/*
 * $Id: PdfObject.cs 106 2009-12-07 12:23:50Z psoares33 $
 * 
 *
 * This file is part of the iText project.
 * Copyright (c) 1998-2012 1T3XT BVBA
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY 1T3XT,
 * 1T3XT DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * you must retain the producer line in every PDF that is created or manipulated
 * using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */

using System;
using System.IO;

namespace iTextSharp.text.pdf {
    /**
     * <CODE>PdfObject</CODE> is the abstract baseclass of all PDF objects.
 * <P>
     * PDF supports seven basic types of objects: bools, numbers, strings, names,
 * arrays, dictionaries and streams. In addition, PDF provides a null object.
 * Objects may be labeled so that they can be referred to by other objects.<BR>
 * All these basic PDF objects are described in the 'Portable Document Format
 * Reference Manual version 1.3' Chapter 4 (pages 37-54).
 *
 * @see        PdfNull
     * @see        Pdfbool
 * @see        PdfNumber
 * @see        PdfString
 * @see        PdfName
 * @see        PdfArray
 * @see        PdfDictionary
 * @see        PdfStream
 * @see        PdfIndirectReference
 */

    public abstract class PdfObject {
    
        // static membervariables (all the possible types of a PdfObject)
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int BOOLEAN = 1;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int NUMBER = 2;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int STRING = 3;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int NAME = 4;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int ARRAY = 5;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int DICTIONARY = 6;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int STREAM = 7;

        /** a possible type of <CODE>PdfObject</CODE> */
        public const int NULL = 8;
    
        /** a possible type of <CODE>PdfObject</CODE> */
        public const int INDIRECT = 10;
            
        /** This is an empty string used for the <CODE>PdfNull</CODE>-object and for an empty <CODE>PdfString</CODE>-object. */
        public const string NOTHING = "";
    
        /** This is the default encoding to be used for converting strings into bytes and vice versa.
         * The default encoding is PdfDocEcoding.
         */
        public const string TEXT_PDFDOCENCODING = "PDF";
    
        /** This is the encoding to be used to output text in Unicode. */
        public const string TEXT_UNICODE = "UnicodeBig";
    
        // membervariables
    
        /** the content of this <CODE>PdfObject</CODE> */
        protected byte[] bytes;
    
        /** the type of this <CODE>PdfObject</CODE> */
        protected int type;
    
        /**
         * Holds value of property indRef.
         */
        protected PRIndirectReference indRef;
    
        // constructors
    
        /**
         * Constructs a <CODE>PdfObject</CODE> of a certain <VAR>type</VAR> without any <VAR>content</VAR>.
         *
         * @param        type            type of the new <CODE>PdfObject</CODE>
         */
    
        protected PdfObject(int type) {
            this.type = type;
        }
    
        /**
         * Constructs a <CODE>PdfObject</CODE> of a certain <VAR>type</VAR> with a certain <VAR>content</VAR>.
         *
         * @param        type            type of the new <CODE>PdfObject</CODE>
         * @param        content            content of the new <CODE>PdfObject</CODE> as a <CODE>String</CODE>.
         */
    
        protected PdfObject(int type, string content) {
            this.type = type;
            bytes = PdfEncodings.ConvertToBytes(content, null);
        }
    
        /**
         * Constructs a <CODE>PdfObject</CODE> of a certain <VAR>type</VAR> with a certain <VAR>content</VAR>.
         *
         * @param        type            type of the new <CODE>PdfObject</CODE>
         * @param        bytes            content of the new <CODE>PdfObject</CODE> as an array of <CODE>byte</CODE>.
         */
    
        protected PdfObject(int type, byte[] bytes) {
            this.bytes = bytes;
            this.type = type;
        }
    
        // methods dealing with the content of this object
    
        /**
         * Writes the PDF representation of this <CODE>PdfObject</CODE> as an array of <CODE>byte</CODE>s to the writer.
         * @param writer for backwards compatibility
         * @param os the outputstream to write the bytes to.
         * @throws IOException
         */
    
        public virtual void ToPdf(PdfWriter writer, Stream os) {
            if (bytes != null)
                os.Write(bytes, 0, bytes.Length);
        }
    
