Deflater.cs

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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.
 *
*/

using System;

namespace Lucene.Net.Support
{
    public class Deflater
    {
        delegate void SetLevelDelegate(int level);
        delegate void SetInputDelegate(byte[] input, int offset, int count);
        delegate void FinishDelegate();
        delegate bool GetIsFinishedDelegate();
        delegate int DeflateDelegate(byte[] output);

        SetLevelDelegate setLevelMethod;
        SetInputDelegate setInputMethod;
        FinishDelegate finishMethod;
        GetIsFinishedDelegate getIsFinishedMethod;
        DeflateDelegate deflateMethod;

        public const int BEST_COMPRESSION = 9;

        internal Deflater(object deflaterInstance)
        {
            Type type = deflaterInstance.GetType();

            setLevelMethod = (SetLevelDelegate)Delegate.CreateDelegate(
                typeof(SetLevelDelegate),
                deflaterInstance,
                type.GetMethod("SetLevel", new Type[] { typeof(int) }));

            setInputMethod = (SetInputDelegate)Delegate.CreateDelegate(
                typeof(SetInputDelegate),
                deflaterInstance,
                type.GetMethod("SetInput", new Type[] { typeof(byte[]), typeof(int), typeof(int) }));

            finishMethod = (FinishDelegate)Delegate.CreateDelegate(
                typeof(FinishDelegate),
                deflaterInstance,
                type.GetMethod("Finish", Type.EmptyTypes));

            getIsFinishedMethod = (GetIsFinishedDelegate)Delegate.CreateDelegate(
                typeof(GetIsFinishedDelegate),
                deflaterInstance,
                type.GetMethod("get_IsFinished", Type.EmptyTypes));

            deflateMethod = (DeflateDelegate)Delegate.CreateDelegate(
                typeof(DeflateDelegate),
                deflaterInstance,
                type.GetMethod("Deflate", new Type[] { typeof(byte[]) }));
        }

        public void SetLevel(int level)
        {
            setLevelMethod(level);
        }

        public void SetInput(byte[] input, int offset, int count)
        {
            setInputMethod(input, offset, count);
        }

        public void Finish()
        {
            finishMethod();
        }

        public bool IsFinished
        {
            get { return getIsFinishedMethod(); }
        }

        public int Deflate(byte[] output)
        {
            return deflateMethod(output);
        }
    }
}