Document the string converter classes

Document QStringConverter, QStringDecoder and QStringEncoder.

In addition, do some touches to the API, renaming one enum value,
add a flags argument to one constructor and make some members private.

Change-Id: I8f99dc3d98fb8860cf6fa46301e34b7eb400511b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/src/corelib/doc/snippets/code/src_corelib_text_qstringconverter.cpp b/src/corelib/doc/snippets/code/src_corelib_text_qstringconverter.cpp
new file mode 100644
index 0000000000..97d28d5428
--- /dev/null
+++ b/src/corelib/doc/snippets/code/src_corelib_text_qstringconverter.cpp
@@ -0,0 +1,83 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//! [0]
+QByteArray encodedString = "...";
+auto toUtf16 = QStringDecoder(QStringDecoder::Utf8);
+QString string = toUtf16(encodedString);
+//! [0]
+
+
+//! [1]
+QString string = "...";
+auto fromUtf16 = QStringEncoder(QStringEncoder::Utf8);
+QByteArray encodedString = fromUtf16(encodedString);
+//! [1]
+
+
+//! [2]
+auto toUtf16 = QStringDecoder(QStringDecoder::Utf8);
+
+QString string;
+while (new_data_available()) {
+    QByteArray chunk = get_new_data();
+    string += toUtf16(chunk);
+}
+//! [2]
+
+//! [3]
+auto fromUtf16 = QStringEncoder(QStringEncoder::Utf8);
+
+QByteArray encoded;
+while (new_data_available()) {
+    QString chunk = get_new_data();
+    encoded += fromUtf16(chunk);
+}
+//! [3]