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/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project 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.
 */
/*
 * Written by Robert Harder and released to the public domain, as explained at
 * http://creativecommons.org/licenses/publicdomain
 */
package org.jboss.netty.handler.codec.base64;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferFactory;
import org.jboss.netty.buffer.HeapChannelBufferFactory;

/**
 * Utility class for {@link ChannelBuffer} that encodes and decodes to and from
 * Base64 notation.
 * 

* The encoding and decoding algorithm in this class has been derived from * Robert Harder's Public Domain * Base64 Encoder/Decoder. * * @apiviz.landmark * @apiviz.uses org.jboss.netty.handler.codec.base64.Base64Dialect */ public final class Base64 { /** Maximum line length (76) of Base64 output. */ private static final int MAX_LINE_LENGTH = 76; /** The equals sign (=) as a byte. */ private static final byte EQUALS_SIGN = (byte) '='; /** The new line character (\n) as a byte. */ private static final byte NEW_LINE = (byte) '\n'; private static final byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding private static final byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding private static byte[] alphabet(Base64Dialect dialect) { if (dialect == null) { throw new NullPointerException("dialect"); } return dialect.alphabet; } private static byte[] decodabet(Base64Dialect dialect) { if (dialect == null) { throw new NullPointerException("dialect"); } return dialect.decodabet; } private static boolean breakLines(Base64Dialect dialect) { if (dialect == null) { throw new NullPointerException("dialect"); } return dialect.breakLinesByDefault; } public static ChannelBuffer encode(ChannelBuffer src) { return encode(src, Base64Dialect.STANDARD); } public static ChannelBuffer encode(ChannelBuffer src, Base64Dialect dialect) { return encode(src, breakLines(dialect), dialect); } public static ChannelBuffer encode( ChannelBuffer src, ChannelBufferFactory bufferFactory) { return encode(src, Base64Dialect.STANDARD, bufferFactory); } public static ChannelBuffer encode( ChannelBuffer src, Base64Dialect dialect, ChannelBufferFactory bufferFactory) { return encode(src, breakLines(dialect), dialect, bufferFactory); } public static ChannelBuffer encode(ChannelBuffer src, boolean breakLines) { return encode(src, breakLines, Base64Dialect.STANDARD); } public static ChannelBuffer encode( ChannelBuffer src, boolean breakLines, Base64Dialect dialect) { return encode(src, breakLines, dialect, HeapChannelBufferFactory.getInstance()); } public static ChannelBuffer encode( ChannelBuffer src, boolean breakLines, ChannelBufferFactory bufferFactory) { return encode(src, breakLines, Base64Dialect.STANDARD, bufferFactory); } public static ChannelBuffer encode( ChannelBuffer src, boolean breakLines, Base64Dialect dialect, ChannelBufferFactory bufferFactory) { if (src == null) { throw new NullPointerException("src"); } ChannelBuffer dest = encode( src, src.readerIndex(), src.readableBytes(), breakLines, dialect, bufferFactory); src.readerIndex(src.writerIndex()); return dest; } public static ChannelBuffer encode(ChannelBuffer src, int off, int len) { return encode(src, off, len, Base64Dialect.STANDARD); } public static ChannelBuffer encode(ChannelBuffer src, int off, int len, Base64Dialect dialect) { return encode(src, off, len, breakLines(dialect), dialect); } public static ChannelBuffer encode(ChannelBuffer src, int off, int len, ChannelBufferFactory bufferFactory) { return encode(src, off, len, Base64Dialect.STANDARD, bufferFactory); } public static ChannelBuffer encode( ChannelBuffer src, int off, int len, Base64Dialect dialect, ChannelBufferFactory bufferFactory) { return encode(src, off, len, breakLines(dialect), dialect, bufferFactory); } public static ChannelBuffer encode( ChannelBuffer src, int off, int len, boolean breakLines) { return encode(src, off, len, breakLines, Base64Dialect.STANDARD); } public static ChannelBuffer encode( ChannelBuffer src, int off, int len, boolean breakLines, Base64Dialect dialect) { return encode(src, off, len, breakLines, dialect, HeapChannelBufferFactory.getInstance()); } public static ChannelBuffer encode( ChannelBuffer src, int off, int len, boolean breakLines, ChannelBufferFactory bufferFactory) { return encode(src, off, len, breakLines, Base64Dialect.STANDARD, bufferFactory); } public static ChannelBuffer encode( ChannelBuffer src, int off, int len, boolean breakLines, Base64Dialect dialect, ChannelBufferFactory bufferFactory) { if (src == null) { throw new NullPointerException("src"); } if (dialect == null) { throw new NullPointerException("dialect"); } if (bufferFactory == null) { throw new NullPointerException("bufferFactory"); } int len43 = len * 4 / 3; ChannelBuffer dest = bufferFactory.getBuffer( src.order(), len43 + (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(src, d + off, 3, dest, e, dialect); lineLength += 4; if (breakLines && lineLength == MAX_LINE_LENGTH) { dest.setByte(e + 4, NEW_LINE); e ++; lineLength = 0; } // end if: end of line } // end for: each piece of array if (d < len) { encode3to4(src, d + off, len - d, dest, e, dialect); e += 4; } // end if: some padding needed return dest.slice(0, e); } private static void encode3to4( ChannelBuffer src, int srcOffset, int numSigBytes, ChannelBuffer dest, int destOffset, Base64Dialect dialect) { byte[] ALPHABET = alphabet(dialect); // 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? src.getByte(srcOffset) << 24 >>> 8 : 0) | (numSigBytes > 1? src.getByte(srcOffset + 1) << 24 >>> 16 : 0) | (numSigBytes > 2? src.getByte(srcOffset + 2) << 24 >>> 24 : 0); switch (numSigBytes) { case 3: dest.setByte(destOffset , ALPHABET[inBuff >>> 18 ]); dest.setByte(destOffset + 1, ALPHABET[inBuff >>> 12 & 0x3f]); dest.setByte(destOffset + 2, ALPHABET[inBuff >>> 6 & 0x3f]); dest.setByte(destOffset + 3, ALPHABET[inBuff & 0x3f]); break; case 2: dest.setByte(destOffset , ALPHABET[inBuff >>> 18 ]); dest.setByte(destOffset + 1, ALPHABET[inBuff >>> 12 & 0x3f]); dest.setByte(destOffset + 2, ALPHABET[inBuff >>> 6 & 0x3f]); dest.setByte(destOffset + 3, EQUALS_SIGN); break; case 1: dest.setByte(destOffset , ALPHABET[inBuff >>> 18 ]); dest.setByte(destOffset + 1, ALPHABET[inBuff >>> 12 & 0x3f]); dest.setByte(destOffset + 2, EQUALS_SIGN); dest.setByte(destOffset + 3, EQUALS_SIGN); break; } } public static ChannelBuffer decode(ChannelBuffer src) { return decode(src, Base64Dialect.STANDARD); } public static ChannelBuffer decode(ChannelBuffer src, Base64Dialect dialect) { return decode(src, dialect, HeapChannelBufferFactory.getInstance()); } public static ChannelBuffer decode(ChannelBuffer src, ChannelBufferFactory bufferFactory) { return decode(src, Base64Dialect.STANDARD, bufferFactory); } public static ChannelBuffer decode(ChannelBuffer src, Base64Dialect dialect, ChannelBufferFactory bufferFactory) { if (src == null) { throw new NullPointerException("src"); } ChannelBuffer dest = decode(src, src.readerIndex(), src.readableBytes(), dialect, bufferFactory); src.readerIndex(src.writerIndex()); return dest; } public static ChannelBuffer decode( ChannelBuffer src, int off, int len) { return decode(src, off, len, Base64Dialect.STANDARD); } public static ChannelBuffer decode( ChannelBuffer src, int off, int len, Base64Dialect dialect) { return decode(src, off, len, dialect, HeapChannelBufferFactory.getInstance()); } public static ChannelBuffer decode( ChannelBuffer src, int off, int len, ChannelBufferFactory bufferFactory) { return decode(src, off, len, Base64Dialect.STANDARD, bufferFactory); } public static ChannelBuffer decode( ChannelBuffer src, int off, int len, Base64Dialect dialect, ChannelBufferFactory bufferFactory) { if (src == null) { throw new NullPointerException("src"); } if (dialect == null) { throw new NullPointerException("dialect"); } if (bufferFactory == null) { throw new NullPointerException("bufferFactory"); } byte[] DECODABET = decodabet(dialect); int len34 = len * 3 / 4; ChannelBuffer dest = bufferFactory.getBuffer(src.order(), len34); // Upper limit on size of output int outBuffPosn = 0; byte[] b4 = new byte[4]; int b4Posn = 0; int i; byte sbiCrop; byte sbiDecode; for (i = off; i < off + len; i ++) { sbiCrop = (byte) (src.getByte(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) { // Equals sign or better? b4[b4Posn ++] = sbiCrop; if (b4Posn > 3) { // Quartet built? outBuffPosn += decode4to3( b4, 0, dest, outBuffPosn, dialect); b4Posn = 0; // If that was the equals sign, break out of 'for' loop if (sbiCrop == EQUALS_SIGN) { break; } } } } else { throw new IllegalArgumentException( "bad Base64 input character at " + i + ": " + src.getUnsignedByte(i) + " (decimal)"); } } return dest.slice(0, outBuffPosn); } private static int decode4to3( byte[] src, int srcOffset, ChannelBuffer dest, int destOffset, Base64Dialect dialect) { byte[] DECODABET = decodabet(dialect); if (src[srcOffset + 2] == EQUALS_SIGN) { // Example: Dk== int outBuff = (DECODABET[src[srcOffset ]] & 0xFF) << 18 | (DECODABET[src[srcOffset + 1]] & 0xFF) << 12; dest.setByte(destOffset, (byte) (outBuff >>> 16)); return 1; } else if (src[srcOffset + 3] == EQUALS_SIGN) { // Example: DkL= int outBuff = (DECODABET[src[srcOffset ]] & 0xFF) << 18 | (DECODABET[src[srcOffset + 1]] & 0xFF) << 12 | (DECODABET[src[srcOffset + 2]] & 0xFF) << 6; dest.setByte(destOffset , (byte) (outBuff >>> 16)); dest.setByte(destOffset + 1, (byte) (outBuff >>> 8)); return 2; } else { // Example: DkLE int outBuff; try { outBuff = (DECODABET[src[srcOffset ]] & 0xFF) << 18 | (DECODABET[src[srcOffset + 1]] & 0xFF) << 12 | (DECODABET[src[srcOffset + 2]] & 0xFF) << 6 | DECODABET[src[srcOffset + 3]] & 0xFF; } catch (IndexOutOfBoundsException e) { throw new IllegalArgumentException("not encoded in Base64"); } dest.setByte(destOffset , (byte) (outBuff >> 16)); dest.setByte(destOffset + 1, (byte) (outBuff >> 8)); dest.setByte(destOffset + 2, (byte) outBuff); return 3; } } private Base64() { // Unused } }





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