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1
11 package org.eclipse.ant.internal.ui.editor.derived;
12
13 import java.io.BufferedReader  ;
14 import java.io.IOException ;
15 import java.io.Reader ;
16
17 import com.ibm.icu.text.BreakIterator;
18 import org.eclipse.swt.graphics.GC;
19
20
24 public class LineBreakingReader {
25
26 private BufferedReader fReader;
27 private GC fGC;
28 private int fMaxWidth;
29
30 private String fLine;
31 private int fOffset;
32
33 private BreakIterator fLineBreakIterator;
34 private boolean fBreakWords;
35
36
43 public LineBreakingReader(Reader reader, GC gc, int maxLineWidth) {
44 fReader= new BufferedReader (reader);
45 fGC= gc;
46 fMaxWidth= maxLineWidth;
47 fOffset= 0;
48 fLine= null;
49 fLineBreakIterator= BreakIterator.getLineInstance();
50 fBreakWords= true;
51 }
52
53 public boolean isFormattedLine() {
54 return fLine != null;
55 }
56
57
64 public String readLine() throws IOException {
65 if (fLine == null) {
66 String line= fReader.readLine();
67 if (line == null)
68 return null;
69
70 int lineLen= fGC.textExtent(line).x;
71 if (lineLen < fMaxWidth) {
72 return line;
73 }
74 fLine= line;
75 fLineBreakIterator.setText(line);
76 fOffset= 0;
77 }
78 int breakOffset= findNextBreakOffset(fOffset);
79 String res;
80 if (breakOffset != BreakIterator.DONE) {
81 res= fLine.substring(fOffset, breakOffset);
82 fOffset= findWordBegin(breakOffset);
83 if (fOffset == fLine.length()) {
84 fLine= null;
85 }
86 } else {
87 res= fLine.substring(fOffset);
88 fLine= null;
89 }
90 return res;
91 }
92
93 private int findNextBreakOffset(int currOffset) {
94 int currWidth= 0;
95 int nextOffset= fLineBreakIterator.following(currOffset);
96 while (nextOffset != BreakIterator.DONE) {
97 String word= fLine.substring(currOffset, nextOffset);
98 int wordWidth= fGC.textExtent(word).x;
99 int nextWidth= wordWidth + currWidth;
100 if (nextWidth > fMaxWidth) {
101 if (currWidth > 0)
102 return currOffset;
103
104 if (!fBreakWords)
105 return nextOffset;
106
107 int length= word.length();
109 while (length >= 0) {
110 length--;
111 word= word.substring(0, length);
112 wordWidth= fGC.textExtent(word).x;
113 if (wordWidth + currWidth < fMaxWidth)
114 return currOffset + length;
115 }
116 return nextOffset;
117 }
118 currWidth= nextWidth;
119 currOffset= nextOffset;
120 nextOffset= fLineBreakIterator.next();
121 }
122 return nextOffset;
123 }
124
125 private int findWordBegin(int idx) {
126 while (idx < fLine.length() && Character.isWhitespace(fLine.charAt(idx))) {
127 idx++;
128 }
129 return idx;
130 }
131 } |
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