org.wildfly.common.codec.Base64Alphabet Maven / Gradle / Ivy
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* Copyright 2017 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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 org.wildfly.common.codec;
import org.wildfly.common.iteration.ByteIterator;
import org.wildfly.common.iteration.CodePointIterator;
/**
* A base-64 alphabet.
*
* @see ByteIterator#base64Encode(Base64Alphabet)
* @see CodePointIterator#base64Decode(Base64Alphabet)
*/
public abstract class Base64Alphabet extends Alphabet {
/**
* Construct a new instance.
*
* @param littleEndian {@code true} if the alphabet is little-endian (LSB first), {@code false} otherwise
*/
protected Base64Alphabet(final boolean littleEndian) {
super(littleEndian);
}
/**
* Encode the given 6-bit value to a code point.
*
* @param val the 6-bit value
* @return the Unicode code point
*/
public abstract int encode(int val);
/**
* Decode the given code point. If the code point is not valid, -1 is returned.
*
* @param codePoint the code point
* @return the decoded 6-bit value or -1 if the code point is not valid
*/
public abstract int decode(int codePoint);
/**
* The standard RFC 4648 base-64 alphabet.
*/
public static final Base64Alphabet STANDARD = new Base64Alphabet(false) {
public int encode(final int val) {
if (val <= 25) {
return 'A' + val;
} else if (val <= 51) {
return 'a' + val - 26;
} else if (val <= 61) {
return '0' + val - 52;
} else if (val == 62) {
return '+';
} else {
assert val == 63;
return '/';
}
}
public int decode(final int codePoint) throws IllegalArgumentException {
if ('A' <= codePoint && codePoint <= 'Z') {
return codePoint - 'A';
} else if ('a' <= codePoint && codePoint <= 'z') {
return codePoint - 'a' + 26;
} else if ('0' <= codePoint && codePoint <= '9') {
return codePoint - '0' + 52;
} else if (codePoint == '+') {
return 62;
} else if (codePoint == '/') {
return 63;
} else {
return -1;
}
}
};
}