/// <summary>
/// Read the trailer from a PDF data file
/// </summary>
/// <param name="Data">Data to read</param>
/// <param name="StartIndex">Starting index of where to look for trailer, or -1 to look from end of file (default: -1)</param>
/// <returns>TRUE if a trailer was successfully read, FALSE otherwise</returns>
public static PDFTrailer ReadTrailer(byte[] Data, int StartIndex = -1)
{
int EndIndex = StartIndex;
if (EndIndex < 0)
{
EndIndex = PDF.FindEOF(Data, Data.Length - 1);
}
if (EndIndex < 0)
{
return(null);
}
int EndOfLineIndex;
byte[] LineData = PDF.ExtractPreviousPDFLine(Data, EndIndex, out EndIndex, out EndOfLineIndex);
while (LineData != null)
{
if ("trailer".Equals(Encoding.UTF8.GetString(LineData).Trim()))
{
int TokenStartIndex = 0;
string Token = PDFObjectParser.GetTokenString(Data, EndOfLineIndex, out TokenStartIndex, out EndIndex);
PDFDictionary TrailerDictionary = (PDFDictionary)PDFDictionary.TryParse(Token, Data, TokenStartIndex, out EndIndex);
if (TrailerDictionary != null)
{
LineData = PDF.ExtractPDFLine(Data, EndIndex, out EndIndex);
if ("startxref".Equals(Encoding.UTF8.GetString(LineData).Trim()))
{
Token = PDFObjectParser.GetTokenString(Data, EndIndex, out TokenStartIndex, out _);
PDFNumber Offset = (PDFNumber)PDFNumber.TryParse(Token, Data, TokenStartIndex, out EndIndex);
PDFCrossReference CrossRef = PDFCrossReference.ReadCrossReference(Data, Offset, out _);
return(new PDFTrailer(TrailerDictionary, CrossRef));
}
else
{
return(null);
}
}
else
{
return(null);
}
}
else
{
LineData = PDF.ExtractPreviousPDFLine(Data, EndIndex, out EndIndex, out EndOfLineIndex);
}
}
return(null);
}
