pdfbox-trunk/pdfbox/src/main/java/org/apache/pdfbox/pdfwriter/ContentStreamWriter.java
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.pdfbox.pdfwriter;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.List;
import java.util.Map;
import org.apache.pdfbox.contentstream.operator.Operator;
import org.apache.pdfbox.contentstream.operator.OperatorName;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSBoolean;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSFloat;
import org.apache.pdfbox.cos.COSInteger;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSNull;
import org.apache.pdfbox.cos.COSString;

/**
 * A class that will take a list of tokens and write out a stream with them.
 *
 * @author Ben Litchfield
 */
public class ContentStreamWriter
{
    private final OutputStream output;
    /**
     * space character.
     */
    public static final byte[] SPACE = new byte[] { 32 };

    /**
     * standard line separator
     */
    public static final byte[] EOL = new byte[] { 0x0A };

    /**
     * This will create a new content stream writer.
     *
     * @param out The stream to write the data to.
     */
    public ContentStreamWriter( OutputStream out )
    {
        output = out;
    }

    /**
     * Writes a single operand token.
     *
     * @param base The operand to write to the stream.
     * @throws IOException If there is an error writing to the stream.
     */
    public void writeToken(COSBase base) throws IOException
    {
        writeObject(base);
    }

    /**
     *  Writes a single operator token.
     *
     * @param op The operator to write to the stream.
     * @throws IOException If there is an error writing to the stream.
     */
    public void writeToken(Operator op) throws IOException
    {
        writeObject(op);
    }

    /**
     * Writes a series of tokens followed by a new line.
     * 
     * @param tokens The tokens to write to the stream.
     * @throws IOException If there is an error writing to the stream.
     */
    public void writeTokens(Object... tokens) throws IOException
    {
        for (Object token : tokens)
        {
            writeObject(token);
        }
        output.write("\n".getBytes(StandardCharsets.US_ASCII));
    }

    /**
     * This will write out the list of tokens to the stream.
     *
     * @param tokens The tokens to write to the stream.
     * @throws IOException If there is an error writing to the stream.
     */
    public void writeTokens( List<?> tokens ) throws IOException
    {
        for (Object token : tokens)
        {
            writeObject(token);
        }
    }

    private void writeObject(Object o) throws IOException
    {
        if (o instanceof COSBase)
        {
            writeObject((COSBase) o);
        }
        else if (o instanceof Operator)
        {
            writeObject((Operator) o);
        }
        else
        {
            throw new IOException("Error:Unknown type in content stream:" + o);
        }
    }

    private void writeObject(Operator op) throws IOException
    {
        if (op.getName().equals(OperatorName.BEGIN_INLINE_IMAGE))
        {
            output.write(OperatorName.BEGIN_INLINE_IMAGE.getBytes(StandardCharsets.ISO_8859_1));
            output.write(EOL);
            COSDictionary dic = op.getImageParameters();
            for (COSName key : dic.keySet())
            {
                COSBase value = dic.getDictionaryObject(key);
                key.writePDF(output);
                output.write(SPACE);
                writeObject(value);
                output.write(EOL);
            }
            output.write(OperatorName.BEGIN_INLINE_IMAGE_DATA.getBytes(StandardCharsets.ISO_8859_1));
            output.write(EOL);
            output.write(op.getImageData());
            output.write(EOL);
            output.write(OperatorName.END_INLINE_IMAGE.getBytes(StandardCharsets.ISO_8859_1));
            output.write(EOL);
        }
        else
        {
            output.write(op.getName().getBytes(StandardCharsets.ISO_8859_1));
            output.write(EOL);
        }
    }

    private void writeObject( COSBase o ) throws IOException
    {
        if( o instanceof COSString )
        {
            COSWriter.writeString((COSString)o, output);
            output.write( SPACE );
        }
        else if( o instanceof COSFloat )
        {
            ((COSFloat)o).writePDF( output );
            output.write( SPACE );
        }
        else if( o instanceof COSInteger )
        {
            ((COSInteger)o).writePDF( output );
            output.write( SPACE );
        }
        else if( o instanceof COSBoolean )
        {
            ((COSBoolean)o).writePDF( output );
            output.write( SPACE );
        }
        else if( o instanceof COSName )
        {
            ((COSName)o).writePDF( output );
            output.write( SPACE );
        }
        else if( o instanceof COSArray )
        {
            COSArray array = (COSArray)o;
            output.write(COSWriter.ARRAY_OPEN);
            for( int i=0; i<array.size(); i++ )
            {
                writeObject(array.get(i));
            }
            output.write(COSWriter.ARRAY_CLOSE);
            output.write(SPACE);
        }
        else if( o instanceof COSDictionary )
        {
            COSDictionary obj = (COSDictionary)o;
            output.write( COSWriter.DICT_OPEN );
            for (Map.Entry<COSName, COSBase> entry : obj.entrySet())
            {
                if (entry.getValue() != null)
                {
                    writeObject(entry.getKey());
                    writeObject(entry.getValue());
                }
            }
            output.write( COSWriter.DICT_CLOSE );
            output.write( SPACE );
        }
        else if (o instanceof COSNull)
        {
            output.write("null".getBytes(StandardCharsets.US_ASCII));
            output.write(SPACE);
        }
        else
        {
            throw new IOException( "Error:Unknown type in content stream:" + o );
        }
    }
}
