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The Base64.java Java example source code
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* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.
*/
package com.sun.org.apache.xml.internal.security.utils;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import com.sun.org.apache.xml.internal.security.exceptions.Base64DecodingException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.Text;
/**
* Implementation of MIME's Base64 encoding and decoding conversions.
* Optimized code. (raw version taken from oreilly.jonathan.util,
* and currently org.apache.xerces.ds.util.Base64)
*
* @author Raul Benito(Of the xerces copy, and little adaptations).
* @author Anli Shundi
* @author Christian Geuer-Pollmann
* @see <A HREF="ftp://ftp.isi.edu/in-notes/rfc2045.txt">RFC 2045
* @see com.sun.org.apache.xml.internal.security.transforms.implementations.TransformBase64Decode
*/
public class Base64 {
/** Field BASE64DEFAULTLENGTH */
public static final int BASE64DEFAULTLENGTH = 76;
private static final int BASELENGTH = 255;
private static final int LOOKUPLENGTH = 64;
private static final int TWENTYFOURBITGROUP = 24;
private static final int EIGHTBIT = 8;
private static final int SIXTEENBIT = 16;
private static final int FOURBYTE = 4;
private static final int SIGN = -128;
private static final char PAD = '=';
private static final byte [] base64Alphabet = new byte[BASELENGTH];
private static final char [] lookUpBase64Alphabet = new char[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] = (char)('A' + i);
}
for (int i = 26, j = 0; i <= 51; i++, j++) {
lookUpBase64Alphabet[i] = (char)('a' + j);
}
for (int i = 52, j = 0; i <= 61; i++, j++) {
lookUpBase64Alphabet[i] = (char)('0' + j);
}
lookUpBase64Alphabet[62] = '+';
lookUpBase64Alphabet[63] = '/';
}
private Base64() {
// we don't allow instantiation
}
/**
* Returns a byte-array representation of a <code>{@link BigInteger}.
* No sign-bit is output.
*
* <b>N.B.: {@link BigInteger}'s toByteArray
* returns eventually longer arrays because of the leading sign-bit.
*
* @param big <code>BigInteger to be converted
* @param bitlen <code>int the desired length in bits of the representation
* @return a byte array with <code>bitlen bits of big
*/
static final byte[] getBytes(BigInteger big, int bitlen) {
//round bitlen
bitlen = ((bitlen + 7) >> 3) << 3;
if (bitlen < big.bitLength()) {
throw new IllegalArgumentException(I18n.translate("utils.Base64.IllegalBitlength"));
}
byte[] bigBytes = big.toByteArray();
if (((big.bitLength() % 8) != 0)
&& (((big.bitLength() / 8) + 1) == (bitlen / 8))) {
return bigBytes;
}
// some copying needed
int startSrc = 0; // no need to skip anything
int bigLen = bigBytes.length; //valid length of the string
if ((big.bitLength() % 8) == 0) { // correct values
startSrc = 1; // skip sign bit
bigLen--; // valid length of the string
}
int startDst = bitlen / 8 - bigLen; //pad with leading nulls
byte[] resizedBytes = new byte[bitlen / 8];
System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, bigLen);
return resizedBytes;
}
/**
* Encode in Base64 the given <code>{@link BigInteger}.
*
* @param big
* @return String with Base64 encoding
*/
public static final String encode(BigInteger big) {
return encode(getBytes(big, big.bitLength()));
}
/**
* Returns a byte-array representation of a <code>{@link BigInteger}.
* No sign-bit is output.
*
* <b>N.B.: {@link BigInteger}'s toByteArray
* returns eventually longer arrays because of the leading sign-bit.
