private long XrefPosition(Tokenizer tokenizer)
{
tokenizer.MoveToEnd();
tokenizer.MoveToPrevious('s');
Token token = tokenizer.Token();
if (!TokenValidator.Validate(token, CharacterSetType.Regular, "startxref"))
{
throw new PdfException(PdfExceptionCodes.INVALID_EOF, "Expected startxref");
}
token = tokenizer.Token();
if (!TokenValidator.IsWhiteSpace(token))
{
throw new PdfException(PdfExceptionCodes.INVALID_EOF, "Expected a whitespace between starxref and position");
}
token = tokenizer.Token();
if (!TokenValidator.IsRegularNumber(token))
{
throw new PdfException(PdfExceptionCodes.INVALID_EOF, "startxref position expected");
}
long xrefPosition = token.ToLong();
token = tokenizer.Token();
if (!TokenValidator.IsDelimiter(token))
{
token = tokenizer.Token();
}
if (!TokenValidator.IsDelimiter(token, "%"))
{
throw new PdfException(PdfExceptionCodes.INVALID_EOF, "Expected %%EOF at end of the file");
}
token = tokenizer.Token();
if (!TokenValidator.IsDelimiter(token, "%"))
{
throw new PdfException(PdfExceptionCodes.INVALID_EOF, "Expected %%EOF at end of the file");
}
token = tokenizer.Token();
if (!TokenValidator.Validate(token, CharacterSetType.Regular, "EOF"))
{
throw new PdfException(PdfExceptionCodes.INVALID_EOF, "Expected %%EOF at end of the file");
}
return(xrefPosition);
}
private DocumentCatalog ReadXRef(Tokenizer tokenizer)
{
long xrefPosition = XrefPosition(tokenizer);
tokenizer.MoveToPosition(xrefPosition);
Token token = tokenizer.Token();
if (!TokenValidator.Validate(token, CharacterSetType.Regular, "xref"))
{
throw new PdfException(PdfExceptionCodes.INVALID_XREF, "Expected xref");
}
token = tokenizer.Token();
if (!TokenValidator.IsWhiteSpace(token))
{
throw new PdfException(PdfExceptionCodes.INVALID_XREF, "after xref must be a whitspace");
}
tokenizer.GetInteger(); // objectNumber
tokenizer.TokenExcludedComments();
int numberOfEntries = tokenizer.GetInteger();
tokenizer.TokenExcludedComments();
PDFObjects pdfObjects = new PDFObjects();
for (int i = 0; i < numberOfEntries; i++)
{
int pos = tokenizer.GetInteger(); // position
tokenizer.TokenExcludedComments(); // whitespace
tokenizer.GetInteger(); // generation
tokenizer.TokenExcludedComments(); // whitespace
string type = tokenizer.Token().ToString(); // f or n
tokenizer.TokenExcludedComments(); // whitespace
if (type != "f" && type != "n")
{
throw new PdfException(PdfExceptionCodes.INVALID_XREF, "only xref f or n entries allowed");
}
if (type == "f") // free element
{
continue;
}
tokenizer.SavePosition();
tokenizer.MoveToPosition(pos);
IndirectObject obj = new IndirectObject(tokenizer);
pdfObjects.AddObject(obj);
tokenizer.RestorePosition();
}
if (tokenizer.Token().ToString() != "trailer")
{
throw new PdfException(PdfExceptionCodes.INVALID_TRAILER, "expected trailer");
}
var trailer = new DictionaryObject(tokenizer);
var rootIndirect = (IndirectReferenceObject)trailer.Dictionary["Root"];
return(pdfObjects.GetDocument <DocumentCatalog>(rootIndirect));
}