Base64Code

Base64Code 编码

[1].[代码] [Java]代码 跳至 [1]

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// Copyright 2003-2009 Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland // www.source-code.biz, www.inventec.ch/chdh // // This module is multi-licensed and may be used under the terms // of any of the following licenses: // //  EPL, Eclipse Public License, http://www.eclipse.org/legal //  LGPL, GNU Lesser General Public License, http://www.gnu.org/licenses/lgpl.html //  AL, Apache License, http://www.apache.org/licenses //  BSD, BSD License, http://www.opensource.org/licenses/bsd-license.php // // Please contact the author if you need another license. // This module is provided "as is", without warranties of any kind.   package com.jlusoft.banbantong.common;   /**   * A Base64 Encoder/Decoder.   * <p>   * This class is used to encode and decode data in Base64 format as described in   * RFC 1521.   * <p>   * Home page: <a href="http://www.source-code.biz">www.source-code.biz</a><br>   * Author: Christian d'Heureuse, Inventec Informatik AG, Zurich, Switzerland<br>   * Multi-licensed: EPL/LGPL/AL/BSD.   * <p>   * Version history:<br>   * 2003-07-22 Christian d'Heureuse (chdh): Module created.<br>   * 2005-08-11 chdh: Lincense changed from GPL to LGPL.<br>   * 2006-11-21 chdh:<br>   * &nbsp; Method encode(String) renamed to encodeString(String).<br>   * &nbsp; Method decode(String) renamed to decodeString(String).<br>   * &nbsp; New method encode(byte[],int) added.<br>   * &nbsp; New method decode(String) added.<br>   * 2009-07-16: Additional licenses (EPL/AL) added.<br>   * 2009-09-16: Additional license (BSD) added.<br>   */   public class Base64Code {        // Mapping table from 6-bit nibbles to Base64 characters.      private static char [] map1 = new char [ 64 ];      static {          int i = 0 ;          for ( char c = 'A' ; c <= 'Z' ; c++)              map1[i++] = c;          for ( char c = 'a' ; c <= 'z' ; c++)              map1[i++] = c;          for ( char c = '0' ; c <= '9' ; c++)              map1[i++] = c;          map1[i++] = '+' ;          map1[i++] = '/' ;      }        // Mapping table from Base64 characters to 6-bit nibbles.      private static byte [] map2 = new byte [ 128 ];      static {          for ( int i = 0 ; i < map2.length; i++)              map2[i] = - 1 ;          for ( int i = 0 ; i < 64 ; i++)              map2[map1[i]] = ( byte ) i;      }        /**       * Encodes a string into Base64 format. No blanks or line breaks are       * inserted.       *       * @param s a String to be encoded.       * @return A String with the Base64 encoded data.       */      public static String encodeString(String s) {          return new String(encode(s.getBytes()));      }            public static String encodeString( byte [] s){          return new String(encode(s));      }        /**       * Encodes a byte array into Base64 format. No blanks or line breaks are       * inserted.       *       * @param in an array containing the data bytes to be encoded.       * @return A character array with the Base64 encoded data.       */      public static char [] encode( byte [] in) {          return encode(in, in.length);      }        /**       * Encodes a byte array into Base64 format. No blanks or line breaks are       * inserted.       *       * @param in an array containing the data bytes to be encoded.       * @param iLen number of bytes to process in <code>in</code>.       * @return A character array with the Base64 encoded data.       */      public static char [] encode( byte [] in, int iLen) {          int oDataLen = (iLen * 4 + 2 ) / 3 ; // output length without padding          int oLen = ((iLen + 2 ) / 3 ) * 4 ; // output length including padding          char [] out = new char [oLen];          int ip = 0 ;          int op = 0 ;          while (ip < iLen) {              int i0 = in[ip++] & 0xff ;              int i1 = ip < iLen ? in[ip++] & 0xff : 0 ;              int i2 = ip < iLen ? in[ip++] & 0xff : 0 ;              int o0 = i0 >>> 2 ;              int o1 = ((i0 & 3 ) << 4 ) | (i1 >>> 4 );              int o2 = ((i1 & 0xf ) << 2 ) | (i2 >>> 6 );              int o3 = i2 & 0x3F ;              out[op++] = map1[o0];              out[op++] = map1[o1];              out[op] = op < oDataLen ? map1[o2] : '=' ;              op++;              out[op] = op < oDataLen ? map1[o3] : '=' ;              op++;          }          return out;      }        /**       * Decodes a string from Base64 format.       *       * @param s a Base64 String to be decoded.       * @return A String containing the decoded data.       * @throws IllegalArgumentException if the input is not valid Base64 encoded       *             data.       */      public static String decodeString(String s) {          return new String(decode(s));      }        /**       * Decodes a byte array from Base64 format.       *       * @param s a Base64 String to be decoded.       * @return An array containing the decoded data bytes.       * @throws IllegalArgumentException if the input is not valid Base64 encoded       *             data.       */      public static byte [] decode(String s) {          return decode(s.toCharArray());      }        /**       * Decodes a byte array from Base64 format. No blanks or line breaks are       * allowed within the Base64 encoded data.       *       * @param in a character array containing the Base64 encoded data.       * @return An array containing the decoded data bytes.       * @throws IllegalArgumentException if the input is not valid Base64 encoded       *             data.       */      public static byte [] decode( char [] in) {          int iLen = in.length;          if (iLen % 4 != 0 )              throw new IllegalArgumentException(                      "Length of Base64 encoded input string is not a multiple of 4." );          while (iLen > 0 && in[iLen - 1 ] == '=' )              iLen--;          int oLen = (iLen * 3 ) / 4 ;          byte [] out = new byte [oLen];          int ip = 0 ;          int op = 0 ;          while (ip < iLen) {              int i0 = in[ip++];              int i1 = in[ip++];              int i2 = ip < iLen ? in[ip++] : 'A' ;              int i3 = ip < iLen ? in[ip++] : 'A' ;              if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127 )                  throw new IllegalArgumentException( "Illegal character in Base64 encoded data." );              int b0 = map2[i0];              int b1 = map2[i1];              int b2 = map2[i2];              int b3 = map2[i3];              if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0 )                  throw new IllegalArgumentException( "Illegal character in Base64 encoded data." );              int o0 = (b0 << 2 ) | (b1 >>> 4 );              int o1 = ((b1 & 0xf ) << 4 ) | (b2 >>> 2 );              int o2 = ((b2 & 3 ) << 6 ) | b3;              out[op++] = ( byte ) o0;              if (op < oLen) out[op++] = ( byte ) o1;              if (op < oLen) out[op++] = ( byte ) o2;          }          return out;      }        // Dummy constructor.      private Base64Code() {      }   } // end class Base64Coder