*
* @param big <code>BigInteger to be converted
* @param bitlen <code>int the desired length in bits of the representation
* @return a byte array with <code>bitlen bits of big
*/
public static final byte[] encode(BigInteger big, int bitlen) {
//round bitlen
bitlen = ((bitlen + 7) >> 3) << 3;
if (bitlen < big.bitLength()) {
throw new IllegalArgumentException(I18n.translate("utils.Base64.IllegalBitlength"));
}
byte[] bigBytes = big.toByteArray();
if (((big.bitLength() % 8) != 0)
&& (((big.bitLength() / 8) + 1) == (bitlen / 8))) {
return bigBytes;
}
// some copying needed
int startSrc = 0; // no need to skip anything
int bigLen = bigBytes.length; //valid length of the string
if ((big.bitLength() % 8) == 0) { // correct values
startSrc = 1; // skip sign bit
bigLen--; // valid length of the string
}
int startDst = bitlen / 8 - bigLen; //pad with leading nulls
byte[] resizedBytes = new byte[bitlen / 8];
System.arraycopy(bigBytes, startSrc, resizedBytes, startDst, bigLen);
return resizedBytes;
}
/**
* Method decodeBigIntegerFromElement
*
* @param element
* @return the biginteger obtained from the node
* @throws Base64DecodingException
*/
public static final BigInteger decodeBigIntegerFromElement(Element element)
throws Base64DecodingException {
return new BigInteger(1, Base64.decode(element));
}
/**
* Method decodeBigIntegerFromText
*
* @param text
* @return the biginter obtained from the text node
* @throws Base64DecodingException
*/
public static final BigInteger decodeBigIntegerFromText(Text text)
throws Base64DecodingException {
return new BigInteger(1, Base64.decode(text.getData()));
}
/**
* This method takes an (empty) Element and a BigInteger and adds the
* base64 encoded BigInteger to the Element.
*
* @param element
* @param biginteger
*/
public static final void fillElementWithBigInteger(Element element, BigInteger biginteger) {
String encodedInt = encode(biginteger);
if (!XMLUtils.ignoreLineBreaks() && encodedInt.length() > BASE64DEFAULTLENGTH) {
encodedInt = "\n" + encodedInt + "\n";
}
Document doc = element.getOwnerDocument();
Text text = doc.createTextNode(encodedInt);
element.appendChild(text);
}
/**
* Method decode
*
* Takes the <CODE>Text children of the Element and interprets
* them as input for the <CODE>Base64.decode() function.
*
* @param element
* @return the byte obtained of the decoding the element
* $todo$ not tested yet
* @throws Base64DecodingException
*/
public static final byte[] decode(Element element) throws Base64DecodingException {
Node sibling = element.getFirstChild();
StringBuffer sb = new StringBuffer();
while (sibling != null) {
if (sibling.getNodeType() == Node.TEXT_NODE) {
Text t = (Text) sibling;
sb.append(t.getData());
}
sibling = sibling.getNextSibling();
}
return decode(sb.toString());
}
/**
* Method encodeToElement
*
* @param doc
* @param localName
* @param bytes
* @return an Element with the base64 encoded in the text.
*
*/
public static final Element encodeToElement(Document doc, String localName, byte[] bytes) {
Element el = XMLUtils.createElementInSignatureSpace(doc, localName);
Text text = doc.createTextNode(encode(bytes));
el.appendChild(text);
return el;
}
/**
* Method decode
*
* @param base64
* @return the UTF bytes of the base64
* @throws Base64DecodingException
*
*/
public static final byte[] decode(byte[] base64) throws Base64DecodingException {
return decodeInternal(base64, -1);
}
/**
* Encode a byte array and fold lines at the standard 76th character unless
* ignore line breaks property is set.
*
* @param binaryData <code>byte[] to be base64 encoded
* @return the <code>String with encoded data
*/
public static final String encode(byte[] binaryData) {
return XMLUtils.ignoreLineBreaks()
? encode(binaryData, Integer.MAX_VALUE)
: encode(binaryData, BASE64DEFAULTLENGTH);
}
/**
* Base64 decode the lines from the reader and return an InputStream
* with the bytes.
*
* @param reader
* @return InputStream with the decoded bytes
* @exception IOException passes what the reader throws
* @throws IOException
* @throws Base64DecodingException
*/
public static final byte[] decode(BufferedReader reader)
throws IOException, Base64DecodingException {
byte[] retBytes = null;
UnsyncByteArrayOutputStream baos = null;
try {
baos = new UnsyncByteArrayOutputStream();
String line;
while (null != (line = reader.readLine())) {
byte[] bytes = decode(line);
baos.write(bytes);
}
retBytes = baos.toByteArray();
} finally {
baos.close();
}
return retBytes;
}
protected static final boolean isWhiteSpace(byte octect) {
return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);
}
protected static final boolean isPad(byte octect) {
return (octect == PAD);
}
/**
* Encodes hex octets into Base64
*
* @param binaryData Array containing binaryData
* @return Encoded Base64 array
*/
/**
* Encode a byte array in Base64 format and return an optionally
* wrapped line.
