# 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 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 Operator)
            {
                Operator op = (Operator)o;
                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() )
                    {
                        Object 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 );
                }
            }
            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 );
            }
        }
    }