--- /dev/null
+//\r
+// © Copyright Henrik Ravn 2004\r
+//\r
+// Use, modification and distribution are subject to the Boost Software License, Version 1.0. \r
+// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)\r
+//\r
+\r
+using System;\r
+using System.Runtime.InteropServices;\r
+using System.Text;\r
+\r
+\r
+namespace DotZLib\r
+{\r
+ #region ChecksumGeneratorBase\r
+ /// <summary>\r
+ /// Implements the common functionality needed for all <see cref="ChecksumGenerator"/>s\r
+ /// </summary>\r
+ /// <example></example>\r
+ public abstract class ChecksumGeneratorBase : ChecksumGenerator\r
+ {\r
+ /// <summary>\r
+ /// The value of the current checksum\r
+ /// </summary>\r
+ protected uint _current;\r
+\r
+ /// <summary>\r
+ /// Initializes a new instance of the checksum generator base - the current checksum is \r
+ /// set to zero\r
+ /// </summary>\r
+ public ChecksumGeneratorBase()\r
+ {\r
+ _current = 0;\r
+ }\r
+\r
+ /// <summary>\r
+ /// Initializes a new instance of the checksum generator basewith a specified value\r
+ /// </summary>\r
+ /// <param name="initialValue">The value to set the current checksum to</param>\r
+ public ChecksumGeneratorBase(uint initialValue)\r
+ {\r
+ _current = initialValue;\r
+ }\r
+\r
+ /// <summary>\r
+ /// Resets the current checksum to zero\r
+ /// </summary>\r
+ public void Reset() { _current = 0; }\r
+\r
+ /// <summary>\r
+ /// Gets the current checksum value\r
+ /// </summary>\r
+ public uint Value { get { return _current; } }\r
+\r
+ /// <summary>\r
+ /// Updates the current checksum with part of an array of bytes\r
+ /// </summary>\r
+ /// <param name="data">The data to update the checksum with</param>\r
+ /// <param name="offset">Where in <c>data</c> to start updating</param>\r
+ /// <param name="count">The number of bytes from <c>data</c> to use</param>\r
+ /// <exception cref="ArgumentException">The sum of offset and count is larger than the length of <c>data</c></exception>\r
+ /// <exception cref="NullReferenceException"><c>data</c> is a null reference</exception>\r
+ /// <exception cref="ArgumentOutOfRangeException">Offset or count is negative.</exception>\r
+ /// <remarks>All the other <c>Update</c> methods are implmeneted in terms of this one. \r
+ /// This is therefore the only method a derived class has to implement</remarks>\r
+ public abstract void Update(byte[] data, int offset, int count);\r
+\r
+ /// <summary>\r
+ /// Updates the current checksum with an array of bytes.\r
+ /// </summary>\r
+ /// <param name="data">The data to update the checksum with</param>\r
+ public void Update(byte[] data)\r
+ {\r
+ Update(data, 0, data.Length);\r
+ }\r
+\r
+ /// <summary>\r
+ /// Updates the current checksum with the data from a string\r
+ /// </summary>\r
+ /// <param name="data">The string to update the checksum with</param>\r
+ /// <remarks>The characters in the string are converted by the UTF-8 encoding</remarks>\r
+ public void Update(string data)\r
+ {\r
+ Update(Encoding.UTF8.GetBytes(data));\r
+ }\r
+\r
+ /// <summary>\r
+ /// Updates the current checksum with the data from a string, using a specific encoding\r
+ /// </summary>\r
+ /// <param name="data">The string to update the checksum with</param>\r
+ /// <param name="encoding">The encoding to use</param>\r
+ public void Update(string data, Encoding encoding)\r
+ {\r
+ Update(encoding.GetBytes(data));\r
+ }\r
+\r
+ }\r
+ #endregion\r
+\r
+ #region CRC32\r
+ /// <summary>\r
+ /// Implements a CRC32 checksum generator\r
+ /// </summary>\r
+ public sealed class CRC32Checksum : ChecksumGeneratorBase \r
+ {\r
+ #region DLL imports\r
+\r
