File indexing completed on 2024-04-28 09:45:27

 /*
     SPDX-FileCopyrightText: 2001-2013 Evan Teran <evan.teran@gmail.com>
     SPDX-FileCopyrightText: 1996-2000 Bernd Johannes Wuebben <wuebben@kde.org>
     SPDX-FileCopyrightText: 2022 Harald Sitter <sitter@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "kcalcdisplay.h"
 
 #include <QApplication>
 #include <QClipboard>
 #include <QMouseEvent>
 #include <QPainter>
 #include <QStyle>
 #include <QStyleOption>
 #include <QTimer>
 
 #include <KNotification>
 
 #include "kcalc_core.h"
 #include "kcalc_settings.h"
 
 //------------------------------------------------------------------------------
 // Name: KCalcDisplay
 // Desc: constructor
 //------------------------------------------------------------------------------
 KCalcDisplay::KCalcDisplay(QWidget *parent)
     : QFrame(parent)
     , beep_(false)
     , groupdigits_(true)
     , twoscomplement_(true)
     , button_(0)
     , lit_(false)
     , num_base_(NB_DECIMAL)
     , precision_(9)
     , fixed_precision_(-1)
     , display_amount_(0)
     , history_index_(0)
     , selection_timer_(new QTimer(this))
 {
     setAccessibleDescription(i18nc("@label accessibility description of the calculation result display", "Result Display"));
     setFocusPolicy(Qt::StrongFocus);
 
     setSizePolicy(QSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed));
 
     setBackgroundRole(QPalette::Base);
     setForegroundRole(QPalette::Text);
     setFrameStyle(QFrame::NoFrame); // set in kalc.ui
     setContentsMargins(6, 0, 6, 6);
 
     KNumber::setDefaultFloatOutput(true);
     KNumber::setDefaultFractionalInput(true);
 
     connect(this, &KCalcDisplay::clicked, this, &KCalcDisplay::slotDisplaySelected);
     connect(selection_timer_, &QTimer::timeout, this, &KCalcDisplay::slotSelectionTimedOut);
 
     sendEvent(EventReset);
 }
 
 //------------------------------------------------------------------------------
 // Name: ~KCalcDisplay
 // Desc: destructor
 //------------------------------------------------------------------------------
 KCalcDisplay::~KCalcDisplay() = default;
 
 //------------------------------------------------------------------------------
 // Name: changeSettings
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::changeSettings()
 {
     QPalette pal = palette();
 
     pal.setColor(QPalette::Text, KCalcSettings::foreColor());
     pal.setColor(QPalette::Base, KCalcSettings::backColor());
 
     setPalette(pal);
 
     setFont(KCalcSettings::displayFont());
 
     setPrecision(KCalcSettings::precision());
 
     if (!KCalcSettings::fixed()) {
         setFixedPrecision(-1);
     } else {
         setFixedPrecision(KCalcSettings::fixedPrecision());
     }
 
     setBeep(KCalcSettings::beep());
     setGroupDigits(KCalcSettings::groupDigits());
     setTwosComplement(KCalcSettings::twosComplement());
     setBinaryGrouping(KCalcSettings::binaryGrouping());
     setOctalGrouping(KCalcSettings::octalGrouping());
     setHexadecimalGrouping(KCalcSettings::hexadecimalGrouping());
     updateDisplay();
 }
 
 //------------------------------------------------------------------------------
 // Name:
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::updateFromCore(const CalcEngine &core, bool store_result_in_history)
 {
     bool tmp_error;
     const KNumber &output = core.lastOutput(tmp_error);
 
 #if 0
     // TODO: do we really need explicit error tracking?
     // isn't the type of the KNumber good enough?
     // I think it is and that this error tracking is cruft
     // left over from a LONG time ago...
     if(output.type() == KNumber::TYPE_ERROR) {
 #else
     if (tmp_error) {
 #endif
     sendEvent(EventError);
 }
 
 if (setAmount(output) && store_result_in_history && (output != KNumber::Zero)) {
     // add this latest value to our history
     history_list_.insert(history_list_.begin(), output);
     history_index_ = 0;
 }
 }
 
