From fc8cc2573c75b2cb81493dba67b2a9e24699c1ec Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Wed, 5 Apr 2017 08:55:19 +0200
Subject: [PATCH] QStringView: add chopped(), chop(), and truncate()

Change-Id: I33925f5b2b3e0904f47f18f3cbab480d7f844734
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 src/corelib/tools/qstringview.cpp             | 45 +++++++++++++++++--
 src/corelib/tools/qstringview.h               |  7 +++
 .../tst_qstringapisymmetry.cpp                |  4 ++
 3 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/src/corelib/tools/qstringview.cpp b/src/corelib/tools/qstringview.cpp
index 65f76965f6..1dc01e321b 100644
--- a/src/corelib/tools/qstringview.cpp
+++ b/src/corelib/tools/qstringview.cpp
@@ -578,7 +578,7 @@ QT_BEGIN_NAMESPACE
 
     \note The behavior is undefined when \a start < 0 or \a start > size().
 
-    \sa left(), right()
+    \sa left(), right(), chopped(), chop(), truncate()
 */
 
 /*!
@@ -591,7 +591,7 @@ QT_BEGIN_NAMESPACE
     \note The behavior is undefined when \a start < 0, \a length < 0,
     or \a start + \a length > size().
 
-    \sa left(), right()
+    \sa left(), right(), chopped(), chop(), truncate()
 */
 
 /*!
@@ -602,7 +602,7 @@ QT_BEGIN_NAMESPACE
 
     \note The behavior is undefined when \a length < 0 or \a length > size().
 
-    \sa mid(), right()
+    \sa mid(), right(), chopped(), chop(), truncate()
 */
 
 /*!
@@ -613,7 +613,44 @@ QT_BEGIN_NAMESPACE
 
     \note The behavior is undefined when \a length < 0 or \a length > size().
 
-    \sa mid(), left()
+    \sa mid(), left(), chopped(), chop(), truncate()
+*/
+
+/*!
+    \fn QStringView QStringView::chopped(qssize_t length) const
+
+    Returns the substring of length size() - \a length starting at the
+    beginning of this object.
+
+    Same as \c{left(size() - length)}.
+
+    \note The behavior is undefined when \a length < 0 or \a length > size().
+
+    \sa mid(), left(), right(), chop(), truncate()
+*/
+
+/*!
+    \fn void QStringView::truncate(qssize_t length)
+
+    Truncates this string view to length \a length.
+
+    Same as \c{*this = left(length)}.
+
+    \note The behavior is undefined when \a length < 0 or \a length > size().
+
+    \sa mid(), left(), right(), chopped(), chop()
+*/
+
+/*!
+    \fn void QStringView::chop(qssize_t length)
+
+    Truncates this string view by \a length characters.
+
+    Same as \c{*this = left(size() - length)}.
+
+    \note The behavior is undefined when \a length < 0 or \a length > size().
+
+    \sa mid(), left(), right(), chopped(), truncate()
 */
 
 /*!
diff --git a/src/corelib/tools/qstringview.h b/src/corelib/tools/qstringview.h
index bd59d4ee2c..3318d2f7ef 100644
--- a/src/corelib/tools/qstringview.h
+++ b/src/corelib/tools/qstringview.h
@@ -233,6 +233,13 @@ public:
     { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, n); }
     Q_DECL_CONSTEXPR QStringView right(qssize_t n) const
     { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data + m_size - n, n); }
+    Q_DECL_CONSTEXPR QStringView chopped(qssize_t n) const Q_REQUIRED_RESULT
+    { return Q_ASSERT(n >= 0), Q_ASSERT(n <= size()), QStringView(m_data, m_size - n); }
+
+    Q_DECL_RELAXED_CONSTEXPR void truncate(qssize_t n)
+    { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size = n; }
+    Q_DECL_RELAXED_CONSTEXPR void chop(qssize_t n)
+    { Q_ASSERT(n >= 0); Q_ASSERT(n <= size()); m_size -= 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 14e84d80b6..0339ab040f 100644
--- a/tests/auto/corelib/tools/qstringapisymmetry/tst_qstringapisymmetry.cpp
+++ b/tests/auto/corelib/tools/qstringapisymmetry/tst_qstringapisymmetry.cpp
@@ -236,6 +236,8 @@ private Q_SLOTS:
     void chop_QString() { chop_impl<QString>(); }
     void chop_QStringRef_data() { chop_data(); }
     void chop_QStringRef() { chop_impl<QStringRef>(); }
+    void chop_QStringView_data() { chop_data(); }
+    void chop_QStringView() { chop_impl<QStringView>(); }
     void chop_QByteArray_data() { chop_data(); }
     void chop_QByteArray() { chop_impl<QByteArray>(); }
 
@@ -243,6 +245,8 @@ private Q_SLOTS:
     void truncate_QString() { truncate_impl<QString>(); }
     void truncate_QStringRef_data() { truncate_data(); }
     void truncate_QStringRef() { truncate_impl<QStringRef>(); }
+    void truncate_QStringView_data() { truncate_data(); }
+    void truncate_QStringView() { truncate_impl<QStringView>(); }
     void truncate_QByteArray_data() { truncate_data(); }
     void truncate_QByteArray() { truncate_impl<QByteArray>(); }