at.chrl.nutils.Base64 Maven / Gradle / Ivy
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package at.chrl.nutils;
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.
*
* 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
* sun.misc.Encoder()/Decoder().
*
*
* 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 String this version is about three times
* as fast due to the fact that the Commons Codec result has to be recoded to a
* String from byte[], which is very expensive.
*
*
* 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 sun.misc.Encoder()/Decoder() produce temporary arrays but
* since performance is quite low it probably does.
*
*
* 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.
* Commons codec seem to always att a trailing line separator.
*
*
* Note! The encode/decode method pairs (types) come in three versions
* with the exact 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.
*
*
* 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.
*
*
* If you find the code useful or you find a bug, please send me a note at
* base64 @ miginfocom . com.
*
* Licence (BSD): ==============
*
* Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com)
* All rights reserved.
*
* 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.
*
* 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 char[] representation
* i accordance with RFC 2045.
*
* @param sArr
* The bytes to convert. If null or length 0 an
* empty array will be returned.
* @param lineSep
* Optional "\r\n" after 76 characters, unless end of file.
* 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 null.
*/
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. null or length 0 will return an
* empty array.
* @return The decoded array of bytes. May be of length 0. Will be
* null 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:
* + The array must have a line length of 76 chars OR no line separators at
* all (one line).
* + Line separator must be "\r\n", as specified in RFC 2045 + The array
* must not contain illegal characters within the encoded string
* + The array CAN have illegal characters at the beginning and end, those
* will be dealt with appropriately.
*
* @param sArr
* The source array. Length 0 will return an empty array.
* null 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 byte[] representation
* i accordance with RFC 2045.
*
* @param sArr
* The bytes to convert. If null or length 0 an
* empty array will be returned.
* @param lineSep
* Optional "\r\n" after 76 characters, unless end of file.
* 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 null.
*/
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.
* null will throw an exception.
* @return The decoded array of bytes. May be of length 0. Will be
* null 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:
* + The array must have a line length of 76 chars OR no line separators at
* all (one line).
* + Line separator must be "\r\n", as specified in RFC 2045 + The array
* must not contain illegal characters within the encoded string
* + The array CAN have illegal characters at the beginning and end, those
* will be dealt with appropriately.
*
* @param sArr
* The source array. Length 0 will return an empty array.
* null 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 String representation
* i accordance with RFC 2045.
*
* @param sArr
* The bytes to convert. If null or length 0 an
* empty array will be returned.
* @param lineSep
* Optional "\r\n" after 76 characters, unless end of file.
* 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 null.
*/
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 String. All illegal characters will
* be ignored and can handle both strings with and without line separators.
* Note! It can be up to about 2x the speed to call
* decode(str.toCharArray()) instead. That will create a
* temporary array though. This version will use str.charAt(i)
* to iterate the string.
*
* @param str
* The source string. null or length 0 will return
* an empty array.
* @return The decoded array of bytes. May be of length 0. Will be
* null 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:
* + The array must have a line length of 76 chars OR no line separators at
* all (one line).
* + Line separator must be "\r\n", as specified in RFC 2045 + The array
* must not contain illegal characters within the encoded string
* + The array CAN have illegal characters at the beginning and end, those
* will be dealt with appropriately.
*
* @param s
* The source string. Length 0 will return an empty array.
* null 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;
}
}