Base64 - szuperkönnyű RFC 4648 base64 implementáció
Rengeteg Base64 könyvtár létezik... Ha nincsen szükséged stream-alapú feldolgozásra, akkor itt egy szupergyors és szuperkönnyű implementáció. Csupán netto 64 sor.
/*
* Lithium Utilities
*
* Copyright 2003-2014 Tibor Bősze <tibor.boesze@gmail.com>
*
* 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.
*/
package hu.lithium.utils.crypto;
/**
* Utility class for encoding/decoding Base64 strings.
*
* @author tibor.boesze@gmail.com
* @version 1.1
*/
public class Base64 {
private static final char[] alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
private static final byte[] decoder = new byte[256];
static {
for (int i = 0; i < 256; i++)
decoder[i] = -1;
for (int i = 0; i < 64; i++)
decoder[alphabet[i]] = (byte) i;
}
private Base64() {
}
public static String encodeString(String s) {
return new String(encode(s.getBytes()));
}
public static char[] encode(byte[] in) {
return encode(in, in.length);
}
public static char[] encode(byte[] in, int iLen) {
int oDataLen = (iLen * 4 + 2) / 3; // output length without padding
int oLen = ((iLen + 2) / 3) * 4; // output length including padding
char[] out = new char[oLen];
int ip = 0;
int op = 0;
while (ip < iLen) {
int i0 = in[ip++] & 0x000000ff;
int i1 = ip < iLen ? in[ip++] & 0x000000ff : 0;
int i2 = ip < iLen ? in[ip++] & 0x000000ff : 0;
int o0 = i0 >>> 2;
int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
int o3 = i2 & 0x3F;
out[op++] = alphabet[o0];
out[op++] = alphabet[o1];
out[op] = op < oDataLen ? alphabet[o2] : '=';
op++;
out[op] = op < oDataLen ? alphabet[o3] : '=';
op++;
}
return out;
}
/**
* Decodes a string from Base64 format.
*
* @param s
* a Base64 String to be decoded.
* @return A String containing the decoded data.
* @throws IllegalArgumentException
* if the input is not valid Base64 encoded data.
*/
public static String decodeString(String s) {
return new String(decode(s));
}
/**
* Decodes a byte array from Base64 format.
*
* @param s
* a Base64 String to be decoded.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException
* if the input is not valid Base64 encoded data.
*/
public static byte[] decode(String s) {
return decode(s.toCharArray());
}
/**
* Decodes a byte array from Base64 format. No blanks or line breaks are
* allowed within the Base64 encoded data.
*
* @param in
* a character array containing the Base64 encoded data.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException
* if the input is not valid Base64 encoded data.
*/
public static byte[] decode(char[] in) {
int iLen = in.length;
if (iLen % 4 != 0)
throw new IllegalArgumentException("Length of Base64 encoded input string is not a multiple of 4.");
while (iLen > 0 && in[iLen - 1] == '=')
iLen--;
int oLen = (iLen * 3) / 4;
byte[] out = new byte[oLen];
int ip = 0;
int op = 0;
while (ip < iLen) {
int i0 = in[ip++] & 0x000000ff;
int i1 = in[ip++] & 0x000000ff;
int i2 = ip < iLen ? in[ip++] & 0x000000ff : 'A';
int i3 = ip < iLen ? in[ip++] & 0x000000ff : 'A';
int b0 = decoder[i0];
int b1 = decoder[i1];
int b2 = decoder[i2];
int b3 = decoder[i3];
if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
throw new IllegalArgumentException("Illegal character in Base64 encoded data.");
int o0 = (b0 << 2) | (b1 >>> 4);
int o1 = ((b1 & 0xf) << 4) | (b2 >>> 2);
int o2 = ((b2 & 3) << 6) | b3;
out[op++] = (byte) o0;
if (op < oLen)
out[op++] = (byte) o1;
if (op < oLen)
out[op++] = (byte) o2;
}
return out;
}
}