IdentityFilter.java

package com.tom_roush.pdfbox.filter;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import com.tom_roush.pdfbox.cos.COSDictionary;

/**
 * The IdentityFilter filter passes the data through without any modifications.
 * It is defined in section 7.6.5 of the PDF 1.7 spec and also stated in table 26.
 * 
 * @author Adam Nichols
 */
final class IdentityFilter extends Filter
{
    private static final int BUFFER_SIZE = 1024;

    @Override
    public DecodeResult decode(InputStream encoded, OutputStream decoded,
                                         COSDictionary parameters, int index)
        throws IOException
    {
        byte[] buffer = new byte[BUFFER_SIZE];
        int amountRead;
        while((amountRead = encoded.read(buffer, 0, BUFFER_SIZE)) != -1)
        {
            decoded.write(buffer, 0, amountRead);
        }
        decoded.flush();
        return new DecodeResult(parameters);
    }

    @Override
    protected void encode(InputStream input, OutputStream encoded, COSDictionary parameters)
        throws IOException
    {
        byte[] buffer = new byte[BUFFER_SIZE];
        int amountRead;
        while((amountRead = input.read(buffer, 0, BUFFER_SIZE)) != -1)
        {
            encoded.write(buffer, 0, amountRead);
        }
        encoded.flush();
    }
}