mirror of
https://github.com/Maxlego08/zKoth.git
synced 2024-09-27 04:12:39 +02:00
269 lines
9.3 KiB
Java
269 lines
9.3 KiB
Java
package fr.maxlego08.koth.zcore.utils;
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public final class Base64 {
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static private final int BASELENGTH = 128;
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static private final int LOOKUPLENGTH = 64;
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static private final int TWENTYFOURBITGROUP = 24;
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static private final int EIGHTBIT = 8;
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static private final int SIXTEENBIT = 16;
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static private final int FOURBYTE = 4;
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static private final int SIGN = -128;
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static private final char PAD = '=';
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static private final boolean fDebug = false;
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static final private byte [] base64Alphabet = new byte[BASELENGTH];
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static final private char [] lookUpBase64Alphabet = new char[LOOKUPLENGTH];
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static {
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for (int i = 0; i < BASELENGTH; ++i) {
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base64Alphabet[i] = -1;
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}
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for (int i = 'Z'; i >= 'A'; i--) {
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base64Alphabet[i] = (byte) (i-'A');
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}
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for (int i = 'z'; i>= 'a'; i--) {
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base64Alphabet[i] = (byte) ( i-'a' + 26);
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}
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for (int i = '9'; i >= '0'; i--) {
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base64Alphabet[i] = (byte) (i-'0' + 52);
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}
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base64Alphabet['+'] = 62;
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base64Alphabet['/'] = 63;
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for (int i = 0; i<=25; i++)
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lookUpBase64Alphabet[i] = (char)('A'+i);
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for (int i = 26, j = 0; i<=51; i++, j++)
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lookUpBase64Alphabet[i] = (char)('a'+ j);
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for (int i = 52, j = 0; i<=61; i++, j++)
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lookUpBase64Alphabet[i] = (char)('0' + j);
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lookUpBase64Alphabet[62] = (char)'+';
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lookUpBase64Alphabet[63] = (char)'/';
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}
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protected static boolean isWhiteSpace(char octect) {
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return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);
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}
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protected static boolean isPad(char octect) {
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return (octect == PAD);
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}
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protected static boolean isData(char octect) {
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return (octect < BASELENGTH && base64Alphabet[octect] != -1);
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}
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protected static boolean isBase64(char octect) {
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return (isWhiteSpace(octect) || isPad(octect) || isData(octect));
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}
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/**
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* Encodes hex octects into Base64
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*
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* @param binaryData Array containing binaryData
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* @return Encoded Base64 array
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*/
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public static String encode(byte[] binaryData) {
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if (binaryData == null)
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return null;
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int lengthDataBits = binaryData.length*EIGHTBIT;
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if (lengthDataBits == 0) {
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return "";
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}
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int fewerThan24bits = lengthDataBits%TWENTYFOURBITGROUP;
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int numberTriplets = lengthDataBits/TWENTYFOURBITGROUP;
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int numberQuartet = fewerThan24bits != 0 ? numberTriplets+1 : numberTriplets;
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char encodedData[] = null;
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encodedData = new char[numberQuartet*4];
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byte k=0, l=0, b1=0,b2=0,b3=0;
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int encodedIndex = 0;
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int dataIndex = 0;
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if (fDebug) {
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System.out.println("number of triplets = " + numberTriplets );
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}
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for (int i=0; i<numberTriplets; i++) {
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b1 = binaryData[dataIndex++];
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b2 = binaryData[dataIndex++];
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b3 = binaryData[dataIndex++];
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if (fDebug) {
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System.out.println( "b1= " + b1 +", b2= " + b2 + ", b3= " + b3 );
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}
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l = (byte)(b2 & 0x0f);
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k = (byte)(b1 & 0x03);
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byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
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byte val2 = ((b2 & SIGN)==0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);
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byte val3 = ((b3 & SIGN)==0)?(byte)(b3>>6):(byte)((b3)>>6^0xfc);
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if (fDebug) {
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System.out.println( "val2 = " + val2 );
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System.out.println( "k4 = " + (k<<4));
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System.out.println( "vak = " + (val2 | (k<<4)));
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}
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ val1 ];
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ val2 | ( k<<4 )];
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ (l <<2 ) | val3 ];
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ b3 & 0x3f ];
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}
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// form integral number of 6-bit groups
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if (fewerThan24bits == EIGHTBIT) {
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b1 = binaryData[dataIndex];
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k = (byte) ( b1 &0x03 );
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if (fDebug) {
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System.out.println("b1=" + b1);
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System.out.println("b1<<2 = " + (b1>>2) );
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}
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byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ val1 ];
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ k<<4 ];
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encodedData[encodedIndex++] = PAD;
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encodedData[encodedIndex++] = PAD;
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} else if (fewerThan24bits == SIXTEENBIT) {
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b1 = binaryData[dataIndex];
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b2 = binaryData[dataIndex +1 ];
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l = ( byte ) ( b2 &0x0f );
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k = ( byte ) ( b1 &0x03 );
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byte val1 = ((b1 & SIGN)==0)?(byte)(b1>>2):(byte)((b1)>>2^0xc0);
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byte val2 = ((b2 & SIGN)==0)?(byte)(b2>>4):(byte)((b2)>>4^0xf0);
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ val1 ];
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ val2 | ( k<<4 )];
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encodedData[encodedIndex++] = lookUpBase64Alphabet[ l<<2 ];
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encodedData[encodedIndex++] = PAD;
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}
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return new String(encodedData);
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}
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/**
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* Decodes Base64 data into octects
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*
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* @param encoded string containing Base64 data
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* @return Array containind decoded data.
