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Added Fletcher16 and Fletcher32 algorithms

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Natalia Portillo
2015-02-02 14:33:53 +00:00
parent 5b98dd32e6
commit 98d6b4f249
2 changed files with 444 additions and 0 deletions
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SharpHash/Checksums/FletcherContext.cs Normal file
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//
// FletcherContext.cs
//
// Author:
// Natalia Portillo <claunia@claunia.com>
//
// Copyright (c) 2015 © Claunia.com
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
using System;
using System.Text;
using System.IO;
namespace SharpHash.Checksums
{
public class Fletcher32Context
{
private UInt16 sum1, sum2;
private byte oddValue;
private bool inodd;
/// <summary>
/// Initializes the Fletcher32 sums
/// </summary>
public void Init()
{
sum1 = 0xFFFF;
sum2 = 0xFFFF;
oddValue = 0;
inodd = false;
}
/// <summary>
/// Updates the hash with data.
/// </summary>
/// <param name="data">Data buffer.</param>
/// <param name="len">Length of buffer to hash.</param>
public void Update(byte[] data, uint len)
{
UInt16 block;
if (!inodd)
{
// Odd size
if (len % 2 != 0)
{
oddValue = data[len - 1];
inodd = true;
for (int i = 0; i < len - 1; i += 2)
{
block = BigEndianBitConverter.ToUInt16(data, i);
sum1 = (UInt16)((sum1 + block) % 0xFFFF);
sum2 = (UInt16)((sum2 + sum1) % 0xFFFF);
}
}
else
{
inodd = false;
for (int i = 0; i < len; i += 2)
{
block = BigEndianBitConverter.ToUInt16(data, i);
sum1 = (UInt16)((sum1 + block) % 0xFFFF);
sum2 = (UInt16)((sum2 + sum1) % 0xFFFF);
}
}
}
// Carrying odd
else
{
byte[] oddData = new byte[2];
oddData[0] = oddValue;
oddData[1] = data[0];
block = BigEndianBitConverter.ToUInt16(oddData, 0);
sum1 = (UInt16)((sum1 + block) % 0xFFFF);
sum2 = (UInt16)((sum2 + sum1) % 0xFFFF);
// Even size, carrying odd
if (len % 2 == 0)
{
oddValue = data[len - 1];
inodd = true;
for (int i = 1; i < len - 1; i += 2)
{
block = BigEndianBitConverter.ToUInt16(data, i);
sum1 = (UInt16)((sum1 + block) % 0xFFFF);
sum2 = (UInt16)((sum2 + sum1) % 0xFFFF);
}
}
else
{
inodd = false;
for (int i = 1; i < len; i += 2)
{
block = BigEndianBitConverter.ToUInt16(data, i);
sum1 = (UInt16)((sum1 + block) % 0xFFFF);
sum2 = (UInt16)((sum2 + sum1) % 0xFFFF);
}
}
}
}
/// <summary>
/// Updates the hash with data.
/// </summary>
/// <param name="data">Data buffer.</param>
public void Update(byte[] data)
{
Update(data, (uint)data.Length);
}
/// <summary>
/// Returns a byte array of the hash value.
/// </summary>
public byte[] Final()
{
UInt32 finalSum = (UInt32)(sum1 + (sum2 << 16));
return BigEndianBitConverter.GetBytes(finalSum);
}
/// <summary>
/// Returns a hexadecimal representation of the hash value.
/// </summary>
public string End()
{
UInt32 finalSum = (UInt32)(sum1 + (sum2 << 16));
StringBuilder fletcherOutput = new StringBuilder();
for (int i = 0; i < BigEndianBitConverter.GetBytes(finalSum).Length; i++)
{
fletcherOutput.Append(BigEndianBitConverter.GetBytes(finalSum)[i].ToString("x2"));
}
return fletcherOutput.ToString();
}
/// <summary>
/// Gets the hash of a file
/// </summary>
/// <param name="filename">File path.</param>
public static byte[] File(string filename)
{
byte[] hash;
File(filename, out hash);
return hash;
}
/// <summary>
/// Gets the hash of a file in hexadecimal and as a byte array.
