2 // © Copyright Henrik Ravn 2004
4 // Use, modification and distribution are subject to the Boost Software License, Version 1.0.
5 // (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9 using System.Runtime.InteropServices;
15 #region ChecksumGeneratorBase
17 /// Implements the common functionality needed for all <see cref="ChecksumGenerator"/>s
19 /// <example></example>
20 public abstract class ChecksumGeneratorBase : ChecksumGenerator
23 /// The value of the current checksum
25 protected uint _current;
28 /// Initializes a new instance of the checksum generator base - the current checksum is
31 public ChecksumGeneratorBase()
37 /// Initializes a new instance of the checksum generator basewith a specified value
39 /// <param name="initialValue">The value to set the current checksum to</param>
40 public ChecksumGeneratorBase(uint initialValue)
42 _current = initialValue;
46 /// Resets the current checksum to zero
48 public void Reset() { _current = 0; }
51 /// Gets the current checksum value
53 public uint Value { get { return _current; } }
56 /// Updates the current checksum with part of an array of bytes
58 /// <param name="data">The data to update the checksum with</param>
59 /// <param name="offset">Where in <c>data</c> to start updating</param>
60 /// <param name="count">The number of bytes from <c>data</c> to use</param>
61 /// <exception cref="ArgumentException">The sum of offset and count is larger than the length of <c>data</c></exception>
62 /// <exception cref="NullReferenceException"><c>data</c> is a null reference</exception>
63 /// <exception cref="ArgumentOutOfRangeException">Offset or count is negative.</exception>
64 /// <remarks>All the other <c>Update</c> methods are implmeneted in terms of this one.
65 /// This is therefore the only method a derived class has to implement</remarks>
66 public abstract void Update(byte[] data, int offset, int count);
69 /// Updates the current checksum with an array of bytes.
71 /// <param name="data">The data to update the checksum with</param>
72 public void Update(byte[] data)
74 Update(data, 0, data.Length);
78 /// Updates the current checksum with the data from a string
80 /// <param name="data">The string to update the checksum with</param>
81 /// <remarks>The characters in the string are converted by the UTF-8 encoding</remarks>
82 public void Update(string data)
84 Update(Encoding.UTF8.GetBytes(data));
88 /// Updates the current checksum with the data from a string, using a specific encoding
90 /// <param name="data">The string to update the checksum with</param>
91 /// <param name="encoding">The encoding to use</param>
92 public void Update(string data, Encoding encoding)
94 Update(encoding.GetBytes(data));
102 /// Implements a CRC32 checksum generator
104 public sealed class CRC32Checksum : ChecksumGeneratorBase
108 [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
109 private static extern uint crc32(uint crc, int data, uint length);
114 /// Initializes a new instance of the CRC32 checksum generator
116 public CRC32Checksum() : base() {}
119 /// Initializes a new instance of the CRC32 checksum generator with a specified value
121 /// <param name="initialValue">The value to set the current checksum to</param>
122 public CRC32Checksum(uint initialValue) : base(initialValue) {}
125 /// Updates the current checksum with part of an array of bytes
127 /// <param name="data">The data to update the checksum with</param>
128 /// <param name="offset">Where in <c>data</c> to start updating</param>
129 /// <param name="count">The number of bytes from <c>data</c> to use</param>
130 /// <exception cref="ArgumentException">The sum of offset and count is larger than the length of <c>data</c></exception>
131 /// <exception cref="NullReferenceException"><c>data</c> is a null reference</exception>
132 /// <exception cref="ArgumentOutOfRangeException">Offset or count is negative.</exception>
133 public override void Update(byte[] data, int offset, int count)
135 if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
136 if ((offset+count) > data.Length) throw new ArgumentException();
137 GCHandle hData = GCHandle.Alloc(data, GCHandleType.Pinned);
140 _current = crc32(_current, hData.AddrOfPinnedObject().ToInt32()+offset, (uint)count);
153 /// Implements a checksum generator that computes the Adler checksum on data
155 public sealed class AdlerChecksum : ChecksumGeneratorBase
159 [DllImport("ZLIB1.dll", CallingConvention=CallingConvention.Cdecl)]
160 private static extern uint adler32(uint adler, int data, uint length);
165 /// Initializes a new instance of the Adler checksum generator
167 public AdlerChecksum() : base() {}
170 /// Initializes a new instance of the Adler checksum generator with a specified value
172 /// <param name="initialValue">The value to set the current checksum to</param>
173 public AdlerChecksum(uint initialValue) : base(initialValue) {}
176 /// Updates the current checksum with part of an array of bytes
178 /// <param name="data">The data to update the checksum with</param>
179 /// <param name="offset">Where in <c>data</c> to start updating</param>
180 /// <param name="count">The number of bytes from <c>data</c> to use</param>
181 /// <exception cref="ArgumentException">The sum of offset and count is larger than the length of <c>data</c></exception>
182 /// <exception cref="NullReferenceException"><c>data</c> is a null reference</exception>
183 /// <exception cref="ArgumentOutOfRangeException">Offset or count is negative.</exception>
184 public override void Update(byte[] data, int offset, int count)
186 if (offset < 0 || count < 0) throw new ArgumentOutOfRangeException();
187 if ((offset+count) > data.Length) throw new ArgumentException();
188 GCHandle hData = GCHandle.Alloc(data, GCHandleType.Pinned);
191 _current = adler32(_current, hData.AddrOfPinnedObject().ToInt32()+offset, (uint)count);