base64.java

网络游戏天堂1的java源代码。。。。。

						} // 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 (numBinaryBytes > 0) {
						encode3to4(b3, 0, numBinaryBytes, buffer, 0);
						position = 0;
						numSigBytes = 4;
					} // end if: got data
					else {
						return -1;
					} // end else
				} // end if: encoding

				// Else decoding
				else {
					byte[] b4 = new byte[4];
					int i = 0;
					for (i = 0; i < 4; i++) {
						// Read four "meaningful" bytes:
						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
					else if (i == 0) {
						return -1;
					} // end else if: also padded correctly
					else {
						// Must have broken out from above.
						throw new java.io.IOException(
								"Improperly padded Base64 input.");
					} // end

				} // end else: decode
			} // end else: get data

			// Got data?
			if (position >= 0) {
				// End of relevant data?
				if ( /* !encode && */position >= numSigBytes) {
					return -1;
				}

				if (encode && breakLines && lineLength >= MAX_LINE_LENGTH) {
					lineLength = 0;
					return '\n';
				} // end if
				else {
					lineLength++; // This isn't important when decoding
					// but throwing an extra "if" seems
					// just as wasteful.

					int b = buffer[position++];

					if (position >= bufferLength) {
						position = -1;
					}

					return b & 0xFF; // This is how you "cast" a byte that's
					// intended to be unsigned.
				} // end else
			} // end if: position >= 0

			// Else error
			else {
				// When JDK1.4 is more accepted, use an assertion here.
				throw new java.io.IOException(
						"Error in Base64 code reading stream.");
			} // end else
		} // end read

		/**
		 * Calls {@link #read} repeatedly until the end of stream is reached or
		 * <var>len</var> 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
		 */
		@Override
		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 && i == 0 )
				// return -1;

				if (b >= 0) {
					dest[off + i] = (byte) b;
				} else if (i == 0) {
					return -1;
				} else {
					break; // Out of 'for' loop
				}
			} // 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 int options;

		private boolean encode;

		private int position;

		private byte[] buffer;

		private int bufferLength;

		private int lineLength;

		private boolean breakLines;

		private byte[] b4; // Scratch used in a few places

		private boolean suspendEncoding;

		/**
		 * 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, ENCODE);
		} // end constructor

		/**
		 * Constructs a {@link Base64#OutputStream} in either ENCODE or DECODE
		 * mode.
		 * <p>
		 * Valid options:
		 * 
		 * <pre>
		 *      ENCODE or DECODE: Encode or Decode as data is read.
		 *      DONT_BREAK_LINES: don't break lines at 76 characters
		 *        (only meaningful when encoding)
		 *        &lt;i&gt;Note: Technically, this makes your encoding non-compliant.&lt;/i&gt;
		 * </pre>
		 * 
		 * <p>
		 * Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>
		 * 
		 * @param out
		 *            the {@link java.io.OutputStream} to which data will be
		 *            written.
		 * @param options
		 *            Specified options.
		 * @see Base64#ENCODE
		 * @see Base64#DECODE
		 * @see Base64#DONT_BREAK_LINES
		 * @since 1.3
		 */
		public OutputStream(java.io.OutputStream out, int options) {
			super(out);
			this.options = options;
			this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;
			this.encode = (options & ENCODE) == ENCODE;
			this.bufferLength = encode ? 3 : 4;
			this.buffer = new byte[bufferLength];
			this.position = 0;
			this.lineLength = 0;
			this.suspendEncoding = false;
			this.b4 = new byte[4];
		} // 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
		 */
		@Override
		public void write(int theByte) throws java.io.IOException {
			// Encoding suspended?
			if (suspendEncoding) {
				super.out.write(theByte);
				return;
			} // end if: supsended

			// Encode?
			if (encode) {
				buffer[position++] = (byte) theByte;
				if (position >= bufferLength) // Enough to encode.
				{
					out.write(encode3to4(b4, buffer, bufferLength));

					lineLength += 4;
					if (breakLines && lineLength >= MAX_LINE_LENGTH) {
						out.write(NEW_LINE);
						lineLength = 0;
					} // end if: end of line

					position = 0;
				} // end if: enough to output
			} // end if: encoding

			// Else, Decoding
			else {
				// Meaningful Base64 character?
				if (DECODABET[theByte & 0x7f] > WHITE_SPACE_ENC) {
					buffer[position++] = (byte) theByte;
					if (position >= bufferLength) // Enough to output.
					{
						int len = Base64.decode4to3(buffer, 0, b4, 0);
						out.write(b4, 0, len);
						// out.write( Base64.decode4to3( buffer ) );
						position = 0;
					} // end if: enough to output
				} // end if: meaningful base64 character
				else if (DECODABET[theByte & 0x7f] != WHITE_SPACE_ENC) {
					throw new java.io.IOException(
							"Invalid character in Base64 data.");
				} // end else: not white space either
			} // end else: decoding
		} // end write

		/**
		 * Calls {@link #write} repeatedly until <var>len</var> 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
		 */
		@Override
		public void write(byte[] theBytes, int off, int len)
				throws java.io.IOException {
			// Encoding suspended?
			if (suspendEncoding) {
				super.out.write(theBytes, off, len);
				return;
			} // end if: supsended

			for (int i = 0; i < len; i++) {
				write(theBytes[off + i]);
			} // end for: each byte written

		} // end write

		/**
		 * Method added by PHIL. [Thanks, PHIL. -Rob] This pads the buffer
		 * without closing the stream.
		 */
		public void flushBase64() throws java.io.IOException {
			if (position > 0) {
				if (encode) {
					out.write(encode3to4(b4, buffer, position));
					position = 0;
				} // end if: encoding
				else {
					throw new java.io.IOException(
							"Base64 input not properly padded.");
				} // end else: decoding
			} // end if: buffer partially full

		} // end flush

		/**
		 * Flushes and closes (I think, in the superclass) the stream.
		 * 
		 * @since 1.3
		 */
		@Override
		public void close() throws java.io.IOException {
			// 1. Ensure that pending characters are written
			flushBase64();

			// 2. Actually close the stream
			// Base class both flushes and closes.
			super.close();

			buffer = null;
			out = null;
		} // end close

		/**
		 * Suspends encoding of the stream. May be helpful if you need to embed
		 * a piece of base640-encoded data in a stream.
		 * 
		 * @since 1.5.1
		 */
		public void suspendEncoding() throws java.io.IOException {
			flushBase64();
			this.suspendEncoding = true;
		} // end suspendEncoding

		/**
		 * Resumes encoding of the stream. May be helpful if you need to embed a
		 * piece of base640-encoded data in a stream.
		 * 
		 * @since 1.5.1
		 */
		public void resumeEncoding() {
			this.suspendEncoding = false;
		} // end resumeEncoding

	} // end inner class OutputStream

} // end class Base64