CSJ2K.j2k.image.output.ImgWriterPGM.write C# (CSharp) Method

        public override void write(int ulx, int uly, int w, int h)
        {
            int k, i, j;
            int fracbits = fb; // In local variable for faster access
            int tOffx, tOffy; // Active tile offset in the X and Y direction

            // Initialize db
            db.ulx = ulx;
            db.uly = uly;
            db.w = w;
            db.h = h;
            // Get the current active tile offset
            //UPGRADE_WARNING: Data types in Visual C# might be different.  Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
            tOffx = src.getCompULX(c) - (int) System.Math.Ceiling(src.ImgULX / (double) src.getCompSubsX(c));
            //UPGRADE_WARNING: Data types in Visual C# might be different.  Verify the accuracy of narrowing conversions. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1042'"
            tOffy = src.getCompULY(c) - (int) System.Math.Ceiling(src.ImgULY / (double) src.getCompSubsY(c));
            // Check the array size
            if (db.data_array != null && db.data_array.Length < w * h)
            {
                // A new one will be allocated by getInternCompData()
                db.data_array = null;
            }
            // Request the data and make sure it is not
            // progressive
            do
            {
                db = (DataBlkInt) src.getInternCompData(db, c);
            }
            while (db.progressive);

            // variables used during coeff saturation
            int tmp, maxVal = (1 << src.getNomRangeBits(c)) - 1;

            // If nominal bitdepth greater than 8, calculate down shift
            int downShift = src.getNomRangeBits(c) - 8;
            if (downShift < 0)
            {
                downShift = 0;
            }

            // Check line buffer
            if (buf == null || buf.Length < w)
            {
                buf = new byte[w]; // Expand buffer
            }

            // Write line by line
            for (i = 0; i < h; i++)
            {
                // Skip to beggining of line in file
                out_Renamed.Seek(this.offset + this.w * (uly + tOffy + i) + ulx + tOffx, System.IO.SeekOrigin.Begin);
                // Write all bytes in the line
                if (fracbits == 0)
                {
                    for (k = db.offset + i * db.scanw + w - 1, j = w - 1; j >= 0; j--, k--)
                    {
                        tmp = db.data_array[k] + levShift;
                        buf[j] = (byte) (((tmp < 0)?0:((tmp > maxVal)?maxVal:tmp)) >> downShift);
                    }
                }
                else
                {
                    for (k = db.offset + i * db.scanw + w - 1, j = w - 1; j >= 0; j--, k--)
                    {
                        tmp = (db.data_array[k] >> fracbits) + levShift;
                        buf[j] = (byte) (((tmp < 0)?0:((tmp > maxVal)?maxVal:tmp)) >> downShift);
                    }
                }
                out_Renamed.Write(buf, 0, w);
            }
        }