Marker


1   package gnu.jemacs.buffer;
2   import gnu.lists.*;
3   import gnu.mapping.*;
4   
5   public final class Marker extends SeqPosition
6   {
7     Buffer buffer;
8   
9     /** Is this the special point marker? */
10    public final boolean isPoint() { return buffer != null && sequence == null; }
11  
12    public Marker()
13    {
14    }
15  
16    public Marker(Marker marker)
17    {
18      buffer = marker.buffer;
19      if (buffer != null)
20        {
21      if (marker.isPoint())
22        set(buffer, buffer.getDot(), true);
23      else
24        set(marker);
25        }
26    }
27  
28    public Marker (Buffer buffer, int offset, boolean isAfter)
29    {
30      super(buffer, offset, isAfter);
31      this.buffer = buffer;
32    }
33  
34    public int getOffset()
35    {
36      if (buffer == null)
37        return -1;
38      else if (isPoint())
39        return buffer.getDot();
40      return nextIndex();
41    }
42  
43    public int getPoint()
44    {
45      return 1 + getOffset();
46    }
47  
48    public Buffer getBuffer()
49    {
50      return buffer;
51    }
52  
53    public void setDot(int newPosition)
54    {
55      set(buffer, newPosition);
56    }
57  
58    public void set(Buffer newBuffer, int newPosition)
59    {
60      if (isPoint())
61        {
62          if (newBuffer != buffer)
63            {
64              String   msg;
65              if (newBuffer == null)
66                msg = "Can't make point-marker point nowhere: ";
67              else
68                msg = "Can't change buffer of point-marker: ";
69              throw new Error  (msg+this);
70            }
71      buffer.setDot(newPosition);
72        }
73      else
74        {
75          if (sequence != null)
76            release();
77      sequence = null;
78          if (newBuffer == null)
79            {
80              buffer = null;
81              return;
82            }
83  
84          if (newPosition < 0)
85            newPosition = 0;
86          else
87            {
88              int newLength = newBuffer.length();
89              if (newPosition > newLength)
90                newPosition = newLength;
91            }
92      set(newBuffer, newPosition, false);
93        }
94    }
95  
96    public void removeChar(int count)
97    {
98      if (isPoint())
99        buffer.removeChar(count);
100     else
101       buffer.removePos(ipos, count);
102   }
103 
104   public void insert (char[] data, int off, int len, Object   style)
105   {
106     int point = getOffset();
107     buffer.insert(data, off, len, style, ipos);
108     point += len;
109     setDot(point);
110   }
111 
112   public void insert (String   string, Object   style)
113   {
114     int point = getOffset();
115     if (isPoint())
116       buffer.insert(string, style);
117     else
118       buffer.insert(string, style, ipos);
119     point += string.length();
120     setDot(point);
121   }
122 
123   /** Insert count copies of ch at the current position. */
124   public void insert (char ch, int count, Object   style)
125   {
126     if (count < 0)
127       return;
128     int n = count > 500 ? 500 : count;
129     StringBuffer   sbuf = new StringBuffer  (n);
130     for (int i = n;  --i >= 0; )
131       sbuf.append(ch);
132     String   str = sbuf.toString();
133     for (;;)
134       {
135     insert(str, style);
136     count -= n;
137     if (count == 0)
138       break;
139     if (count < 500)
140       {
141         n = count;
142         sbuf.setLength(n);
143         str = sbuf.toString();
144       }
145       }
146   }
147 
148   public void forwardChar(int i)
149   {
150     int point = getOffset();
151     int max = buffer.maxDot();
152     if (point + i > max)
153       {
154     point = max;
155     Signal.signal("End of buffer");
156       }
157     point += i;
158     setDot(point);
159   }
160 
161   public void backwardChar(int i)
162   {
163     int point = getOffset();
164     if (point < i)
165       {
166     point = 0;
167     Signal.signal("Beginning of buffer");
168       }
169     point -= i;
170     setDot(point);
171   }
172 
173   public int currentColumn()
174   {
175     return buffer.currentColumn(getOffset());
