iTextSharp.text.pdf.PdfSignatureAppearance.FRangeStream.Read C# (CSharp) Метод

            public override int Read(byte[] b, int off, int len)
            {
                if (b == null) {
                    throw new ArgumentNullException();
                } else if ((off < 0) || (off > b.Length) || (len < 0) ||
                ((off + len) > b.Length) || ((off + len) < 0)) {
                    throw new ArgumentOutOfRangeException();
                } else if (len == 0) {
                    return 0;
                }
                if (rangePosition >= range[range.Length - 2] + range[range.Length - 1]) {
                    return 0;
                }
                for (int k = 0; k < range.Length; k += 2) {
                    long start = range[k];
                    long end = start + range[k + 1];
                    if (rangePosition < start)
                        rangePosition = start;
                    if (rangePosition >= start && rangePosition < end) {
                        int lenf = (int)Math.Min((long)len, end - rangePosition);
                        if (raf == null)
                            Array.Copy(bout, rangePosition, b, off, lenf);
                        else {
                            raf.Seek(rangePosition, SeekOrigin.Begin);
                            ReadFully(b, off, lenf);
                        }
                        rangePosition += lenf;
                        return lenf;
                    }
                }
                return 0;
            }