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Library for connecting to Smartsheet Services

There is a newer version: 3.2.3

/*
 * Copyright (C) 2024 Smartsheet
 *
 * 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.smartsheet.api.internal;

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

/**
 * Compare the given expected content length with the actual number of bytes read.
 * Throws an exception if more bytes are read than the expected length, or if the
 * stream ends before reading the expected number of bytes.
 * 
 * If reset is called the totalBytesRead property is reset to 0.
 */
public class LengthEnforcingInputStream extends FilterInputStream {
    private long expectedLength;
    private long totalBytesRead = 0L;

    /**
     * Constructor
     */
    public LengthEnforcingInputStream(InputStream inputStream, long expectedLength) {
        super(inputStream);
        this.expectedLength = expectedLength;
    }

    @Override
    public synchronized int read() throws IOException {
        int bytesRead = in.read();
        if (bytesRead == -1) {
            checkLength();
        } else {
            totalBytesRead += bytesRead;
            checkForTooManyBytes();
        }
        return bytesRead;
    }

    @Override
    public synchronized int read(byte[] b, int off, int len) throws java.io.IOException {
        int bytesRead = in.read(b, off, len);
        if (bytesRead == -1) {
            checkLength();
        } else {
            totalBytesRead += bytesRead;
            checkForTooManyBytes();
        }
        return bytesRead;
    }

    private void checkForTooManyBytes() throws EOFException {
        if (totalBytesRead > expectedLength) {
            throw new EOFException("Incorrect stream length, expected: " + expectedLength + ", actual: " + totalBytesRead);
        }
    }

    private void checkLength() throws EOFException {
        if (totalBytesRead != expectedLength) {
            throw new EOFException("Incorrect stream length, expected: " + expectedLength + ", actual: " + totalBytesRead);
        }
    }

    /**
     * When reset is called the total bytes read counter is set back to 0.
     */
    @Override
    public synchronized void reset() throws IOException {
        totalBytesRead = 0;
        super.reset();
    }
}