/*

 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * @(#)UUEncoderStream.java   1.3 02/03/27

 */

package com.sun.xml.internal.messaging.saaj.packaging.mime.util;

import java.io.*;

/**

 * This class implements a UUEncoder. It is implemented as

 * a FilterOutputStream, so one can just wrap this class around

 * any output stream and write bytes into this filter. The Encoding

 * is done as the bytes are written out.

 *

 * @author John Mani

 */

public class UUEncoderStream extends FilterOutputStream {

    private byte[] buffer;      // cache of bytes that are yet to be encoded

    private int bufsize = 0;    // size of the cache

    private boolean wrotePrefix = false;

    protected String name;      // name of file

    protected int mode;         // permissions mode

    /**

     * Create a UUencoder that encodes the specified input stream

     * @param out        the output stream

     */

    public UUEncoderStream(OutputStream out) {

        this(out, "encoder.buf", 644);

    }

    /**

     * Create a UUencoder that encodes the specified input stream

     * @param out        the output stream

     * @param name       Specifies a name for the encoded buffer

     */

    public UUEncoderStream(OutputStream out, String name) {

        this(out, name, 644);

    }

    /**

     * Create a UUencoder that encodes the specified input stream

     * @param out        the output stream

     * @param name       Specifies a name for the encoded buffer

     * @param mode       Specifies permission mode for the encoded buffer

     */

    public UUEncoderStream(OutputStream out, String name, int mode) {

        super(out);

        this.name = name;

        this.mode = mode;

        buffer = new byte[45];

    }

    /**

     * Set up the buffer name and permission mode.

     * This method has any effect only if it is invoked before

     * you start writing into the output stream

     */

    public void setNameMode(String name, int mode) {

        this.name = name;

        this.mode = mode;

    }

    public void write(byte[] b, int off, int len) throws IOException {

        for (int i = 0; i < len; i++)

            write(b[off + i]);

    }

    public void write(byte[] data) throws IOException {

        write(data, 0, data.length);

    }

    public void write(int c) throws IOException {

        /* buffer up characters till we get a line's worth, then encode

         * and write them out. Max number of characters allowed per

         * line is 45.

         */

        buffer[bufsize++] = (byte)c;

        if (bufsize == 45) {

            writePrefix();

            encode();

            bufsize = 0;

        }

    }

    public void flush() throws IOException {

        if (bufsize > 0) { // If there's unencoded characters in the buffer

            writePrefix();

            encode();      // .. encode them

        }

        writeSuffix();

        out.flush();

    }

    public void close() throws IOException {

        flush();

        out.close();

    }

    /**

     * Write out the prefix: "begin <mode> <name>"

     */

    private void writePrefix() throws IOException {

        if (!wrotePrefix) {

            PrintStream ps = new PrintStream(out);

            ps.println("begin " + mode + " " + name);

            ps.flush();

            wrotePrefix = true;

        }

    }

    /**

     * Write a single line containing space and the suffix line

     * containing the single word "end" (terminated by a newline)

     */

    private void writeSuffix() throws IOException {

        PrintStream ps = new PrintStream(out);

        ps.println(" \nend");

        ps.flush();

    }

    /**

     * Encode a line.

     * Start off with the character count, followed by the encoded atoms

     * and terminate with LF. (or is it CRLF or the local line-terminator ?)

     * Take three bytes and encodes them into 4 characters

     * If bufsize if not a multiple of 3, the remaining bytes are filled

     * with '1'. This insures that the last line won't end in spaces

     * and potentiallly be truncated.

     */

    private void encode() throws IOException {

        byte a, b, c;

        int c1, c2, c3, c4;

        int i = 0;

        // Start off with the count of characters in the line

        out.write((bufsize & 0x3f) + ' ');

        while (i < bufsize) {

            a = buffer[i++];

            if (i < bufsize) {

                b = buffer[i++];

                if (i < bufsize)

                    c = buffer[i++];

                else // default c to 1

                    c = 1;

            }

            else { // default b & c to 1

                b = 1;

                c = 1;

            }

            c1 = (a >>> 2) & 0x3f;

            c2 = ((a << 4) & 0x30) | ((b >>> 4) & 0xf);

            c3 = ((b << 2) & 0x3c) | ((c >>> 6) & 0x3);

            c4 = c & 0x3f;

            out.write(c1 + ' ');

            out.write(c2 + ' ');

            out.write(c3 + ' ');

            out.write(c4 + ' ');

        }

        // Terminate with LF. (should it be CRLF or local line-terminator ?)

        out.write('\n');

    }

    /**** begin TEST program *****

    public static void main(String argv[]) throws Exception {

        FileInputStream infile = new FileInputStream(argv[0]);

        UUEncoderStream encoder = new UUEncoderStream(System.out);

        int c;

        while ((c = infile.read()) != -1)

            encoder.write(c);

        encoder.close();

    }

    **** end TEST program *****/

}