/// </summary>
/// <param name="filename">File path.</param>
/// <param name="hash">Byte array of the hash value.</param>
public static string File(string filename, out byte[] hash)
{
FileStream fileStream = new FileStream(filename, FileMode.Open);
UInt16 localSum1, localSum2, block;
UInt32 finalSum;
byte[] blockBytes;
localSum1 = 0xFFFF;
localSum2 = 0xFFFF;
block = 0;
if (fileStream.Length % 2 == 0)
{
for (int i = 0; i < fileStream.Length; i+=2)
{
blockBytes = new byte[2];
fileStream.Read(blockBytes, i, 2);
block = BigEndianBitConverter.ToUInt16(blockBytes, 0);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
}
else
{
for (int i = 0; i < fileStream.Length-1; i+=2)
{
blockBytes = new byte[2];
fileStream.Read(blockBytes, i, 2);
block = BigEndianBitConverter.ToUInt16(blockBytes, 0);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
byte[] oddData = new byte[2];
blockBytes = new byte[1];
fileStream.Read(blockBytes, (int)(fileStream.Length-2), 1);
oddData[0] = blockBytes[0];
oddData[1] = 0;
block = BigEndianBitConverter.ToUInt16(oddData, 0);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
finalSum = (UInt32)(localSum1 + (localSum2 << 16));
hash = BitConverter.GetBytes(finalSum);
StringBuilder fletcherOutput = new StringBuilder();
for (int i = 0; i < hash.Length; i++)
{
fletcherOutput.Append(hash[i].ToString("x2"));
}
return fletcherOutput.ToString();
}
/// <summary>
/// Gets the hash of the specified data buffer.
/// </summary>
/// <param name="data">Data buffer.</param>
/// <param name="len">Length of the data buffer to hash.</param>
/// <param name="hash">Byte array of the hash value.</param>
public string Data(byte[] data, uint len, out byte[] hash)
{
UInt16 localSum1, localSum2, block;
UInt32 finalSum;
localSum1 = 0xFFFF;
localSum2 = 0xFFFF;
block = 0;
if (len % 2 == 0)
{
for (int i = 0; i < len; i+=2)
{
block = BigEndianBitConverter.ToUInt16(data, i);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
}
else
{
for (int i = 0; i < len-1; i+=2)
{
block = BigEndianBitConverter.ToUInt16(data, i);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
byte[] oddData = new byte[2];
oddData[0] = data[len - 1];
oddData[1] = 0;
block = BigEndianBitConverter.ToUInt16(oddData, 0);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
finalSum = (UInt32)(localSum1 + (localSum2 << 16));
hash = BitConverter.GetBytes(finalSum);
StringBuilder fletcherOutput = new StringBuilder();
for (int i = 0; i < hash.Length; i++)
{
fletcherOutput.Append(hash[i].ToString("x2"));
}
return fletcherOutput.ToString();
}
/// <summary>
/// Gets the hash of the specified data buffer.
/// </summary>
/// <param name="data">Data buffer.</param>
/// <param name="hash">Byte array of the hash value.</param>
public string Data(byte[] data, out byte[] hash)
{
return Data(data, (uint)data.Length, out hash);
}
}
public class Fletcher16Context
{
private byte sum1, sum2;
/// <summary>
/// Initializes the Fletcher16 sums
/// </summary>
public void Init()
{
sum1 = 0xFF;
sum2 = 0xFF;
}
/// <summary>
/// Updates the hash with data.
/// </summary>
/// <param name="data">Data buffer.</param>
/// <param name="len">Length of buffer to hash.</param>
public void Update(byte[] data, uint len)
{
for (int i = 0; i < len; i++)
{
sum1 = (byte)((sum1 + data[i]) % 0xFF);
sum2 = (byte)((sum2 + sum1) % 0xFF);
}
}
/// <summary>
/// Updates the hash with data.
