package gnu.jemacs.buffer;import gnu.lists.*;import gnu.mapping.*;public final class Marker extends SeqPosition{  Buffer buffer;  /** Is this the special point marker? */  public final boolean isPoint() { return buffer != null && sequence == null; }  public Marker()  {  }  public Marker(Marker marker)  {    buffer = marker.buffer;    if (buffer != null)      {	if (marker.isPoint())	  set(buffer, buffer.getDot(), true);	else	  set(marker);      }  }  public Marker (Buffer buffer, int offset, boolean isAfter)  {    super(buffer, offset, isAfter);    this.buffer = buffer;  }  public int getOffset()  {    if (buffer == null)      return -1;    else if (isPoint())      return buffer.getDot();    return nextIndex();  }  public int getPoint()  {    return 1 + getOffset();  }  public Buffer getBuffer()  {    return buffer;  }  public void setDot(int newPosition)  {    set(buffer, newPosition);  }  public void set(Buffer newBuffer, int newPosition)  {    if (isPoint())      {        if (newBuffer != buffer)          {            String msg;            if (newBuffer == null)              msg = "Can't make point-marker point nowhere: ";            else              msg = "Can't change buffer of point-marker: ";            throw new Error(msg+this);          }	buffer.setDot(newPosition);      }    else      {        if (sequence != null)          release();	sequence = null;        if (newBuffer == null)          {            buffer = null;            return;          }        if (newPosition < 0)          newPosition = 0;        else          {            int newLength = newBuffer.length();            if (newPosition > newLength)              newPosition = newLength;          }	set(newBuffer, newPosition, false);      }  }  public void removeChar(int count)  {    if (isPoint())      buffer.removeChar(count);    else      buffer.removePos(ipos, count);  }  public void insert (char[] data, int off, int len, Object style)  {    int point = getOffset();    buffer.insert(data, off, len, style, ipos);    point += len;    setDot(point);  }  public void insert (String string, Object style)  {    int point = getOffset();    if (isPoint())      buffer.insert(string, style);    else      buffer.insert(string, style, ipos);    point += string.length();    setDot(point);  }  /** Insert count copies of ch at the current position. */  public void insert (char ch, int count, Object style)  {    if (count < 0)      return;    int n = count > 500 ? 500 : count;    StringBuffer sbuf = new StringBuffer(n);    for (int i = n;  --i >= 0; )      sbuf.append(ch);    String str = sbuf.toString();    for (;;)      {	insert(str, style);	count -= n;	if (count == 0)	  break;	if (count < 500)	  {	    n = count;	    sbuf.setLength(n);	    str = sbuf.toString();	  }      }  }  public void forwardChar(int i)  {    int point = getOffset();    int max = buffer.maxDot();    if (point + i > max)      {	point = max;	Signal.signal("End of buffer");      }    point += i;    setDot(point);  }  public void backwardChar(int i)  {    int point = getOffset();    if (point < i)      {	point = 0;	Signal.signal("Beginning of buffer");      }    point -= i;    setDot(point);  }  public int currentColumn()  {    return buffer.currentColumn(getOffset());  }  // force is currently ignored FIXME  public int moveToColumn(int column, boolean force)  {     int lineStart = buffer.lineStartOffset(getOffset());    InPort port = buffer.openReader(lineStart, buffer.maxDot() - lineStart);    int resultColumn = 0;    try      {	int offset = lineStart;	for (;;)	  {	    int ch = port.read();	    if (ch < 0 || ch == '\n')	      {		if (force)		  {		    // FIXME		  }		break;	      }	    int width = buffer.charWidth((char) ch, resultColumn);	    offset++;	    resultColumn += width;	    if (resultColumn >= column)	      {		if (resultColumn > column && force)		  {		    // FIXME		  }		break;	      }	  }	setDot(offset);	return resultColumn;      }    catch (java.io.IOException ex)      {	throw new WrappedException(ex);      }  }  public int forwardLine(int lines)  {    long value = buffer.forwardLine(lines, getOffset());    setDot((int) value);    return (int) (value >> 32);  }  /** Move to start of frame line COUNTs down.   * Assume window width is WIDTH.   * If LINES is negative, this is moving up. */  /*  public int verticalMotion(int count, int width)  {    if (count == 0)      {	moveToColumn ((currentColumn() / width) * width, false);	return 0;      }    if (count > 0)      {	int todo = count + currentColumn() / width;	endOfLine();	// The loop iterates over buffer lines;	// H is the number of screen lines in the current line, i.e.	// the ceiling of dividing the buffer line width by width.	for (;;)	  {	    int h = (currentColumn() + width - 1) / width;	    if (h <= 0) h = 1;	    if (h > todo)	      break;	    if (eobp())	      break;	    todo -= h;	    forwardChar(1);  // move past '\n'.	    endOfLine();  // and on to the end of the next line.	  }	if (todo >= h && todo > 0)	  return count - todo + h - 1; // Hit end of buffer.      }    else // count > 0 -- Similar algorithm, but for upward motion.      {	int todo = - count;	for (;;)	  {	    int h = (currentColumn() + width - 1) / width;	    if (h <= 0) h = 1;	    if (h > todo)	      break;	    beginningOfLine();	    if (bobp())	      break;	    todo -= h;	    backwardChar(1); // Move to end of previous line	  }	if (todo >= h && todo > 0)	  return count + todo - 1 + h; // Hit beginning of buffer.	todo = h - todo - 1;      }    moveToColumn(todo * width, false);    return count;  }  */  public boolean isBeginningOfLine()  {    int offset = getOffset();    return offset == 0 || buffer.charAt(offset - 1) == '\n';  }  public boolean isEndOfLine()  {    int offset = getOffset();    return offset == buffer.length() || buffer.charAt(offset) == '\n';  }  public int hashCode()  {    if (buffer == null)      return 0;    return buffer.hashCode() ^ getOffset();  }  public boolean equals (Object other)  {    if (! (other instanceof Marker))      return false;    Marker m2 = (Marker) other;    return buffer == m2.buffer && getOffset() == m2.getOffset();  }  public String toString()  {    if (buffer == null)      return "#<marker in no buffer>";    StringBuffer sbuf = new StringBuffer(80);    sbuf.append("#<marker at ");    sbuf.append(getPoint());    sbuf.append(" in ");    sbuf.append(buffer.getName());    sbuf.append('>');    return sbuf.toString();  }}