/*
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 bytesit.stefanochizzolini.clown.bytes;
using it.stefanochizzolini.clown.bytes.filters;
using filesit.stefanochizzolini.clown.files;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
namespace it.stefanochizzolini.clown.objects{
/**
<summary>PDF stream object [PDF:1.6:3.2.7].</summary>
*/
public class PdfStream
: PdfDataObject
{
#region dynamic
#region fields
private bytes::Buffer body;
private PdfDictionary header;
#endregion
#region constructors
public PdfStream(
) : this(
new PdfDictionary(),
new bytes::Buffer()
)
{}
public PdfStream(
PdfDictionary header
) : this(
header,
new bytes::Buffer()
)
{}
public PdfStream(
bytes::Buffer body
) : this(
new PdfDictionary(),
body
)
{}
public PdfStream(
PdfDictionary header,
bytes::Buffer body
)
{
this.header = header;
this.body = body;
}
#endregion
#region interface
#region public
/**
<summary>Gets the decoded stream body.</summary>
*/
public bytes::Buffer Body
{
get
{
/*
NOTE: Encoding filters are removed by default because they belong to a lower layer
(token layer), so that it's appropriate and consistent to transparently keep
the object layer unaware of such a facility.
*/
return GetBody(true);
}
}
public override object Clone(
files::File context
)
{
PdfStream clone = new PdfStream(
(PdfDictionary)header.Clone(context),
(bytes::Buffer)body.Clone()
);
return clone;
}
/**
<summary>Gets the stream body.</summary>
<param name="decode">Defines whether the body has to be decoded.</param>
*/
public bytes::Buffer GetBody(
bool decode
)
{
if(decode)
{
// Get 'Filter' entry!
/*
NOTE: Such an entry defines possible encodings applied to the stream.
*/
PdfDirectObject filterObj = header[PdfName.Filter];
// Is the stream encoded?
if(filterObj != null)
{
/*
NOTE: If the stream is encoded, we must decode it before continuing.
*/
// TODO:IMPL 'DecodeParms' entry management!!!
PdfDataObject filterDataObj = files.File.Resolve(filterObj);
if(filterDataObj is PdfName) // PdfName.
{body.Decode(Filter.Get((PdfName)filterDataObj));}
else // MUST be PdfArray.
{
// [FIX:0.0.5:1:SC] It failed to deal with filter chains.
IEnumerator<PdfDirectObject> filterObjIterator = ((PdfArray)filterDataObj).GetEnumerator();
while(filterObjIterator.MoveNext())
{body.Decode(Filter.Get((PdfName)files.File.Resolve(filterObjIterator.Current)));}
}
// Update 'Filter' entry!
header[PdfName.Filter] = null; // The stream is free from encodings.
}
}
return body;
}
public PdfDictionary Header
{get{return header;}}
#endregion
#region internal
internal override void WriteTo(
bytes::IOutputStream stream
)
{
bool unencodedBody;
byte[] bodyData;
int bodyLength;
// 1. Header.
// Encoding.
/*
NOTE: As the contract establishes that a stream instance should be kept
free from encodings in order to be editable, encoding is NOT applied to
the actual online stream, but to its serialized representation only.
That is, as encoding is just a serialization practise, it is excluded from
alive, instanced streams.
*/
PdfDirectObject filterObj = header[PdfName.Filter];
// Is the body free from encodings?
if(filterObj == null) // Unencoded body.
{
/*
NOTE: As online representation is unencoded,
header entries related to the encoded stream body are temporary
(instrumental to the current serialization process).
*/
unencodedBody = true;
// Set the filter to apply!
filterObj = PdfName.FlateDecode; // zlib/deflate filter.
// Get encoded body data applying the filter to the stream!
bodyData = body.Encode(Filter.Get((PdfName)filterObj));
// Set encoded length!
bodyLength = bodyData.Length;
// Update 'Filter' entry!
header[PdfName.Filter] = filterObj;
}
else // Encoded body.
{
unencodedBody = false;
// Get encoded body data!
bodyData = body.ToByteArray();
// Set encoded length!
bodyLength = (int)body.Length;
}
// Set encoded length!
header[PdfName.Length] = new PdfInteger(bodyLength);
header.WriteTo(stream);
// Is the body free from encodings?
if(unencodedBody)
{
// Restore actual header entries!
((PdfInteger)header[PdfName.Length]).Value = (int)body.Length;
header[PdfName.Filter] = null;
}
// 2. Body.
// [FIX:1909707:AH] Invalid end-of-line marker for stream objects.
stream.Write("\nstream\n");
stream.Write(bodyData);
stream.Write("\nendstream");
}
#endregion
#endregion
#endregion
}
}
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