MatteoZan.it

In my little free time I develop some open source projects, for example my last creature is “Minimalistic Explorer“. This project is made in C# WPF for the UI and actually core is written in C#, but I hope to port the existing core in C++/CLI.

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The following code snippet performs the following task:

1. Get icon of the given file
2. Convert in a bitmap preserving the alpha channel
3. Convert it in a ImageSource

This code is shortcut to retrieve the displayed icon of a file. alternative way to do this is useing shell32.dll and SHGetFileInfo.

I have not used IconBitmapDecoder becuase this class lost the alpha channel.

   1:  public BitmapSource GetIconFromPath(string path)

   2:  {

   3:      System.Drawing.Icon icon = System.Drawing.Icon.ExtractAssociatedIcon(path);

   4:      System.Drawing.Bitmap bitmap = icon.ToBitmap();

   5:      return System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(bitmap.GetHbitmap(),

   6:              IntPtr.Zero, System.Windows.Int32Rect.Empty,

   7:              System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());

   8:  }

The following code is a code snippet that enable the Low Fragmentation Heap for all heaps. Remembers that a process has at last one heap but for example a CRT console application has practically at last two heaps. The first heap is default heap of process and the second is the CRT heap. If you use a lot of external DLLs is very common that one of this DLL allocate a private heap.

   1:  // code snippet that try to enable LFH for all heaps of your runnig program.

   2:      HANDLE* hHeaps = NULL;

   3:      int numHeap = GetProcessHeaps(0, NULL);

   4:      if(numHeap > 0)

   5:      {

   6:          ULONG ulEnableLFH = 2;

   7:          hHeaps = (HANDLE*)malloc(sizeof(HANDLE)*numHeap);

   8:          if(GetProcessHeaps(numHeap, hHeaps) == numHeap)

   9:          {

  10:              for(int i = 0; i < numHeap; i++)

  11:              {

  12:                  if(!HeapSetInformation(hHeaps[i], HeapCompatibilityInformation, &ulEnableLFH, sizeof(ulEnableLFH)))

  13:                  {

  14:                      printf("Failed to enable LFH for heap %d.", i);

  15:                  }

  16:              }

  17:          }

  18:          else

  19:          {

  20:              // quite strange !!!

  21:          }

  22:          free(hHeaps);

  23:      }

Suggested reading Windows Internals 4th edition for more details.

Nell’ultimo week-end, un applicazione in sviluppo è terminata inaspettatamente un infinità di volta. Generando un gran numero di memory dump, tutti di dimensioni considerevoli. La domanda sorge spontanea.
Come posso analizzare tutti questi dump senza sprecare un sacco del mio tempo?

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NtQuerySystemaInformation http://msdn.microsoft.com/en-us/library/ms724509(VS.85).aspx is useful undocumented and discouraged API of ntdll.dll. This API shouldn’t be used but in some case is a short way to get a lot information.

With this API you can make a lot of thinks but in this example is used to get some information about process.

This function should be linked at runtime, see more information at this link: http://msdn.microsoft.com/en-us/library/ms686944(VS.85).aspx.

To invoke NtQuerySystemInformation you should pass the follow argument:

• Kind of information that you want get, in this example the SystemProcessInformation.
• Address of a chunk of memory to place all information.
• Size of previous chunk of memory.
• A integer passed by reference that will filled with the size of return value.

Unfortunately size of second arguments isn’t know, a solution is pass a chunk of memory and if it is too small retry. This solution is possible because the NtQuerySystemInformation in case of a chunk of memory is too small it return a specific error code.

In this example enumerations and structures used by this program are placed in stdafx.h header file.

This example is written with Visual Studio 2008.

Download example

Reflection is a power tool of managed language like Java and .NET (C#, VB.NET,C++/CLI and others). In the last days I have discovered that MethodInfo class don’t provide a method to check if is overridden or not.This activity is vary simple but on internet you can found a dozen of example about Reflection without one about this case.

   1:  using System;

   2:  using System.Collections.Generic;

   3:  using System.Text;

   4:  using System.Reflection;

   5:  

   6:  namespace ReflectionMethod

   7:  {

   8:      internal class Program

   9:      {

  10:          static void Main(string[] args)

  11:          {

  12:              BaseClass derived = new DerivedClass();

  13:  

  14:              Type type = derived.GetType();

  15:  

  16:              MethodInfo method1 = type.GetMethod("Method2");

  17:  

  18:              Console.WriteLine(String.Format("This method is overridden? {0}",

  19:                  IsOverridden(method1)));

  20:  

  21:              Console.ReadKey();

  22:          }

  23:  

  24:          public static Boolean IsOverridden(MethodInfo info)

  25:          {

  26:              MethodInfo baseDef = info.GetBaseDefinition();

  27:  

  28:              return !(info.DeclaringType.FullName == baseDef.DeclaringType.FullName);

  29:          }

  30:      }

  31:  }

Thanks Franks

For learns the WiX toolset I have decided to write a setup for install a Wizard of Visual Studio. This setup is very easy with WiX and his Visual Studio extension.

This wxs file make the follow steps:

1. Install the IWizard implementation in the GAC repository of target system.
2. Copy the Template for Visual Studio 2005 or 2008 in his ProjectTemplate folder.
3. Execute the command to install the template in visual studio (devenv /installvstemplates)

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Si tratta di un progettino per il corso di inteligenza artificiale, in sostanza è un pianificatore STRIPS scritto in prolog (algoritmo usato A*).
Il problema che modella è quello di un robot che deve portare il caffè a varie persone disponendo di due macchinette del caffè.
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Questa piccola guida serve a spiegare a chi non ha conoscenze tecniche da Sistemista/Programmatore di installare delle Web Applicazioni e testarle.

Prima di tutto bisogna procurarsi gli installer di MySQL (io installo la 4.1) e l’installer di JBoss (scarico la 4.0.x l’installar che è un file jar). Come prerequisito deve essere gia installato Java nella versione 1.4 o superiore dal sito di sun. (more…)