A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance with RFC 2045.
/*
* This file is part of aion-emu <aion-emu.com>.
*
* aion-emu is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* aion-emu is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with aion-emu. If not, see <http://www.gnu.org/licenses/>.
*/
//package com.aionemu.commons.utils;
import java.util.Arrays;
/**
* A very fast and memory efficient class to encode and decode to and from BASE64 in full accordance with RFC 2045.<br>
* <br>
* On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is about 10 times faster on small arrays (10 -
* 1000 bytes) and 2-3 times as fast on larger arrays (10000 - 1000000 bytes) compared to
* <code>sun.misc.Encoder()/Decoder()</code>.<br>
* <br>
* <p/>
* On byte arrays the encoder is about 20% faster than Jakarta Commons Base64 Codec for encode and about 50% faster for
* decoding large arrays. This implementation is about twice as fast on very small arrays (< 30 bytes). If
* source/destination is a <code>String</code> this version is about three times as fast due to the fact that the
* Commons Codec result has to be recoded to a <code>String</code> from <code>byte[]</code>, which is very expensive.<br>
* <br>
* <p/>
* This encode/decode algorithm doesn't create any temporary arrays as many other codecs do, it only allocates the
* resulting array. This produces less garbage and it is possible to handle arrays twice as large as algorithms that
* create a temporary array. (E.g. Jakarta Commons Codec). It is unknown whether Sun's
* <code>sun.misc.Encoder()/Decoder()</code> produce temporary arrays but since performance is quite low it probably
* does.<br>
* <br>
* <p/>
* The encoder produces the same output as the Sun one except that the Sun's encoder appends a trailing line separator
* if the last character isn't a pad. Unclear why but it only adds to the length and is probably a side effect. Both are
* in conformance with RFC 2045 though.<br>
* Commons codec seem to always att a trailing line separator.<br>
* <br>
* <p/>
* <b>Note!</b> The encode/decode method pairs (types) come in three versions with the <b>exact</b> same algorithm and
* thus a lot of code redundancy. This is to not create any temporary arrays for transcoding to/from different format
* types. The methods not used can simply be commented out.<br>
* <br>
* <p/>
* There is also a "fast" version of all decode methods that works the same way as the normal ones, but har a few
* demands on the decoded input. Normally though, these fast verions should be used if the source if the input is known
* and it hasn't bee tampered with.<br>
* <br>
* <p/>
* If you find the code useful or you find a bug, please send me a note at base64 @ miginfocom . com.
* <p/>
* Licence (BSD):
* <p/>
* Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com) All rights reserved.
* <p/>
* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
* following conditions are met: Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation and/or other materials provided with the
* distribution. Neither the name of the MiG InfoCom AB nor the names of its contributors may be used to endorse or
* promote products derived from this software without specific prior written permission.
* <p/>
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @author Mikael Grev Date: 2004-aug-02 Time: 11:31:11
* @version 2.2
*/
public class Base64
{
private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
private static final int[] IA = new int[256];
static
{
Arrays.fill(IA, -1);
for (int i = 0, iS = CA.length; i < iS; i++)
IA[CA[i]] = i;
IA['='] = 0;
}
// ****************************************************************************************
// * char[] version
// ****************************************************************************************
/**
* Encodes a raw byte array into a BASE64 <code>char[]</code> representation i accordance with RFC 2045.
*
* @param sArr
* The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
* @param lineSep
* Optional "\r\n" after 76 characters, unless end of file.<br>
* No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a little
* faster.
* @return A BASE64 encoded array. Never <code>null</code>.
*/
public static char[] encodeToChar(byte[] sArr, boolean lineSep)
{
// Check special case
int sLen = sArr != null ? sArr.length : 0;
if (sLen == 0)
return new char[0];
int eLen = (sLen / 3) * 3; // Length of even 24-bits.
int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count
int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array
char[] dArr = new char[dLen];
// Encode even 24-bits
for (int s = 0, d = 0, cc = 0; s < eLen;)
{
// Copy next three bytes into lower 24 bits of int, paying attension to sign.
int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (sArr[s++] & 0xff);
// Encode the int into four chars
dArr[d++] = CA[(i >>> 18) & 0x3f];
dArr[d++] = CA[(i >>> 12) & 0x3f];
dArr[d++] = CA[(i >>> 6) & 0x3f];
dArr[d++] = CA[i & 0x3f];
// Add optional line separator
if (lineSep && ++cc == 19 && d < dLen - 2)
{
dArr[d++] = '\r';
dArr[d++] = '\n';
cc = 0;
}
}
// Pad and encode last bits if source isn't even 24 bits.
int left = sLen - eLen; // 0 - 2.
if (left > 0)
{
// Prepare the int
int i = ((sArr[eLen] & 0xff) << 10) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
// Set last four chars
dArr[dLen - 4] = CA[i >> 12];
dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];
dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';
dArr[dLen - 1] = '=';
}
return dArr;
}
/**
* Decodes a BASE64 encoded char array. All illegal characters will be ignored and can handle both arrays with and
* without line separators.
