Files
Aaru.Server/DiscImageChef.Checksums/FletcherContext.cs

456 lines
15 KiB
C#

// /***************************************************************************
// The Disc Image Chef
// ----------------------------------------------------------------------------
//
// Filename : FletcherContext.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
//
// Component : Checksums.
//
// --[ Description ] ----------------------------------------------------------
//
// Implements Fletcher-32 and Fletcher-16 algorithms.
//
// --[ License ] --------------------------------------------------------------
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2017 Natalia Portillo
// ****************************************************************************/
// Disabled because the speed is abnormally slow
/*
using System;
using System.Text;
using System.IO;
namespace DiscImageChef.Checksums
{
public class Fletcher32Context
{
UInt16 sum1, sum2;
byte oddValue;
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, 0, 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, 0, 2);
block = BigEndianBitConverter.ToUInt16(blockBytes, 0);
localSum1 = (UInt16)((localSum1 + block) % 0xFFFF);
localSum2 = (UInt16)((localSum2 + localSum1) % 0xFFFF);
}
byte[] oddData = new byte[2];
oddData[0] = (byte)fileStream.ReadByte();
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 static 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 static string Data(byte[] data, out byte[] hash)
{
return Data(data, (uint)data.Length, out hash);
}
}
public class Fletcher16Context
{
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 static 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 static string Data(byte[] data, out byte[] hash)
{
return Data(data, (uint)data.Length, out hash);
}
}
}
*/