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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.openssl;

import org.wildfly.openssl.util.DirectByteBufferDeallocator;

import java.nio.ByteBuffer;

public class ByteBufferUtils {

    private ByteBufferUtils() {
        // Hide the default constructor since this is a utility class.
    }


    /**
     * Default byte buffer expansion. Doubles current size. Buffers are assumed
     * to be in 'write to' mode since there would be no need to expand a buffer
     * while it was in 'read from' mode.
     *
     * @param in Buffer to expand
     * @return The expanded buffer with any data from the input buffer copied
     * in to it
     */
    public static ByteBuffer expand(ByteBuffer in) {
        return expand(in, in.capacity() * 2);
    }


    /**
     * Expands buffer to the given size unless it is already as big or bigger.
     * Buffers are assumed to be in 'write to' mode since there would be no need
     * to expand a buffer while it was in 'read from' mode.
     *
     * @param in      Buffer to expand
     * @param newSize The size t which the buffer should be expanded
     * @return The expanded buffer with any data from the input buffer
     * copied in to it or the original buffer if there was no
     * need for expansion
     */
    public static ByteBuffer expand(ByteBuffer in, int newSize) {
        if (in.capacity() >= newSize) {
            return in;
        }

        ByteBuffer out;
        boolean direct = false;
        if (in.isDirect()) {
            out = ByteBuffer.allocateDirect(newSize);
            direct = true;
        } else {
            out = ByteBuffer.allocate(newSize);
        }

        // Copy data
        in.flip();
        out.put(in);

        if (direct) {
            cleanDirectBuffer(in);
        }

        return out;
    }

    public static void cleanDirectBuffer(final ByteBuffer buf) {
        DirectByteBufferDeallocator.free(buf);
    }

}