ru.zinin.redis.util.Base64Util Maven / Gradle / Ivy
/*
* Copyright 2011 Alexander V. Zinin
*
* 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 ru.zinin.redis.util;
import java.io.UnsupportedEncodingException;
/**
* Date: 01.11.11 21:13
*
* @author Alexander V. Zinin ([email protected])
*/
public class Base64Util {
private static final String DEFAULT_CHARSET = "utf-8";
// Dummy constructor.
private Base64Util() {
}
// Mapping table from 6-bit nibbles to Base64 characters.
private static char[] map1 = new char[64];
static {
int i = 0;
for (char c = 'A'; c <= 'Z'; c++) {
map1[i++] = c;
}
for (char c = 'a'; c <= 'z'; c++) {
map1[i++] = c;
}
for (char c = '0'; c <= '9'; c++) {
map1[i++] = c;
}
map1[i++] = '+';
map1[i++] = '/';
}
// Mapping table from Base64 characters to 6-bit nibbles.
private static byte[] map2 = new byte[128];
static {
for (int i = 0; i < map2.length; i++) {
map2[i] = -1;
}
for (int i = 0; i < 64; i++) {
map2[map1[i]] = (byte) i;
}
}
/**
* Encodes a string into Base64 format.
* No blanks or line breaks are inserted.
*
* @param s a String to be encoded.
* @param charset when convert string to byte arrat use this charset
*
* @return A String with the Base64 encoded data.
*
* @throws java.io.UnsupportedEncodingException
* if specified charset not supported
*/
public static String encodeString(String s, String charset) throws UnsupportedEncodingException {
return new String(encode(s.getBytes(charset)));
}
/**
* Invoke {@link Base64Util#encodeString(String, String)} with {@link Base64Util#DEFAULT_CHARSET}
*
* @param s a String to be encoded.
*
* @return A String with the Base64 encoded data.
*/
public static String encodeString(String s) {
try {
return encodeString(s, DEFAULT_CHARSET);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted.
*
* @param in an array containing the data bytes to be encoded.
*
* @return A character array with the Base64 encoded data.
*/
public static char[] encode(byte[] in) {
return encode(in, in.length);
}
/**
* Encodes a byte array into Base64 format.
* No blanks or line breaks are inserted.
*
* @param in an array containing the data bytes to be encoded.
* @param iLen number of bytes to process in in.
*
* @return A character array with the Base64 encoded data.
*/
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++] & 0xff;
int i1 = ip < iLen ? in[ip++] & 0xff : 0;
int i2 = ip < iLen ? in[ip++] & 0xff : 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++] = map1[o0];
out[op++] = map1[o1];
out[op] = op < oDataLen ? map1[o2] : '=';
op++;
out[op] = op < oDataLen ? map1[o3] : '=';
op++;
}
return out;
}
/**
* Decodes a string from Base64 format.
*
* @param s a Base64 String to be decoded.
* @param charset when convert byte array to string use this charset
*
* @return A String containing the decoded data.
*
* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
* @throws java.io.UnsupportedEncodingException
* if specified charset not supported
*/
public static String decodeString(String s, String charset) throws UnsupportedEncodingException {
return new String(decode(s), charset);
}
/**
* Invoke {@link Base64Util#decodeString(String, String)} with {@link Base64Util#DEFAULT_CHARSET}
*
* @param s a Base64 String to be decoded.
*
* @return A String containing the decoded data.
*/
public static String decodeString(String s) {
try {
return decodeString(s, DEFAULT_CHARSET);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
}
/**
* 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++];
int i1 = in[ip++];
int i2 = ip < iLen ? in[ip++] : 'A';
int i3 = ip < iLen ? in[ip++] : 'A';
if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127) {
throw new IllegalArgumentException("Illegal character in Base64 encoded data.");
}
int b0 = map2[i0];
int b1 = map2[i1];
int b2 = map2[i2];
int b3 = map2[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;
}
}