commons-net.jar Source Code

commons-net.jar is the bytecode of Apache Commons Net library, which implements the client side of many basic Internet protocols.

Apache Commons Net Source Code files are provided in the binary packge (commons-net-3.8.0-bin.zip). You can download it at Apache Commons Net Website.

The source code of commons-net-3.8.0.jar is provided below:

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org/apache/commons/net/io/FromNetASCIIInputStream.java

/*
 * 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.apache.commons.net.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.nio.charset.StandardCharsets;

/**
 * This class wraps an input stream, replacing all occurrences
 * of <CR><LF> (carriage return followed by a linefeed),
 * which is the NETASCII standard for representing a newline, with the
 * local line separator representation.  You would use this class to
 * implement ASCII file transfers requiring conversion from NETASCII.
 *
 *
 */

public final class FromNetASCIIInputStream extends PushbackInputStream
{
    static final boolean _noConversionRequired;
    static final String _lineSeparator;
    static final byte[] _lineSeparatorBytes;

    static {
        _lineSeparator = System.getProperty("line.separator");
        _noConversionRequired = _lineSeparator.equals("\r\n");
        _lineSeparatorBytes = _lineSeparator.getBytes(StandardCharsets.US_ASCII);
    }

    private int length;

    /**
     * Returns true if the NetASCII line separator differs from the system
     * line separator, false if they are the same.  This method is useful
     * to determine whether or not you need to instantiate a
     * FromNetASCIIInputStream object.
     *
     * @return True if the NETASCII line separator differs from the local
     *   system line separator, false if they are the same.
     */
    public static boolean isConversionRequired()
    {
        return !_noConversionRequired;
    }

    /**
     * Creates a FromNetASCIIInputStream instance that wraps an existing
     * InputStream.
     * @param input the stream to wrap
     */
    public FromNetASCIIInputStream(final InputStream input)
    {
        super(input, _lineSeparatorBytes.length + 1);
    }


    private int readInt() throws IOException
    {
        int ch;

        ch = super.read();

        if (ch == '\r')
        {
            ch = super.read();
            if (ch == '\n')
            {
                unread(_lineSeparatorBytes);
                ch = super.read();
                // This is a kluge for read(byte[], ...) to read the right amount
                --length;
            }
            else
            {
                if (ch != -1) {
                    unread(ch);
                }
                return '\r';
            }
        }

        return ch;
    }


    /**
     * Reads and returns the next byte in the stream.  If the end of the
     * message has been reached, returns -1.  Note that a call to this method
     * may result in multiple reads from the underlying input stream in order
     * to convert NETASCII line separators to the local line separator format.
     * This is transparent to the programmer and is only mentioned for
     * completeness.
     *
     * @return The next character in the stream. Returns -1 if the end of the
     *          stream has been reached.
     * @throws IOException If an error occurs while reading the underlying
     *            stream.
     */
    @Override
    public int read() throws IOException
    {
        if (_noConversionRequired) {
            return super.read();
        }

        return readInt();
    }


    /**
     * Reads the next number of bytes from the stream into an array and
     * returns the number of bytes read.  Returns -1 if the end of the
     * stream has been reached.
     *
     * @param buffer  The byte array in which to store the data.
     * @return The number of bytes read. Returns -1 if the
     *          end of the message has been reached.
     * @throws IOException If an error occurs in reading the underlying
     *            stream.
     */
    @Override
    public int read(final byte buffer[]) throws IOException
    {
        return read(buffer, 0, buffer.length);
    }


    /**
     * Reads the next number of bytes from the stream into an array and returns
     * the number of bytes read.  Returns -1 if the end of the
     * message has been reached.  The characters are stored in the array
     * starting from the given offset and up to the length specified.
     *
     * @param buffer The byte array in which to store the data.
     * @param offset  The offset into the array at which to start storing data.
     * @param length   The number of bytes to read.
     * @return The number of bytes read. Returns -1 if the
     *          end of the stream has been reached.
     * @throws IOException If an error occurs while reading the underlying
     *            stream.
     */
    @Override
    public int read(final byte buffer[], int offset, final int length) throws IOException
    {
        if (_noConversionRequired) {
            return super.read(buffer, offset, length);
        }

        if (length < 1) {
            return 0;
        }

        int ch;
        final int off;

        ch = available();

        this.length = length > ch ? ch : length;

        // If nothing is available, block to read only one character
        if (this.length < 1) {
            this.length = 1;
        }


        if ((ch = readInt()) == -1) {
            return -1;
        }

        off = offset;

        do
        {
            buffer[offset++] = (byte)ch;
        }
        while (--this.length > 0 && (ch = readInt()) != -1);


        return offset - off;
    }


    // PushbackInputStream in JDK 1.1.3 returns the wrong thing
    // TODO - can we delete this override now?
    /**
     * Returns the number of bytes that can be read without blocking EXCEPT
     * when newline conversions have to be made somewhere within the
     * available block of bytes.  In other words, you really should not
     * rely on the value returned by this method if you are trying to avoid
     * blocking.
     */
    @Override
    public int available() throws IOException
    {
        if (in == null) {
            throw new IOException("Stream closed");
        }
        return buf.length - pos + in.available();
    }

}

org/apache/commons/net/io/FromNetASCIIInputStream.java

 

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