base64.java

openwave公司的用于彩信开发的MM7协议实现java原代码,决对超值.

package com.openwave.mms.mm7.util;

/**
 * Encodes and decodes to and from Base64 notation.
 *
 * <p>
 * Change Log:
 * </p>
 * <ul>
 *  <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream
 *      where last buffer being read, if not completely full, was not returned.</li>
 *  <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
 *  <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
 * </ul>
 *
 * <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/xmlizable">http://iharder.net/xmlizable</a>
 * periodically to check for updates or to contribute improvements.
 * </p>
 *
 * @author Robert Harder
 * @author [e-mail]
 * @version 1.3.4
 */
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(){}
    
    /**
     * 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 )
    {
        return encodeObject( serializableObject, true );
    }   // end encodeObject
    
    /**
     * 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
     * @param breakLines Break lines at 80 characters or less.
     * @return The Base64-encoded object
     * @since 1.4
     */
    public static String encodeObject( java.io.Serializable serializableObject, boolean breakLines )
    {
        java.io.ByteArrayOutputStream baos  = null; 
        java.io.OutputStream          b64os = null; 
        java.io.ObjectOutputStream    oos   = null; 
        
        try
        {
            baos  = new java.io.ByteArrayOutputStream();
            b64os = new Base64.OutputStream( baos, Base64.ENCODE, breakLines );
            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, true );
    }   // end encodeBytes
    
    /**
     * Encodes a byte array into Base64 notation.
     * Equivalen to calling
     * <code>encodeBytes( source, 0, source.length )</code>
     *
     * @param source The data to convert
     * @param breakLines Break lines at 80 characters or less.
     * @since 1.4
     */
    public static String encodeBytes( byte[] source, boolean breakLines )
    {   
        return encodeBytes( source, 0, source.length, breakLines );
    }   // end encodeBytes
    
    
    /**
     * Encodes a byte array into Base64 notation.
     *
     * @param source The data to convert
     * @param off Offset in array where conversion should begin
     * @param len Length of data to convert
     * @since 1.4
     */
    public static String encodeBytes( byte[] source, int off, int len )
    {
        return encodeBytes( source, off, len, true );
    }   // end encodeBytes
    
    
    /**
     * Encodes a byte array into Base64 notation.
     *
     * @param source The data to convert
     * @param off Offset in array where conversion should begin
     * @param len Length of data to convert
     * @param breakLines Break lines at 80 characters or less.
     * @since 1.4
     */
    public static String encodeBytes( byte[] source, int off, int len, boolean breakLines )
    {
        int    len43   = len * 4 / 3;
        byte[] outBuff = new byte[   ( len43 )                      // Main 4:3
                                   + ( (len % 3) > 0 ? 4 : 0 )      // Account for padding
                                   + (breakLines ? ( len43 / MAX_LINE_LENGTH ) : 0) ]; // New lines      
        int d = 0;
        int e = 0;
        int len2 = len - 2;
        int lineLength = 0;
        for( ; d < len2; d+=3, e+=4 )
        {
            encode3to4( source, d+off, 3, outBuff, e );
            
            lineLength += 4;
            if( breakLines && lineLength == MAX_LINE_LENGTH )
            {   
                outBuff[e+4] = NEW_LINE;
                e++;
                lineLength = 0;
            }   // end if: end of line
        }   // en dfor: each piece of array
        
        if( d < len )
        {
            encode3to4( source, d+off, len - d, outBuff, e );
            e += 4;
        }   // end if: some padding needed