*
* @param binaryData <code>byte[] data to be encoded
* @param length <code>int length of wrapped lines; No wrapping if less than 4.
* @return a <code>String with encoded data
*/
public static final String encode(byte[] binaryData,int length) {
if (length < 4) {
length = Integer.MAX_VALUE;
}
if (binaryData == null) {
return null;
}
int lengthDataBits = binaryData.length * EIGHTBIT;
if (lengthDataBits == 0) {
return "";
}
int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
int numberQuartet = fewerThan24bits != 0 ? numberTriplets + 1 : numberTriplets;
int quartesPerLine = length / 4;
int numberLines = (numberQuartet - 1) / quartesPerLine;
char encodedData[] = null;
encodedData = new char[numberQuartet * 4 + numberLines];
byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
int encodedIndex = 0;
int dataIndex = 0;
int i = 0;
for (int line = 0; line < numberLines; line++) {
for (int quartet = 0; quartet < 19; quartet++) {
b1 = binaryData[dataIndex++];
b2 = binaryData[dataIndex++];
b3 = binaryData[dataIndex++];
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);
byte val3 = ((b3 & SIGN) == 0) ? (byte)(b3 >> 6) : (byte)((b3) >> 6 ^ 0xfc);
encodedData[encodedIndex++] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex++] = lookUpBase64Alphabet[(l << 2) | val3];
encodedData[encodedIndex++] = lookUpBase64Alphabet[b3 & 0x3f];
i++;
}
encodedData[encodedIndex++] = 0xa;
}
for (; i < numberTriplets; i++) {
b1 = binaryData[dataIndex++];
b2 = binaryData[dataIndex++];
b3 = binaryData[dataIndex++];
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);
byte val3 = ((b3 & SIGN) == 0) ? (byte)(b3 >> 6) : (byte)((b3) >> 6 ^ 0xfc);
encodedData[encodedIndex++] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex++] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex++] = lookUpBase64Alphabet[(l << 2) | val3];
encodedData[encodedIndex++] = lookUpBase64Alphabet[b3 & 0x3f];
}
// form integral number of 6-bit groups
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++] = lookUpBase64Alphabet[k << 4];
encodedData[encodedIndex++] = PAD;
encodedData[encodedIndex++] = 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++] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex++] = lookUpBase64Alphabet[l << 2];
encodedData[encodedIndex++] = PAD;
}
//encodedData[encodedIndex] = 0xa;
return new String(encodedData);
}
/**
* Decodes Base64 data into octets
*
* @param encoded String containing base64 encoded data
* @return byte array containing the decoded data
* @throws Base64DecodingException if there is a problem decoding the data
*/
public static final byte[] decode(String encoded) throws Base64DecodingException {
if (encoded == null) {
return null;
}
byte[] bytes = new byte[encoded.length()];
int len = getBytesInternal(encoded, bytes);
return decodeInternal(bytes, len);
}
protected static final int getBytesInternal(String s, byte[] result) {
int length = s.length();
int newSize = 0;
for (int i = 0; i < length; i++) {
byte dataS = (byte)s.charAt(i);
if (!isWhiteSpace(dataS)) {
result[newSize++] = dataS;
}
}
return newSize;
}
protected static final byte[] decodeInternal(byte[] base64Data, int len)
throws Base64DecodingException {
// remove white spaces
if (len == -1) {
len = removeWhiteSpace(base64Data);
}
if (len % FOURBYTE != 0) {
throw new Base64DecodingException("decoding.divisible.four");
//should be divisible by four
}
int numberQuadruple = (len / FOURBYTE);
if (numberQuadruple == 0) {
return new byte[0];
}
byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0;
int i = 0;
int encodedIndex = 0;
int dataIndex = 0;
//decodedData = new byte[ (numberQuadruple)*3];
dataIndex = (numberQuadruple - 1) * 4;
encodedIndex = (numberQuadruple - 1) * 3;
//first last bits.