 //------------------------------------------------------------------------------
 // Name: enterDigit
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::enterDigit(int data)
 {
     switch (data) {
     case 0:
         newCharacter(QLatin1Char('0'));
         break;
     case 1:
         newCharacter(QLatin1Char('1'));
         break;
     case 2:
         newCharacter(QLatin1Char('2'));
         break;
     case 3:
         newCharacter(QLatin1Char('3'));
         break;
     case 4:
         newCharacter(QLatin1Char('4'));
         break;
     case 5:
         newCharacter(QLatin1Char('5'));
         break;
     case 6:
         newCharacter(QLatin1Char('6'));
         break;
     case 7:
         newCharacter(QLatin1Char('7'));
         break;
     case 8:
         newCharacter(QLatin1Char('8'));
         break;
     case 9:
         newCharacter(QLatin1Char('9'));
         break;
     case 0xa:
         newCharacter(QLatin1Char('A'));
         break;
     case 0xb:
         newCharacter(QLatin1Char('B'));
         break;
     case 0xc:
         newCharacter(QLatin1Char('C'));
         break;
     case 0xd:
         newCharacter(QLatin1Char('D'));
         break;
     case 0xe:
         newCharacter(QLatin1Char('E'));
         break;
     case 0xf:
         newCharacter(QLatin1Char('F'));
         break;
     default:
         Q_ASSERT(0);
         break;
     }
 }
 
 //------------------------------------------------------------------------------
 // Name: slotHistoryForward
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotHistoryForward()
 {
     if (history_list_.empty()) {
         return;
     }
 
     if (history_index_ <= 0) {
         return;
     }
 
     history_index_--;
     setAmount(history_list_[history_index_]);
 }
 
 //------------------------------------------------------------------------------
 // Name: slotHistoryBack
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotHistoryBack()
 {
     if (history_list_.empty()) {
         return;
     }
 
     if (history_index_ >= history_list_.size()) {
         return;
     }
 
     setAmount(history_list_[history_index_]);
     history_index_++;
 }
 
 //------------------------------------------------------------------------------
 // Name: sendEvent
 // Desc:
 //------------------------------------------------------------------------------
 bool KCalcDisplay::sendEvent(Event event)
 {
     switch (event) {
     case EventClear:
     case EventReset:
         display_amount_ = KNumber::Zero;
         str_int_ = QStringLiteral("0");
         str_int_exp_.clear();
 
         eestate_ = false;
         period_ = false;
         neg_sign_ = false;
 
         updateDisplay();
 
         return true;
 
     case EventChangeSign:
         return changeSign();
 
     case EventError:
         updateDisplay();
         return true;
 
     default:
         return false;
     }
 }
 
 //------------------------------------------------------------------------------
 // Name: slotCut
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotCut()
 {
     slotCopy();
     sendEvent(EventReset);
 }
 
 //------------------------------------------------------------------------------
 // Name: slotCopy
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotCopy()
 {
     QString txt = text_;
 
     switch (num_base_) {
     case NB_HEX:
         txt.prepend(QLatin1String("0x"));
         txt.remove(QLatin1Char(' '));
         break;
     case NB_BINARY:
         txt.prepend(QLatin1String("0b"));
         txt.remove(QLatin1Char(' '));
         break;
     case NB_OCTAL:
         txt.prepend(QLatin1String("0"));
         txt.remove(QLatin1Char(' '));
         break;
     case NB_DECIMAL:
         txt.remove(QLocale().groupSeparator());
         break;
     }
 
     QApplication::clipboard()->setText(txt, QClipboard::Clipboard);
     QApplication::clipboard()->setText(txt, QClipboard::Selection);
 }
 
