base64.java

一个基于JUnit测试框架的关于数据库的测试框架

package org.dbunit.util;

/**
 * <p>
 * I am placing this code in the Public Domain. Do with it as you will.
 * This software comes with no guarantees or warranties but with
 * plenty of well-wishing instead!
 * Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
 * periodically to check for updates or to contribute improvements.
 * </p>
 *
 * @author Robert Harder
 * @author [e-mail]
 * @version 1.3
 */
public class Base64
{

    /** Specify encoding (value is <tt>true</tt>). */
    public final static boolean ENCODE = true;


    /** Specify decoding (value is <tt>false</tt>). */
    public final static boolean DECODE = false;


    /** Maximum line length (76) of Base64 output. */
    private final static int MAX_LINE_LENGTH = 76;


    /** The equals sign (=) as a byte. */
    private final static byte EQUALS_SIGN = (byte)'=';


    /** The new line character (\n) as a byte. */
    private final static byte NEW_LINE = (byte)'\n';


    /** The 64 valid Base64 values. */
    private final static byte[] ALPHABET =
            {
                (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
                (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
                (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
                (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
                (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
                (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
                (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
                (byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
                (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5',
                (byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/'
            };

    /**
     * Translates a Base64 value to either its 6-bit reconstruction value
     * or a negative number indicating some other meaning.
     **/
    private final static byte[] DECODABET =
            {
                -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal  0 -  8
                -5, -5, // Whitespace: Tab and Linefeed
                -9, -9, // Decimal 11 - 12
                -5, // Whitespace: Carriage Return
                -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 14 - 26
                -9, -9, -9, -9, -9, // Decimal 27 - 31
                -5, // Whitespace: Space
                -9, -9, -9, -9, -9, -9, -9, -9, -9, -9, // Decimal 33 - 42
                62, // Plus sign at decimal 43
                -9, -9, -9, // Decimal 44 - 46
                63, // Slash at decimal 47
                52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // Numbers zero through nine
                -9, -9, -9, // Decimal 58 - 60
                -1, // Equals sign at decimal 61
                -9, -9, -9, // Decimal 62 - 64
                0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, // Letters 'A' through 'N'
                14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // Letters 'O' through 'Z'
                -9, -9, -9, -9, -9, -9, // Decimal 91 - 96
                26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, // Letters 'a' through 'm'
                39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // Letters 'n' through 'z'
                -9, -9, -9, -9                                 // Decimal 123 - 126
                /*,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 127 - 139
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 140 - 152
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 153 - 165
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 166 - 178
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 179 - 191
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 192 - 204
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 205 - 217
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 218 - 230
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,     // Decimal 231 - 243
                -9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9         // Decimal 244 - 255 */
            };

    private final static byte BAD_ENCODING = -9; // Indicates error in encoding
    private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
    private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding


    /** Defeats instantiation. */
    private Base64()
    {
    }


    /** Testing. */
    public static void main(String[] args)
    {
        String s = "Hello, world";
        s = "abcd";
        //s = System.getProperties().toString();
        //System.out.println( s + ": \n [" + encode( s ) + "]\n [" + decode(encode(s)) + "]" );

        byte[] b = encodeString(s).getBytes();
        byte[] c = decode(b, 0, b.length);

        System.out.println("\n\n" + s + ":" + new String(b) + ":" + new String(c));

        try
        {
            java.io.FileInputStream fis = new java.io.FileInputStream("c:\\abcd.txt");
            InputStream b64is = new InputStream(fis, DECODE);
            int ib = 0;
            while ((ib = b64is.read()) > 0)
            {   //System.out.print( new String( ""+(char)ib ) );
            }
        }   // end try
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }


/* ********  E N C O D I N G   M E T H O D S  ******** */


    /**
     * Encodes the first three bytes of array <var>threeBytes</var>
     * and returns a four-byte array in Base64 notation.
     *
     * @param threeBytes the array to convert
     * @return four byte array in Base64 notation.
     * @since 1.3
     */
    private static byte[] encode3to4(byte[] threeBytes)
    {
        return encode3to4(threeBytes, 3);
    }   // end encodeToBytes