*
* @param sArr
* The source array. <code>null</code> or length 0 will return an empty array.
* @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
* (including '=') isn't divideable by 4. (I.e. definitely corrupted).
*/
public static byte[] decode(char[] sArr)
{
// Check special case
int sLen = sArr != null ? sArr.length : 0;
if (sLen == 0)
return new byte[0];
// Count illegal characters (including '\r', '\n') to know what size the returned array will be,
// so we don't have to reallocate & copy it later.
int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
for (int i = 0; i < sLen; i++)
// If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
if (IA[sArr[i]] < 0)
sepCnt++;
// Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
if ((sLen - sepCnt) % 4 != 0)
return null;
int pad = 0;
for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0;)
if (sArr[i] == '=')
pad++;
int len = ((sLen - sepCnt) * 6 >> 3) - pad;
byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
for (int s = 0, d = 0; d < len;)
{
// Assemble three bytes into an int from four "valid" characters.
int i = 0;
for (int j = 0; j < 4; j++)
{ // j only increased if a valid char was found.
int c = IA[sArr[s++]];
if (c >= 0)
i |= c << (18 - j * 6);
else
j--;
}
// Add the bytes
dArr[d++] = (byte) (i >> 16);
if (d < len)
{
dArr[d++] = (byte) (i >> 8);
if (d < len)
dArr[d++] = (byte) i;
}
}
return dArr;
}
/**
* Decodes a BASE64 encoded char array that is known to be resonably well formatted. The method is about twice as
* fast as {@link #decode(char[])}. The preconditions are:<br>
* + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
* + Line separator must be "\r\n", as specified in RFC 2045 + The array must not contain illegal characters within
* the encoded string<br>
* + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
*
* @param sArr
* The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
* @return The decoded array of bytes. May be of length 0.
*/
public static byte[] decodeFast(char[] sArr)
{
// Check special case
int sLen = sArr.length;
if (sLen == 0)
return new byte[0];
int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
// Trim illegal chars from start
while (sIx < eIx && IA[sArr[sIx]] < 0)
sIx++;
// Trim illegal chars from end
while (eIx > 0 && IA[sArr[eIx]] < 0)
eIx--;
// get the padding count (=) (0, 1 or 2)
int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count '=' at end.
int cCnt = eIx - sIx + 1; // Content count including possible separators
int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;
int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
// Decode all but the last 0 - 2 bytes.
int d = 0;
for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)
{
// Assemble three bytes into an int from four "valid" characters.
int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
// Add the bytes
dArr[d++] = (byte) (i >> 16);
dArr[d++] = (byte) (i >> 8);
dArr[d++] = (byte) i;
// If line separator, jump over it.
if (sepCnt > 0 && ++cc == 19)
{
sIx += 2;
cc = 0;
}
}
if (d < len)
{
// Decode last 1-3 bytes (incl '=') into 1-3 bytes
int i = 0;
for (int j = 0; sIx <= eIx - pad; j++)
i |= IA[sArr[sIx++]] << (18 - j * 6);
for (int r = 16; d < len; r -= 8)
dArr[d++] = (byte) (i >> r);
}
return dArr;
}
// ****************************************************************************************
// * byte[] version
// ****************************************************************************************
/**
* Encodes a raw byte array into a BASE64 <code>byte[]</code> representation i accordance with RFC 2045.
*
* @param sArr
* The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
* @param lineSep
* Optional "\r\n" after 76 characters, unless end of file.<br>
* No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a little
* faster.
* @return A BASE64 encoded array. Never <code>null</code>.