 //------------------------------------------------------------------------------
 // Name: slotPaste
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotPaste(bool bClipboard)
 {
     QString tmp_str = (QApplication::clipboard())->text(bClipboard ? QClipboard::Clipboard : QClipboard::Selection);
 
     if (tmp_str.isNull()) {
         if (beep_) {
             KNotification::beep();
         }
         return;
     }
 
     NumBase tmp_num_base = num_base_;
 
     // fix up string
     tmp_str = tmp_str.trimmed();
 
     if (groupdigits_) {
         tmp_str.remove(QLocale().groupSeparator());
     }
 
     tmp_str = tmp_str.toLower();
 
     // determine base
     if (tmp_str.startsWith(QLatin1String("0x"))) {
         tmp_num_base = NB_HEX;
         tmp_str.remove(0, 2);
     } else if (tmp_str.startsWith(QLatin1String("0b"))) {
         tmp_num_base = NB_BINARY;
         tmp_str.remove(0, 2);
     } else if (tmp_str.startsWith(QLatin1Char('0'))) {
         // we don't want this to trigger on "0.xxxxxx" cases
         if (tmp_str.length() < 2 || QString(tmp_str[1]) != KNumber::decimalSeparator()) {
             tmp_num_base = NB_OCTAL;
             tmp_str.remove(0, 1);
         }
     }
 
     // for locales where the groups separator is not a comma (,) but a non breaking space
     // accept (and correct) both decimal separators (comma and dot) for convenience
     if (KNumber::decimalSeparator() == QChar::fromLatin1(',')
         && (QLocale().groupSeparator() != QChar::fromLatin1(',') && QLocale().groupSeparator() != QChar::fromLatin1('.'))
         && tmp_str.count(QChar::fromLatin1('.')) == 1) {
         tmp_str.replace(QChar::fromLatin1('.'), QChar::fromLatin1(','));
     }
 
     if (tmp_num_base != NB_DECIMAL) {
         bool was_ok;
         const qint64 tmp_result = tmp_str.toULongLong(&was_ok, tmp_num_base);
 
         if (!was_ok) {
             setAmount(KNumber::NaN);
             if (beep_) {
                 KNotification::beep();
             }
             return;
         }
         setAmount(KNumber(tmp_result));
     } else {
         setAmount(KNumber(tmp_str));
         if (beep_ && display_amount_ == KNumber::NaN) {
             KNotification::beep();
         }
     }
 }
 
 //------------------------------------------------------------------------------
 // Name: slotDisplaySelected
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotDisplaySelected()
 {
     if (button_ == Qt::LeftButton) {
         if (lit_) {
             slotCopy();
             selection_timer_->start(100);
         } else {
             selection_timer_->stop();
         }
 
         invertColors();
     } else {
         slotPaste(false); // Selection
     }
 }
 
 //------------------------------------------------------------------------------
 // Name: slotSelectionTimedOut
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::slotSelectionTimedOut()
 {
     lit_ = false;
     invertColors();
     selection_timer_->stop();
 }
 
 //------------------------------------------------------------------------------
 // Name: invertColors
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::invertColors()
 {
     QPalette tmp_palette = palette();
     tmp_palette.setColor(QPalette::Base, palette().color(QPalette::Text));
     tmp_palette.setColor(QPalette::Text, palette().color(QPalette::Base));
     setPalette(tmp_palette);
 }
 
 //------------------------------------------------------------------------------
 // Name: mousePressEvent
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::mousePressEvent(QMouseEvent *e)
 {
     if (e->button() == Qt::LeftButton) {
         lit_ = !lit_;
         button_ = Qt::LeftButton;
     } else {
         button_ = Qt::MiddleButton;
     }
 
     Q_EMIT clicked();
 }
 
 //------------------------------------------------------------------------------
 // Name: setPrecision
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setPrecision(int precision)
 {
     precision_ = precision;
 }
 
