ee.sk.digidoc.Base64Util Maven / Gradle / Ivy
package ee.sk.digidoc;
import java.io.OutputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.StringTokenizer;
import org.apache.log4j.Logger;
//import ee.sk.xmlenc.EncryptedData;
//import javax.swing.filechooser.FileFilter;
/**
* Base64 utility methods.
* Based on an implementation by Apache,
* but changed to suit the needs of this
* project.
*/
public class Base64Util {
/** log4j logger */
private static Logger m_logger = Logger.getLogger(Base64Util.class);;
public static final int BASE64DEFAULTLENGTH = 64;
public static final String LINE_SEPARATOR = "\n";
static String chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/**
* Encode a byte array and fold lines at the standard 76th character.
*
* @param raw byte[] to be base64 encoded
* @return the String with encoded data
*/
public static String encode(byte[] raw) {
return encode(raw, Base64Util.BASE64DEFAULTLENGTH);
}
/**
* Encode a byte array in Base64 format and return an optionally
* wrapped line
*
* @param raw byte[] data to be encoded
* @param wrap int length of wrapped lines; No wrapping if less than 4.
* @return a String with encoded data
*/
public static String encode(byte[] raw, int wrap) {
if(raw == null) return null;
//calculate length of encoded string
int encLen = ((raw.length + 2) / 3) * 4;
//adjust for newlines
if (wrap > 3) {
wrap -= wrap % 4;
encLen += 2 * (encLen / wrap);
} else { //disable wrapping
wrap = Integer.MAX_VALUE;
}
StringBuffer encoded = new StringBuffer(encLen);
int len3 = (raw.length / 3) * 3;
int outLen = 0; //length of output line
for (int i = 0; i < len3; i += 3, outLen += 4) {
if (outLen + 4 > wrap) {
encoded.append(LINE_SEPARATOR);
outLen = 0;
}
encoded.append(encodeFullBlock(raw, i));
}
if (outLen >= wrap) { //this will produce an extra newline if needed !? Sun had it this way...
encoded.append(LINE_SEPARATOR);
}
if (len3 < raw.length) {
encoded.append(encodeBlock(raw, raw.length, len3));
}
return encoded.toString();
}
/**
* Encodes a byte array in Base64 format and writes to
* StringBuffer object. For regular blocks writes only full
* lines and leaves the rest unused. Caller should check
* how many bytes were actually enocded and return the rest
* at the beginning of the next block
*
* @param raw byte[] data to be encoded
* @param rawLen number of bytes used in raw
* @param sb output buffer
* @param bLastBlock true if this is the last block to write
* @return number of raw bytes encoded and written to output stream. Thus
*
*/
public static int encodeToBlock(byte[] raw, int rawLen, StringBuffer sb, boolean bLastBlock)
throws IOException
{
int wrap = Base64Util.BASE64DEFAULTLENGTH, outLen = 0;
int len3 = (rawLen / 3) * 3;
int nBytesPerLine = (wrap / 4) * 3;
int nUsedBytes = 0, nTotal = 0;
//if(m_logger.isDebugEnabled())
// m_logger.debug("Encoding: " + raw.length + " bytes, last-block: " + bLastBlock);
if(!bLastBlock) {
nUsedBytes = (rawLen / nBytesPerLine) * nBytesPerLine;
for (int i = 0; i < nUsedBytes; i += 3, outLen += 4) {
if (outLen + 4 > wrap) {
sb.append(LINE_SEPARATOR);
nTotal++;
outLen = 0;
}
char[] encdata = encodeFullBlock(raw, i);
nTotal += encdata.length;
sb.append(encdata);
}
if (outLen >= wrap) { //this will produce an extra newline if needed !? Sun had it this way...
sb.append(LINE_SEPARATOR);
nTotal++;
}
}
else {
nUsedBytes = rawLen;
for (int i = 0; i < len3; i += 3, outLen += 4) {
if (outLen + 4 > wrap) {
sb.append(LINE_SEPARATOR);
outLen = 0;
nTotal++;
}
char[] encdata = encodeFullBlock(raw, i);
nTotal += encdata.length;
sb.append(encdata);
}
if (outLen >= wrap) { //this will produce an extra newline if needed !? Sun had it this way...
