Пример #1
0
        /// <summary>Prepares a new block for decompression if any remain in the stream</summary>
        /// <remarks>If a previous block has completed, its CRC is checked and merged into the stream CRC.
        /// If the previous block was the final block in the stream, the stream CRC is validated</remarks>
        /// <return>true if a block was successfully initialised, or false if the end of file marker was encountered</return>
        /// <exception>If either the block or stream CRC check failed, if the following data is
        /// not a valid block-header or end-of-file marker, or if the following block could not be decoded</exception>
        private bool InitialiseNextBlock()  {

			/* If we're already at the end of the stream, do nothing */
			if (this.streamComplete) 
				return false;			

			/* If a block is complete, check the block CRC and integrate it into the stream CRC */
			if (this.blockDecompressor != null) {
				uint blockCRC = this.blockDecompressor.CheckCrc();
				this.streamCRC = ((this.streamCRC << 1) | (this.streamCRC >> 31)) ^ blockCRC;
			}

			/* Read block-header or end-of-stream marker */
			 uint marker1 = this.bitInputStream.ReadBits(24);
			 uint marker2 = this.bitInputStream.ReadBits(24);

			if (marker1 == BZip2BlockCompressor.BLOCK_HEADER_MARKER_1 && marker2 == BZip2BlockCompressor.BLOCK_HEADER_MARKER_2) {
				// Initialise a new block
				try {
					this.blockDecompressor = new BZip2BlockDecompressor(this.bitInputStream, this.streamBlockSize);
				} catch (IOException) {
					// If the block could not be decoded, stop trying to read more data
					this.streamComplete = true;
					throw;
				}
				return true;
			}
		    if (marker1 == BZip2OutputStream.STREAM_END_MARKER_1 && marker2 == BZip2OutputStream.STREAM_END_MARKER_2) {
		        // Read and verify the end-of-stream CRC
		        this.streamComplete = true;
                uint storedCombinedCRC = this.bitInputStream.ReadInteger(); ///.ReadBits(32);

                if (storedCombinedCRC != this.streamCRC) 
		            throw new Exception ("BZip2 stream CRC error");

		        return false;
		    }

		    /* If what was read is not a valid block-header or end-of-stream marker, the stream is broken */
			this.streamComplete = true;
			throw new Exception ("BZip2 stream format error");
		}
Пример #2
0
        public override void Close()  
        {
            if (this.bitInputStream == null) 
                return;

            this.streamComplete = true;
            this.blockDecompressor = null;
            this.bitInputStream = null;

            try {
                this.inputStream.Close();
            } finally {
                this.inputStream = null;
            }
        }