 //------------------------------------------------------------------------------
 // Name: setFixedPrecision
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setFixedPrecision(int precision)
 {
     if (fixed_precision_ > precision_) {
         fixed_precision_ = -1;
     } else {
         fixed_precision_ = precision;
     }
 }
 
 //------------------------------------------------------------------------------
 // Name: setBeep
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setBeep(bool flag)
 {
     beep_ = flag;
 }
 
 //------------------------------------------------------------------------------
 // Name: setGroupDigits
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setGroupDigits(bool flag)
 {
     groupdigits_ = flag;
 }
 
 //------------------------------------------------------------------------------
 // Name: setTwosComplement
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setTwosComplement(bool flag)
 {
     twoscomplement_ = flag;
 }
 
 //------------------------------------------------------------------------------
 // Name: setBinaryGrouping
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setBinaryGrouping(int digits)
 {
     binaryGrouping_ = digits;
 }
 
 //------------------------------------------------------------------------------
 // Name: setOctalGrouping
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setOctalGrouping(int digits)
 {
     octalGrouping_ = digits;
 }
 
 //------------------------------------------------------------------------------
 // Name: setHexadecimalGrouping
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setHexadecimalGrouping(int digits)
 {
     hexadecimalGrouping_ = digits;
 }
 
 //------------------------------------------------------------------------------
 // Name: getAmount
 // Desc:
 //------------------------------------------------------------------------------
 const KNumber &KCalcDisplay::getAmount() const
 {
     return display_amount_;
 }
 
 //------------------------------------------------------------------------------
 // Name: setAmount
 // Desc:
 //------------------------------------------------------------------------------
 bool KCalcDisplay::setAmount(const KNumber &new_amount)
 {
     QString display_str;
 
     str_int_ = QStringLiteral("0");
     str_int_exp_.clear();
     period_ = false;
     neg_sign_ = false;
     eestate_ = false;
 
     if ((num_base_ != NB_DECIMAL) && (new_amount.type() != KNumber::TYPE_ERROR)) {
         display_amount_ = new_amount.integerPart();
 
         if (twoscomplement_) {
             // treat number as 64-bit unsigned
             const quint64 tmp_workaround = display_amount_.toUint64();
             display_str = QString::number(tmp_workaround, num_base_).toUpper();
         } else {
             // QString::number treats non-decimal as unsigned
             qint64 tmp_workaround = display_amount_.toInt64();
             const bool neg = tmp_workaround < 0;
             if (neg) {
                 tmp_workaround = qAbs(tmp_workaround);
             }
 
             display_str = QString::number(tmp_workaround, num_base_).toUpper();
             if (neg) {
                 display_str.prepend(QLocale().negativeSign());
             }
         }
     } else {
         // num_base_ == NB_DECIMAL || new_amount.type() == KNumber::TYPE_ERROR
         display_amount_ = new_amount;
         display_str = display_amount_.toQString(KCalcSettings::precision(), fixed_precision_);
     }
 
     setText(display_str);
     Q_EMIT changedAmount(display_amount_);
     return true;
 }
 
 //------------------------------------------------------------------------------
 // Name: setText
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setText(const QString &string)
 {
     // note that "C" locale is being used internally
     text_ = string;
 
     // don't mess with special numbers
     const bool special = (string.contains(QLatin1String("nan")) || string.contains(QLatin1String("inf")));
 
     // The decimal mode needs special treatment for two reasons, because: a) it uses KGlobal::locale() to get a localized
     // format and b) it has possible numbers after the decimal place. Neither applies to Binary, Hexadecimal or Octal.
 
