khtml_caret_p.h

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  friend class EditableCaretBoxIterator;
  friend class EditableCharacterIterator;
};

/**
 * Iterates over the editable inner elements of a caret line box.
 *
 * The incrementor will traverse all caret boxes according to the associated
 * linear document's caret advance policy. In contrast to \c CaretBoxIterator
 * this iterator only regards caret boxes which are editable.
 *
 * @author Leo Savernik
 * @internal
 * @since 3.3
 */
class EditableCaretBoxIterator : public CaretBoxIterator {
  KHTMLPart *m_part;
  bool adjacent;
  CaretAdvancePolicy advpol;	// caret advance policy

public:
  /** initializes a new iterator from the given line iterator,
   * beginning with the given caret box iterator, if specified
   */
  EditableCaretBoxIterator(LineIterator &lit, bool fromEnd = false,
  		CaretBoxIterator *it = 0)
  		: CaretBoxIterator(it ? *it : (fromEnd ? (*lit)->end() : (*lit)->preBegin())),
                m_part(lit.lines->m_part), adjacent(false),
                advpol(lit.lines->advancePolicy())
  {
    if (!it) {
      if (fromEnd) --*this; else ++*this;
    }
  }

  /** empty constructor. Use only to copy another iterator into this one.
   */
  EditableCaretBoxIterator() {}

  /** returns @p true when the current caret box is adjacent to the
   * previously iterated caret box, i. e. no intervening caret boxes.
   */
  bool isAdjacent() const { return adjacent; }

  /** increments the iterator to point to the next editable caret box.
   */
  EditableCaretBoxIterator &operator ++() { advance(false); return *this; }

  /** decrements the iterator to point to the previous editable caret box.
   */
  EditableCaretBoxIterator &operator --() { advance(true); return *this; }

  /** advances to the editable caret box to come
   * @param toBegin true, move towards beginning, false, move towards end.
   */
  void advance(bool toBegin);

protected:
  /** finds out if the given box is editable.
   * @param boxit iterator to given caret box
   * @param fromEnd true when advancing towards the beginning
   * @return @p true if box is editable
   */
  bool isEditable(const CaretBoxIterator &boxit, bool fromEnd);
};

/**
 * Iterates through the editable lines of a document.
 *
 * This iterator, opposing to @p LineIterator, only regards editable lines.
 * Additionally, this iterator enforces the caret advance policy.
 *
 * The iterator can be compared to normal LineIterators, especially to
 * @ref LinearDocument::preBegin and @ref LinearDocument::end
 *
 * The line iterator becomes invalid when the associated LinearDocument object
 * is destroyed.
 * @since 3.2
 * @internal
 * @author Leo Savernik
 */
class EditableLineIterator : public LineIterator {
public:
  /** Initializes a new iterator.
   *
   * The iterator is set to the first following editable line or to the
   * end if no editable line follows.
   * @param it a line iterator to initialize this from
   * @param fromEnd @p true, traverse towards the beginning in search of an
   *	editable line
   */
  EditableLineIterator(const LineIterator &it, bool fromEnd = false)
  		: LineIterator(it)
  {
    if (!cbl) return;
    if (!isEditable(*this)) advance(fromEnd);
  }

  /** empty constructor.
   *
   * Only use if you want to copy another iterator onto it later.
   */
  EditableLineIterator() {}

  /** seek next line
   *
   * Guaranteed to crash if beyond beginning/end of document.
   */
  EditableLineIterator &operator ++() { advance(false); return *this; }

  /** seek previous line.
   *
   * Guaranteed to crash if beyond beginning/end of document.
   */
  EditableLineIterator &operator --() { advance(true); return *this; }

  /** advances to the line to come.
   * @param toBegin true, move to previous line, false, move to next line.
   */
  void advance(bool toBegin);

protected:
  /** finds out if the current line is editable.
   *
   * @param it check caret box line iterator points to
   * @return @p true if line is editable
   */
  bool isEditable(LineIterator &it)
  {
    EditableCaretBoxIterator fbit = it;
    return fbit != (*it)->end();
  }

};

/** Represents a render table as a linear list of rows.
 *
 * This iterator abstracts from table sections and treats tables as a linear
 * representation of all rows they contain.
 * @author Leo Savernik
 * @internal
 * @since 3.2
 */
class TableRowIterator {
protected:
  TableSectionIterator sec;	// current section
  int index;			// index of row within section
public:
  /** Constructs a new iterator.
   * @param table table to iterate through.
   * @param fromEnd @p true to iterate towards the beginning
   * @param row pointer to row to start with, 0 starts at the first/last
   *	row.
   */
  TableRowIterator(RenderTable *table, bool fromEnd = false,
  		RenderTableSection::RowStruct *row = 0);

  /** Constructs a new iterator.
   * @param section table section to begin with
   * @param index index within table section
   */
  TableRowIterator(RenderTableSection *section, int index)
  	: sec(section), index(index)
  {}

  /** empty constructor. This must be assigned another iterator before it is
   * useable.
   */
  TableRowIterator() {}

  /** returns the current table row.
   * @return the row or 0 if the end of the table has been reached.
   */
  RenderTableSection::RowStruct *operator *()
  {
    if (!*sec) return 0;
    return &(*sec)->grid[index];
  }

  /** advances to the next row
   */
  TableRowIterator &operator ++();

