previewform.cpp Example File

tools/codecs/previewform.cpp
/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples 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."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QtWidgets>

#include "previewform.h"

// Helpers for creating hex dumps
static void indent(QTextStream &str, int indent)
{
    for (int i = 0; i < indent; ++i)
        str << ' ';
}

static void formatHex(QTextStream &str, const QByteArray &data)
{
    const int fieldWidth = str.fieldWidth();
    const QTextStream::FieldAlignment alignment = str.fieldAlignment();
    const int base = str.integerBase();
    const QChar padChar = str.padChar();
    str.setIntegerBase(16);
    str.setPadChar(QLatin1Char('0'));
    str.setFieldAlignment(QTextStream::AlignRight);

    const unsigned char *p = reinterpret_cast<const unsigned char *>(data.constBegin());
    for (const unsigned char *end = p + data.size(); p < end; ++p) {
        str << ' ';
        str.setFieldWidth(2);
        str << unsigned(*p);
        str.setFieldWidth(fieldWidth);
    }
    str.setFieldAlignment(alignment);
    str.setPadChar(padChar);
    str.setIntegerBase(base);
}

static void formatPrintableCharacters(QTextStream &str, const QByteArray &data)
{
    for (int i = 0, size = data.size(); i < size; ++i) {
        const char c = data.at(i);
        switch (c) {
        case '\0':
            str << "\\0";
            break;
        case '\t':
            str << "\\t";
            break;
        case '\r':
            str << "\\r";
            break;
        case '\n':
            str << "\\n";
            break;
        default:
            if (c >= 32 && uchar(c) < 127)
                str << ' ' << c;
            else
                str << "..";
            break;
        }
    }
}

static QString formatHexDump(const QByteArray &data)
{
    enum { lineWidth = 16 };
    QString result;
    QTextStream str(&result);
    str.setIntegerBase(16);
    str.setPadChar(QLatin1Char('0'));
    const int fieldWidth = str.fieldWidth();
    const QTextStream::FieldAlignment alignment = str.fieldAlignment();
    for (int a = 0, size = data.size(); a < size; a += lineWidth) {
        str.setFieldAlignment(QTextStream::AlignRight);
        str.setFieldWidth(8);
        str << a;
        str.setFieldWidth(fieldWidth);
        str.setFieldAlignment(alignment);

        const int end = qMin(a + lineWidth, size);
        const QByteArray line = data.mid(a, end - a);

        formatHex(str, line);
        indent(str, 3 * (lineWidth - line.size()));

        str << ' ';
        formatPrintableCharacters(str, line);
        indent(str, 2 * (lineWidth - line.size()));
        str << '\n';
    }
    return result;
}

PreviewForm::PreviewForm(QWidget *parent)
    : QDialog(parent)
{
    setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
    encodingComboBox = new QComboBox;

    QLabel *encodingLabel = new QLabel(tr("&Encoding:"));
    encodingLabel->setBuddy(encodingComboBox);

    textEdit = new QPlainTextEdit;
    textEdit->setLineWrapMode(QPlainTextEdit::NoWrap);
    textEdit->setReadOnly(true);
    hexDumpEdit = new QPlainTextEdit;
    hexDumpEdit->setLineWrapMode(QPlainTextEdit::NoWrap);
    hexDumpEdit->setReadOnly(true);
    hexDumpEdit->setFont(QFontDatabase::systemFont(QFontDatabase::FixedFont));

    QDialogButtonBox *buttonBox =
        new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel);
    okButton = buttonBox->button(QDialogButtonBox::Ok);

    connect(encodingComboBox, QOverload<int>::of(&QComboBox::activated),
            this, &PreviewForm::updateTextEdit);
    connect(buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
    connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);

    QGridLayout *mainLayout = new QGridLayout(this);
    mainLayout->addWidget(encodingLabel, 0, 0);
    mainLayout->addWidget(encodingComboBox, 0, 1);
    tabWidget = new QTabWidget;
    tabWidget->addTab(textEdit, tr("Preview"));
    tabWidget->addTab(hexDumpEdit, tr("Hex Dump"));
    mainLayout->addWidget(tabWidget, 1, 0, 1, 2);
    statusLabel = new QLabel;
    mainLayout->addWidget(statusLabel, 2, 0, 1, 2);
    mainLayout->addWidget(buttonBox, 3, 0, 1, 2);

    const QRect screenGeometry = QApplication::desktop()->screenGeometry(this);
    resize(screenGeometry.width() * 2 / 5, screenGeometry.height() / 2);
}

void PreviewForm::setCodecList(const QList<QTextCodec *> &list)
{
    encodingComboBox->clear();
    foreach (const QTextCodec *codec, list) {
        encodingComboBox->addItem(QLatin1String(codec->name()),
                                  QVariant(codec->mibEnum()));
    }
}

void PreviewForm::reset()
{
    decodedStr.clear();
    textEdit->clear();
    hexDumpEdit->clear();
    statusLabel->clear();
    statusLabel->setStyleSheet(QString());
    okButton->setEnabled(false);
    tabWidget->setCurrentIndex(0);
}

void PreviewForm::setEncodedData(const QByteArray &data)
{
    reset();
    encodedData = data;
    hexDumpEdit->setPlainText(formatHexDump(data));
    updateTextEdit();
}

void PreviewForm::updateTextEdit()
{
    int mib = encodingComboBox->itemData(
                      encodingComboBox->currentIndex()).toInt();
    const QTextCodec *codec = QTextCodec::codecForMib(mib);
    const QString name = QLatin1String(codec->name());

    QTextCodec::ConverterState state;
    decodedStr = codec->toUnicode(encodedData.constData(), encodedData.size(), &state);

    bool success = true;
    if (state.remainingChars) {
        success = false;
        const QString message =
            tr("%1: conversion error at character %2")
            .arg(name).arg(encodedData.size() - state.remainingChars + 1);
        statusLabel->setText(message);
        statusLabel->setStyleSheet(QStringLiteral("background-color: \"red\";"));
    } else if (state.invalidChars) {
        statusLabel->setText(tr("%1: %n invalid characters", 0, state.invalidChars).arg(name));
        statusLabel->setStyleSheet(QStringLiteral("background-color: \"yellow\";"));
    } else {
        statusLabel->setText(tr("%1: %n bytes converted", 0, encodedData.size()).arg(name));
        statusLabel->setStyleSheet(QString());
    }
    if (success)
        textEdit->setPlainText(decodedStr);
    else
        textEdit->clear();
    okButton->setEnabled(success);
}

© 2017 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.