001 /** 002 * 003 * Copyright 2005 Jeremy Rayner 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 **/ 018 package org.codehaus.groovy.antlr; 019 020 import java.util.List; 021 import java.util.ArrayList; 022 023 /** 024 * A simple buffer that provides line/col access to chunks of source code 025 * held within itself. 026 * 027 * @author <a href="mailto:groovy@ross-rayner.com">Jeremy Rayner</a> 028 * @version $Revision: 2250 $ 029 */ 030 public class SourceBuffer { 031 private List lines; 032 private StringBuffer current; 033 034 public SourceBuffer() { 035 lines = new ArrayList(); 036 //lines.add(new StringBuffer()); // dummy row for position [0] in the List 037 038 current = new StringBuffer(); 039 lines.add(current); 040 } 041 042 /** 043 * Obtains a snippet of the source code within the bounds specified 044 * @param start (inclusive line/ inclusive column) 045 * @param end (inclusive line / exclusive column) 046 * @return specified snippet of source code as a String, or null if no source available 047 */ 048 public String getSnippet(LineColumn start, LineColumn end) { 049 // preconditions 050 if (start == null || end == null) { return null; } // no text to return 051 if (start.equals(end)) { return null; } // no text to return 052 if (lines.size() == 1 && current.length() == 0) { return null; } // buffer hasn't been filled yet 053 054 // working variables 055 int startLine = start.getLine(); 056 int startColumn = start.getColumn(); 057 int endLine = end.getLine(); 058 int endColumn = end.getColumn(); 059 060 // reset any out of bounds requests 061 if (startLine < 1) { startLine = 1;} 062 if (endLine < 1) { endLine = 1;} 063 if (startColumn < 1) { startColumn = 1;} 064 if (endColumn < 1) { endColumn = 1;} 065 if (startLine > lines.size()) { startLine = lines.size(); } 066 if (endLine > lines.size()) { endLine = lines.size(); } 067 068 // obtain the snippet from the buffer within specified bounds 069 StringBuffer snippet = new StringBuffer(); 070 for (int i = startLine - 1; i < endLine;i++) { 071 String line = ((StringBuffer)lines.get(i)).toString(); 072 if (startLine == endLine) { 073 // reset any out of bounds requests (again) 074 if (startColumn > line.length()) { startColumn = line.length();} 075 if (startColumn < 1) { startColumn = 1;} 076 if (endColumn > line.length()) { endColumn = line.length() + 1;} 077 if (endColumn < 1) { endColumn = 1;} 078 079 line = line.substring(startColumn - 1, endColumn - 1); 080 } else { 081 if (i == startLine - 1) { 082 if (startColumn - 1 < line.length()) { 083 line = line.substring(startColumn - 1); 084 } 085 } 086 if (i == endLine - 1) { 087 if (endColumn - 1 < line.length()) { 088 line = line.substring(0,endColumn - 1); 089 } 090 } 091 } 092 snippet.append(line); 093 } 094 return snippet.toString(); 095 } 096 097 /** 098 * Writes the specified character into the buffer 099 * @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 }