* 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 http://iharder.net/base64 * periodically to check for updates or to contribute improvements. *
* * @author Robert Harder (rharder@usa.net) * @author Last changed by: $Author: gommma $ * @version $Revision: 769 $ $Date: 2008-08-02 09:31:15 +0200 (sab, 02 ago 2008) $ * @since 1.3 */ public class Base64 { /** Specify encoding (value is true). */ public final static boolean ENCODE = true; /** Specify decoding (value is false). */ 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 { FileInputStream fis = new 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 threeBytes * 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 threeBytes * and returns a four-byte array in Base64 notation. * The actual number of significant bytes in your array is * given by numSigBytes. * The array threeBytes needs only be as big as * numSigBytes. * * @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 source * and writes the resulting four Base64 bytes to destination. * The source and destination arrays can be manipulated * anywhere along their length by specifying * srcOffset and destOffset. * This method does not check to make sure your arrays * are large enough to accomodate srcOffset + 3 for * the source array or destOffset + 4 for * the destination array. * The actual number of significant bytes in your array is * given by numSigBytes. * * @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 destination 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 null. * * @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(); b64os.close(); baos.close(); } catch (Exception e) { } } // end finally return new String(baos.toByteArray()); } // end encode /** * Encodes a byte array into Base64 notation. * Equivalen to calling *encodeBytes( source, 0, source.length )
*
* @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.
*
* @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)
{
int len43 = len * 4 / 3;
byte[] outBuff = new byte[(len43) // Main 4:3
+ ((len % 3) > 0 ? 4 : 0) // Account for padding
+ (len43 / MAX_LINE_LENGTH)]; // 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, 3, outBuff, e);
lineLength += 4;
if (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, len - d, outBuff, e);
e += 4;
} // end if: some padding needed
return new String(outBuff, 0, e);
} // end encodeBytes
/**
* Encodes a string in Base64 notation with line breaks
* after every 75 Base64 characters.
*
* @param s the string to encode
* @return the encoded string
* @since 1.3
*/
public static String encodeString(String s)
{
return encodeBytes(s.getBytes());
} // end encodeString
/* ******** D E C O D I N G M E T H O D S ******** */
/**
* Decodes the first four bytes of array fourBytes
* and returns an array up to three bytes long with the
* decoded values.
*
* @param fourBytes the array with Base64 content
* @return array with decoded values
* @since 1.3
*/
private static byte[] decode4to3(byte[] fourBytes)
{
byte[] outBuff1 = new byte[3];
int count = decode4to3(fourBytes, 0, outBuff1, 0);
byte[] outBuff2 = new byte[count];
for (int i = 0; i < count; i++)
outBuff2[i] = outBuff1[i];
return outBuff2;
}
/**
* Decodes four bytes from array source
* and writes the resulting bytes (up to three of them)
* to destination.
* The source and destination arrays can be manipulated
* anywhere along their length by specifying
* srcOffset and destOffset.
* This method does not check to make sure your arrays
* are large enough to accomodate srcOffset + 4 for
* the source array or destOffset + 3 for
* the destination array.
* This method returns the actual number of bytes that
* were converted from the Base64 encoding.
*
*
* @param source the array to convert
* @param srcOffset the index where conversion begins
* @param destination the array to hold the conversion
* @param destOffset the index where output will be put
* @return the number of decoded bytes converted
* @since 1.3
*/
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset)
{
// Example: Dk==
if (source[srcOffset + 2] == EQUALS_SIGN)
{
int outBuff = ((DECODABET[source[srcOffset]] << 24) >>> 6)
| ((DECODABET[source[srcOffset + 1]] << 24) >>> 12);
destination[destOffset] = (byte)(outBuff >>> 16);
return 1;
}
// Example: DkL=
else if (source[srcOffset + 3] == EQUALS_SIGN)
{
int outBuff = ((DECODABET[source[srcOffset]] << 24) >>> 6)
| ((DECODABET[source[srcOffset + 1]] << 24) >>> 12)
| ((DECODABET[source[srcOffset + 2]] << 24) >>> 18);
destination[destOffset] = (byte)(outBuff >>> 16);
destination[destOffset + 1] = (byte)(outBuff >>> 8);
return 2;
}
// Example: DkLE
else
{
int outBuff = ((DECODABET[source[srcOffset]] << 24) >>> 6)
| ((DECODABET[source[srcOffset + 1]] << 24) >>> 12)
| ((DECODABET[source[srcOffset + 2]] << 24) >>> 18)
| ((DECODABET[source[srcOffset + 3]] << 24) >>> 24);
destination[destOffset] = (byte)(outBuff >> 16);
destination[destOffset + 1] = (byte)(outBuff >> 8);
destination[destOffset + 2] = (byte)(outBuff);
return 3;
}
} // end decodeToBytes
/**
* Decodes data from Base64 notation.
