com.xceptance.common.lang.ParseNumbers Maven / Gradle / Ivy

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XLT (Xceptance LoadTest) is an extensive load and performance test tool developed and maintained by Xceptance.
There is a newer version: 8.1.0
/*
 * Copyright (c) 2005-2022 Xceptance Software Technologies GmbH
 *
 * 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.xceptance.common.lang;

/**
 * This is a small helper class for parsing strings and converting them into longs. This implementation is optimized for
 * speed not for functionality. It is only able to parse plain numbers with base 10, e.g. 100828171 (see
 * String.parseLong())
 * 
 * @author René Schwietzke
 */
public final class ParseNumbers
{
    private static final int DIGITOFFSET = 48;
    private static final int BASE = 10;
    
    /**
     * Parses the string and returns the result as long. Raises a NumberFormatException in case of a non-convertible
     * string. Falls back to JDK code in case of an error.
     * 
     * @param s
     *            the string to parse
     * @return the converted string as long
     * @throws NumberFormatException
     */
    public static long parseLong(final String s)
    {
        // no string
        if (s == null)
        {
            throw new NumberFormatException("null");
        }

        // determine length
        final int length = s.length();

        // no string
        if (length == 0)
        {
            throw new NumberFormatException("empty");
        }
        
        try
        {
            long value = 0;
            for (int i = 0; i < length; i++)
            {
                final int digit = s.charAt(i) - DIGITOFFSET;

                if (digit >= 0 && digit <= 9)
                {
                    value = value * BASE + digit;
                }
                else
                {
                    throw new NumberFormatException(s);
                }
            }

            return value;
        }
        catch (final NumberFormatException e)
        {
            return Long.parseLong(s);
        }
    }

    /**
     * Parses the string and returns the result as int. Raises a NumberFormatException in case of a non-convertible
     * string. Due to conversion limitations, the content of s might be larger than an int, precision might be
     * inaccurate.
     * 
     * @param s
     *            the string to parse
     * @return the converted string as int
     * @throws java.lang.NumberFormatException
     */
    public static int parseInt(final String s)
    {
        try
        {
            return (int) parseLong(s);
        }
        catch (final NumberFormatException e)
        {
            return Integer.parseInt(s);
        }
    }

    /**
     * Private to prevent instances of this class.
     */
    private ParseNumbers()
    {
    }
}