File indexing completed on 2024-05-19 04:00:02

 /*
     SPDX-FileCopyrightText: 2003-2005 Hamish Rodda <rodda@kde.org>
     SPDX-FileCopyrightText: 2001-2005 Christoph Cullmann <cullmann@kde.org>
     SPDX-FileCopyrightText: 2014 Dominik Haumann <dhaumann@kde.org>
     SPDX-FileCopyrightText: 2002 Christian Couder <christian@kdevelop.org>
     SPDX-FileCopyrightText: 2001 Joseph Wenninger <jowenn@kde.org>
     SPDX-FileCopyrightText: 1999 Jochen Wilhelmy <digisnap@cs.tu-berlin.de>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 #ifndef KTEXTEDITOR_CURSOR_H
 #define KTEXTEDITOR_CURSOR_H
 
 #include <ktexteditor_export.h>
 
 #include <QtGlobal>
 
 class QDebug;
 class QString;
 class QStringView;
 
 namespace KTextEditor
 {
 class Document;
 class Range;
 
 /**
  * \class Cursor cursor.h <KTextEditor/Cursor>
  *
  * \short The Cursor represents a position in a Document.
  *
  * \section kte_cursor_intro Introduction
  * A Cursor represents a position in a Document through a tuple
  * of two int%s, namely the line() and column(). A Cursor maintains
  * no affiliation with a particular Document, meaning that it remains
  * constant if not changed through the Cursor API.
  *
  * \section kte_cursor_notes Important Notes
  *
  * Working with a cursor, one should be aware of the following notes:
  * - Lines and columns start a 0.
  * - The Cursor class is designed to be passed by value (only 8 Bytes).
  * - Think of cursors as having their position at the start of a character,
  *   not in the middle of one.
  * - invalid() Cursor%s are located at (-1, -1). In addition, a Cursor
  *   is invalid(), if either its line() and/or its column() is arbitrarily
  *   negative, i.e. < 0.
  * - All Cursor%s with line() >= 0 and column() >= 0 are valid. In this case
  *   isValid() returns \e true.
  * - A Cursor has a non-virtual destructor. Hence, you cannot derive from Cursor.
  *
  * \section kte_cursor_properties Cursor Efficiency
  *
  * The Cursor consists of just two int%s, the line() and the column().
  * Therefore, a Cursor instance takes 8 Bytes of memory. Further, a Cursor
  * is a non-virtual class, turning it into a primitive old data type (POD).
  * Thus, it can be moved and copied very efficiently.
  *
  * \section kte_cursor_more Additional Concepts
  *
  * In addition to the Cursor, the KTextEditor API provides advanced concepts:
  * - The DocumentCursor is a Cursor bound to a specific Document. In addition
  *   to the Cursor API, it provides convenience functions like
  *   DocumentCursor::isValidTextPosition() or DocumentCursor::move().
  *   The DocumentCursor does not maintain its position, though.
  * - The MovingCursor is also bound to a specific Document. In addition to the
  *   DocumentCursor, the MovingCursor maintains its position, meaning that
  *   whenever the Document changes, the MovingCursor moves, too.
  * - The Cursor forms the basis for the Range.
  *
  * \sa DocumentCursor, MovingCursor, Range
  */
 class KTEXTEDITOR_EXPORT Cursor
 {
 public:
     /**
      * The default constructor creates a cursor at position (0, 0).
      */
     constexpr Cursor() noexcept = default;
 
     /**
      * This constructor creates a cursor initialized with \p line
      * and \p column.
      * \param line line for cursor
      * \param column column for cursor
      */
     constexpr Cursor(int line, int column) noexcept
         : m_line(line)
         , m_column(column)
     {
     }
 
     /**
      * Returns whether the current position of this cursor is a valid position
      * (line + column must both be >= 0).
      *
      * @note If you want to check, whether a cursor position is a valid
      *       \e text-position, use DocumentCursor::isValidTextPosition(),
      *       or Document::isValidTextPosition().
      */
     constexpr bool isValid() const noexcept
     {
         return m_line >= 0 && m_column >= 0;
     }
 
