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Implement "entropy" command.

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Natalia Portillo
2015-05-19 06:04:21 +01:00
parent eb33aad7ef
commit 4fc2e234b0
5 changed files with 217 additions and 0 deletions
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180
DiscImageChef/Commands/Entropy.cs Normal file
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/***************************************************************************
The Disc Image Chef
----------------------------------------------------------------------------
Filename : Checksum.cs
Version : 1.0
Author(s) : Natalia Portillo
Component : Verbs.
Revision : $Revision$
Last change by : $Author$
Date : $Date$
--[ Description ] ----------------------------------------------------------
Implements the 'checksum' verb.
--[ License ] --------------------------------------------------------------
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/>.
----------------------------------------------------------------------------
Copyright (C) 2011-2014 Claunia.com
****************************************************************************/
//$Id$
using System;
using DiscImageChef.ImagePlugins;
using DiscImageChef.Checksums;
using System.Collections.Generic;
namespace DiscImageChef.Commands
{
public static class Entropy
{
public static void doEntropy(EntropySubOptions options)
{
if (MainClass.isDebug)
{
Console.WriteLine("--debug={0}", options.Debug);
Console.WriteLine("--verbose={0}", options.Verbose);
Console.WriteLine("--separated-tracks={0}", options.SeparatedTracks);
Console.WriteLine("--whole-disc={0}", options.WholeDisc);
Console.WriteLine("--input={0}", options.InputFile);
Console.WriteLine("--duplicated-sectors={0}", options.DuplicatedSectors);
}
ImagePlugin inputFormat = ImageFormat.Detect(options.InputFile);
if (inputFormat == null)
{
Console.WriteLine("Unable to recognize image format, not checksumming");
return;
}
inputFormat.OpenImage(options.InputFile);
if (options.SeparatedTracks)
{
try
{
List<Track> inputTracks = inputFormat.GetTracks();
foreach (Track currentTrack in inputTracks)
{
SHA1Context sha1ctxTrack = new SHA1Context();
ulong[] entTable = new ulong[256];
ulong trackSize = 0;
List<string> uniqueSectorsPerTrack = new List<string>();
ulong sectors = currentTrack.TrackEndSector - currentTrack.TrackStartSector + 1;
Console.WriteLine("Track {0} has {1} sectors", currentTrack.TrackSequence, sectors);
for (ulong i = currentTrack.TrackStartSector; i <= currentTrack.TrackEndSector; i++)
{
Console.Write("\rEntropying sector {0} of track {1}", i + 1, currentTrack.TrackSequence);
byte[] sector = inputFormat.ReadSector(i, currentTrack.TrackSequence);
if(options.DuplicatedSectors)
{
byte[] garbage;
string sectorHash = sha1ctxTrack.Data(sector, out garbage);
if(!uniqueSectorsPerTrack.Contains(sectorHash))
uniqueSectorsPerTrack.Add(sectorHash);
}
foreach(byte b in sector)
entTable[b]++;
trackSize += (ulong)sector.LongLength;
}
double entropy = 0;
foreach(ulong l in entTable)
{
double frequency = (double)l/(double)trackSize;
entropy += -(frequency * Math.Log(frequency, 2));
}
Console.WriteLine("Entropy for track {0} is {1:F4}.", currentTrack.TrackSequence, entropy);
if(options.DuplicatedSectors)
Console.WriteLine("Track {0} has {1} unique sectors ({1:P3})", currentTrack.TrackSequence, uniqueSectorsPerTrack.Count, (double)uniqueSectorsPerTrack.Count/(double)sectors);
Console.WriteLine();
}
}
catch (Exception ex)
{
if (options.Debug)
Console.WriteLine("Could not get tracks because {0}", ex.Message);
else
Console.WriteLine("Unable to get separate tracks, not calculating their entropy");
}
}
if (options.WholeDisc)
{
SHA1Context sha1Ctx = new SHA1Context();
ulong[] entTable = new ulong[256];
ulong diskSize = 0;
List<string> uniqueSectors = new List<string>();
ulong sectors = inputFormat.GetSectors();
Console.WriteLine("Sectors {0}", sectors);
sha1Ctx.Init();
for (ulong i = 0; i < sectors; i++)
{
Console.Write("\rEntropying sector {0}", i + 1);
byte[] sector = inputFormat.ReadSector(i);
if(options.DuplicatedSectors)
{
byte[] garbage;
string sectorHash = sha1Ctx.Data(sector, out garbage);
if(!uniqueSectors.Contains(sectorHash))
uniqueSectors.Add(sectorHash);
}
foreach(byte b in sector)
entTable[b]++;
diskSize += (ulong)sector.LongLength;
}
double entropy = 0;
foreach(ulong l in entTable)
{
double frequency = (double)l/(double)diskSize;
entropy += -(frequency * Math.Log(frequency, 2));
}
Console.WriteLine();
Console.WriteLine("Entropy for disk is {0:F4}.", entropy);
if(options.DuplicatedSectors)
Console.WriteLine("Disk has {0} unique sectors ({1:P3})", uniqueSectors.Count, (double)uniqueSectors.Count/(double)sectors);
}
}
}
}