public int Deflate()

in src/ICSharpCode.SharpZipLib/Zip/Compression/Deflater.cs [427:522]
75 lines of code
16 McCabe index (conditional complexity)

		public int Deflate(byte[] output, int offset, int length)
		{
			int origLength = length;

			if (state == CLOSED_STATE)
			{
				throw new InvalidOperationException("Deflater closed");
			}

			if (state < BUSY_STATE)
			{
				// output header
				int header = (DEFLATED +
					((DeflaterConstants.MAX_WBITS - 8) << 4)) << 8;
				int level_flags = (level - 1) >> 1;
				if (level_flags < 0 || level_flags > 3)
				{
					level_flags = 3;
				}
				header |= level_flags << 6;
				if ((state & IS_SETDICT) != 0)
				{
					// Dictionary was set
					header |= DeflaterConstants.PRESET_DICT;
				}
				header += 31 - (header % 31);

				pending.WriteShortMSB(header);
				if ((state & IS_SETDICT) != 0)
				{
					int chksum = engine.Adler;
					engine.ResetAdler();
					pending.WriteShortMSB(chksum >> 16);
					pending.WriteShortMSB(chksum & 0xffff);
				}

				state = BUSY_STATE | (state & (IS_FLUSHING | IS_FINISHING));
			}

			for (; ; )
			{
				int count = pending.Flush(output, offset, length);
				offset += count;
				totalOut += count;
				length -= count;

				if (length == 0 || state == FINISHED_STATE)
				{
					break;
				}

				if (!engine.Deflate((state & IS_FLUSHING) != 0, (state & IS_FINISHING) != 0))
				{
					switch (state)
					{
						case BUSY_STATE:
							// We need more input now
							return origLength - length;

						case FLUSHING_STATE:
							if (level != NO_COMPRESSION)
							{
								/* We have to supply some lookahead.  8 bit lookahead
								 * is needed by the zlib inflater, and we must fill
								 * the next byte, so that all bits are flushed.
								 */
								int neededbits = 8 + ((-pending.BitCount) & 7);
								while (neededbits > 0)
								{
									/* write a static tree block consisting solely of
									 * an EOF:
									 */
									pending.WriteBits(2, 10);
									neededbits -= 10;
								}
							}
							state = BUSY_STATE;
							break;

						case FINISHING_STATE:
							pending.AlignToByte();

							// Compressed data is complete.  Write footer information if required.
							if (!noZlibHeaderOrFooter)
							{
								int adler = engine.Adler;
								pending.WriteShortMSB(adler >> 16);
								pending.WriteShortMSB(adler & 0xffff);
							}
							state = FINISHED_STATE;
							break;
					}
				}
			}
			return origLength - length;
		}