*
* @param s the string to decode
* @return the decoded data
* @since 1.4
*/
public static byte[] decode(String s)
{
byte[] bytes = s.getBytes();
return decode(bytes, 0, bytes.length);
} // end decode
/**
* Decodes data from Base64 notation and
* returns it as a string.
* Equivalent to calling
* new String( decode( s ) )
*
* @param s the string to decode
* @return The data as a string
* @since 1.4
*/
public static String decodeToString(String s)
{
return new String(decode(s));
} // end decodeToString
/**
* Attempts to decode Base64 data and deserialize a Java
* Object within. Returns null if there was an error.
*
* @param encodedObject The Base64 data to decode
* @return The decoded and deserialized object
* @since 1.4
*/
public static Object decodeToObject(String encodedObject)
{
byte[] objBytes = decode(encodedObject);
java.io.ByteArrayInputStream bais = null;
java.io.ObjectInputStream ois = null;
try
{
bais = new java.io.ByteArrayInputStream(objBytes);
ois = new java.io.ObjectInputStream(bais);
return ois.readObject();
} // end try
catch (java.io.IOException e)
{
e.printStackTrace();
return null;
} // end catch
catch (ClassNotFoundException e)
{
e.printStackTrace();
return null;
} // end catch
finally
{
try
{
bais.close();
ois.close();
}
catch (Exception e)
{
}
} // end finally
} // end decodeObject
/**
* Decodes Base64 content in byte array format and returns
* the decoded byte array.
*
* @param source The Base64 encoded data
* @param off The offset of where to begin decoding
* @param len The length of characters to decode
* @return decoded data
* @since 1.3
*/
public static byte[] decode(byte[] source, int off, int len)
{
int len34 = len * 3 / 4;
byte[] outBuff = new byte[len34]; // Upper limit on size of output
int outBuffPosn = 0;
byte[] b4 = new byte[4];
int b4Posn = 0;
int i = 0;
byte sbiCrop = 0;
byte sbiDecode = 0;
for (i = 0; i < len; i++)
{
sbiCrop = (byte)(source[i] & 0x7f); // Only the low seven bits
sbiDecode = DECODABET[sbiCrop];
if (sbiDecode >= WHITE_SPACE_ENC) // White space, Equals sign or better
{
if (sbiDecode >= EQUALS_SIGN_ENC)
{
b4[b4Posn++] = sbiCrop;
if (b4Posn > 3)
{
outBuffPosn += decode4to3(b4, 0, outBuff, outBuffPosn);
b4Posn = 0;
// If that was the equals sign, break out of 'for' loop
if (sbiCrop == EQUALS_SIGN)
break;
} // end if: quartet built
} // end if: equals sign or better
} // end if: white space, equals sign or better
else
{
System.err.println("Bad Base64 input character at " + i + ": " + source[i] + "(decimal)");
return null;
} // end else:
} // each input character
byte[] out = new byte[outBuffPosn];
System.arraycopy(outBuff, 0, out, 0, outBuffPosn);
return out;
} // end decode
/* ******** I N N E R C L A S S I N P U T S T R E A M ******** */
/**
* A {@link Base64.InputStream} will read data from another
* {@link java.io.InputStream}, given in the constructor,
* and encode/decode to/from Base64 notation on the fly.
*
* @see Base64
* @see java.io.FilterInputStream
* @since 1.3
*/
public static class InputStream extends java.io.FilterInputStream
{
private boolean encode; // Encoding or decoding
private int position; // Current position in the buffer
private byte[] buffer; // Small buffer holding converted data
private int bufferLength; // Length of buffer (3 or 4)
private int numSigBytes; // Number of meaningful bytes in the buffer
/**
* Constructs a {@link Base64.InputStream} in DECODE mode.
*
* @param in the {@link java.io.InputStream} from which to read data.
* @since 1.3
*/
public InputStream(java.io.InputStream in)
{
this(in, Base64.DECODE);
} // end constructor
/**
* Constructs a {@link Base64.InputStream} in
* either ENCODE or DECODE mode.
*
* @param in the {@link java.io.InputStream} from which to read data.
* @param encode Conversion direction
* @see Base64#ENCODE
* @see Base64#DECODE
* @since 1.3
*/
public InputStream(java.io.InputStream in, boolean encode)
{
super(in);
this.encode = encode;
this.bufferLength = encode ? 4 : 3;
this.buffer = new byte[bufferLength];
this.position = -1;
} // end constructor
/**
* Reads enough of the input stream to convert
* to/from Base64 and returns the next byte.
