1 /***
2 *
3 * Copyright 2005 Jeremy Rayner
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 **/
18 package org.codehaus.groovy.antlr;
19
20 import java.util.List;
21 import java.util.ArrayList;
22
23 /***
24 * A simple buffer that provides line/col access to chunks of source code
25 * held within itself.
26 *
27 * @author <a href="mailto:groovy@ross-rayner.com">Jeremy Rayner</a>
28 * @version $Revision: 1.4 $
29 */
30 public class SourceBuffer {
31 private List lines;
32 private StringBuffer current;
33
34 public SourceBuffer() {
35 lines = new ArrayList();
36
37
38 current = new StringBuffer();
39 lines.add(current);
40 }
41
42 /***
43 * Obtains a snippet of the source code within the bounds specified
44 * @param start (inclusive line/ inclusive column)
45 * @param end (inclusive line / exclusive column)
46 * @return specified snippet of source code as a String, or null if no source available
47 */
48 public String getSnippet(LineColumn start, LineColumn end) {
49
50 if (start == null || end == null) { return null; }
51 if (start.equals(end)) { return null; }
52 if (lines.size() == 1 && current.length() == 0) { return null; }
53
54
55 int startLine = start.getLine();
56 int startColumn = start.getColumn();
57 int endLine = end.getLine();
58 int endColumn = end.getColumn();
59
60
61 if (startLine < 1) { startLine = 1;}
62 if (endLine < 1) { endLine = 1;}
63 if (startColumn < 1) { startColumn = 1;}
64 if (endColumn < 1) { endColumn = 1;}
65 if (startLine > lines.size()) { startLine = lines.size(); }
66 if (endLine > lines.size()) { endLine = lines.size(); }
67
68
69 StringBuffer snippet = new StringBuffer();
70 for (int i = startLine - 1; i < endLine;i++) {
71 String line = ((StringBuffer)lines.get(i)).toString();
72 if (startLine == endLine) {
73
74 if (startColumn > line.length()) { startColumn = line.length();}
75 if (startColumn < 1) { startColumn = 1;}
76 if (endColumn > line.length()) { endColumn = line.length() + 1;}
77 if (endColumn < 1) { endColumn = 1;}
78
79 line = line.substring(startColumn - 1, endColumn - 1);
80 } else {
81 if (i == startLine - 1) {
82 if (startColumn - 1 < line.length()) {
83 line = line.substring(startColumn - 1);
84 }
85 }
86 if (i == endLine - 1) {
87 if (endColumn - 1 < line.length()) {
88 line = line.substring(0,endColumn - 1);
89 }
90 }
91 }
92 snippet.append(line);
93 }
94 return snippet.toString();
95 }
96
97 /***
98 * Writes the specified character into the buffer
99 * @param c
100 */
101 public void write(int c) {
102 if (c != -1) {
103 current.append((char)c);
104 }
105 if (c == '\n') {
106 current = new StringBuffer();
107 lines.add(current);
108 }
109 }
110 }