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Tomcat example source code file (Ascii.java)

This example Tomcat source code file (Ascii.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Tomcat tags/keywords

a, a, ascii, ascii, numberformatexception, numberformatexception

The Tomcat Ascii.java source code

/*
 *  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 org.apache.tomcat.util.buf;

/**
 * This class implements some basic ASCII character handling functions.
 *
 * @author dac@eng.sun.com
 * @author James Todd [gonzo@eng.sun.com]
 */
public final class Ascii {
    /*
     * Character translation tables.
     */

    private static final byte[] toUpper = new byte[256];
    private static final byte[] toLower = new byte[256];

    /*
     * Character type tables.
     */

    private static final boolean[] isAlpha = new boolean[256];
    private static final boolean[] isUpper = new boolean[256];
    private static final boolean[] isLower = new boolean[256];
    private static final boolean[] isWhite = new boolean[256];
    private static final boolean[] isDigit = new boolean[256];

    /*
     * Initialize character translation and type tables.
     */

    static {
        for (int i = 0; i < 256; i++) {
            toUpper[i] = (byte)i;
            toLower[i] = (byte)i;
        }

        for (int lc = 'a'; lc <= 'z'; lc++) {
            int uc = lc + 'A' - 'a';

            toUpper[lc] = (byte)uc;
            toLower[uc] = (byte)lc;
            isAlpha[lc] = true;
            isAlpha[uc] = true;
            isLower[lc] = true;
            isUpper[uc] = true;
        }

        isWhite[ ' '] = true;
        isWhite['\t'] = true;
        isWhite['\r'] = true;
        isWhite['\n'] = true;
        isWhite['\f'] = true;
        isWhite['\b'] = true;

        for (int d = '0'; d <= '9'; d++) {
            isDigit[d] = true;
        }
    }

    /**
     * Returns the upper case equivalent of the specified ASCII character.
     */

    public static int toUpper(int c) {
        return toUpper[c & 0xff] & 0xff;
    }

    /**
     * Returns the lower case equivalent of the specified ASCII character.
     */

    public static int toLower(int c) {
        return toLower[c & 0xff] & 0xff;
    }

    /**
     * Returns true if the specified ASCII character is upper or lower case.
     */

    public static boolean isAlpha(int c) {
        return isAlpha[c & 0xff];
    }

    /**
     * Returns true if the specified ASCII character is upper case.
     */

    public static boolean isUpper(int c) {
        return isUpper[c & 0xff];
    }

    /**
     * Returns true if the specified ASCII character is lower case.
     */

    public static boolean isLower(int c) {
        return isLower[c & 0xff];
    }

    /**
     * Returns true if the specified ASCII character is white space.
     */

    public static boolean isWhite(int c) {
        return isWhite[c & 0xff];
    }

    /**
     * Returns true if the specified ASCII character is a digit.
     */

    public static boolean isDigit(int c) {
        return isDigit[c & 0xff];
    }

    /**
     * Parses an unsigned integer from the specified subarray of bytes.
     * @param b the bytes to parse
     * @param off the start offset of the bytes
     * @param len the length of the bytes
     * @exception NumberFormatException if the integer format was invalid
     */
    public static int parseInt(byte[] b, int off, int len)
        throws NumberFormatException
    {
        int c;

        if (b == null || len <= 0 || !isDigit(c = b[off++])) {
            throw new NumberFormatException();
        }

        int n = c - '0';

        while (--len > 0) {
            if (!isDigit(c = b[off++])) {
                throw new NumberFormatException();
            }
            n = n * 10 + c - '0';
        }

        return n;
    }

    public static int parseInt(char[] b, int off, int len)
        throws NumberFormatException
    {
        int c;

        if (b == null || len <= 0 || !isDigit(c = b[off++])) {
            throw new NumberFormatException();
        }

        int n = c - '0';

        while (--len > 0) {
            if (!isDigit(c = b[off++])) {
                throw new NumberFormatException();
            }
            n = n * 10 + c - '0';
        }

        return n;
    }

    /**
     * Parses an unsigned long from the specified subarray of bytes.
     * @param b the bytes to parse
     * @param off the start offset of the bytes
     * @param len the length of the bytes
     * @exception NumberFormatException if the long format was invalid
     */
    public static long parseLong(byte[] b, int off, int len)
        throws NumberFormatException
    {
        int c;

        if (b == null || len <= 0 || !isDigit(c = b[off++])) {
            throw new NumberFormatException();
        }

        long n = c - '0';
        long m;
        
        while (--len > 0) {
            if (!isDigit(c = b[off++])) {
                throw new NumberFormatException();
            }
            m = n * 10 + c - '0';

            if (m < n) {
                // Overflow
                throw new NumberFormatException();
            } else {
                n = m;
            }
        }

        return n;
    }

    public static long parseLong(char[] b, int off, int len)
        throws NumberFormatException
    {
        int c;

        if (b == null || len <= 0 || !isDigit(c = b[off++])) {
            throw new NumberFormatException();
        }

        long n = c - '0';
        long m;

        while (--len > 0) {
            if (!isDigit(c = b[off++])) {
                throw new NumberFormatException();
            }
            m = n * 10 + c - '0';

            if (m < n) {
                // Overflow
                throw new NumberFormatException();
            } else {
                n = m;
            }
        }

        return n;
    }

}

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