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Java FTP client, Java FTP NIO file system, Groovy FTP client
There is a newer version: 2.6.0
package org.xbib.io.ftp.client;

import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import java.io.UnsupportedEncodingException;

/**
 * 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");
        try {
            _lineSeparatorBytes = _lineSeparator.getBytes("US-ASCII");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("Broken JVM - cannot find US-ASCII charset!", e);
        }
    }

    private int __length = 0;

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

    /**
     * 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 final boolean isConversionRequired() {
        return !_noConversionRequired;
    }

    private int __read() 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 __read();
    }


    /**
     * 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(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(byte buffer[], int offset, int length) throws IOException {
        if (_noConversionRequired) {
            return super.read(buffer, offset, length);
        }

        if (length < 1) {
            return 0;
        }

        int ch, off;

        ch = available();

        __length = (length > ch ? ch : length);

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


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

        off = offset;

        do {
            buffer[offset++] = (byte) ch;
        }
        while (--__length > 0 && (ch = __read()) != -1);


        return (offset - off);
    }

    /***
     * 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();
    }

}