     /**
      * Returns an invalid cursor.
      * The returned cursor position is set to (-1, -1).
      * \see isValid()
      */
     constexpr static Cursor invalid() noexcept
     {
         return Cursor(-1, -1);
     }
 
     /**
      * Returns a cursor representing the start of any document - i.e., line 0, column 0.
      */
     constexpr static Cursor start() noexcept
     {
         return Cursor();
     }
 
     /**
      * Returns the cursor position as string in the format "(line, column)".
      * \see fromString()
      */
     QString toString() const;
 
     /**
      * Returns a Cursor created from the string \p str containing the format
      * "(line, column)". In case the string cannot be parsed, Cursor::invalid()
      * is returned.
      * \see toString()
      */
     static Cursor fromString(QStringView str) noexcept;
 
     /**
      * \name Position
      *
      * The following functions provide access to, and manipulation of, the cursor's position.
      * \{
      */
     /**
      * Set the current cursor position to \e position.
      *
      * \param position new cursor position
      */
     void setPosition(Cursor position) noexcept
     {
         m_line = position.m_line;
         m_column = position.m_column;
     }
 
     /**
      * \overload
      *
      * Set the cursor position to \e line and \e column.
      *
      * \param line new cursor line
      * \param column new cursor column
      */
     void setPosition(int line, int column) noexcept
     {
         m_line = line;
         m_column = column;
     }
 
     /**
      * Retrieve the line on which this cursor is situated.
      * \return line number, where 0 is the first line.
      */
     constexpr int line() const noexcept
     {
         return m_line;
     }
 
     /**
      * Set the cursor line to \e line.
      * \param line new cursor line
      */
     void setLine(int line) noexcept
     {
         m_line = line;
     }
 
     /**
      * Retrieve the column on which this cursor is situated.
      * \return column number, where 0 is the first column.
      */
     constexpr int column() const noexcept
     {
         return m_column;
     }
 
     /**
      * Set the cursor column to \e column.
      * \param column new cursor column
      */
     void setColumn(int column) noexcept
     {
         m_column = column;
     }
 
     /**
      * Determine if this cursor is located at the start of a line (= at column 0).
      * \return \e true if the cursor is situated at the start of the line, \e false if it isn't.
      */
     constexpr bool atStartOfLine() const noexcept
     {
         return m_column == 0;
     }
 
     /**
      * Determine if this cursor is located at the start of a document (= at position (0, 0)).
      * \return \e true if the cursor is situated at the start of the document, \e false if it isn't.
      */
     constexpr bool atStartOfDocument() const noexcept
     {
         return m_line == 0 && m_column == 0;
     }
 
     /**
      * Get both the line and column of the cursor position.
      * \param line will be filled with current cursor line
      * \param column will be filled with current cursor column
      */
     void position(int &line, int &column) const noexcept
     {
         line = m_line;
         column = m_column;
     }
     //!\}
 
     /**
      * Addition operator. Takes two cursors and returns their summation.
      * \param c1 the first position
      * \param c2 the second position
      * \return a the summation of the two input cursors
      */
     constexpr friend Cursor operator+(Cursor c1, Cursor c2) noexcept
     {
         return Cursor(c1.line() + c2.line(), c1.column() + c2.column());
     }
 
     /**
      * Addition assignment operator. Adds \p c2 to this cursor.
      * \param c1 the cursor being added to
      * \param c2 the position to add
      * \return a reference to the cursor which has just been added to
      */
     friend Cursor &operator+=(Cursor &c1, Cursor c2) noexcept
     {
         c1.setPosition(c1.line() + c2.line(), c1.column() + c2.column());
         return c1;
     }
 
     /**
      * Subtraction operator. Takes two cursors and returns the subtraction
      * of \p c2 from \p c1.
      *
      * \param c1 the first position
      * \param c2 the second position
      * \return a cursor representing the subtraction of \p c2 from \p c1
      */
     constexpr friend Cursor operator-(Cursor c1, Cursor c2) noexcept
     {
         return Cursor(c1.line() - c2.line(), c1.column() - c2.column());
     }
 