     if ((groupdigits_ || num_base_ == NB_DECIMAL) && !special) {
         switch (num_base_) {
         case NB_DECIMAL:
             text_ = formatDecimalNumber(text_);
             break;
 
         case NB_BINARY:
             text_ = groupDigits(text_, binaryGrouping_);
             break;
 
         case NB_OCTAL:
             text_ = groupDigits(text_, octalGrouping_);
             break;
 
         case NB_HEX:
             text_ = groupDigits(text_, hexadecimalGrouping_);
             break;
         }
     } else if (special) {
 #if 0
         // TODO: enable this code, it replaces the "inf" with an actual infinity
         //       symbol, but what should be put into the clip board when they copy?
         if(string.contains(QLatin1String("inf"))) {
             text_.replace("inf", QChar(0x221e));
         }
 #endif
     }
 
     update();
     setAccessibleName(text_); // "Labels should be represented by only QAccessibleInterface and return their text as name"
     Q_EMIT changedText(text_);
 }
 
 //------------------------------------------------------------------------------
 // Name: setFont
 // Desc: Set the base font and recalculate the font size to better fit
 //------------------------------------------------------------------------------
 void KCalcDisplay::setFont(const QFont &font)
 {
     // Overwrite current baseFont
     baseFont_ = font;
     updateFont();
 }
 
 //------------------------------------------------------------------------------
 // Name: updateFont
 // Desc: Update font using baseFont to better fit
 //------------------------------------------------------------------------------
 void KCalcDisplay::updateFont()
 {
     // Make a working copy of the font
     QFont* newFont = new QFont(baseFont());
 
     // Calculate ideal font size
     // constants arbitrarily chosen, adjust/increase if scaling issues arise
     newFont->setPointSizeF(qMax(double(baseFont().pointSize()), qMin(contentsRect().height() / 4.5, contentsRect().width() / 24.6)));
 
     // Apply font
     QFrame::setFont(*newFont);
     
     // Free the memory
     delete newFont;
 }
 
 //------------------------------------------------------------------------------
 // Name: baseFont
 // Desc:
 //------------------------------------------------------------------------------
 const QFont& KCalcDisplay::baseFont() const
 {
     return baseFont_;
 }
 
 //------------------------------------------------------------------------------
 // Name: formatDecimalNumber
 // Desc: Convert decimal number to locale-dependent format.
 //      We cannot use QLocale::formatNumber(), because the
 //      precision is limited to "double".
 //------------------------------------------------------------------------------
 QString KCalcDisplay::formatDecimalNumber(QString string)
 {
     QLocale locale;
 
     string.replace(QLatin1Char('.'), locale.decimalPoint());
 
     if (groupdigits_ && !(locale.numberOptions() & QLocale::OmitGroupSeparator)) {
         // find position after last digit
         int pos = string.indexOf(locale.decimalPoint());
         if (pos < 0) {
             // do not group digits after the exponent part
             const int expPos = string.indexOf(QLatin1Char('e'));
             if (expPos > 0) {
                 pos = expPos;
             } else {
                 pos = string.length();
             }
         }
 
         // find first digit to not group leading spaces or signs
         int firstDigitPos = 0;
         for (int i = 0, total = string.length(); i < total; ++i) {
             if (string.at(i).isDigit()) {
                 firstDigitPos = i;
                 break;
             }
         }
 
         const auto groupSeparator = locale.groupSeparator();
         const int groupSize = 3;
 
         string.reserve(string.length() + (pos - 1) / groupSize);
         while ((pos -= groupSize) > firstDigitPos) {
             string.insert(pos, groupSeparator);
         }
     }
 
     string.replace(QLatin1Char('-'), locale.negativeSign());
     string.replace(QLatin1Char('+'), locale.positiveSign());
 
     // Digits in unicode is encoded in contiguous range and with the digit zero as the first.
     // To convert digits to other locales,
     // just add the digit value and the leading zero's code point.
     // ref: Unicode15 chapter 4.6 Numeric Value https://www.unicode.org/versions/Unicode15.0.0/ch04.pdf
 
     // QLocale switched return type of many functions from QChar to QString,
     // because UTF-16 may need surrogate pairs to represent these fields.
     // We only need digits, thus we only need the first QChar with Qt>=6.
 
