package WebMail;/** * <p>Title: 企業(yè)郵箱管理系統(tǒng)</p> * <p>Description: 收發(fā)郵件</p> * <p>Copyright: Copyright (c) 2003</p> * <p>Company: 南京仕邦有限公司</p> * @author W.L.B * @version 1.0 */public final class  Base64{  static private final int  BASELENGTH         = 255;  static private final int  LOOKUPLENGTH       = 64;  static private final int  TWENTYFOURBITGROUP = 24;  static private final int  EIGHTBIT           = 8;  static private final int  SIXTEENBIT         = 16;  static private final int  SIXBIT             = 6;  static private final int  FOURBYTE           = 4;  static private final int  SIGN               = -128;  static private final byte PAD                = (byte) '=';  static private byte [] base64Alphabet       = new byte[BASELENGTH];  static private byte [] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];  static  {    for (int i = 0; i < BASELENGTH; i++ )    {      base64Alphabet[i] = -1;    }    for (int i = 'Z'; i >= 'A'; i--)    {      base64Alphabet[i] = (byte) (i - 'A');    }    for (int i = 'z'; i>= 'a'; i--)    {      base64Alphabet[i] = (byte) (i - 'a' + 26);    }    for (int i = '9'; i >= '0'; i--)    {      base64Alphabet[i] = (byte) (i - '0' + 52);    }    base64Alphabet['+']  = 62;    base64Alphabet['/']  = 63;    for (int i = 0; i <= 25; i++ )      lookUpBase64Alphabet[i] = (byte) ('A' + i);    for (int i = 26,  j = 0; i <= 51; i++, j++ )      lookUpBase64Alphabet[i] = (byte) ('a'+ j);    for (int i = 52,  j = 0; i <= 61; i++, j++ )      lookUpBase64Alphabet[i] = (byte) ('0' + j);    lookUpBase64Alphabet[62] = (byte) '+';    lookUpBase64Alphabet[63] = (byte) '/';  } public static boolean isBase64( String isValidString ) {   return isArrayByteBase64(isValidString.getBytes()); } public static boolean isBase64( byte octect ) {   //shall we ignore white space? JEFF??   return (octect == PAD || base64Alphabet[octect] != -1); } public static boolean isArrayByteBase64( byte[] arrayOctect ) {   int length = arrayOctect.length;   if (length == 0)   {     // shouldn't a 0 length array be valid base64 data?     // return false;     return true;   }   for (int i=0; i < length; i++)   {     if ( !Base64.isBase64(arrayOctect[i]) )       return false;   }   return true; } /**     * Encodes hex octects into Base64.     *     * @param binaryData Array containing binary data to encode.     * @return Base64-encoded data.     */ public static byte[] encode( byte[] binaryData ) {   int      lengthDataBits    = binaryData.length*EIGHTBIT;   int      fewerThan24bits   = lengthDataBits%TWENTYFOURBITGROUP;   int      numberTriplets    = lengthDataBits/TWENTYFOURBITGROUP;   byte     encodedData[]     = null;   if (fewerThan24bits != 0)   {     //data not divisible by 24 bit     encodedData = new byte[ (numberTriplets + 1 ) * 4 ];   }   else   {     // 16 or 8 bit     encodedData = new byte[ numberTriplets * 4 ];   }   byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;   int encodedIndex = 0;   int dataIndex   = 0;   int i           = 0;   for ( i = 0; i<numberTriplets; i++ )   {     dataIndex = i*3;     b1 = binaryData[dataIndex];     b2 = binaryData[dataIndex + 1];     b3 = binaryData[dataIndex + 2];     l  = (byte)(b2 & 0x0f);     k  = (byte)(b1 & 0x03);     encodedIndex = i * 4;     byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);     byte val2 = ((b2 & SIGN)==0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);     byte val3 = ((b3 & SIGN)==0)?