     /**
      * Subtraction assignment operator. Subtracts \p c2 from \p c1.
      * \param c1 the cursor being subtracted from
      * \param c2 the position to subtract
      * \return a reference to the cursor which has just been subtracted from
      */
     friend Cursor &operator-=(Cursor &c1, Cursor c2) noexcept
     {
         c1.setPosition(c1.line() - c2.line(), c1.column() - c2.column());
         return c1;
     }
 
     /**
      * Equality operator.
      *
      * \note comparison between two invalid cursors is undefined.
      *       comparison between and invalid and a valid cursor will always be \e false.
      *
      * \param c1 first cursor to compare
      * \param c2 second cursor to compare
      * \return \e true, if c1's and c2's line and column are \e equal.
      */
     constexpr friend bool operator==(Cursor c1, Cursor c2) noexcept
     {
         return c1.line() == c2.line() && c1.column() == c2.column();
     }
 
     /**
      * Inequality operator.
      * \param c1 first cursor to compare
      * \param c2 second cursor to compare
      * \return \e true, if c1's and c2's line and column are \e not equal.
      */
     constexpr friend bool operator!=(Cursor c1, Cursor c2) noexcept
     {
         return !(c1 == c2);
     }
 
     /**
      * Greater than operator.
      * \param c1 first cursor to compare
      * \param c2 second cursor to compare
      * \return \e true, if c1's position is greater than c2's position,
      *         otherwise \e false.
      */
     constexpr friend bool operator>(Cursor c1, Cursor c2) noexcept
     {
         return c1.line() > c2.line() || (c1.line() == c2.line() && c1.m_column > c2.m_column);
     }
 
     /**
      * Greater than or equal to operator.
      * \param c1 first cursor to compare
      * \param c2 second cursor to compare
      * \return \e true, if c1's position is greater than or equal to c2's
      *         position, otherwise \e false.
      */
     constexpr friend bool operator>=(Cursor c1, Cursor c2) noexcept
     {
         return c1.line() > c2.line() || (c1.line() == c2.line() && c1.m_column >= c2.m_column);
     }
 
     /**
      * Less than operator.
      * \param c1 first cursor to compare
      * \param c2 second cursor to compare
      * \return \e true, if c1's position is greater than or equal to c2's
      *         position, otherwise \e false.
      */
     constexpr friend bool operator<(Cursor c1, Cursor c2) noexcept
     {
         return !(c1 >= c2);
     }
 
     /**
      * Less than or equal to operator.
      * \param c1 first cursor to compare
      * \param c2 second cursor to compare
      * \return \e true, if c1's position is lesser than or equal to c2's
      *         position, otherwise \e false.
      */
     constexpr friend bool operator<=(Cursor c1, Cursor c2) noexcept
     {
         return !(c1 > c2);
     }
 
 private:
     /**
      * \internal
      *
      * Cursor line
      */
     int m_line = 0;
 
     /**
      * \internal
      *
      * Cursor column
      */
     int m_column = 0;
 };
 
 /**
  * QHash function for KTextEditor::Cursor.
  * Returns the hash value for @p cursor.
  */
 KTEXTEDITOR_EXPORT size_t qHash(KTextEditor::Cursor cursor, size_t seed = 0) noexcept;
 
 } // namespace KTextEditor
 
 Q_DECLARE_TYPEINFO(KTextEditor::Cursor, Q_PRIMITIVE_TYPE);
 
 /**
  * qDebug() stream operator.  Writes this cursor to the debug output in a nicely formatted way.
  */
 KTEXTEDITOR_EXPORT QDebug operator<<(QDebug s, KTextEditor::Cursor cursor);
 
 namespace QTest
 {
 // forward declaration of template in qtestcase.h
 template<typename T>
 char *toString(const T &);
 
 /**
  * QTestLib integration to have nice output in e.g. QCOMPARE failures.
  */
 template<>
 KTEXTEDITOR_EXPORT char *toString(const KTextEditor::Cursor &cursor);
 }
 
 #endif