     auto zero = locale.zeroDigit().at(0).unicode();
 
     for (auto &i : string) {
         if (i.isDigit()) {
             i = QChar(zero + i.digitValue());
         }
     }
 
     return string;
 }
 
 //------------------------------------------------------------------------------
 // Name: groupDigits
 // Desc:
 //------------------------------------------------------------------------------
 QString KCalcDisplay::groupDigits(const QString &displayString, int numDigits)
 {
     QString tmpDisplayString;
     const int stringLength = displayString.length();
 
     for (int i = stringLength; i > 0; i--) {
         if (i % numDigits == 0 && i != stringLength) {
             tmpDisplayString = tmpDisplayString + QLatin1Char(' ');
         }
 
         tmpDisplayString = tmpDisplayString + displayString[stringLength - i];
     }
 
     return tmpDisplayString;
 }
 
 //------------------------------------------------------------------------------
 // Name: text
 // Desc:
 //------------------------------------------------------------------------------
 QString KCalcDisplay::text() const
 {
     return text_;
 }
 
 //------------------------------------------------------------------------------
 // Name: setBase
 // Desc: change representation of display to new base (i.e. binary, decimal,
 //       octal, hexadecimal). The amount being displayed is changed to this
 //       base, but for now this amount can not be modified anymore (like
 //       being set with "setAmount"). Return value is the new base.
 //------------------------------------------------------------------------------
 int KCalcDisplay::setBase(NumBase new_base)
 {
     switch (new_base) {
     case NB_HEX:
         num_base_ = NB_HEX;
         period_ = false;
         break;
     case NB_DECIMAL:
         num_base_ = NB_DECIMAL;
         break;
     case NB_OCTAL:
         num_base_ = NB_OCTAL;
         period_ = false;
         break;
     case NB_BINARY:
         num_base_ = NB_BINARY;
         period_ = false;
         break;
     default:
         Q_ASSERT(0);
     }
 
     // reset amount
     setAmount(display_amount_);
     return num_base_;
 }
 
 //------------------------------------------------------------------------------
 // Name: setStatusText
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::setStatusText(int i, const QString &text)
 {
     if (i < NUM_STATUS_TEXT) {
         str_status_[i] = text;
     }
 
     update();
 }
 
 //------------------------------------------------------------------------------
 // Name: updateDisplay
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::updateDisplay()
 {
     // Put sign in front.
     QString tmp_string;
     if (neg_sign_) {
         tmp_string = QLatin1Char('-') + str_int_;
     } else {
         tmp_string = str_int_;
     }
 
     bool ok;
 
     switch (num_base_) {
     case NB_BINARY:
         Q_ASSERT(!period_ && !eestate_);
         setText(tmp_string);
         display_amount_ = KNumber(str_int_.toULongLong(&ok, 2));
         if (neg_sign_) {
             display_amount_ = -display_amount_;
         }
         break;
 
     case NB_OCTAL:
         Q_ASSERT(!period_ && !eestate_);
         setText(tmp_string);
         display_amount_ = KNumber(str_int_.toULongLong(&ok, 8));
         if (neg_sign_) {
             display_amount_ = -display_amount_;
         }
         break;
 
     case NB_HEX:
         Q_ASSERT(!period_ && !eestate_);
         setText(tmp_string);
         display_amount_ = KNumber(str_int_.toULongLong(&ok, 16));
         if (neg_sign_) {
             display_amount_ = -display_amount_;
         }
         break;
 
     case NB_DECIMAL:
         if (!eestate_) {
             setText(tmp_string);
             display_amount_ = KNumber(tmp_string);
         } else {
             if (str_int_exp_.isNull()) {
                 // add 'e0' to display but not to conversion
                 display_amount_ = KNumber(tmp_string);
                 setText(tmp_string + QLatin1String("e0"));
             } else {
                 tmp_string += QLatin1Char('e') + str_int_exp_;
                 setText(tmp_string);
                 display_amount_ = KNumber(tmp_string);
             }
         }
         break;
 