sb.append(LINE_SEPARATOR);
nTotal++;
}
if (len3 < rawLen) {
char[] encdata = encodeBlock(raw, rawLen, len3);
nTotal += encdata.length;
sb.append(encdata);
}
}
if(m_logger.isDebugEnabled())
m_logger.debug("Input: " + rawLen + " used: " + nUsedBytes + " last: " + bLastBlock + " wrote: " + nTotal);
return nUsedBytes;
}
/**
* Encodes a byte array in Base64 format and writes to
* output stream. For regular blocks writes only full
* lines and leaves the rest unused. Caller should check
* how many bytes wre actually enocded and return the rest
* at the beginning of the next block
*
* @param raw byte[] data to be encoded
* @param outs output stream
* @param bLastBlock true if this is the last block to write
* @return number of raw bytes encoded and written to output stream. Thus
*
*/
public static int encodeToStream(byte[] raw, OutputStream outs, boolean bLastBlock)
throws IOException
{
int wrap = Base64Util.BASE64DEFAULTLENGTH, outLen = 0;
int len3 = (raw.length / 3) * 3;
int nBytesPerLine = (wrap / 4) * 3;
int nUsedBytes = 0, nTotal = 0;
//if(m_logger.isDebugEnabled())
// m_logger.debug("Encoding: " + raw.length + " bytes, last-block: " + bLastBlock);
if(!bLastBlock) {
nUsedBytes = (raw.length / nBytesPerLine) * nBytesPerLine;
for (int i = 0; i < nUsedBytes; i += 3, outLen += 4) {
if (outLen + 4 > wrap) {
outs.write(LINE_SEPARATOR.getBytes());
nTotal++;
outLen = 0;
}
char[] encdata = encodeFullBlock(raw, i);
nTotal += encdata.length;
outs.write(new String(encdata).getBytes());
}
if (outLen >= wrap) { //this will produce an extra newline if needed !? Sun had it this way...
outs.write(LINE_SEPARATOR.getBytes());
nTotal++;
}
}
else {
nUsedBytes = raw.length;
for (int i = 0; i < len3; i += 3, outLen += 4) {
if (outLen + 4 > wrap) {
outs.write(LINE_SEPARATOR.getBytes());
outLen = 0;
nTotal++;
}
char[] encdata = encodeFullBlock(raw, i);
nTotal += encdata.length;
outs.write(new String(encdata).getBytes());
}
if (outLen >= wrap) { //this will produce an extra newline if needed !? Sun had it this way...
outs.write(LINE_SEPARATOR.getBytes());
nTotal++;
}
if (len3 < raw.length) {
char[] encdata = encodeBlock(raw, raw.length, len3);
nTotal += encdata.length;
outs.write(new String(encdata).getBytes());
}
}
if(m_logger.isDebugEnabled())
m_logger.debug("Encoded: " + raw.length + " last: " + bLastBlock + " wrote: " + nTotal);
return nUsedBytes;
}
/**
* Method encodeBlock
*
* @param raw
* @param offset
* @return
*/
protected static char[] encodeBlock(byte[] raw, int rawLen, int offset) {
int block = 0;
int slack = rawLen - offset - 1;
if(m_logger.isDebugEnabled())
m_logger.debug("raw: " + rawLen + " offset " + offset + " slack: " + slack);
int end = (slack >= 2) ? 2 : slack;
for (int i = 0; i < 3; i++) {
byte b = (offset + i < rawLen) ? raw[offset + i] : 0;
int neuter = (b < 0) ? b + 256 : b;
block <<= 8;
block += neuter;
}
char[] base64 = new char[4];
for (int i = 3; i >= 0; i--) {
int sixBit = block & 0x3f;
base64[i] = getChar(sixBit);
block >>= 6;
}
if (slack < 1)
base64[2] = '=';
if (slack < 2)
base64[3] = '=';
return base64;
}
/**
* Method encodeFullBlock
*
* @param raw
* @param offset
* @return
*/
protected static char[] encodeFullBlock(byte[] raw, int offset) {
int block = 0;
for (int i = 0; i < 3; i++) {
block <<= 8;
block += (0xff & raw[offset + i]);
}
block = ((raw[offset] & 0xff) << 16) + ((raw[offset + 1] & 0xff) << 8)
+ (raw[offset + 2] & 0xff);
char[] base64 = new char[4];
for (int i = 3; i >= 0; i--) {
int sixBit = block & 0x3f;
base64[i] = getChar(sixBit);
block >>= 6;
}
return base64;
}
/**
* Method getChar
*
* @param sixBit
* @return
*/
protected static char getChar(int sixBit) {
if ((sixBit >= 0) && (sixBit < 26))
return (char) ('A' + sixBit);
if ((sixBit >= 26) && (sixBit < 52))
return (char) ('a' + (sixBit - 26));
if ((sixBit >= 52) && (sixBit < 62))
return (char) ('0' + (sixBit - 52));
if (sixBit == 62)
return '+';
if (sixBit == 63)
return '/';
return '?';
}
/**
* Decodes base64 block and ignores all whitespace.
* @param base64 base64 input data
* @return decoded data
*/
public static byte[] decode(byte[] base64) {
// try to allocate mem in one step to avoid fragmentation
ByteArrayOutputStream bos = new ByteArrayOutputStream(base64.length / 4 * 3);
char[] four = new char[4];
int i = 0, j, aux;
do {
j = 0;
while(j < 4 && i < base64.length) {
char c = (char)base64[i];
// ignore whitespace and padding
if(c != ' ' && c != '\t' && c != '\n' && c != '=' && c != '\r') {
four[j] = c;
j++;
}
i++;
}
if(j > 0) {
aux = 0;
for(int k = 0; k < j; k++)
aux = aux | (chars.indexOf(four[k]) << (6 * (3 - k)));
for(int m = 0; m < j-1; m++) {
byte b = (byte)((aux >>> (8 * (2 - m))) & 0xFF);
bos.write(b);
}
}
} while(i < base64.length);
return bos.toByteArray();
/* old version
try {
return decode(new String(base64, "UTF-8"));
} catch (java.io.UnsupportedEncodingException ex) {
// should never be reached because Encoding is valid and fixed
return null;
}*/
}
/**
* Decode a Base64-encoded string to a byte array
* and writes decoded data to output stream. Returns
* the number of bytes from input data used. Caller must
* pass in the unused bytes on the next call.