b1 = base64Alphabet[base64Data[dataIndex++]];
b2 = base64Alphabet[base64Data[dataIndex++]];
if ((b1==-1) || (b2==-1)) {
//if found "no data" just return null
throw new Base64DecodingException("decoding.general");
}
byte d3, d4;
b3 = base64Alphabet[d3 = base64Data[dataIndex++]];
b4 = base64Alphabet[d4 = base64Data[dataIndex++]];
if ((b3 == -1) || (b4 == -1) ) {
//Check if they are PAD characters
if (isPad(d3) && isPad(d4)) { //Two PAD e.g. 3c[Pad][Pad]
if ((b2 & 0xf) != 0) { //last 4 bits should be zero
throw new Base64DecodingException("decoding.general");
}
decodedData = new byte[encodedIndex + 1];
decodedData[encodedIndex] = (byte)(b1 << 2 | b2 >> 4) ;
} else if (!isPad(d3) && isPad(d4)) { //One PAD e.g. 3cQ[Pad]
if ((b3 & 0x3) != 0) { //last 2 bits should be zero
throw new Base64DecodingException("decoding.general");
}
decodedData = new byte[encodedIndex + 2];
decodedData[encodedIndex++] = (byte)(b1 << 2 | b2 >> 4);
decodedData[encodedIndex] = (byte)(((b2 & 0xf) << 4) |((b3 >> 2) & 0xf));
} else {
//an error like "3c[Pad]r", "3cdX", "3cXd", "3cXX" where X is non data
throw new Base64DecodingException("decoding.general");
}
} else {
//No PAD e.g 3cQl
decodedData = new byte[encodedIndex+3];
decodedData[encodedIndex++] = (byte)(b1 << 2 | b2 >> 4) ;
decodedData[encodedIndex++] = (byte)(((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
decodedData[encodedIndex++] = (byte)(b3 << 6 | b4);
}
encodedIndex = 0;
dataIndex = 0;
//the begin
for (i = numberQuadruple - 1; i > 0; i--) {
b1 = base64Alphabet[base64Data[dataIndex++]];
b2 = base64Alphabet[base64Data[dataIndex++]];
b3 = base64Alphabet[base64Data[dataIndex++]];
b4 = base64Alphabet[base64Data[dataIndex++]];
if ((b1 == -1) ||
(b2 == -1) ||
(b3 == -1) ||
(b4 == -1)) {
//if found "no data" just return null
throw new Base64DecodingException("decoding.general");
}
decodedData[encodedIndex++] = (byte)(b1 << 2 | b2 >> 4) ;
decodedData[encodedIndex++] = (byte)(((b2 & 0xf) << 4) |((b3 >> 2) & 0xf));
decodedData[encodedIndex++] = (byte)(b3 << 6 | b4 );
}
return decodedData;
}
/**
* Decodes Base64 data into outputstream
*
* @param base64Data String containing Base64 data
* @param os the outputstream
* @throws IOException
* @throws Base64DecodingException
*/
public static final void decode(String base64Data, OutputStream os)
throws Base64DecodingException, IOException {
byte[] bytes = new byte[base64Data.length()];
int len = getBytesInternal(base64Data, bytes);
decode(bytes,os,len);
}
/**
* Decodes Base64 data into outputstream
*
* @param base64Data Byte array containing Base64 data
* @param os the outputstream
* @throws IOException
* @throws Base64DecodingException
*/
public static final void decode(byte[] base64Data, OutputStream os)
throws Base64DecodingException, IOException {
decode(base64Data,os,-1);
}
protected static final void decode(byte[] base64Data, OutputStream os, int len)
throws Base64DecodingException, IOException {
// remove white spaces
if (len == -1) {
len = removeWhiteSpace(base64Data);
}
if (len % FOURBYTE != 0) {
throw new Base64DecodingException("decoding.divisible.four");
//should be divisible by four
}
int numberQuadruple = (len / FOURBYTE);
if (numberQuadruple == 0) {
return;
}
//byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0;
int i = 0;
int dataIndex = 0;
//the begin
for (i=numberQuadruple - 1; i > 0; i--) {
b1 = base64Alphabet[base64Data[dataIndex++]];
b2 = base64Alphabet[base64Data[dataIndex++]];
b3 = base64Alphabet[base64Data[dataIndex++]];
b4 = base64Alphabet[base64Data[dataIndex++]];
if ((b1 == -1) ||
(b2 == -1) ||
(b3 == -1) ||
(b4 == -1) ) {
//if found "no data" just return null
throw new Base64DecodingException("decoding.general");
}
os.write((byte)(b1 << 2 | b2 >> 4));
os.write((byte)(((b2 & 0xf) << 4 ) | ((b3 >> 2) & 0xf)));
os.write( (byte)(b3 << 6 | b4));
}
b1 = base64Alphabet[base64Data[dataIndex++]];
b2 = base64Alphabet[base64Data[dataIndex++]];
// first last bits.