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*/
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public static byte[] decode(String encoded) {
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if (encoded == null)
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return null;
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char[] base64Data = encoded.toCharArray();
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// remove white spaces
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int len = removeWhiteSpace(base64Data);
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if (len%FOURBYTE != 0) {
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return null;//should be divisible by four
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}
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int numberQuadruple = (len/FOURBYTE );
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if (numberQuadruple == 0)
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return new byte[0];
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byte decodedData[] = null;
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byte b1=0,b2=0,b3=0,b4=0;
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char d1=0,d2=0,d3=0,d4=0;
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int i = 0;
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int encodedIndex = 0;
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int dataIndex = 0;
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decodedData = new byte[ (numberQuadruple)*3];
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for (; i<numberQuadruple-1; i++) {
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if (!isData( (d1 = base64Data[dataIndex++]) )||
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!isData( (d2 = base64Data[dataIndex++]) )||
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!isData( (d3 = base64Data[dataIndex++]) )||
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!isData( (d4 = base64Data[dataIndex++]) ))
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return null;//if found "no data" just return null
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b1 = base64Alphabet[d1];
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b2 = base64Alphabet[d2];
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b3 = base64Alphabet[d3];
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b4 = base64Alphabet[d4];
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decodedData[encodedIndex++] = (byte)( b1 <<2 | b2>>4 ) ;
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decodedData[encodedIndex++] = (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
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decodedData[encodedIndex++] = (byte)( b3<<6 | b4 );
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}
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if (!isData( (d1 = base64Data[dataIndex++]) ) ||
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!isData( (d2 = base64Data[dataIndex++]) )) {
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return null;//if found "no data" just return null
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}
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b1 = base64Alphabet[d1];
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b2 = base64Alphabet[d2];
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d3 = base64Data[dataIndex++];
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d4 = base64Data[dataIndex++];
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if (!isData( (d3 ) ) ||
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!isData( (d4 ) )) {//Check if they are PAD characters
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if (isPad( d3 ) && isPad( d4)) { //Two PAD e.g. 3c[Pad][Pad]
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if ((b2 & 0xf) != 0)//last 4 bits should be zero
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return null;
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byte[] tmp = new byte[ i*3 + 1 ];
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System.arraycopy( decodedData, 0, tmp, 0, i*3 );
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tmp[encodedIndex] = (byte)( b1 <<2 | b2>>4 ) ;
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return tmp;
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} else if (!isPad( d3) && isPad(d4)) { //One PAD e.g. 3cQ[Pad]
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b3 = base64Alphabet[ d3 ];
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if ((b3 & 0x3 ) != 0)//last 2 bits should be zero
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return null;
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byte[] tmp = new byte[ i*3 + 2 ];
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System.arraycopy( decodedData, 0, tmp, 0, i*3 );
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tmp[encodedIndex++] = (byte)( b1 <<2 | b2>>4 );
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tmp[encodedIndex] = (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
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return tmp;
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} else {
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return null;//an error like "3c[Pad]r", "3cdX", "3cXd", "3cXX" where X is non data
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}
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} else { //No PAD e.g 3cQl
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b3 = base64Alphabet[ d3 ];
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b4 = base64Alphabet[ d4 ];
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decodedData[encodedIndex++] = (byte)( b1 <<2 | b2>>4 ) ;
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decodedData[encodedIndex++] = (byte)(((b2 & 0xf)<<4 ) |( (b3>>2) & 0xf) );
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decodedData[encodedIndex++] = (byte)( b3<<6 | b4 );
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}
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return decodedData;
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}
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/**
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* remove WhiteSpace from MIME containing encoded Base64 data.
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*
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* @param data the byte array of base64 data (with WS)
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* @return the new length
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*/
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protected static int removeWhiteSpace(char[] data) {
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if (data == null)
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return 0;
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// count characters that's not whitespace
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int newSize = 0;
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int len = data.length;
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for (int i = 0; i < len; i++) {
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if (!isWhiteSpace(data[i]))
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data[newSize++] = data[i];
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}
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return newSize;
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}
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} |