    /**
     * Encodes up to the first three bytes of array <var>threeBytes</var>
     * and returns a four-byte array in Base64 notation.
     * The actual number of significant bytes in your array is
     * given by <var>numSigBytes</var>.
     * The array <var>threeBytes</var> needs only be as big as
     * <var>numSigBytes</var>.
     *
     * @param threeBytes the array to convert
     * @param numSigBytes the number of significant bytes in your array
     * @return four byte array in Base64 notation.
     * @since 1.3
     */
    private static byte[] encode3to4(byte[] threeBytes, int numSigBytes)
    {
        byte[] dest = new byte[4];
        encode3to4(threeBytes, 0, numSigBytes, dest, 0);
        return dest;
    }


    /**
     * Encodes up to three bytes of the array <var>source</var>
     * and writes the resulting four Base64 bytes to <var>destination</var>.
     * The source and destination arrays can be manipulated
     * anywhere along their length by specifying
     * <var>srcOffset</var> and <var>destOffset</var>.
     * This method does not check to make sure your arrays
     * are large enough to accomodate <var>srcOffset</var> + 3 for
     * the <var>source</var> array or <var>destOffset</var> + 4 for
     * the <var>destination</var> array.
     * The actual number of significant bytes in your array is
     * given by <var>numSigBytes</var>.
     *
     * @param source the array to convert
     * @param srcOffset the index where conversion begins
     * @param numSigBytes the number of significant bytes in your array
     * @param destination the array to hold the conversion
     * @param destOffset the index where output will be put
     * @return the <var>destination</var> array
     * @since 1.3
     */
    private static byte[] encode3to4(
            byte[] source, int srcOffset, int numSigBytes,
            byte[] destination, int destOffset)
    {
        //           1         2         3
        // 01234567890123456789012345678901 Bit position
        // --------000000001111111122222222 Array position from threeBytes
        // --------|    ||    ||    ||    | Six bit groups to index ALPHABET
        //          >>18  >>12  >> 6  >> 0  Right shift necessary
        //                0x3f  0x3f  0x3f  Additional AND

        // Create buffer with zero-padding if there are only one or two
        // significant bytes passed in the array.
        // We have to shift left 24 in order to flush out the 1's that appear
        // when Java treats a value as negative that is cast from a byte to an int.
        int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
                | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
                | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);

        switch (numSigBytes)
        {
            case 3:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
                destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
                return destination;

            case 2:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
                destination[destOffset + 3] = EQUALS_SIGN;
                return destination;

            case 1:
                destination[destOffset] = ALPHABET[(inBuff >>> 18)];
                destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
                destination[destOffset + 2] = EQUALS_SIGN;
                destination[destOffset + 3] = EQUALS_SIGN;
                return destination;

            default:
                return destination;
        }   // end switch
    }   // end encode3to4


    /**
     * Serializes an object and returns the Base64-encoded
     * version of that serialized object. If the object
     * cannot be serialized or there is another error,
     * the method will return <tt>null</tt>.
     *
     * @param serializableObject The object to encode
     * @return The Base64-encoded object
     * @since 1.4
     */
    public static String encodeObject(java.io.Serializable serializableObject)
    {
        java.io.ByteArrayOutputStream baos = null;
        java.io.OutputStream b64os = null;
        java.io.ObjectOutputStream oos = null;

        try
        {
            baos = new java.io.ByteArrayOutputStream();
            b64os = new OutputStream(baos, Base64.ENCODE);
            oos = new java.io.ObjectOutputStream(b64os);

            oos.writeObject(serializableObject);
        }   // end try
        catch (java.io.IOException e)
        {
            e.printStackTrace();
            return null;
        }   // end catch
        finally
        {
            try
            {
                oos.close();
            }
            catch (Exception e)
            {
            }
            try
            {
                b64os.close();
            }
            catch (Exception e)
            {
            }
            try
            {
                baos.close();
            }
            catch (Exception e)
            {
            }
        }   // end finally

        return new String(baos.toByteArray());
    }   // end encode


    /**
     * Encodes a byte array into Base64 notation.
     * Equivalen to calling
     * <code>encodeBytes( source, 0, source.length )</code>
     *
     * @param source The data to convert
     * @since 1.4
     */
    public static String encodeBytes(byte[] source)
    {
        return encodeBytes(source, 0, source.length);
    }   // end encodeBytes


    /**
     * Encodes a byte array into Base64 notation.