(byte)(b3>>6):(byte)((b3)>>6^0xfc);     encodedData[encodedIndex]   = lookUpBase64Alphabet[ val1 ];     encodedData[encodedIndex+1] =         lookUpBase64Alphabet[ val2 | ( k<<4 )];     encodedData[encodedIndex+2] =         lookUpBase64Alphabet[ (l <<2 ) | val3 ];     encodedData[encodedIndex+3] = lookUpBase64Alphabet[ b3 & 0x3f ];   }   // form integral number of 6-bit groups   dataIndex    = i*3;   encodedIndex = i*4;   if (fewerThan24bits == EIGHTBIT )   {     b1 = binaryData[dataIndex];     k = (byte) ( b1 &0x03 );     byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);     encodedData[encodedIndex]     = lookUpBase64Alphabet[ val1 ];     encodedData[encodedIndex + 1] = lookUpBase64Alphabet[ k<<4 ];     encodedData[encodedIndex + 2] = PAD;     encodedData[encodedIndex + 3] = PAD;   }   else if (fewerThan24bits == SIXTEENBIT)   {     b1 = binaryData[dataIndex];     b2 = binaryData[dataIndex +1 ];     l = (byte) (b2 & 0x0f);     k = (byte) (b1 & 0x03);     byte val1 = ((b1 & SIGN) == 0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);     byte val2 = ((b2 & SIGN) == 0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);     encodedData[encodedIndex]     = lookUpBase64Alphabet[ val1 ];     encodedData[encodedIndex + 1] =         lookUpBase64Alphabet[ val2 | ( k<<4 )];     encodedData[encodedIndex + 2] = lookUpBase64Alphabet[ l<<2 ];     encodedData[encodedIndex + 3] = PAD;   }   return encodedData; } /**  * Decodes Base64 data into octects  *  * @param binaryData Byte array containing Base64 data  * @return Array containing decoded data.  */ public static byte[] decode( byte[] base64Data ) {   // handle the edge case, so we don't have to worry about it later   if(base64Data.length == 0) { return new byte[0]; }   int      numberQuadruple    = base64Data.length/FOURBYTE;   byte     decodedData[]      = null;   byte     b1=0,b2=0,b3=0, b4=0, marker0=0, marker1=0;   // Throw away anything not in base64Data   int encodedIndex = 0;   int dataIndex    = 0;   {     // this sizes the output array properly - rlw     int lastData = base64Data.length;     // ignore the '=' padding     while (base64Data[lastData-1] == PAD)     {       if (--lastData == 0)       {         return new byte[0];       }     }     decodedData = new byte[ lastData - numberQuadruple ];   }   for (int i = 0; i < numberQuadruple; i++)   {     dataIndex = i * 4;     marker0   = base64Data[dataIndex + 2];     marker1   = base64Data[dataIndex + 3];     b1 = base64Alphabet[base64Data[dataIndex]];     b2 = base64Alphabet[base64Data[dataIndex +1]];     if (marker0 != PAD && marker1 != PAD)     {       //No PAD e.g 3cQl       b3 = base64Alphabet[ marker0 ];       b4 = base64Alphabet[ marker1 ];       decodedData[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 ) ;       decodedData[encodedIndex + 1] =           (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );       decodedData[encodedIndex + 2] = (byte)( b3<<6 | b4 );     }     else if (marker0 == PAD)     {       //Two PAD e.g. 3c[Pad][Pad]       decodedData[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 ) ;     }     else if (marker1 == PAD)     {       //One PAD e.g. 3cQ[Pad]       b3 = base64Alphabet[ marker0 ];       decodedData[encodedIndex]   = (byte)(  b1 <<2 | b2>>4 );       decodedData[encodedIndex + 1] =           (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );     }     encodedIndex += 3;   }   return decodedData; } /**  * 測試用  * @param arg  */ public static void main(String arg[]) {   String dd = "PCFET0NUWVBFIEhUTUwgUFVCTElDICItLy9XM0MvL0RURCBIVE1MIDQuMCBUcmFuc2l0aW9uYWwv"+       "L0VOIj4NCjxIVE1MPjxIRUFEPg0KPE1FVEEgaHR0cC1lcXVpdj1Db250ZW50LVR5cGUgY29udGVu"+       "dD0idGV4dC9odG1sOyBjaGFyc2V0PWdiMjMxMiI+DQo8TUVUQSBjb250ZW50PSJNU0hUTUwgNi4w"+       "MC4yNzI2LjI1MDAiIG5hbWU9R0VORVJBVE9SPg0KPFNUWUxFPjwvU1RZTEU+DQo8L0hFQUQ+DQo8"+       "Qk9EWSBiZ0NvbG9yPSNmZmZmZmY+DQo8RElWPjxGT05UIHNpemU9Mj48L0ZPTlQ+Jm5ic3A7PC9E"+       "SVY+PC9CT0RZPjwvSFRNTD4NCg==";   String ss = new String( decode(dd.getBytes()) );   System.out.println(ss); }}