BigIntegerParser.java

/*
 * Copyright 2023 Terminal Utils Authors
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 net.morimekta.terminal.args.parser;

import net.morimekta.terminal.args.ArgException;
import net.morimekta.terminal.args.ValueParser;

import java.math.BigInteger;

/**
 * A converter to big integer values.
 */
public class BigIntegerParser implements ValueParser<BigInteger> {
    @Override
    public BigInteger parse(String s) {
        try {
            if (s.startsWith("0x")) {
                return parseInternal(s.substring(2), 16);
            } else {
                return parseInternal(s, 10);
            }
        } catch (NumberFormatException nfe) {
            throw new ArgException("Invalid big integer value %s", s, nfe);
        }
    }

    private BigInteger parseInternal(String s, int radix) {
        if (s.matches("^0+$")) {
            return new BigInteger("0");
        }
        s = s.replaceAll("^0+", "");
        return new BigInteger(s, radix);
    }
}