Description
Encodes a byte array into Base64 notation.
License
Apache License
Parameter
| Parameter | Description |
|---|
| source | The data to convert |
Exception
| Parameter | Description |
|---|
| NullPointerException | if source array is null |
Return
The data in Base64-encoded form
Declaration
public static String encode(byte[] source)
Method Source Code
//package com.java2s;
/*// ww w . ja va 2 s . c om
*
* Copyright 2014 Roland Huss
*
* Licensed 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.
*/
public class Main {
/** The 64 valid Base64 values. */
/* Host platform me be something funny like EBCDIC, so we hardcode these values. */
private final static byte[] ALPHABET = { (byte) 'A', (byte) 'B', (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F',
(byte) 'G', (byte) 'H', (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N',
(byte) 'O', (byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T', (byte) 'U', (byte) 'V',
(byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z', (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd',
(byte) 'e', (byte) 'f', (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l',
(byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r', (byte) 's', (byte) 't',
(byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x', (byte) 'y', (byte) 'z', (byte) '0', (byte) '1',
(byte) '2', (byte) '3', (byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
(byte) '+', (byte) '/' };
private static final byte EQUALS_SIGN = (byte) '=';
/**
* Encodes a byte array into Base64 notation.
* Does not GZip-compress data.
*
* @param source The data to convert
* @return The data in Base64-encoded form
* @throws NullPointerException if source array is null
* @since 1.4
*/
public static String encode(byte[] source) {
byte[] encoded = encodeBytesToBytes(source, source.length);
try {
return new String(encoded, "US-ASCII");
} catch (java.io.UnsupportedEncodingException uue) {
return new String(encoded);
}
}
public static byte[] encodeBytesToBytes(byte[] source, int len) {
int encLen = (len / 3) * 4 + (len % 3 > 0 ? 4 : 0); // Bytes needed for actual encoding
byte[] outBuff = new byte[encLen];
int d = 0;
int e = 0;
int len2 = len - 2;
for (; d < len2; d += 3, e += 4) {
encode3to4(source, d, 3, outBuff, e);
}
if (d < len) {
encode3to4(source, d, len - d, outBuff, e);
e += 4;
}
// Only resize array if we didn't guess it right.
if (e <= outBuff.length - 1) {
byte[] finalOut = new byte[e];
System.arraycopy(outBuff, 0, finalOut, 0, e);
return finalOut;
} else {
return outBuff;
}
}
private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination,
int destOffset) {
// 1 2 3
// 01234567890123456789012345678901 Bit position
// --------000000001111111122222222 Array position from threeBytes
// --------| || || || | Six bit groups to index ALPHABET
// >>18 >>12 >> 6 >> 0 Right shift necessary
// 0x3f 0x3f 0x3f Additional AND
// Create buffer with zero-padding if there are only one or two
// significant bytes passed in the array.
// We have to shift left 24 in order to flush out the 1's that appear
// when Java treats a value as negative that is cast from a byte to an int.
int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
| (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
| (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);
switch (numSigBytes) {
case 3:
destination[destOffset] = ALPHABET[(inBuff >>> 18)];
destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
return destination;
case 2:
destination[destOffset] = ALPHABET[(inBuff >>> 18)];
destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
destination[destOffset + 3] = EQUALS_SIGN;
return destination;
case 1:
destination[destOffset] = ALPHABET[(inBuff >>> 18)];
destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
destination[destOffset + 2] = EQUALS_SIGN;
destination[destOffset + 3] = EQUALS_SIGN;
return destination;
default:
return destination;
} // end switch
}
}
Related
- encode(byte[] data)
- encode(byte[] in, int len)
- encode(byte[] input)
- encode(byte[] message)
- encode(byte[] rawData)
- encode(String prefix, byte[] buf, ZipOutputStream zos, File[] files)
- encodeAsUtf8(byte[] bytes)
- encodeBitString(byte[] in, OutputStream os)
- encodeByteArray(DataOutputStream out, byte[] bytes)