*/
public static byte[] encodeToByte(byte[] sArr, boolean lineSep)
{
// Check special case
int sLen = sArr != null ? sArr.length : 0;
if (sLen == 0)
return new byte[0];
int eLen = (sLen / 3) * 3; // Length of even 24-bits.
int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count
int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of returned array
byte[] dArr = new byte[dLen];
// Encode even 24-bits
for (int s = 0, d = 0, cc = 0; s < eLen;)
{
// Copy next three bytes into lower 24 bits of int, paying attension to sign.
int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8 | (sArr[s++] & 0xff);
// Encode the int into four chars
dArr[d++] = (byte) CA[(i >>> 18) & 0x3f];
dArr[d++] = (byte) CA[(i >>> 12) & 0x3f];
dArr[d++] = (byte) CA[(i >>> 6) & 0x3f];
dArr[d++] = (byte) CA[i & 0x3f];
// Add optional line separator
if (lineSep && ++cc == 19 && d < dLen - 2)
{
dArr[d++] = '\r';
dArr[d++] = '\n';
cc = 0;
}
}
// Pad and encode last bits if source isn't an even 24 bits.
int left = sLen - eLen; // 0 - 2.
if (left > 0)
{
// Prepare the int
int i = ((sArr[eLen] & 0xff) << 10) | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);
// Set last four chars
dArr[dLen - 4] = (byte) CA[i >> 12];
dArr[dLen - 3] = (byte) CA[(i >>> 6) & 0x3f];
dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f] : (byte) '=';
dArr[dLen - 1] = '=';
}
return dArr;
}
/**
* Decodes a BASE64 encoded byte array. All illegal characters will be ignored and can handle both arrays with and
* without line separators.
*
* @param sArr
* The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
* @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
* (including '=') isn't divideable by 4. (I.e. definitely corrupted).
*/
public static byte[] decode(byte[] sArr)
{
// Check special case
int sLen = sArr.length;
// Count illegal characters (including '\r', '\n') to know what size the returned array will be,
// so we don't have to reallocate & copy it later.
int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
for (int i = 0; i < sLen; i++)
// If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
if (IA[sArr[i] & 0xff] < 0)
sepCnt++;
// Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
if ((sLen - sepCnt) % 4 != 0)
return null;
int pad = 0;
for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0;)
if (sArr[i] == '=')
pad++;
int len = ((sLen - sepCnt) * 6 >> 3) - pad;
byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
for (int s = 0, d = 0; d < len;)
{
// Assemble three bytes into an int from four "valid" characters.
int i = 0;
for (int j = 0; j < 4; j++)
{ // j only increased if a valid char was found.
int c = IA[sArr[s++] & 0xff];
if (c >= 0)
i |= c << (18 - j * 6);
else
j--;
}
// Add the bytes
dArr[d++] = (byte) (i >> 16);
if (d < len)
{
dArr[d++] = (byte) (i >> 8);
if (d < len)
dArr[d++] = (byte) i;
}
}
return dArr;
}
/**
* Decodes a BASE64 encoded byte array that is known to be resonably well formatted. The method is about twice as
* fast as {@link #decode(byte[])}. The preconditions are:<br>
* + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
* + Line separator must be "\r\n", as specified in RFC 2045 + The array must not contain illegal characters within
* the encoded string<br>
* + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
*
* @param sArr
* The source array. Length 0 will return an empty array. <code>null</code> will throw an exception.
* @return The decoded array of bytes. May be of length 0.
*/
public static byte[] decodeFast(byte[] sArr)
{
// Check special case
int sLen = sArr.length;
if (sLen == 0)
return new byte[0];
int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
// Trim illegal chars from start
while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0)
sIx++;
// Trim illegal chars from end
while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0)
eIx--;
// get the padding count (=) (0, 1 or 2)
int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count '=' at end.
int cCnt = eIx - sIx + 1; // Content count including possible separators
int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;
int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
// Decode all but the last 0 - 2 bytes.
int d = 0;
for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)
{
// Assemble three bytes into an int from four "valid" characters.
int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];
// Add the bytes
dArr[d++] = (byte) (i >> 16);
dArr[d++] = (byte) (i >> 8);
dArr[d++] = (byte) i;
// If line separator, jump over it.
if (sepCnt > 0 && ++cc == 19)
{
sIx += 2;
cc = 0;
}
}
if (d < len)
{
// Decode last 1-3 bytes (incl '=') into 1-3 bytes
int i = 0;
for (int j = 0; sIx <= eIx - pad; j++)
i |= IA[sArr[sIx++]] << (18 - j * 6);
for (int r = 16; d < len; r -= 8)
dArr[d++] = (byte) (i >> r);
}
return dArr;
}
// ****************************************************************************************
// * String version
// ****************************************************************************************
/**
* Encodes a raw byte array into a BASE64 <code>String</code> representation i accordance with RFC 2045.
*
* @param sArr
* The bytes to convert. If <code>null</code> or length 0 an empty array will be returned.