*
* @return next byte
* @since 1.3
*/
public int read() throws java.io.IOException
{
// Do we need to get data?
if (position < 0)
{
if (encode)
{
byte[] b3 = new byte[3];
numSigBytes = 0;
for (int i = 0; i < 3; i++)
{
try
{
int b = in.read();
// If end of stream, b is -1.
if (b >= 0)
{
b3[i] = (byte)b;
numSigBytes++;
} // end if: not end of stream
} // end try: read
catch (java.io.IOException e)
{
// Only a problem if we got no data at all.
if (i == 0)
throw e;
} // end catch
} // end for: each needed input byte
if (numSigBytes > 0)
{
encode3to4(b3, 0, numSigBytes, buffer, 0);
position = 0;
} // end if: got data
} // end if: encoding
// Else decoding
else
{
byte[] b4 = new byte[4];
int i = 0;
for (i = 0; i < 4; i++)
{
int b = 0;
do
{
b = in.read();
}
while (b >= 0 && DECODABET[b & 0x7f] < WHITE_SPACE_ENC);
if (b < 0)
break; // Reads a -1 if end of stream
b4[i] = (byte)b;
} // end for: each needed input byte
if (i == 4)
{
numSigBytes = decode4to3(b4, 0, buffer, 0);
position = 0;
} // end if: got four characters
} // end else: decode
} // end else: get data
// Got data?
if (position >= 0)
{
// End of relevant data?
if (position >= numSigBytes)
return -1;
int b = buffer[position++];
if (position >= bufferLength)
position = -1;
return b;
} // end if: position >= 0
// Else error
else
return -1;
} // end read
/**
* Calls {@link #read} repeatedly until the end of stream
* is reached or len bytes are read.
* Returns number of bytes read into array or -1 if
* end of stream is encountered.
*
* @param dest array to hold values
* @param off offset for array
* @param len max number of bytes to read into array
* @return bytes read into array or -1 if end of stream is encountered.
* @since 1.3
*/
public int read(byte[] dest, int off, int len) throws java.io.IOException
{
int i;
int b;
for (i = 0; i < len; i++)
{
b = read();
if (b < 0)
return -1;
dest[off + i] = (byte)b;
} // end for: each byte read
return i;
} // end read
} // end inner class InputStream
/* ******** I N N E R C L A S S O U T P U T S T R E A M ******** */
/**
* A {@link Base64.OutputStream} will write data to another
* {@link java.io.OutputStream}, given in the constructor,
* and encode/decode to/from Base64 notation on the fly.
*
* @see Base64
* @see java.io.FilterOutputStream
* @since 1.3
*/
public static class OutputStream extends java.io.FilterOutputStream
{
private boolean encode;
private int position;
private byte[] buffer;
private int bufferLength;
private int lineLength;
/**
* Constructs a {@link Base64.OutputStream} in ENCODE mode.
*
* @param out the {@link java.io.OutputStream} to which data will be written.
* @since 1.3
*/
public OutputStream(java.io.OutputStream out)
{
this(out, Base64.ENCODE);
} // end constructor
/**
* Constructs a {@link Base64.OutputStream} in
* either ENCODE or DECODE mode.
*
* @param out the {@link java.io.OutputStream} to which data will be written.
* @param encode Conversion direction
* @see Base64#ENCODE
* @see Base64#DECODE
* @since 1.3
*/
public OutputStream(java.io.OutputStream out, boolean encode)
{
super(out);
this.encode = encode;
this.bufferLength = encode ? 3 : 4;
this.buffer = new byte[bufferLength];
this.position = 0;
this.lineLength = 0;
} // end constructor
/**
* Writes the byte to the output stream after
* converting to/from Base64 notation.
* When encoding, bytes are buffered three
* at a time before the output stream actually
* gets a write() call.
* When decoding, bytes are buffered four
* at a time.
*
* @param theByte the byte to write
* @since 1.3
*/
public void write(int theByte) throws java.io.IOException
{
buffer[position++] = (byte)theByte;
if (position >= bufferLength)
{
if (encode)
{
out.write(Base64.encode3to4(buffer, bufferLength));
lineLength += 4;
if (lineLength >= MAX_LINE_LENGTH)
{
out.write(NEW_LINE);
lineLength = 0;
} // end if: end o fline
} // end if: encoding
else
out.write(Base64.decode4to3(buffer));
position = 0;
} // end if: convert and flush
} // end write
/**
* Calls {@link #write} repeatedly until len
* bytes are written.
*
* @param theBytes array from which to read bytes
* @param off offset for array
* @param len max number of bytes to read into array
* @since 1.3
*/
public void write(byte[] theBytes, int off, int len) throws java.io.IOException
{
for (int i = 0; i < len; i++)
{
write(theBytes[off + i]);
} // end for: each byte written
} // end write
/**
* Appropriately pads Base64 notation when encoding
* or throws an exception if Base64 input is not
* properly padded when decoding.
*
* @since 1.3
*/
public void flush() throws java.io.IOException
{
if (position > 0)
{
if (encode)
{
out.write(Base64.encode3to4(buffer, position));
} // end if: encoding
else
{
throw new java.io.IOException("Base64 input not properly padded.");
} // end else: decoding
} // end if: buffer partially full
super.flush();
out.flush();
} // end flush
/**
* Flushes and closes stream.
*
* @since 1.3
*/
public void close() throws java.io.IOException
{
this.flush();
super.close();
out.close();
buffer = null;
out = null;
} // end close
} // end inner class OutputStream
} // end class Base64