/*
* Copyright 2011 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp.parsing.parser;
import com.google.javascript.jscomp.parsing.parser.util.SourcePosition;
import com.google.javascript.jscomp.parsing.parser.util.SourceRange;
import java.util.ArrayList;
import java.util.Arrays;
/**
* Maps offsets into a source string into line/column positions.
*
* Immutable.
*/
public class LineNumberTable {
private final SourceFile sourceFile;
private final int[] lineStartOffsets;
public LineNumberTable(SourceFile sourceFile) {
this.sourceFile = sourceFile;
this.lineStartOffsets = computeLineStartOffsets(sourceFile.contents);
}
private static int[] computeLineStartOffsets(String source) {
// TODO(johnlenz): do this more efficiently.
ArrayList<Integer> lineStartOffsets = new ArrayList<>();
lineStartOffsets.add(0);
for (int index = 0; index < source.length(); index++) {
char ch = source.charAt(index);
if (isLineTerminator(ch)) {
if (index + 1 < source.length() && ch == '\r'
&& source.charAt(index + 1) == '\n') {
index++;
}
lineStartOffsets.add(index + 1);
}
}
lineStartOffsets.add(Integer.MAX_VALUE);
return toIntArray(lineStartOffsets);
}
public static int[] toIntArray(ArrayList<Integer> integers) {
int[] ret = new int[integers.size()];
for (int i = 0; i < ret.length; i++) {
ret[i] = integers.get(i).intValue();
}
return ret;
}
private static boolean isLineTerminator(char ch) {
switch (ch) {
case '\n': // Line Feed
case '\r': // Carriage Return
case '\u2028': // Line Separator
case '\u2029': // Paragraph Separator
return true;
default:
return false;
}
}
public SourcePosition getSourcePosition(int offset) {
int line = getLine(offset);
return new SourcePosition(sourceFile, offset, line, getColumn(line, offset));
}
public int getLine(int offset) {
int index = Arrays.binarySearch(lineStartOffsets, offset);
// start of line
if (index >= 0) {
return index;
}
return -index - 2;
}
public int offsetOfLine(int line) {
return lineStartOffsets[line];
}
public int getColumn(int offset) {
int line = getLine(offset);
return getColumn(line, offset);
}
private int getColumn(int line, int offset) {
return offset - offsetOfLine(line);
}
public SourceRange getSourceRange(int startOffset, int endOffset) {
return new SourceRange(getSourcePosition(startOffset), getSourcePosition(endOffset));
}
}