Java Byte Array to Long atol(byte[] s)

Description

atol

License

Open Source License

Declaration

public static long atol(byte[] s) throws NumberFormatException 

Method Source Code

//package com.java2s;
/*//from   w w w  .ja v a2  s.  c o m
 * Copyright (c) 2008-2016, GigaSpaces Technologies, Inc. All Rights Reserved.
 *
 * 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.
 */

public class Main {
    public static long atol(byte[] s) throws NumberFormatException {
        long result = 0;
        boolean negative = false;
        int i = 0, len = s.length;
        long limit = -Long.MAX_VALUE;
        long multmin;
        int digit;

        if (len > 0) {
            byte firstChar = s[0];
            if (firstChar < '0') { // Possible leading "-"
                if (firstChar == '-') {
                    negative = true;
                    limit = Long.MIN_VALUE;
                } else
                    throw new NumberFormatException();

                if (len == 1) // Cannot have lone "-"
                    throw new NumberFormatException();
                i++;
            }
            multmin = limit / 10;
            while (i < len) {
                // Accumulating negatively avoids surprises near MAX_VALUE
                digit = Character.digit(s[i++], 10);
                if (digit < 0) {
                    throw new NumberFormatException();
                }
                if (result < multmin) {
                    throw new NumberFormatException();
                }
                result *= 10;
                if (result < limit + digit) {
                    throw new NumberFormatException();
                }
                result -= digit;
            }
        } else {
            throw new NumberFormatException();
        }
        return negative ? result : -result;
    }
}

Related

1. arr2long(byte[] b)
2. atol(byte[] s, int offset)
3. bufferToLong(byte[] ioBuffer)
4. byte2long(byte[] b)
5. byte2long(byte[] b)