*
* @param base64 String encoded string. Whitespace will
* be ignored.
* @param out output stream to write decoded data
* @param bLastBlock true if this is the last block of input data
* @return number of handled bytes from input data
*/
public static int decodeBlock(String base64, OutputStream out, boolean bLastBlock)
{
int nUsed = 0, nPos = 0, nDec = 0;
StringBuffer sbBlock = null;
do {
// collect the next 4 characters, skip whitespace
sbBlock = new StringBuffer();
while(nPos < base64.length() && sbBlock.length() < 4) {
char ch = base64.charAt(nPos);
if(ch != ' ' && ch != '\n' && ch != '\t' && ch != '\r')
sbBlock.append(ch);
nPos++;
}
// if last block then pad
while(bLastBlock && sbBlock.length() < 4)
sbBlock.append('=');
// decode if possible
if(sbBlock.length() == 4) {
//byte[] decdata = decodeWithoutWhitespace(sbBlock.toString());
int block = (getValue(sbBlock.charAt(0)) << 18)
+ (getValue(sbBlock.charAt(1)) << 12)
+ (getValue(sbBlock.charAt(2)) << 6)
+ (getValue(sbBlock.charAt(3)));
byte[] decdata = new byte[3];
for (int j = 2; j >= 0; j--) {
decdata[j] = (byte) (block & 0xff);
block >>= 8;
}
nDec += decdata.length;
try {
out.write(decdata);
} catch(IOException ex) {
}
nUsed = nPos;
}
} while(nPos < base64.length());
if(m_logger.isDebugEnabled())
m_logger.debug("Decoding: " + base64.length() + " last: " + bLastBlock + " used: " + nUsed + " decoded: " + nDec);
return nUsed;
}
/**
* Decode a Base64-encoded string to a byte array
*
* @param base64 String encoded string (single line only !!)
* @return Decoded data in a byte array
*/
public static byte[] decode(String base64) {
if (base64.length() < 30) {
//cat.debug("I was asked to decode \"" + base64 + "\"");
} else {
//cat.debug("I was asked to decode \"" + base64.substring(0, 20) + "...\"");
}
//strip whitespace from anywhere in the string. Not the most memory
//efficient solution but elegant anyway :-)
StringTokenizer tok = new StringTokenizer(base64, " \n\r\t", false);
StringBuffer buf = new StringBuffer(base64.length());
while (tok.hasMoreElements()) {
buf.append(tok.nextToken());
}
base64 = buf.toString();
int pad = 0;
for (int i = base64.length() - 1; (i > 0) && (base64.charAt(i) == '='); i--) {
pad++;
}
int length = base64.length() / 4 * 3 - pad;
byte[] raw = new byte[length];
for (int i = 0, rawIndex = 0; i < (base64.length()-3); i += 4, rawIndex += 3) {
int block = (getValue(base64.charAt(i)) << 18)
+ (getValue(base64.charAt(i + 1)) << 12)
+ (getValue(base64.charAt(i + 2)) << 6)
+ (getValue(base64.charAt(i + 3)));
for (int j = 2; j >= 0; j--) {
if (rawIndex + j < raw.length) {
raw[rawIndex + j] = (byte) (block & 0xff);
}
block >>= 8;
}
}
return raw;
}
/**
* Decode a Base64-encoded string to a byte array
* This works only if you have stripped whitespace yourself
* @param base64 String encoded string (single line only !!)
* @return Decoded data in a byte array
*/
public static byte[] decodeWithoutWhitespace(String base64) {
int pad = 0;
for (int i = base64.length() - 1; (i > 0) && (base64.charAt(i) == '='); i--) {
pad++;
}
int length = base64.length() / 4 * 3 - pad;
byte[] raw = new byte[length];
for (int i = 0, rawIndex = 0; i < base64.length(); i += 4, rawIndex += 3) {
int block = (getValue(base64.charAt(i)) << 18)
+ (getValue(base64.charAt(i + 1)) << 12)
+ (getValue(base64.charAt(i + 2)) << 6)
+ (getValue(base64.charAt(i + 3)));
for (int j = 2; j >= 0; j--) {
if (rawIndex + j < raw.length) {
raw[rawIndex + j] = (byte) (block & 0xff);
}
block >>= 8;
}
}
return raw;
}
/**
* Method getValue
*
* @param c
* @return
*/
protected static int getValue(char c) {
if ((c >= 'A') && (c <= 'Z'))
return c - 'A';
if ((c >= 'a') && (c <= 'z'))
return c - 'a' + 26;
if ((c >= '0') && (c <= '9'))
return c - '0' + 52;
if (c == '+')
return 62;
if (c == '/')
return 63;
if (c == '=')
return 0;
return -1;
}
}