protected internal virtual bool ContainsFlateFilter(PdfStream pdfStream)
{
PdfObject filter = pdfStream.Get(PdfName.Filter);
if (filter != null)
{
if (filter.GetObjectType() == PdfObject.NAME)
{
if (PdfName.FlateDecode.Equals(filter))
{
return(true);
}
}
else
{
if (filter.GetObjectType() == PdfObject.ARRAY)
{
if (((PdfArray)filter).Contains(PdfName.FlateDecode))
{
return(true);
}
}
else
{
throw new PdfException(PdfException.FilterIsNotANameOrArray);
}
}
}
return(false);
}
protected internal virtual bool CheckEncryption(PdfStream pdfStream)
{
if (crypto == null || crypto.IsEmbeddedFilesOnly())
{
return(false);
}
else
{
PdfObject filter = pdfStream.Get(PdfName.Filter, true);
if (filter != null)
{
if (PdfName.Crypt.Equals(filter))
{
return(false);
}
else
{
if (filter.GetObjectType() == PdfObject.ARRAY)
{
PdfArray filters = (PdfArray)filter;
if (!filters.IsEmpty() && PdfName.Crypt.Equals(filters.Get(0, true)))
{
return(false);
}
}
}
}
return(true);
}
}
protected internal virtual void UpdateCompressionFilter(PdfStream pdfStream)
{
PdfObject filter = pdfStream.Get(PdfName.Filter);
if (filter == null)
{
pdfStream.Put(PdfName.Filter, PdfName.FlateDecode);
}
else
{
PdfArray filters = new PdfArray();
filters.Add(PdfName.FlateDecode);
if (filter is PdfArray)
{
filters.AddAll((PdfArray)filter);
}
else
{
filters.Add(filter);
}
PdfObject decodeParms = pdfStream.Get(PdfName.DecodeParms);
if (decodeParms != null)
{
if (decodeParms is PdfDictionary)
{
PdfArray array = new PdfArray();
array.Add(new PdfNull());
array.Add(decodeParms);
pdfStream.Put(PdfName.DecodeParms, array);
}
else
{
if (decodeParms is PdfArray)
{
((PdfArray)decodeParms).Add(0, new PdfNull());
}
else
{
throw new PdfException(PdfException.DecodeParameterType1IsNotSupported).SetMessageParams(decodeParms.GetType
().ToString());
}
}
}
pdfStream.Put(PdfName.Filter, filters);
}
}
protected internal virtual byte[] DecodeFlateBytes(PdfStream stream, byte[] bytes)
{
PdfObject filterObject = stream.Get(PdfName.Filter);
if (filterObject == null)
{
return(bytes);
}
// check if flateDecode filter is on top
PdfName filterName;
PdfArray filtersArray = null;
if (filterObject is PdfName)
{
filterName = (PdfName)filterObject;
}
else
{
if (filterObject is PdfArray)
{
filtersArray = (PdfArray)filterObject;
filterName = filtersArray.GetAsName(0);
}
else
{
throw new PdfException(PdfException.FilterIsNotANameOrArray);
}
}
if (!PdfName.FlateDecode.Equals(filterName))
{
return(bytes);
}
// get decode params if present
PdfDictionary decodeParams;
PdfArray decodeParamsArray = null;
PdfObject decodeParamsObject = stream.Get(PdfName.DecodeParms);
if (decodeParamsObject == null)
{
decodeParams = null;
}
else
{
if (decodeParamsObject.GetObjectType() == PdfObject.DICTIONARY)
{
decodeParams = (PdfDictionary)decodeParamsObject;
}
else
{
if (decodeParamsObject.GetObjectType() == PdfObject.ARRAY)
{
decodeParamsArray = (PdfArray)decodeParamsObject;
decodeParams = decodeParamsArray.GetAsDictionary(0);
}
else
{
throw new PdfException(PdfException.DecodeParameterType1IsNotSupported).SetMessageParams(decodeParamsObject
.GetType().ToString());
}
}
}
// decode
byte[] res = FlateDecodeFilter.FlateDecode(bytes, true);
if (res == null)
{
res = FlateDecodeFilter.FlateDecode(bytes, false);
}
bytes = FlateDecodeFilter.DecodePredictor(res, decodeParams);
//remove filter and decode params
filterObject = null;
if (filtersArray != null)
{
filtersArray.Remove(0);
if (filtersArray.Size() == 1)
{
filterObject = filtersArray.Get(0);
}
else
{
if (!filtersArray.IsEmpty())
{
filterObject = filtersArray;
}
}
}
decodeParamsObject = null;
if (decodeParamsArray != null)
{
decodeParamsArray.Remove(0);
if (decodeParamsArray.Size() == 1 && decodeParamsArray.Get(0).GetObjectType() != PdfObject.NULL)
{
decodeParamsObject = decodeParamsArray.Get(0);
}
else
{
if (!decodeParamsArray.IsEmpty())
{
decodeParamsObject = decodeParamsArray;
}
}
}
if (filterObject == null)
{
stream.Remove(PdfName.Filter);
}
else
{
stream.Put(PdfName.Filter, filterObject);
}
if (decodeParamsObject == null)
{
stream.Remove(PdfName.DecodeParms);
}
else
{
stream.Put(PdfName.DecodeParms, decodeParamsObject);
}
return(bytes);
}
