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/*******************************************************************************
* Copyright (c) 2007, 2008 Borland Software Corporation and others.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Borland Software Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.m2m.internal.qvt.oml.common.util;
import java.util.ArrayList;
/**
* Implemens quick search of a line number for a given position within a string
*/
public class StringLineNumberProvider implements LineNumberProvider {
/**
* Creates a new StringLineNumberProvider object for the given string
* @param s - the string to parse into lines
*/
public StringLineNumberProvider(String s) {
myLineEnds = new ArrayList<Integer>();
parseString(s);
}
public int getLineEnd(int lineNumber) {
return getLineEndInt(lineNumber - 1);
}
public int getLineCount() {
return myLineEnds.size();
}
public int getLineNumber(int offset){
if (offset < 0) {
return -1;
}
return getLineNumberInt(offset) + 1;
}
/* Internal implementation: zero-based line numeration */
private int getLineEndInt(int lineNumber) {
return ((Integer) myLineEnds.get(lineNumber)).intValue();
}
/* Internal implementation: zero-based line numeration
* Dihotomic search of a line containig given offset
*/
public int getLineNumberInt(int offset){
int a = 0;
if (getLineEndInt(a) >= offset) {
return a;
}
int b = myLineEnds.size() - 1;
if (getLineEndInt(b) < offset) {
return b;
}
int result = b;
while (a <= b) {
int c = (a + b) / 2;
int cValue = getLineEndInt(c);
if (cValue > offset) {
result = c;
b = c - 1;
}
else if (cValue < offset) {
a = c + 1;
}
else return c;
}
return result;
}
/* Find out line ends */
private void parseString(String s) {
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == '\n') {
myLineEnds.add(new Integer(i));
}
// Workaround for the case when \r is present and \n is lost
if ((s.charAt(i) == '\r') && (i < s.length() - 1)) {
if (s.charAt(i + 1) != '\n') {
myLineEnds.add(new Integer(i));
}
}
}
if ((s.length() != 0 ) && (
myLineEnds.isEmpty() ||
(getLineEndInt(getLineCount() - 1) != s.length() - 1)
)) {
myLineEnds.add(new Integer(s.length() - 1));
}
}
private final ArrayList<Integer> myLineEnds;
}
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