     default:
         Q_ASSERT(0);
     }
 
     Q_EMIT changedAmount(display_amount_);
 }
 
 //------------------------------------------------------------------------------
 // Name: newCharacter
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::newCharacter(const QChar new_char)
 {
     // test if character is valid
     switch (new_char.toLatin1()) {
     case 'e':
         // EE can be set only once and in decimal mode
         if (num_base_ != NB_DECIMAL || eestate_) {
             if (beep_) {
                 KNotification::beep();
             }
             return;
         }
         eestate_ = true;
         break;
 
     case 'F':
     case 'E':
     case 'D':
     case 'C':
     case 'B':
     case 'A':
         if (num_base_ == NB_DECIMAL) {
             if (beep_) {
                 KNotification::beep();
             }
             return;
         }
         Q_FALLTHROUGH();
     case '9':
     case '8':
         if (num_base_ == NB_OCTAL) {
             if (beep_) {
                 KNotification::beep();
             }
             return;
         }
         Q_FALLTHROUGH();
     case '7':
     case '6':
     case '5':
     case '4':
     case '3':
     case '2':
         if (num_base_ == NB_BINARY) {
             if (beep_) {
                 KNotification::beep();
             }
             return;
         }
         Q_FALLTHROUGH();
     case '1':
     case '0':
         break;
 
     default:
         if (new_char == QLocale().decimalPoint()) {
             // Period can be set only once and only in decimal
             // mode, also not in EE-mode
             if (num_base_ != NB_DECIMAL || period_ || eestate_) {
                 if (beep_) {
                     KNotification::beep();
                 }
                 return;
             }
             period_ = true;
         } else {
             if (beep_) {
                 KNotification::beep();
             }
             return;
         }
     }
 
     // change exponent or mantissa
     if (eestate_) {
         // ignore '.' before 'e'. turn e.g. '123.e' into '123e'
         if (new_char == QLatin1Char('e') && str_int_.endsWith(QLocale().decimalPoint())) {
             str_int_.chop(1);
             period_ = false;
         }
 
         // 'e' only starts ee_mode, leaves strings unchanged
         // do not add '0' if at start of exp
         if (new_char != QLatin1Char('e') && !(str_int_exp_.isNull() && new_char == QLatin1Char('0'))) {
             str_int_exp_.append(new_char);
         }
     } else {
         // handle first character
         if (str_int_ == QLatin1Char('0')) {
             switch (new_char.toLatin1()) {
             case 'e':
                 // display "0e" not just "e"
                 // "0e" does not make sense either, but...
                 str_int_.append(new_char);
                 break;
             default:
                 if (new_char == QLocale().decimalPoint()) {
                     // display "0." not just "."
                     str_int_.append(new_char);
                 } else {
                     // no leading '0's
                     str_int_[0] = new_char;
                 }
             }
         } else {
             str_int_.append(new_char);
         }
     }
 
     updateDisplay();
 }
 
 //------------------------------------------------------------------------------
 // Name: deleteLastDigit
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::deleteLastDigit()
 {
     // Only partially implemented !!
     if (eestate_) {
         if (str_int_exp_.isNull()) {
             eestate_ = false;
         } else {
             const int length = str_int_exp_.length();
             if (length > 1) {
                 str_int_exp_.chop(1);
             } else {
                 str_int_exp_ = QLatin1String((const char *)nullptr);
             }
         }
     } else {
         const int length = str_int_.length();
         if (length > 1) {
             if (str_int_[length - 1] == QLocale().decimalPoint()) {
                 period_ = false;
             }
             str_int_.chop(1);
         } else {
             Q_ASSERT(!period_);
             str_int_[0] = QLatin1Char('0');
         }
     }
 
     updateDisplay();
 }
 
 //------------------------------------------------------------------------------
 // Name: changeSign
 // Desc: change Sign of display. Problem: Only possible here, when in input
 //       mode. Otherwise return 'false' so that the kcalc_core can handle
 //       things.
 //------------------------------------------------------------------------------
 bool KCalcDisplay::changeSign()
 {
     // stupid way, to see if in input_mode or display_mode
     if (str_int_ == QLatin1Char('0')) {
         return false;
     }
 