176   }
177 
178   // force is currently ignored FIXME
179   public int moveToColumn(int column, boolean force)
180   { 
181     int lineStart = buffer.lineStartOffset(getOffset());
182     InPort port = buffer.openReader(lineStart, buffer.maxDot() - lineStart);
183     int resultColumn = 0;
184     try
185       {
186     int offset = lineStart;
187     for (;;)
188       {
189         int ch = port.read();
190         if (ch < 0 || ch == '\n')
191           {
192         if (force)
193           {
194             // FIXME
195           }
196         break;
197           }
198         int width = buffer.charWidth((char) ch, resultColumn);
199         offset++;
200         resultColumn += width;
201         if (resultColumn >= column)
202           {
203         if (resultColumn > column && force)
204           {
205             // FIXME
206           }
207         break;
208           }
209       }
210     setDot(offset);
211     return resultColumn;
212       }
213     catch (java.io.IOException   ex)
214       {
215     throw new WrappedException(ex);
216       }
217   }
218 
219   public int forwardLine(int lines)
220   {
221     long value = buffer.forwardLine(lines, getOffset());
222     setDot((int) value);
223     return (int) (value >> 32);
224   }
225 
226   /** Move to start of frame line COUNTs down.
227    * Assume window width is WIDTH.
228    * If LINES is negative, this is moving up. */
229 
230   /*
231   public int verticalMotion(int count, int width)
232   {
233     if (count == 0)
234       {
235     moveToColumn ((currentColumn() / width) * width, false);
236     return 0;
237       }
238     if (count > 0)
239       {
240     int todo = count + currentColumn() / width;
241     endOfLine();
242     // The loop iterates over buffer lines;
243     // H is the number of screen lines in the current line, i.e.
244     // the ceiling of dividing the buffer line width by width.
245     for (;;)
246       {
247         int h = (currentColumn() + width - 1) / width;
248         if (h <= 0) h = 1;
249         if (h > todo)
250           break;
251         if (eobp())
252           break;
253         todo -= h;
254         forwardChar(1);  // move past '\n'.
255         endOfLine();  // and on to the end of the next line.
256       }
257     if (todo >= h && todo > 0)
258       return count - todo + h - 1; // Hit end of buffer.
259       }
260     else // count > 0 -- Similar algorithm, but for upward motion.
261       {
262     int todo = - count;
263     for (;;)
264       {
265         int h = (currentColumn() + width - 1) / width;
266         if (h <= 0) h = 1;
267         if (h > todo)
268           break;
269         beginningOfLine();
270         if (bobp())
271           break;
272         todo -= h;
273         backwardChar(1); // Move to end of previous line
274       }
275     if (todo >= h && todo > 0)
276       return count + todo - 1 + h; // Hit beginning of buffer.
277     todo = h - todo - 1;
278       }
279     moveToColumn(todo * width, false);
280     return count;
281   }
282   */
283 
284   public boolean isBeginningOfLine()
285   {
286     int offset = getOffset();
287     return offset == 0 || buffer.charAt(offset - 1) == '\n';
288   }
289 
290   public boolean isEndOfLine()
291   {
292     int offset = getOffset();
293     return offset == buffer.length() || buffer.charAt(offset) == '\n';
294   }
295 
296   public int hashCode()
297   {
298     if (buffer == null)
299       return 0;
300     return buffer.hashCode() ^ getOffset();
301   }
302 
303   public boolean equals (Object   other)
304   {
305     if (! (other instanceof Marker))
306       return false;
307     Marker m2 = (Marker) other;
308     return buffer == m2.buffer && getOffset() == m2.getOffset();
309   }
310 
311   public String   toString()
312   {
313     if (buffer == null)
314       return "#<marker in no buffer>";
315     StringBuffer   sbuf = new StringBuffer  (80);
316     sbuf.append("#<marker at ");
317     sbuf.append(getPoint());
318     sbuf.append(" in ");
319     sbuf.append(buffer.getName());
320     sbuf.append('>');
321     return sbuf.toString();
322   }
323 }
324
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