PdfReference.cs :  » PDF » PDF-Clown » it » stefanochizzolini » clown » objects » C# / CSharp Open Source

/*
  Copyright 2006,2008 Stefano Chizzolini. http://clown.stefanochizzolini.it

  Contributors:
    * Stefano Chizzolini (original code developer, http://www.stefanochizzolini.it)

  This file should be part of the source code distribution of "PDF Clown library"
  (the Program): see the accompanying README files for more info.

  This Program is free software; you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free Software
  Foundation; either version 2 of the License, or (at your option) any later version.

  This Program is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY, either expressed or implied; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the License for more details.

  You should have received a copy of the GNU General Public License along with this
  Program (see README files); if not, go to the GNU website (http://www.gnu.org/).

  Redistribution and use, with or without modification, are permitted provided that such
  redistributions retain the above copyright notice, license and disclaimer, along with
  this list of conditions.
*/

using it.stefanochizzolini.clown.bytes;
using it.stefanochizzolini.clown.files;
using it.stefanochizzolini.clown.tokens;

using System;

namespace it.stefanochizzolini.clown.objects{
  /**
    <summary>PDF indirect reference object [PDF:1.6:3.2.9].</summary>
  */
  public class PdfReference
    : PdfDirectObject,
      IPdfIndirectObject,
      IEquatable<PdfReference>
  {
    #region static
    #region fields
    private const string XRefOffsetFormat = "0000000000";
    private const string XRefGenerationFormat = "00000";
    #endregion
    #endregion

    #region dynamic
    #region fields
    private PdfIndirectObject indirectObject;

    private int generationNumber;
    private int objectNumber;

    private File file;
    #endregion

    #region constructors
    internal PdfReference(
      PdfIndirectObject indirectObject,
      int objectNumber,
      int generationNumber
      )
    {
      this.indirectObject = indirectObject;

      this.objectNumber = objectNumber;
      this.generationNumber = generationNumber;
    }

    /**
      <remarks>
        <para>This is a necessary hack because indirect objects are unreachable on parsing bootstrap
        (see File(IInputStream) constructor).</para>
      </remarks>
    */
    internal PdfReference(
      Parser.Reference reference,
      File file
      )
    {
      this.objectNumber = reference.ObjectNumber;
      this.generationNumber = reference.GenerationNumber;

      this.file = file;
    }
    #endregion

    #region interface
    #region public
    public string CrossReference(
      long offset
      )
    {
      return (offset.ToString(XRefOffsetFormat) + " "
          + generationNumber.ToString(XRefGenerationFormat) + " "
          + IndirectObject.Usage
          + "\r\n");
    }

    public override bool Equals(
      object obj
      )
    {
      if(!(obj is PdfReference))
        return false;

      return Equals((PdfReference)obj);
    }

    public int GenerationNumber
    {get{return generationNumber;}}

    public override int GetHashCode(
      )
    {return IndirectObject.GetHashCode();}

    public string ID
    {get{return (objectNumber + " " + generationNumber);}}

    public string IndirectReference
    {get{return (ID + " R");}}

    public int ObjectNumber
    {get{return objectNumber;}}

    public override string ToString(
      )
    {return IndirectReference;}

    #region IEquatable
    public bool Equals(
      PdfReference obj
      )
    {return ID.Equals(obj.ID);}
    #endregion

    #region IPdfIndirectObject
    public override object Clone(
      File context
      )
    {return ((PdfIndirectObject)IndirectObject.Clone(context)).Reference;}

    public PdfDataObject DataObject
    {
      get{return IndirectObject.DataObject;}
      set{IndirectObject.DataObject = value;}
    }

    public void Delete(
      )
    {IndirectObject.Delete();}

    public PdfIndirectObject IndirectObject
    {
      get
      {
        if(indirectObject == null)
        {indirectObject = file.IndirectObjects[objectNumber];}

        return indirectObject;
      }
    }

    public PdfReference Reference
    {get{return this;}}
    #endregion
    #endregion

    #region internal
    internal override void WriteTo(
      IOutputStream stream
      )
    {stream.Write(IndirectReference);}
    #endregion
    #endregion
    #endregion
  }
}