/// <summary>
/// Converts the specified value to string.
/// If the value does not exist, the function returns the empty string.
/// If the value is not convertible, the function throws an InvalidCastException.
/// If the index is out of range, the function throws an ArgumentOutOfRangeException.
/// </summary>
public string GetString(int index)
{
if (index < 0 || index >= Count)
{
throw new ArgumentOutOfRangeException("index", index, PSSR.IndexOutOfRange);
}
object obj = this[index];
if (obj == null)
{
return(String.Empty);
}
PdfString str = obj as PdfString;
if (str != null)
{
return(str.Value);
}
PdfStringObject strObject = obj as PdfStringObject;
if (strObject != null)
{
return(strObject.Value);
}
throw new InvalidCastException("GetString: Object is not a string.");
}
/// <summary>
/// Reads PDF object from input stream.
/// </summary>
/// <param name="pdfObject">Either the instance of a derived type or null. If it is null
/// an appropriate object is created.</param>
/// <param name="objectID">The address of the object.</param>
/// <param name="includeReferences">If true, specifies that all indirect objects
/// are included recursively.</param>
public PdfObject ReadObject(PdfObject pdfObject, PdfObjectID objectID, bool includeReferences)
{
MoveToObject(objectID);
int objectNumber = ReadInteger();
int generationNumber = ReadInteger();
#if DEBUG
// The following assertion sometime failed (see below)
//Debug.Assert(objectID == new PdfObjectID(objectNumber, generationNumber));
if (objectID != new PdfObjectID(objectNumber, generationNumber))
{
// A special kind of bug? Or is this an undocumented PDF feature?
// PDF4NET 2.6 provides a sample called 'Unicode', which produces a file 'unicode.pdf'
// The iref table of this file contains the following entries:
// iref
// 0 148
// 0000000000 65535 f
// 0000000015 00000 n
// 0000000346 00000 n
// ....
// 0000083236 00000 n
// 0000083045 00000 n
// 0000083045 00000 n
// 0000083045 00000 n
// 0000083045 00000 n
// 0000080334 00000 n
// ....
// Object 84, 85, 86, and 87 maps to the same dictionary, but all PDF readers I tested
// ignores this mismatch! The following assertion failed about 50 times with this file.
#if true_
string message = String.Format("xref entry {0} {1} maps to object {2} {3}.",
objectID.ObjectNumber, objectID.GenerationNumber, objectNumber, generationNumber);
Debug.Assert(false, message);
#endif
}
#endif
// Always use object ID from iref table (see above)
objectNumber = objectID.ObjectNumber;
generationNumber = objectID.GenerationNumber;
#if true_
Debug.WriteLine(String.Format("obj: {0} {1}", objectNumber, generationNumber));
#endif
ReadSymbol(Symbol.Obj);
bool checkForStream = false;
Symbol symbol = ScanNextToken();
switch (symbol)
{
case Symbol.BeginArray:
PdfArray array;
if (pdfObject == null)
array = new PdfArray(this.document);
else
array = (PdfArray)pdfObject;
//PdfObject.RegisterObject(array, objectID, generation);
pdfObject = ReadArray(array, includeReferences);
pdfObject.SetObjectID(objectNumber, generationNumber);
break;
case Symbol.BeginDictionary:
PdfDictionary dict;
if (pdfObject == null)
dict = new PdfDictionary(this.document);
else
dict = (PdfDictionary)pdfObject;
//PdfObject.RegisterObject(dict, objectID, generation);
checkForStream = true;
pdfObject = ReadDictionary(dict, includeReferences);
pdfObject.SetObjectID(objectNumber, generationNumber);
break;
// Acrobat 6 Professional proudly presents: The Null object!
// Even with a one-digit object number an indirect reference «x 0 R» to this object is
// one character larger than the direct use of «null». Probable this is the reason why
// it is true that Acrobat Web Capture 6.0 creates this object, but obviously never
// creates a reference to it!
case Symbol.Null:
pdfObject = new PdfNullObject(this.document);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.Boolean:
pdfObject = new PdfBooleanObject(this.document, this.lexer.Token == Boolean.TrueString);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.Integer:
pdfObject = new PdfIntegerObject(this.document, this.lexer.TokenToInteger);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.UInteger:
pdfObject = new PdfUIntegerObject(this.document, this.lexer.TokenToUInteger);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.Real:
pdfObject = new PdfRealObject(this.document, this.lexer.TokenToReal);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.String:
pdfObject = new PdfStringObject(this.document, this.lexer.Token);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.Name:
pdfObject = new PdfNameObject(this.document, this.lexer.Token);
pdfObject.SetObjectID(objectNumber, generationNumber);
ReadSymbol(Symbol.EndObj);
return pdfObject;
case Symbol.Keyword:
// Should not come here anymore
throw new NotImplementedException("Keyword");
default:
// Should not come here anymore
throw new NotImplementedException("unknown token");
}
symbol = ScanNextToken();
if (symbol == Symbol.BeginStream)
{
PdfDictionary dict = (PdfDictionary)pdfObject;
Debug.Assert(checkForStream, "Unexpected stream...");
int length = GetStreamLength(dict);
byte[] bytes = this.lexer.ReadStream(length);
#if true_
if (dict.Elements.GetString("/Filter") == "/FlateDecode")
{
if (dict.Elements["/Subtype"] == null)
{
try
{
byte[] decoded = Filtering.FlateDecode.Decode(bytes);
if (decoded.Length == 0)
goto End;
string pageContent = Filtering.FlateDecode.DecodeToString(bytes);
if (pageContent.Length > 100)
pageContent = pageContent.Substring(pageContent.Length - 100);
pageContent.GetType();
bytes = decoded;
dict.Elements.Remove("/Filter");
dict.Elements.SetInteger("/Length", bytes.Length);
}
catch
{
}
}
End:;
}
#endif
PdfDictionary.PdfStream stream = new PdfDictionary.PdfStream(bytes, dict);
dict.Stream = stream;
ReadSymbol(Symbol.EndStream);
symbol = ScanNextToken();
}
if (symbol != Symbol.EndObj)
throw new PdfReaderException(PSSR.UnexpectedToken(this.lexer.Token));
return pdfObject;
}