  /** advances to the previous row
   */
  TableRowIterator &operator --();

protected:
};

/** Iterates through the editable lines of a document, in a topological order.
 *
 * The differences between this and the EditableLineIterator lies in the way
 * lines are inquired. While the latter steps through the lines in document
 * order, the former takes into consideration ergonomics.
 *
 * This is especially useful for tables. EditableLineIterator traverses all
 * table cells from left to right, top to bottom, while this one will
 * actually snap to the cell in the right position, and traverse only
 * upwards/downwards, thus providing a more intuitive navigation.
 *
 * @author Leo Savernik
 * @internal
 * @since 3.2
 */
class ErgonomicEditableLineIterator : public EditableLineIterator {
protected:
  int xCoor;		// x-coordinate to determine cell position
public:
  /** Initializes a new ergonomic editable line iterator from the given one.
   * @param it line iterator
   * @param x absolute x-coordinate for cell determination
   */
  ErgonomicEditableLineIterator(const LineIterator &it, int x)
  	: EditableLineIterator(it), xCoor(x) {}

  /** Constructs an uninitialized iterator which must be assigned a line iterator before
   * it can be used.
   */
  ErgonomicEditableLineIterator() {}

  /** seek next line.
   *
   * The next line will be one that is visually situated below this line.
   */
  ErgonomicEditableLineIterator &operator ++();

  /** seek previous line.
   *
   * The previous line will be one that is visually situated above this line.
   */
  ErgonomicEditableLineIterator &operator --();

protected:
  /** determines the topologically next render object.
   * @param oldCell table cell the original object was under.
   * @param newObject object to determine whether and which transition
   *	between cells is to be handled. It does not have to be an object in the correct
   *	topological cell, a simple delivery from an editable line iterator suffices.
   * @param toBegin if @p true, iterate towards the beginning
   */
  void determineTopologicalElement(RenderTableCell *oldCell,
  		RenderObject *newObject, bool toBegin);

  /** initializes the iterator to point to the first previous/following editable
   * line.
   * @param newBlock take this as base block.
   * @param toBegin @p true, iterate towards beginning.
   */
  void calcAndStoreNewLine(RenderBlock *newBlock, bool toBegin);

};

/**
 * Provides iterating through the document in terms of characters. Only the
 * editable characters are regarded.
 *
 * This iterator represents the document, which is structured as a tree itself,
 * as a linear stream of characters.
 */
class EditableCharacterIterator {
protected:
  EditableLineIterator _it;
  EditableCaretBoxIterator ebit;
  long _offset;		// offset within current caret box.
  int _char;
  bool _end:1;		// true when end of document has been reached

public:

  /** empty constructor.
   *
   * Only use if you want to assign another iterator as no fields will
   * be initialized.
   */
  EditableCharacterIterator() {}

  /** constructs a new iterator from the given linear document.
   *
   * @param ld linear representation of document.
   */
  EditableCharacterIterator(LinearDocument *ld)
  		: _it(ld->current()),
                ebit(_it, false, &_it.currentCaretBox()),
      		_offset(_it.currentModifiedOffset()), _char(-1), _end(false)
  {
    // ### temporary fix for illegal nodes
    if (_it == ld->end()) { _end = true; return; }
    initFirstChar();
  }

  /** returns the current character, or -1 if not on a text node, or beyond
   * the end.
   */
  int chr() const { return _char; }

  /** returns the current character as a unicode symbol, substituting
   * a blank for a non-text node.
   */
  QChar operator *() const { return QChar(_char >= 0 ? _char : ' '); }

  /** returns true when the end of the document has been reached.
   */
  bool isEnd() const { return _end; }
  /** returns the current offset
   */
  long offset() const { return _offset; }
  /** returns the current render object.
   */
  RenderObject *renderer() const { return (*ebit)->object(); }
  /** returns the current caret box.
   *
   * Will crash if beyond end.
   */
  CaretBox *caretBox() const { return *ebit; }
  /** returns the current inline box.
   *
   * May be 0 if the current element has none, or if the end has been reached.
   * Therefore, do *not* use this to test for the end condition, use node()
   * instead.
   */
  InlineBox *inlineBox() const { return (*ebit)->inlineBox(); }
  /** returns whether the current line box represents the outside of its
   * render object.
   */
//  bool boxIsOutside() const { return _it.isOutside(); }

  /** moves to the next editable character.
   */
  EditableCharacterIterator &operator ++();

  /** moves to the previous editable character.
   */
  EditableCharacterIterator &operator --();

protected:
  /** initializes the _char member by reading the character at the current
   * offset, peeking ahead as necessary.
   */
  void initFirstChar();
  /** reads ahead the next node and updates the data structures accordingly
   */
  void peekNext()
  {
    EditableCaretBoxIterator copy = ebit;
    ++copy;
    if (copy == (*_it)->end()) { _char = -1; return; }

    CaretBox *box = *copy;
    InlineBox *b = box->inlineBox();
    if (b && !box->isOutside() && b->isInlineTextBox())
      _char = static_cast<RenderText *>(b->object())->str->s[b->minOffset()].unicode();
    else
      _char = -1;
  }
  /** reads ahead the previous node and updates the data structures accordingly
   */
  void peekPrev()
  {
    --ebit;
  }

};


}/*namespace khtml*/


#endif