/// </summary>
/// <param name="data">Data buffer.</param>
public void Update(byte[] data)
{
Update(data, (uint)data.Length);
}
/// <summary>
/// Returns a byte array of the hash value.
/// </summary>
public byte[] Final()
{
UInt16 finalSum = (UInt16)(sum1 + (sum2 << 8));
return BigEndianBitConverter.GetBytes(finalSum);
}
/// <summary>
/// Returns a hexadecimal representation of the hash value.
/// </summary>
public string End()
{
UInt16 finalSum = (UInt16)(sum1 + (sum2 << 8));
StringBuilder fletcherOutput = new StringBuilder();
for (int i = 0; i < BigEndianBitConverter.GetBytes(finalSum).Length; i++)
{
fletcherOutput.Append(BigEndianBitConverter.GetBytes(finalSum)[i].ToString("x2"));
}
return fletcherOutput.ToString();
}
/// <summary>
/// Gets the hash of a file
/// </summary>
/// <param name="filename">File path.</param>
public static byte[] File(string filename)
{
byte[] hash;
File(filename, out hash);
return hash;
}
/// <summary>
/// Gets the hash of a file in hexadecimal and as a byte array.
/// </summary>
/// <param name="filename">File path.</param>
/// <param name="hash">Byte array of the hash value.</param>
public static string File(string filename, out byte[] hash)
{
FileStream fileStream = new FileStream(filename, FileMode.Open);
byte localSum1, localSum2, block;
UInt16 finalSum;
localSum1 = 0xFF;
localSum2 = 0xFF;
block = 0;
for (int i = 0; i < fileStream.Length; i+=2)
{
block = (byte)fileStream.ReadByte();
localSum1 = (byte)((localSum1 + block) % 0xFF);
localSum2 = (byte)((localSum2 + localSum1) % 0xFF);
}
finalSum = (UInt16)(localSum1 + (localSum2 << 8));
hash = BitConverter.GetBytes(finalSum);
StringBuilder fletcherOutput = new StringBuilder();
for (int i = 0; i < hash.Length; i++)
{
fletcherOutput.Append(hash[i].ToString("x2"));
}
return fletcherOutput.ToString();
}
/// <summary>
/// Gets the hash of the specified data buffer.
/// </summary>
/// <param name="data">Data buffer.</param>
/// <param name="len">Length of the data buffer to hash.</param>
/// <param name="hash">Byte array of the hash value.</param>
public string Data(byte[] data, uint len, out byte[] hash)
{
byte localSum1, localSum2;
UInt16 finalSum;
localSum1 = 0xFF;
localSum2 = 0xFF;
for (int i = 0; i < len; i++)
{
localSum1 = (byte)((localSum1 + data[i]) % 0xFF);
localSum2 = (byte)((localSum2 + localSum1) % 0xFF);
}
finalSum = (UInt16)(localSum1 + (localSum2 << 8));
hash = BitConverter.GetBytes(finalSum);
StringBuilder fletcherOutput = new StringBuilder();
for (int i = 0; i < hash.Length; i++)
{
fletcherOutput.Append(hash[i].ToString("x2"));
}
return fletcherOutput.ToString();
}
/// <summary>
/// Gets the hash of the specified data buffer.
/// </summary>
/// <param name="data">Data buffer.</param>
/// <param name="hash">Byte array of the hash value.</param>
public string Data(byte[] data, out byte[] hash)
{
return Data(data, (uint)data.Length, out hash);
}
}
}

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SharpHash/SharpHash.csproj
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@@ -49,6 +49,7 @@
<Compile Include="Checksums\SHA512Context.cs" /> <Compile Include="Checksums\SHA512Context.cs" />
<Compile Include="BigEndianBitConverter.cs" /> <Compile Include="BigEndianBitConverter.cs" />
<Compile Include="Checksums\SHA3Context.cs" /> <Compile Include="Checksums\SHA3Context.cs" />
<Compile Include="Checksums\FletcherContext.cs" />
</ItemGroup> </ItemGroup>
<Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" /> <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
<ItemGroup> <ItemGroup>