io.jsonwebtoken.impl.lang.RequiredBitLengthConverter Maven / Gradle / Ivy

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/*
 * Copyright © 2022 jsonwebtoken.io
 *
 * 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 io.jsonwebtoken.impl.lang;

import io.jsonwebtoken.lang.Assert;

public class RequiredBitLengthConverter implements Converter {

    private final Converter converter;

    private final int bitLength;
    private final boolean exact;

    public RequiredBitLengthConverter(Converter converter, int bitLength) {
        this(converter, bitLength, true);
    }

    public RequiredBitLengthConverter(Converter converter, int bitLength, boolean exact) {
        this.converter = Assert.notNull(converter, "Converter cannot be null.");
        this.bitLength = Assert.gt(bitLength, 0, "bitLength must be greater than 0");
        this.exact = exact;
    }

    private byte[] assertLength(byte[] bytes) {
        long len = Bytes.bitLength(bytes);
        if (exact && len != this.bitLength) {
            String msg = "Byte array must be exactly " + Bytes.bitsMsg(this.bitLength) + ". Found " + Bytes.bitsMsg(len);
            throw new IllegalArgumentException(msg);
        } else if (len < this.bitLength) {
            String msg = "Byte array must be at least " + Bytes.bitsMsg(this.bitLength) + ". Found " + Bytes.bitsMsg(len);
            throw new IllegalArgumentException(msg);
        }
        return bytes;
    }

    @Override
    public Object applyTo(byte[] bytes) {
        assertLength(bytes);
        return this.converter.applyTo(bytes);
    }

    @Override
    public byte[] applyFrom(Object o) {
        byte[] result = this.converter.applyFrom(o);
        return assertLength(result);
    }
}