com.dyuproject.protostuff.NumberParser Maven / Gradle / Ivy

Go to download
//========================================================================
//Copyright 2007-2010 David Yu [email protected]
//------------------------------------------------------------------------
//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.dyuproject.protostuff;

import com.dyuproject.protostuff.StringSerializer.STRING;

/**
 * An IO utility for dealing with raw ascii bytes.
 *
 * @author David Yu
 * @created Nov 19, 2010
 */
public final class NumberParser
{
    
    private NumberParser() {}
    
    /**
     * Parse an ascii int from a raw buffer.
     */
    public static int parseInt(final byte[] buffer, final int start, final int length, 
            final int radix) throws NumberFormatException
    {
        if(length == 0)
            throw new NumberFormatException(STRING.deser(buffer, start, length));
        
        if (buffer[start] == '-')
        {
            if(length == 1)
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            
            return parseInt(buffer, start+1, length-1, radix, false);
        }

        return parseInt(buffer, start, length, radix, true);
    }

    static int parseInt(final byte[] buffer, int start, final int length, 
            final int radix, final boolean positive) throws NumberFormatException
    {
        int max = Integer.MIN_VALUE / radix;
        int result = 0;
        for (int offset = start, limit = start + length; offset < limit;)
        {
            int digit = Character.digit(buffer[offset++], radix);
            if (digit == -1)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
            if (max > result)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
            int next = result * radix - digit;
            if (next > result)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
            result = next;
        }
        if (positive)
        {
            result = -result;
            if (result < 0)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
        }
        return result;
    }
    
    /**
     * Parse an ascii long from a raw buffer.
     */
    public static long parseLong(final byte[] buffer, final int start, final int length, 
            final int radix) throws NumberFormatException
    {
        if(length == 0)
            throw new NumberFormatException(STRING.deser(buffer, start, length));
        
        if (buffer[start] == '-')
        {
            if(length == 1)
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            
            return parseLong(buffer, start+1, length-1, radix, false);
        }

        return parseLong(buffer, start, length, radix, true);
    }

    static long parseLong(final byte[] buffer, final int start, final int length, 
            final int radix, final boolean positive) throws NumberFormatException
    {
        long max = Long.MIN_VALUE / radix;
        long result = 0;
        for (int offset = start, limit = start + length; offset < limit;)
        {
            int digit = Character.digit(buffer[offset++], radix);
            if (digit == -1)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
            if (max > result)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
            long next = result * radix - digit;
            if (next > result)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
            result = next;
        }
        if (positive)
        {
            result = -result;
            if (result < 0)
            {
                throw new NumberFormatException(STRING.deser(buffer, start, length));
            }
        }
        
        return result;
    }

}