Example #1
0
        // null input means write an empty payload with formatting info. This is needed for the final block.
        public void GetBlock(DeflateInput input, OutputBuffer output, bool isFinal)
        {
            Debug.Assert(output != null);
            Debug.Assert(output.FreeBytes >= PaddingSize);

            // determine number of bytes to write
            int count = 0;

            if (input != null)
            {
                // allow space for padding and bits not yet flushed to buffer
                count = Math.Min(input.Count, output.FreeBytes - PaddingSize - output.BitsInBuffer);

                // we don't expect the output buffer to ever be this big (currently 4K), but we'll check this
                // just in case that changes.
                if (count > MaxUncompressedBlockSize - PaddingSize)
                {
                    count = MaxUncompressedBlockSize - PaddingSize;
                }
            }

            // write header and flush bits
            if (isFinal)
            {
                output.WriteBits(FastEncoderStatics.BFinalNoCompressionHeaderBitCount,
                                 FastEncoderStatics.BFinalNoCompressionHeader);
            }
            else
            {
                output.WriteBits(FastEncoderStatics.NoCompressionHeaderBitCount,
                                 FastEncoderStatics.NoCompressionHeader);
            }

            // now we're aligned
            output.FlushBits();

            // write len, nlen
            WriteLenNLen((ushort)count, output);

            // write uncompressed bytes
            if (input != null && count > 0)
            {
                output.WriteBytes(input.Buffer, input.StartIndex, count);
                input.ConsumeBytes(count);
            }
        }