* @param lineSep
* Optional "\r\n" after 76 characters, unless end of file.<br>
* No line separator will be in breach of RFC 2045 which specifies max 76 per line but will be a little
* faster.
* @return A BASE64 encoded array. Never <code>null</code>.
*/
public static String encodeToString(byte[] sArr, boolean lineSep)
{
// Reuse char[] since we can't create a String incrementally anyway and StringBuffer/Builder would be slower.
return new String(encodeToChar(sArr, lineSep));
}
/**
* Decodes a BASE64 encoded <code>String</code>. All illegal characters will be ignored and can handle both strings
* with and without line separators.<br>
* <b>Note!</b> It can be up to about 2x the speed to call <code>decode(str.toCharArray())</code> instead. That will
* create a temporary array though. This version will use <code>str.charAt(i)</code> to iterate the string.
*
* @param str
* The source string. <code>null</code> or length 0 will return an empty array.
* @return The decoded array of bytes. May be of length 0. Will be <code>null</code> if the legal characters
* (including '=') isn't divideable by 4. (I.e. definitely corrupted).
*/
public static byte[] decode(String str)
{
// Check special case
int sLen = str != null ? str.length() : 0;
if (sLen == 0)
return new byte[0];
// Count illegal characters (including '\r', '\n') to know what size the returned array will be,
// so we don't have to reallocate & copy it later.
int sepCnt = 0; // Number of separator characters. (Actually illegal characters, but that's a bonus...)
for (int i = 0; i < sLen; i++)
// If input is "pure" (I.e. no line separators or illegal chars) base64 this loop can be commented out.
if (IA[str.charAt(i)] < 0)
sepCnt++;
// Check so that legal chars (including '=') are evenly divideable by 4 as specified in RFC 2045.
if ((sLen - sepCnt) % 4 != 0)
return null;
// Count '=' at end
int pad = 0;
for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0;)
if (str.charAt(i) == '=')
pad++;
int len = ((sLen - sepCnt) * 6 >> 3) - pad;
byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
for (int s = 0, d = 0; d < len;)
{
// Assemble three bytes into an int from four "valid" characters.
int i = 0;
for (int j = 0; j < 4; j++)
{ // j only increased if a valid char was found.
int c = IA[str.charAt(s++)];
if (c >= 0)
i |= c << (18 - j * 6);
else
j--;
}
// Add the bytes
dArr[d++] = (byte) (i >> 16);
if (d < len)
{
dArr[d++] = (byte) (i >> 8);
if (d < len)
dArr[d++] = (byte) i;
}
}
return dArr;
}
/**
* Decodes a BASE64 encoded string that is known to be resonably well formatted. The method is about twice as fast
* as {@link #decode(String)}. The preconditions are:<br>
* + The array must have a line length of 76 chars OR no line separators at all (one line).<br>
* + Line separator must be "\r\n", as specified in RFC 2045 + The array must not contain illegal characters within
* the encoded string<br>
* + The array CAN have illegal characters at the beginning and end, those will be dealt with appropriately.<br>
*
* @param s
* The source string. Length 0 will return an empty array. <code>null</code> will throw an exception.
* @return The decoded array of bytes. May be of length 0.
*/
public static byte[] decodeFast(String s)
{
// Check special case
int sLen = s.length();
if (sLen == 0)
return new byte[0];
int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.
// Trim illegal chars from start
while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)
sIx++;
// Trim illegal chars from end
while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)
eIx--;
// get the padding count (=) (0, 1 or 2)
int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count '=' at end.
int cCnt = eIx - sIx + 1; // Content count including possible separators
int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1 : 0;
int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded bytes
byte[] dArr = new byte[len]; // Preallocate byte[] of exact length
// Decode all but the last 0 - 2 bytes.
int d = 0;
for (int cc = 0, eLen = (len / 3) * 3; d < eLen;)
{
// Assemble three bytes into an int from four "valid" characters.
int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12 | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];
// Add the bytes
dArr[d++] = (byte) (i >> 16);
dArr[d++] = (byte) (i >> 8);
dArr[d++] = (byte) i;
// If line separator, jump over it.
if (sepCnt > 0 && ++cc == 19)
{
sIx += 2;
cc = 0;
}
}
if (d < len)
{
// Decode last 1-3 bytes (incl '=') into 1-3 bytes
int i = 0;
for (int j = 0; sIx <= eIx - pad; j++)
i |= IA[s.charAt(sIx++)] << (18 - j * 6);
for (int r = 16; d < len; r -= 8)
dArr[d++] = (byte) (i >> r);
}
return dArr;
}
}
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