        /**
         * Gets the presentation of this object in a byte array
         * @return a byte array
         */
        public virtual byte[] GetBytes() {
            return bytes;
        }

        /**
         * Can this object be in an object stream?
         * @return true if this object can be in an object stream.
         */
        public bool CanBeInObjStm() {
            switch (type) {
                case NULL:
                case BOOLEAN:
                case NUMBER:
                case STRING:
                case NAME:
                case ARRAY:
                case DICTIONARY:
                    return true;
                case STREAM:
                case INDIRECT:
                default:
                    return false;
            }
        }
    
        /**
         * Returns the length of the PDF representation of the <CODE>PdfObject</CODE>.
         * <P>
         * In some cases, namely for <CODE>PdfString</CODE> and <CODE>PdfStream</CODE>,
         * this method differs from the method <CODE>length</CODE> because <CODE>length</CODE>
         * returns the length of the actual content of the <CODE>PdfObject</CODE>.</P>
         * <P>
         * Remark: the actual content of an object is in most cases identical to its representation.
         * The following statement is always true: Length() &gt;= PdfLength().</P>
         *
         * @return        a length
         */
    
        //    public int PdfLength() {
        //        return ToPdf(null).length;
        //    }
    
        /**
         * Returns the <CODE>String</CODE>-representation of this <CODE>PdfObject</CODE>.
         *
         * @return        a <CODE>String</CODE>
         */
    
        public override string ToString() {
            if (bytes == null)
                return "";
            else
                return PdfEncodings.ConvertToString(bytes, null);
        }
    
        /**
         * Returns the length of the actual content of the <CODE>PdfObject</CODE>.
         * <P>
         * In some cases, namely for <CODE>PdfString</CODE> and <CODE>PdfStream</CODE>,
         * this method differs from the method <CODE>pdfLength</CODE> because <CODE>pdfLength</CODE>
         * returns the length of the PDF representation of the object, not of the actual content
         * as does the method <CODE>length</CODE>.</P>
         * <P>
         * Remark: the actual content of an object is in some cases identical to its representation.
         * The following statement is always true: Length() &gt;= PdfLength().</P>
         *
         * @return        a length
         */
    
        public int Length {
            get {
                return ToString().Length;
            }
        }
    
        /**
         * Changes the content of this <CODE>PdfObject</CODE>.
         *
         * @param        content            the new content of this <CODE>PdfObject</CODE>
         */
    
        protected string Content {
            set {
                bytes = PdfEncodings.ConvertToBytes(value, null);
            }
        }
    
        // methods dealing with the type of this object
    
        /**
         * Returns the type of this <CODE>PdfObject</CODE>.
         *
         * @return        a type
         */
    
        public int Type {
            get {
                return type;
            }
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfNull</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsNull() {
            return (this.type == NULL);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfBoolean</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsBoolean() {
            return (this.type == BOOLEAN);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfNumber</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsNumber() {
            return (this.type == NUMBER);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfString</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsString() {
            return (this.type == STRING);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfName</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsName() {
            return (this.type == NAME);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfArray</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsArray() {
            return (this.type == ARRAY);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfDictionary</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsDictionary() {
            return (this.type == DICTIONARY);
        }
    
        /**
         * Checks if this <CODE>PdfObject</CODE> is of the type <CODE>PdfStream</CODE>.
         *
         * @return        <CODE>true</CODE> or <CODE>false</CODE>
         */
    
        public bool IsStream() {
            return (this.type == STREAM);
        }

        /**
         * Checks if this is an indirect object.
         * @return true if this is an indirect object
         */
        public bool IsIndirect() {
            return (this.type == INDIRECT);
        }
    
        public PRIndirectReference IndRef {
            get {
                return indRef;
            }
            set {
                indRef = value;
            }
        }
    }
}
