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/*
 * @(#)QEncoderStream.java    1.4 02/03/27
 */



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

import java.io.IOException;
import java.io.OutputStream;

This class implements a Q Encoder as defined by RFC 2047 for
encoding MIME headers. It subclasses the QPEncoderStream class.
Author:
John Mani/**
 * This class implements a Q Encoder as defined by RFC 2047 for
 * encoding MIME headers. It subclasses the QPEncoderStream class.
 *
 * @author John Mani
 */

public class QEncoderStream extends QPEncoderStream {

    private String specials;
    private static String WORD_SPECIALS = "=_?\"#$%&'(),.:;<>@[\\]^`{|}~";
    private static String TEXT_SPECIALS = "=_?";

    
Create a Q encoder that encodes the specified input stream
Params:
out –        the output stream
encodingWord – true if we are Q-encoding a word within a
                 phrase./**
     * Create a Q encoder that encodes the specified input stream
     * @param out        the output stream
     * @param encodingWord true if we are Q-encoding a word within a
     *                  phrase.
     */
    public QEncoderStream(OutputStream out, boolean encodingWord) {
        super(out, Integer.MAX_VALUE); // MAX_VALUE is 2^31, should
                                       // suffice (!) to indicate that
                                       // CRLFs should not be inserted
                                       // when encoding rfc822 headers

        // a RFC822 "word" token has more restrictions than a
        // RFC822 "text" token.
        specials = encodingWord ? WORD_SPECIALS : TEXT_SPECIALS;
    }

    
Encodes the specified byte to this output stream.
Params:
c –   the byte.
Throws:
IOException –  if an I/O error occurs./**
     * Encodes the specified <code>byte</code> to this output stream.
     * @param      c   the <code>byte</code>.
     * @exception  IOException  if an I/O error occurs.
     */
    @Override
    public void write(int c) throws IOException {
        c = c & 0xff; // Turn off the MSB.
        if (c == ' ')
            output('_', false);
        else if (c < 040 || c >= 0177 || specials.indexOf(c) >= 0)
            // Encoding required.
            output(c, true);
        else // No encoding required
            output(c, false);
    }

    
Returns the length of the encoded version of this byte array.
Params:
b – byte array.
encodingWord – whether use word or text specials.
Returns:
length./**
     * Returns the length of the encoded version of this byte array.
     *
     * @param b byte array.
     * @param encodingWord whether use word or text specials.
     *
     * @return length.
     */
    public static int encodedLength(byte[] b, boolean encodingWord) {
        int len = 0;
        String specials = encodingWord ? WORD_SPECIALS: TEXT_SPECIALS;
        for (int i = 0; i < b.length; i++) {
            int c = b[i] & 0xff; // Mask off MSB
            if (c < 040 || c >= 0177 || specials.indexOf(c) >= 0)
                // needs encoding
                len += 3; // Q-encoding is 1 -> 3 conversion
            else
                len++;
        }
        return len;
    }

    /**** begin TEST program ***
    public static void main(String argv[]) throws Exception {
        FileInputStream infile = new FileInputStream(argv[0]);
        QEncoderStream encoder = new QEncoderStream(System.out);
        int c;

        while ((c = infile.read()) != -1)
            encoder.write(c);
        encoder.close();
    }
    *** end TEST program ***/
}