//******************************************************************************************************//  ChecksumExtensions.cs - Gbtc////  Copyright © 2012, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://www.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  09/24/2008 - J. Ritchie Carroll//       Generated original version of source code.//  06/10/2009 - Mehulbhi Thakkar//		 Added extension method for CRC-ModBus calculation.//  09/14/2009 - Stephen C. Wills//       Added new header and license agreement.//  12/14/2012 - Starlynn Danyelle Gilliam//       Modified Header.////******************************************************************************************************  namespace GSF.IO.Checksums{    /// <summary>Defines extension functions related to computing checksums.</summary>    public static class ChecksumExtensions    {        /// <summary>Calculates the Adler-32 checksum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform checksum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin checksum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform checksum over.</param>        /// <returns>Computed Adler-32 checksum over the specified portion of the buffer.</returns>        public static uint Adler32Checksum(this byte[] data, int startIndex, int length)        {            Adler32 checksum = new Adler32();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates the CRC16 check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform check-sum over.</param>        /// <returns>Computed CRC16 checksum over the specified portion of the buffer.</returns>        public static ushort Crc16Checksum(this byte[] data, int startIndex, int length)        {            Crc16 checksum = new Crc16();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates the CRC-CCITT check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform check-sum over.</param>        /// <returns>Computed CRC-CCITT checksum over the specified portion of the buffer.</returns>        /// <remarks>        /// The CRC-CCITT is a table based 16-bit CRC popular for modem protocols defined for use by the        /// Consultative Committee on International Telegraphy and Telephony (CCITT)         /// </remarks>        public static ushort CrcCCITTChecksum(this byte[] data, int startIndex, int length)        {            CrcCCITT checksum = new CrcCCITT();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates the CRC-ModBus check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform check-sum over.</param>        /// <returns>Computed CRC-ModBus checksum over the specified portion of the buffer.</returns>		        public static ushort ModBusCrcChecksum(this byte[] data, int startIndex, int length)        {            Crc16 checksum = new Crc16(ChecksumType.ModBus);             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates the CRC32 check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform check-sum over.</param>        /// <returns>Computed CRC32 checksum over the specified portion of the buffer.</returns>        public static uint Crc32Checksum(this byte[] data, int startIndex, int length)        {            Crc32 checksum = new Crc32();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates byte length (8-bit) XOR-based check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform XOR check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin XOR check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform XOR check-sum over.</param>        /// <returns>Byte length XOR check-sum.</returns>        public static byte Xor8Checksum(this byte[] data, int startIndex, int length)        {            Xor8 checksum = new Xor8();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates word length (16-bit) XOR-based check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform XOR check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin XOR check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform XOR check-sum overs</param>        /// <returns>Word length XOR check-sum.</returns>        public static ushort Xor16Checksum(this byte[] data, int startIndex, int length)        {            Xor16 checksum = new Xor16();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates double-word length (32-bit) XOR-based check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform XOR check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin XOR check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform XOR check-sum over.</param>        /// <returns>Double-word length XOR check-sum.</returns>        public static uint Xor32Checksum(this byte[] data, int startIndex, int length)        {            Xor32 checksum = new Xor32();             checksum.Update(data, startIndex, length);             return checksum.Value;        }         /// <summary>Calculates quad-word length (64-bit) XOR-based check-sum on specified portion of a buffer.</summary>        /// <param name="data">Data buffer to perform XOR check-sum on.</param>        /// <param name="startIndex">Starts index in data buffer to begin XOR check-sum.</param>        /// <param name="length">Total number of bytes from <paramref name="startIndex">startIndex</paramref> to        /// perform XOR check-sum over.</param>        /// <returns>Quad-word length XOR check-sum.</returns>        public static ulong Xor64Checksum(this byte[] data, int startIndex, int length)        {            Xor64 checksum = new Xor64();             checksum.Update(data, startIndex, length);             return checksum.Value;        }    }}