com.mebigfatguy.inventory.utils.LengthLimitedInputStream.java Source code

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Here is the source code for com.mebigfatguy.inventory.utils.LengthLimitedInputStream.java

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/*
 * inventory - an ear/war inventory recorder
 * Copyright 2016-2018 MeBigFatGuy.com
 * Copyright 2016-2018 Dave Brosius
 *
 * 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 com.mebigfatguy.inventory.utils;

import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.commons.lang3.builder.ToStringStyle;

public class LengthLimitedInputStream extends InputStream {

    private InputStream parentStream;
    private long remainingLength;

    public LengthLimitedInputStream(InputStream parent, long length) {
        parentStream = parent;
        remainingLength = length;
    }

    @Override
    public int read() throws IOException {
        if (remainingLength == 0) {
            return -1;
        }
        int data = parentStream.read();
        --remainingLength;
        return data;
    }

    @Override
    public int read(byte[] b) throws IOException {
        return read(b, 0, b.length);
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        if (len > remainingLength) {
            len = (int) remainingLength;
        }

        if (len <= 0) {
            throw new EOFException("Read past the end of the stream");
        }

        int actLen = parentStream.read(b, off, len);
        remainingLength -= actLen;
        return actLen;
    }

    @Override
    public long skip(long n) throws IOException {
        if (remainingLength == 0) {
            throw new EOFException("Read past the end of the stream");
        }

        if (n > remainingLength) {
            remainingLength = 0;
            return remainingLength;
        }

        remainingLength -= n;
        return n;

    }

    @Override
    public int available() throws IOException {
        if (remainingLength > Integer.MAX_VALUE) {
            return Integer.MAX_VALUE;
        }

        return (int) remainingLength;
    }

    @Override
    public void close() throws IOException {
        remainingLength = 0;
    }

    @Override
    public synchronized void reset() throws IOException {
        throw new IOException("Mark not supported by LengthLimitedInputStream");
    }

    @Override
    public String toString() {
        return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_STYLE);
    }

}