From 0b9fb15b1a9bd9b5c8658e38c753343ff7ecd390 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Tue, 31 Jan 2017 00:36:54 +0100
Subject: QStringView: add mid(), left(), right()

Change-Id: If1d2cf175d51b3c02881e21937b0a2d33b78aadd
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Reviewed-by: Ville Voutilainen <ville.voutilainen@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 src/corelib/tools/qstringview.cpp                  | 46 ++++++++++++++++++++++
 src/corelib/tools/qstringview.h                    |  9 +++++
 .../qstringapisymmetry/tst_qstringapisymmetry.cpp  |  6 +++
 3 files changed, 61 insertions(+)

diff --git a/src/corelib/tools/qstringview.cpp b/src/corelib/tools/qstringview.cpp
index fe00965a5c..ec77e11740 100644
--- a/src/corelib/tools/qstringview.cpp
+++ b/src/corelib/tools/qstringview.cpp
@@ -548,4 +548,50 @@ QT_BEGIN_NAMESPACE
     \sa back(), front(), first()
 */
 
+/*!
+    \fn QStringView QStringView::mid(size_type start) const
+
+    Returns the substring starting at position \a start in this object,
+    and extending to the end of the string.
+
+    \note The behavior is undefined when \a start < 0 or \a start > size().
+
+    \sa left(), right()
+*/
+
+/*!
+    \fn QStringView QStringView::mid(size_type start, size_type length) const
+    \overload
+
+    Returns the substring of length \a length starting at position
+    \a start in this object.
+
+    \note The behavior is undefined when \a start < 0, \a length < 0,
+    or \a start + \a length > size().
+
+    \sa left(), right()
+*/
+
+/*!
+    \fn QStringView QStringView::left(size_type length) const
+
+    Returns the substring of length \a length starting at position
+    0 in this object.
+
+    \note The behavior is undefined when \a length < 0 or \a length > size().
+
+    \sa mid(), right()
+*/
+
+/*!
+    \fn QStringView QStringView::right(size_type length) const
+
+    Returns the substring of length \a length starting at position
+    size() - \a length in this object.
+
+    \note The behavior is undefined when \a length < 0 or \a length > size().
+
+    \sa mid(), left()
+*/
+
 QT_END_NAMESPACE
diff --git a/src/corelib/tools/qstringview.h b/src/corelib/tools/qstringview.h
index b1722e4657..1eb267f78e 100644
--- a/src/corelib/tools/qstringview.h
+++ b/src/corelib/tools/qstringview.h
@@ -183,6 +183,15 @@ public:
 
     Q_DECL_CONSTEXPR QChar at(size_type n) const { return (*this)[n]; }
 
+    Q_DECL_CONSTEXPR QStringView mid(size_type pos) const
+    { return Q_ASSERT(pos >= 0), Q_ASSERT(pos <= size()), QStringView(m_data + pos, m_size - pos); }
+    Q_DECL_CONSTEXPR QStringView mid(size_type pos, size_type n) const
+    { return Q_ASSERT(pos >= 0), Q_ASSERT(n >= 0), Q_ASSERT(pos + n <= size()), QStringView(m_data + pos, n); }
+    Q_DECL_CONSTEXPR QStringView left(size_type n) const
+    { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, n); }
+    Q_DECL_CONSTEXPR QStringView right(size_type n) const
+    { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data + m_size - n, n); }
+
     //
     // STL compatibility API:
     //
diff --git a/tests/auto/corelib/tools/qstringapisymmetry/tst_qstringapisymmetry.cpp b/tests/auto/corelib/tools/qstringapisymmetry/tst_qstringapisymmetry.cpp
index d5c22be029..dd8cbbfbcd 100644
--- a/tests/auto/corelib/tools/qstringapisymmetry/tst_qstringapisymmetry.cpp
+++ b/tests/auto/corelib/tools/qstringapisymmetry/tst_qstringapisymmetry.cpp
@@ -197,6 +197,8 @@ private Q_SLOTS:
     void mid_QString() { mid_impl<QString>(); }
     void mid_QStringRef_data() { mid_data(); }
     void mid_QStringRef() { mid_impl<QStringRef>(); }
+    void mid_QStringView_data() { mid_data(); }
+    void mid_QStringView() { mid_impl<QStringView>(); }
     void mid_QLatin1String_data() { mid_data(); }
     void mid_QLatin1String() { mid_impl<QLatin1String>(); }
     void mid_QByteArray_data() { mid_data(); }
@@ -206,6 +208,8 @@ private Q_SLOTS:
     void left_QString() { left_impl<QString>(); }
     void left_QStringRef_data() { left_data(); }
     void left_QStringRef() { left_impl<QStringRef>(); }
+    void left_QStringView_data() { left_data(); }
+    void left_QStringView() { left_impl<QStringView>(); }
     void left_QLatin1String_data() { left_data(); }
     void left_QLatin1String() { left_impl<QLatin1String>(); }
     void left_QByteArray_data() { left_data(); }
@@ -215,6 +219,8 @@ private Q_SLOTS:
     void right_QString() { right_impl<QString>(); }
     void right_QStringRef_data() { right_data(); }
     void right_QStringRef() { right_impl<QStringRef>(); }
+    void right_QStringView_data() { right_data(); }
+    void right_QStringView() { right_impl<QStringView>(); }
     void right_QLatin1String_data() { right_data(); }
     void right_QLatin1String() { right_impl<QLatin1String>(); }
     void right_QByteArray_data() { right_data(); }
-- 
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