iTextSharp.text.pdf.codec.TIFFFaxDecompressor.SetToBlack C# (CSharp) Method

        private void SetToBlack(int bitNum, int numBits)
        {
            // bitNum is relative to current scanline so bump it by lineBitNum
            bitNum += lineBitNum;

            int lastBit = bitNum + numBits;
            int byteNum = bitNum >> 3;

            // Handle bits in first byte
            int shift = bitNum & 0x7;
            if (shift > 0) {
                int maskVal = 1 << (7 - shift);
                byte val = buffer[byteNum];
                while (maskVal > 0 && bitNum < lastBit) {
                    val |= (byte)maskVal;
                    maskVal >>= 1;
                    ++bitNum;
                }
                buffer[byteNum] = val;
            }

            // Fill in 8 bits at a time
            byteNum = bitNum >> 3;
            while (bitNum < lastBit - 7) {
                buffer[byteNum++] = (byte) 255;
                bitNum += 8;
            }

            // Fill in remaining bits
            while (bitNum < lastBit) {
                byteNum = bitNum >> 3;
                buffer[byteNum] |= (byte)(1 << (7 - (bitNum & 0x7)));
                ++bitNum;
            }
        }