if ((b1 == -1) || (b2 == -1) ) {
//if found "no data" just return null
throw new Base64DecodingException("decoding.general");
}
byte d3, d4;
b3 = base64Alphabet[d3 = base64Data[dataIndex++]];
b4 = base64Alphabet[d4 = base64Data[dataIndex++]];
if ((b3 == -1 ) || (b4 == -1) ) { //Check if they are PAD characters
if (isPad(d3) && isPad(d4)) { //Two PAD e.g. 3c[Pad][Pad]
if ((b2 & 0xf) != 0) { //last 4 bits should be zero
throw new Base64DecodingException("decoding.general");
}
os.write((byte)(b1 << 2 | b2 >> 4));
} else if (!isPad(d3) && isPad(d4)) { //One PAD e.g. 3cQ[Pad]
if ((b3 & 0x3 ) != 0) { //last 2 bits should be zero
throw new Base64DecodingException("decoding.general");
}
os.write((byte)(b1 << 2 | b2 >> 4));
os.write((byte)(((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)));
} else {
//an error like "3c[Pad]r", "3cdX", "3cXd", "3cXX" where X is non data
throw new Base64DecodingException("decoding.general");
}
} else {
//No PAD e.g 3cQl
os.write((byte)(b1 << 2 | b2 >> 4));
os.write( (byte)(((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)));
os.write((byte)(b3 << 6 | b4));
}
}
/**
* Decodes Base64 data into outputstream
*
* @param is containing Base64 data
* @param os the outputstream
* @throws IOException
* @throws Base64DecodingException
*/
public static final void decode(InputStream is, OutputStream os)
throws Base64DecodingException, IOException {
//byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0;
int index=0;
byte[] data = new byte[4];
int read;
//the begin
while ((read = is.read()) > 0) {
byte readed = (byte)read;
if (isWhiteSpace(readed)) {
continue;
}
if (isPad(readed)) {
data[index++] = readed;
if (index == 3) {
data[index++] = (byte)is.read();
}
break;
}
if ((data[index++] = readed) == -1) {
//if found "no data" just return null
throw new Base64DecodingException("decoding.general");
}
if (index != 4) {
continue;
}
index = 0;
b1 = base64Alphabet[data[0]];
b2 = base64Alphabet[data[1]];
b3 = base64Alphabet[data[2]];
b4 = base64Alphabet[data[3]];
os.write((byte)(b1 << 2 | b2 >> 4));
os.write((byte)(((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)));
os.write((byte)(b3 << 6 | b4));
}
byte d1 = data[0], d2 = data[1], d3 = data[2], d4 = data[3];
b1 = base64Alphabet[d1];
b2 = base64Alphabet[d2];
b3 = base64Alphabet[d3];
b4 = base64Alphabet[d4];
if ((b3 == -1) || (b4 == -1)) { //Check if they are PAD characters
if (isPad(d3) && isPad(d4)) { //Two PAD e.g. 3c[Pad][Pad]
if ((b2 & 0xf) != 0) { //last 4 bits should be zero
throw new Base64DecodingException("decoding.general");
}
os.write((byte)(b1 << 2 | b2 >> 4));
} else if (!isPad(d3) && isPad(d4)) { //One PAD e.g. 3cQ[Pad]
b3 = base64Alphabet[d3];
if ((b3 & 0x3) != 0) { //last 2 bits should be zero
throw new Base64DecodingException("decoding.general");
}
os.write((byte)(b1 << 2 | b2 >> 4));
os.write((byte)(((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)));
} else {
//an error like "3c[Pad]r", "3cdX", "3cXd", "3cXX" where X is non data
throw new Base64DecodingException("decoding.general");
}
} else {
//No PAD e.g 3cQl
os.write((byte)(b1 << 2 | b2 >> 4));
os.write((byte)(((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf)));
os.write((byte)(b3 << 6 | b4));
}
}
/**
* remove WhiteSpace from MIME containing encoded Base64 data.
*
* @param data the byte array of base64 data (with WS)
* @return the new length
*/
protected static final int removeWhiteSpace(byte[] data) {
if (data == null) {
return 0;
}
// count characters that's not whitespace
int newSize = 0;
int len = data.length;
for (int i = 0; i < len; i++) {
byte dataS = data[i];
if (!isWhiteSpace(dataS)) {
data[newSize++] = dataS;
}
}
return newSize;
}
}
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