     if (eestate_) {
         if (!str_int_exp_.isNull()) {
             if (str_int_exp_[0] != QLatin1Char('-')) {
                 str_int_exp_.prepend(QLatin1Char('-'));
             } else {
                 str_int_exp_.remove(QLatin1Char('-'));
             }
         }
     } else {
         neg_sign_ = !neg_sign_;
     }
 
     updateDisplay();
     return true;
 }
 
 //------------------------------------------------------------------------------
 // Name: initStyleOption
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::initStyleOption(QStyleOptionFrame *option) const
 {
     if (!option) {
         return;
     }
 
     option->initFrom(this);
     option->state &= ~QStyle::State_HasFocus; // don't draw focus highlight
 
     if (frameShadow() == QFrame::Sunken) {
         option->state |= QStyle::State_Sunken;
     } else if (frameShadow() == QFrame::Raised) {
         option->state |= QStyle::State_Raised;
     }
 
     option->lineWidth = style()->pixelMetric(QStyle::PM_DefaultFrameWidth, option, this);
     option->midLineWidth = 0;
 }
 
 //------------------------------------------------------------------------------
 // Name: paintEvent
 // Desc:
 //------------------------------------------------------------------------------
 void KCalcDisplay::paintEvent(QPaintEvent *)
 {
     QPainter painter(this);
 
     QStyleOptionFrame option;
     initStyleOption(&option);
 
     style()->drawPrimitive(QStyle::PE_PanelLineEdit, &option, &painter, this);
 
     // draw display text
     const int margin = style()->pixelMetric(QStyle::PM_DefaultFrameWidth, nullptr, nullptr);
     QRect cr = contentsRect();
     cr.adjust(margin * 2, 0, -margin * 2, 0); // provide a margin
 
     const int align = QStyle::visualAlignment(layoutDirection(), Qt::AlignRight | Qt::AlignVCenter);
     painter.drawText(cr, align | Qt::TextSingleLine, text_);
 
     // draw the status texts using half of the normal
     // font size but not smaller than 7pt
     QFont fnt(font());
     fnt.setPointSizeF(qMax((fnt.pointSize() / 2.0), 7.0));
     painter.setFont(fnt);
 
     QFontMetrics fm(fnt);
     const uint w = fm.boundingRect(QStringLiteral("________")).width();
     const uint h = fm.height();
 
     for (int n = 0; n < NUM_STATUS_TEXT; ++n) {
         painter.drawText(5 + n * w, h, str_status_[n]);
     }
 }
 
 //------------------------------------------------------------------------------
 // Name: resizeEvent
 // Desc: resize display and adjust font size
 //------------------------------------------------------------------------------
 void KCalcDisplay::resizeEvent(QResizeEvent* event)
 {
     QFrame::resizeEvent(event);
 
     // Update font size
     updateFont();
 }
 
 //------------------------------------------------------------------------------
 // Name: sizeHint
 // Desc:
 //------------------------------------------------------------------------------
 QSize KCalcDisplay::sizeHint() const
 {
     // font metrics of base font
     const QFontMetrics fmBase(baseFont());
     
     // basic size
     QSize sz = fmBase.size(0, QStringLiteral("M"));
 
     // expanded by 3/4 font height to make room for the status texts
     QFont fnt(baseFont());
     fnt.setPointSize(qMax(((fnt.pointSize() * 3) / 4), 7));
 
     const QFontMetrics fm(fnt);
     sz.setHeight(sz.height() + fm.height());
 
     QStyleOptionFrame option;
     initStyleOption(&option);
 
     return (style()->sizeFromContents(QStyle::CT_LineEdit, &option, sz, this));
 }
 
 #include "moc_kcalcdisplay.cpp"