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package javax.swing.text.rtf;

import java.io.*;
import java.lang.*;

A generic superclass for streams which read and parse text
consisting of runs of characters interspersed with occasional
``specials'' (formatting characters).
 Most of the functionality
of this class would be redundant except that the
ByteToChar converters
are suddenly private API. Presumably this class will disappear
when the API is made public again. (sigh) That will also let us handle
multibyte character sets...
 A subclass should override at least write(char)
and writeSpecial(int). For efficiency's sake it's a
good idea to override write(String) as well. The subclass'
initializer may also install appropriate translation and specials tables.
See Also:
OutputStream/**
 * A generic superclass for streams which read and parse text
 * consisting of runs of characters interspersed with occasional
 * ``specials'' (formatting characters).
 *
 * <p> Most of the functionality
 * of this class would be redundant except that the
 * <code>ByteToChar</code> converters
 * are suddenly private API. Presumably this class will disappear
 * when the API is made public again. (sigh) That will also let us handle
 * multibyte character sets...
 *
 * <P> A subclass should override at least <code>write(char)</code>
 * and <code>writeSpecial(int)</code>. For efficiency's sake it's a
 * good idea to override <code>write(String)</code> as well. The subclass'
 * initializer may also install appropriate translation and specials tables.
 *
 * @see OutputStream
 */
abstract class AbstractFilter extends OutputStream
{
    
A table mapping bytes to characters /** A table mapping bytes to characters */
    protected char[] translationTable;
    
A table indicating which byte values should be interpreted as
 characters and which should be treated as formatting codes /** A table indicating which byte values should be interpreted as
     *  characters and which should be treated as formatting codes */
    protected boolean[] specialsTable;

    
A translation table which does ISO Latin-1 (trivial) /** A translation table which does ISO Latin-1 (trivial) */
    static final char[] latin1TranslationTable;
    
A specials table which indicates that no characters are special /** A specials table which indicates that no characters are special */
    static final boolean[] noSpecialsTable;
    
A specials table which indicates that all characters are special /** A specials table which indicates that all characters are special */
    static final boolean[] allSpecialsTable;

    static {
      int i;

      noSpecialsTable = new boolean[256];
      for (i = 0; i < 256; i++)
        noSpecialsTable[i] = false;

      allSpecialsTable = new boolean[256];
      for (i = 0; i < 256; i++)
        allSpecialsTable[i] = true;

      latin1TranslationTable = new char[256];
      for (i = 0; i < 256; i++)
        latin1TranslationTable[i] = (char)i;
    }

    
A convenience method that reads text from a FileInputStream
and writes it to the receiver.
The format in which the file
is read is determined by the concrete subclass of
AbstractFilter to which this method is sent.
This method does not close the receiver after reaching EOF on
the input stream.
The user must call close() to ensure that all
data are processed.
Params:
in –      An InputStream providing text./**
     * A convenience method that reads text from a FileInputStream
     * and writes it to the receiver.
     * The format in which the file
     * is read is determined by the concrete subclass of
     * AbstractFilter to which this method is sent.
     * <p>This method does not close the receiver after reaching EOF on
     * the input stream.
     * The user must call <code>close()</code> to ensure that all
     * data are processed.
     *
     * @param in      An InputStream providing text.
     */
    public void readFromStream(InputStream in)
      throws IOException
    {
        byte[] buf;
        int count;

        buf = new byte[16384];

        while(true) {
            count = in.read(buf);
            if (count < 0)
                break;

            this.write(buf, 0, count);
        }
    }

    public void readFromReader(Reader in)
      throws IOException
    {
        char[] buf;
        int count;

        buf = new char[2048];

        while(true) {
            count = in.read(buf);
            if (count < 0)
                break;
            for (int i = 0; i < count; i++) {
              this.write(buf[i]);
            }
        }
    }

    public AbstractFilter()
    {
        translationTable = latin1TranslationTable;
        specialsTable = noSpecialsTable;
    }

    
Implements the abstract method of OutputStream, of which this class
is a subclass.
/**
     * Implements the abstract method of OutputStream, of which this class
     * is a subclass.
     */
    public void write(int b)
      throws IOException
    {
      if (b < 0)
        b += 256;
      if (specialsTable[b])
        writeSpecial(b);
      else {
        char ch = translationTable[b];
        if (ch != (char)0)
          write(ch);
      }
    }

    
Implements the buffer-at-a-time write method for greater
efficiency.
 PENDING: Does write(byte[])
call write(byte[], int, int) or is it the other way
around?
/**
     * Implements the buffer-at-a-time write method for greater
     * efficiency.
     *
     * <p> <strong>PENDING:</strong> Does <code>write(byte[])</code>
     * call <code>write(byte[], int, int)</code> or is it the other way
     * around?
     */
    public void write(byte[] buf, int off, int len)
      throws IOException
    {
      StringBuilder accumulator = null;
      while (len > 0) {
        short b = (short)buf[off];

        // stupid signed bytes
        if (b < 0)
            b += 256;

        if (specialsTable[b]) {
          if (accumulator != null) {
            write(accumulator.toString());
            accumulator = null;
          }
          writeSpecial(b);
        } else {
          char ch = translationTable[b];
          if (ch != (char)0) {
            if (accumulator == null)
              accumulator = new StringBuilder();
            accumulator.append(ch);
          }
        }

        len --;
        off ++;
      }

      if (accumulator != null)
        write(accumulator.toString());
    }

    
Hopefully, all subclasses will override this method to accept strings
of text, but if they don't, AbstractFilter's implementation
will spoon-feed them via write(char).
Params:
s – The string of non-special characters written to the
         OutputStream./**
     * Hopefully, all subclasses will override this method to accept strings
     * of text, but if they don't, AbstractFilter's implementation
     * will spoon-feed them via <code>write(char)</code>.
     *
     * @param s The string of non-special characters written to the
     *          OutputStream.
     */
    public void write(String s)
      throws IOException
    {
      int index, length;

      length = s.length();
      for(index = 0; index < length; index ++) {
        write(s.charAt(index));
      }
    }

    
Subclasses must provide an implementation of this method which
accepts a single (non-special) character.
Params:
ch – The character written to the OutputStream./**
     * Subclasses must provide an implementation of this method which
     * accepts a single (non-special) character.
     *
     * @param ch The character written to the OutputStream.
     */
    protected abstract void write(char ch) throws IOException;

    
Subclasses must provide an implementation of this method which
accepts a single special byte. No translation is performed
on specials.
Params:
b – The byte written to the OutputStream./**
     * Subclasses must provide an implementation of this method which
     * accepts a single special byte. No translation is performed
     * on specials.
     *
     * @param b The byte written to the OutputStream.
     */
    protected abstract void writeSpecial(int b) throws IOException;
}