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]\r
+ private static extern uint crc32(uint crc, int data, uint length);\r
+\r
+ #endregion\r
+\r
+ /// <summary>\r
+ /// Initializes a new instance of the CRC32 checksum generator\r
+ /// </summary>\r
+ public CRC32Checksum() : base() {}\r
+\r
+ /// <summary>\r
+ /// Initializes a new instance of the CRC32 checksum generator with a specified value\r
+ /// </summary>\r
+ /// <param name="initialValue">The value to set the current checksum to</param>\r
+ public CRC32Checksum(uint initialValue) : base(initialValue) {}\r
+\r
+ /// <summary>\r
+ /// Updates the current checksum with part of an array of bytes\r
+ /// </summary>\r
+ /// <param name="data">The data to update the checksum with</param>\r
+ /// <param name="offset">Where in <c>data</c> to start updating</param>\r
+ /// <param name="count">The number of bytes from <c>data</c> to use</param>\r
+ /// <exception cref="ArgumentException">The sum of offset and count is larger than the length of <c>data</c></exception>\r
+ /// <exception cref="NullReferenceException"><c>data</c> is a null reference</exception>\r
+ /// <exception cref="ArgumentOutOfRangeException">Offset or count is negative.</exception>\r
+ public override void Update(byte[] data, int offset, int count)\r
+ {\r
+ if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();\r
+ if ((offset+count) > data.Length) throw new ArgumentException();\r
+ GCHandle hData = GCHandle.Alloc(data, GCHandleType.Pinned);\r
+ try\r
+ {\r
+ _current = crc32(_current, hData.AddrOfPinnedObject().ToInt32()+offset, (uint)count);\r
+ }\r
+ finally\r
+ {\r
+ hData.Free();\r
+ }\r
+ }\r
+\r
+ }\r
+ #endregion\r
+\r
+ #region Adler\r
+ /// <summary>\r
+ /// Implements a checksum generator that computes the Adler checksum on data\r
+ /// </summary>\r
+ public sealed class AdlerChecksum : ChecksumGeneratorBase \r
+ {\r
+ #region DLL imports\r
+\r
+ [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]\r
+ private static extern uint adler32(uint adler, int data, uint length);\r
+\r
+ #endregion\r
+\r
+ /// <summary>\r
+ /// Initializes a new instance of the Adler checksum generator\r
+ /// </summary>\r
+ public AdlerChecksum() : base() {}\r
+\r
+ /// <summary>\r
+ /// Initializes a new instance of the Adler checksum generator with a specified value\r
+ /// </summary>\r
+ /// <param name="initialValue">The value to set the current checksum to</param>\r
+ public AdlerChecksum(uint initialValue) : base(initialValue) {}\r
+\r
+ /// <summary>\r
+ /// Updates the current checksum with part of an array of bytes\r
+ /// </summary>\r
+ /// <param name="data">The data to update the checksum with</param>\r
+ /// <param name="offset">Where in <c>data</c> to start updating</param>\r
+ /// <param name="count">The number of bytes from <c>data</c> to use</param>\r
+ /// <exception cref="ArgumentException">The sum of offset and count is larger than the length of <c>data</c></exception>\r
+ /// <exception cref="NullReferenceException"><c>data</c> is a null reference</exception>\r
+ /// <exception cref="ArgumentOutOfRangeException">Offset or count is negative.</exception>\r
+ public override void Update(byte[] data, int offset, int count)\r
+ {\r
+ if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();\r
+ if ((offset+count) > data.Length) throw new ArgumentException();\r
+ GCHandle hData = GCHandle.Alloc(data, GCHandleType.Pinned);\r
+ try\r
+ {\r
+ _current = adler32(_current, hData.AddrOfPinnedObject().ToInt32()+offset, (uint)count);\r
+ }\r
+ finally\r
+ {\r
+ hData.Free();\r
+ }\r
+ }\r
+\r
+ }\r
+ #endregion\r
+\r
+}
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