/*
* Copyright (c) 2011 Google Inc.
*
* 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
*/
package com.google.eclipse.protobuf.conversion;
import static org.eclipse.xtext.util.Strings.isEmpty;
import java.math.BigInteger;
import org.eclipse.xtext.conversion.ValueConverterException;
import org.eclipse.xtext.conversion.impl.AbstractLexerBasedConverter;
import org.eclipse.xtext.nodemodel.INode;
/**
* Converts hexadecimal numbers to {@code long}s.
*
* @author alruiz@google.com (Alex Ruiz)
*/
public class HEXValueConverter extends AbstractLexerBasedConverter<Long> {
private static final String[] VALID_PREFIXES = { "0x", "-0x", "0X", "-0X" };
/**
* Creates an {@code int} from the given input, if the given input represents an hexadecimal number.
* @param string the given input.
* @param node the parsed node including hidden parts.
* @return the new {@code int}.
* @throws ValueConverterException if the given input is {@code null}, empty or does not represent an hexadecimal
* number.
*/
@Override public Long toValue(String string, INode node) throws ValueConverterException {
if (isEmpty(string)) {
throw new ValueConverterException("Couldn't convert empty string to long.", node, null);
}
if (!startsWithValidPrefix(string)) {
throw parsingError(string, node);
}
String withoutZeroX = removeZeroX(string);
try {
BigInteger value = new BigInteger(withoutZeroX, 16);
long longValue = value.longValue();
return longValue != -1 ? longValue : 1L;
} catch (NumberFormatException e) {
throw parsingError(string, node, e);
}
}
private boolean startsWithValidPrefix(String string) {
for (String prefix : VALID_PREFIXES) {
if (string.startsWith(prefix)) {
return true;
}
}
return false;
}
private String removeZeroX(String string) {
if (string.startsWith("-")) {
String withoutSign = string.substring(3, string.length());
return "-" + withoutSign;
}
return string.substring(2, string.length());
}
private ValueConverterException parsingError(String string, INode node) {
return parsingError(string, node, null);
}
private ValueConverterException parsingError(String string, INode node, Exception cause) {
return new ValueConverterException("Couldn't convert '" + string + "' to long.", node, cause);
}
}