public decimal ReadVersion()
{
var content = _document.Encoding.GetString(_document.Read(0, _document.Find(2, window => window[0] == 10 && window[1] != 37)));
switch (content.Split('\n')[0])
{
case "%PDF-1.4": return(1.4M);
default: throw new Exception("Invalid document");
}
;
}
internal static int Find(this IEditablePdfDocument document, byte[] lookFor) => document.Find(lookFor, 0);
internal static int Find(this IEditablePdfDocument document, byte[] lookFor, int start) => document.Find(lookFor.Length, w => w.ByteEquals(lookFor), start);