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//========================================================================
//Copyright 2007-2010 David Yu [email protected]
//------------------------------------------------------------------------
//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.
//========================================================================

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package io.protostuff;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * An InputStream implementations which reads from some other InputStream but is limited to a particular number of
 * bytes.
 * 
 * @author David Yu
 * @created Jan 14, 2010
 */
public final class LimitedInputStream extends FilterInputStream
{
    private int limit;

    public LimitedInputStream(InputStream in)
    {
        super(in);
    }

    public LimitedInputStream(InputStream in, int limit)
    {
        super(in);
        this.limit = limit;
    }

    LimitedInputStream limit(int limit)
    {
        this.limit = limit;
        return this;
    }

    @Override
    public int available() throws IOException
    {
        return Math.min(super.available(), limit);
    }

    @Override
    public int read() throws IOException
    {
        if (limit <= 0)
        {
            return -1;
        }
        final int result = super.read();
        if (result >= 0)
        {
            --limit;
        }
        return result;
    }

    @Override
    public int read(final byte[] b, final int off, int len) throws IOException
    {
        if (limit <= 0)
        {
            return -1;
        }
        len = Math.min(len, limit);
        final int result = super.read(b, off, len);
        if (result >= 0)
        {
            limit -= result;
        }
        return result;
    }

    @Override
    public long skip(final long n) throws IOException
    {
        final long result = super.skip(Math.min(n, limit));
        if (result >= 0)
        {
            limit -= result;
        }
        return result;
    }
}