コード例 #1
0
ファイル: Sha512.cs プロジェクト: goldmint/gm-web-cab
        /// <summary>
        /// Updates internal state with data from the provided array.
        /// </summary>
        /// <param name="data">Array of bytes</param>
        /// <param name="index">Offset of byte sequence</param>
        /// <param name="length">Sequence length</param>
        public void Update(byte[] data, int index, int length)
        {
            Contract.Requires <ArgumentNullException>(data != null);
            Contract.Requires <ArgumentOutOfRangeException>(index >= 0 && length >= 0);
            Contract.Requires <ArgumentException>((index + length) <= data.Length);

            Array16 <ulong> block;
            int             bytesInBuffer = (int)_totalBytes & (BlockSize - 1);

            _totalBytes += (uint)length;

            if (_totalBytes >= ulong.MaxValue / 8)
            {
                throw new InvalidOperationException("Too much data");
            }
            // Fill existing buffer
            if (bytesInBuffer != 0)
            {
                var toCopy = Math.Min(BlockSize - bytesInBuffer, length);
                Buffer.BlockCopy(data, index, _buffer, bytesInBuffer, toCopy);
                index         += toCopy;
                length        -= toCopy;
                bytesInBuffer += toCopy;
                if (bytesInBuffer == BlockSize)
                {
                    ByteIntegerConverter.Array16LoadBigEndian64(out block, _buffer, 0);
                    Sha512Internal.Core(out _state, ref _state, ref block);
                    CryptoBytes.InternalWipe(_buffer, 0, _buffer.Length);
                    bytesInBuffer = 0;
                }
            }
            // Hash complete blocks without copying
            while (length >= BlockSize)
            {
                ByteIntegerConverter.Array16LoadBigEndian64(out block, data, index);
                Sha512Internal.Core(out _state, ref _state, ref block);
                index  += BlockSize;
                length -= BlockSize;
            }
            // Copy remainder into buffer
            if (length > 0)
            {
                Buffer.BlockCopy(data, index, _buffer, bytesInBuffer, length);
            }
        }