_QLatin1String() { mid_impl<QLatin1String>(); }
     void mid_QByteArray_data() { mid_data(); }
     void mid_QByteArray() { mid_impl<QByteArray>(); }
+    void mid_QByteArrayView_data() { mid_data(); }
+    void mid_QByteArrayView() { mid_impl<QByteArrayView>(); }
 
     void left_QString_data() { left_data(); }
     void left_QString() { left_impl<QString>(); }
@@ -741,6 +743,8 @@ private Q_SLOTS:
     void left_QLatin1String() { left_impl<QLatin1String>(); }
     void left_QByteArray_data();
     void left_QByteArray() { left_impl<QByteArray>(); }
+    void left_QByteArrayView_data() { left_data(); }
+    void left_QByteArrayView() { left_impl<QByteArrayView>(); }
 
     void right_QString_data() { right_data(); }
     void right_QString() { right_impl<QString>(); }
@@ -752,6 +756,8 @@ private Q_SLOTS:
     void right_QLatin1String() { right_impl<QLatin1String>(); }
     void right_QByteArray_data();
     void right_QByteArray() { right_impl<QByteArray>(); }
+    void right_QByteArrayView_data() { right_data(); }
+    void right_QByteArrayView() { right_impl<QByteArrayView>(); }
 
     void sliced_QString_data() { sliced_data(); }
     void sliced_QString() { sliced_impl<QString>(); }