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UpdateResource

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7 Sep 20032 min read 175.3K   60   42
How to manipulate raw resources (RT_RCDATA) using UpdateResource().

Introduction

Over the years, I've seen various flavors of the question "How do I include a file or data with my program that I can extract at run-time and do something with it?" For example, the asker might have had a .WAV file or a .MDB (MS Access) file that s/he wanted to include in the actual executable itself. For one reason or another, they do not want to package the two files separately. One advantage this has over a separate data/configuration file is that it'll never get lost. If the user decides they want to start fresh, they can remove everything but the application itself, and when the application is started up again, it extracts an empty database, all without the user knowing the behind-the-scenes details.

So thre are really two questions on the table here: "How to include the file?" and "Once the file is included, how to extract it and 'use' it?" Let's look at a simple example.

Including the file

In this example, I'll show the necessary code to take the entire Windows calculator (calc.exe) and add it as a resource to some test .EXE. The .EXE could just as easily be the application where these code snippets reside. The first thing we must do is open calc.exe in read-only mode, and read the entire file into a buffer.

HANDLE hFile;
DWORD dwFileSize,      
      dwBytesRead;
LPBYTE lpBuffer;

hFile = CreateFile(L"C:\\Winnt\\System32\\calc.exe", GENERIC_READ, 
                   0,
                   NULL,
                   OPEN_EXISTING,
                   FILE_ATTRIBUTE_NORMAL,
                   NULL);

if (INVALID_HANDLE_VALUE != hFile)
{
    dwFileSize = GetFileSize(hFile, NULL);

    lpBuffer = new BYTE[dwFileSize];

    if (ReadFile(hFile, lpBuffer, dwFileSize, &dwBytesRead, NULL) != FALSE)
    {
        // do something with lpBuffer here
    }

    delete [] lpBuffer;        
    
    CloseHandle(hFile);
}

Updating the resource data

Now it's simply a matter of getting access to the resource data of the test file and updating it with the data pointed to by lpBuffer. The third parameter to UpdateResource() is the name we want to give the resource. I just chose an arbitrary name of 104.

HANDLE hResource;

hResource = BeginUpdateResource(L"C:\\...\\t3.exe", FALSE);
if (NULL != hResource)
{
    if (UpdateResource(hResource, 
        RT_RCDATA, 
        MAKEINTRESOURCE(104), 
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), 
        (LPVOID) lpBuffer, 
        dwFileSize) != FALSE)
    {
        EndUpdateResource(hResource, FALSE);
    }
}

At this point, you can actually open the test file with Visual Studio and see the addition of our data in the "Data" section. Be sure to open the file as a "resource"!

Extracting the data

So now your application has been delivered, and you need to extract the resource data.

Extracting the resource data uses functions from the same family as UpdateResource(). The required steps are to load the file containing the resource data, find the desired resource, load the resource, and then lock it.

HMODULE hLibrary;
HRSRC hResource;
HGLOBAL hResourceLoaded;
LPBYTE lpBuffer;

hLibrary = LoadLibrary(L"C:\\...\\t3.exe");
if (NULL != hLibrary)
{
    hResource = FindResource(hLibrary, MAKEINTRESOURCE(104), RT_RCDATA);
    if (NULL != hResource)
    {
        hResourceLoaded = LoadResource(hLibrary, hResource);
        if (NULL != hResourceLoaded)        
        {
            lpBuffer = (LPBYTE) LockResource(hResourceLoaded);            
            if (NULL != lpBuffer)            
            {                
                // do something with lpBuffer here            
            }
        }    
    }

    FreeLibrary(hLibrary);
}

Saving the data to a file

All that's left is to create a file with the data pointed to by lpBuffer. Nothing special needs to be done to the data. It's the entire Windows calculator!

DWORD dwFileSize,
      dwBytesWritten;
HANDLE hFile;

dwFileSize = SizeofResource(hLibrary, hResource);

hFile = CreateFile(L"C:\\Winnt\\Temp\\calc2.exe",
                   GENERIC_WRITE,
                   0,
                   NULL,
                   CREATE_ALWAYS,
                   FILE_ATTRIBUTE_NORMAL,
                   NULL);

if (INVALID_HANDLE_VALUE != hFile)
{
    WriteFile(hFile, lpBuffer, dwFileSize, &dwBytesWritten, NULL);

    CloseHandle(hFile);
}

Now you should be able to run the newly created file, calc2.exe! As I indicated at the beginning of the article, this can be done with any sort of file that you want to include along with your main application or DLL.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
Software Developer (Senior) Pinnacle Business Systems
United States United States

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Comments and Discussions

 
GeneralHello Sir ! How To... Pin
ThatsAlok20-Jan-05 1:47
ThatsAlok20-Jan-05 1:47 
GeneralRe: Hello Sir ! How To... Pin
kurackurcevic4-Dec-09 17:03
kurackurcevic4-Dec-09 17:03 
GeneralGreat, this really helps a lot! Pin
Paul.Huang29-Jan-04 22:23
Paul.Huang29-Jan-04 22:23 
GeneralArticle editing suggestion Pin
Gary Wheeler9-Sep-03 3:52
Gary Wheeler9-Sep-03 3:52 
Generalyes, but Pin
eco8-Sep-03 21:04
eco8-Sep-03 21:04 
GeneralRe: yes, but Pin
David Crow9-Sep-03 2:06
David Crow9-Sep-03 2:06 
GeneralRe: yes, but Pin
IGx8918-Sep-03 15:24
IGx8918-Sep-03 15:24 
GeneralRe: yes, but Pin
David Crow19-Sep-03 2:04
David Crow19-Sep-03 2:04 
I would not have thought to call UpdateResource() with more than one resource. I'm curious how you would do so since the third parameter is the name used to identify the resource.


Five birds are sitting on a fence.
Three of them decide to fly off.
How many are left?

GeneralRe: yes, but Pin
IGx8919-Sep-03 2:56
IGx8919-Sep-03 2:56 
GeneralRe: yes, but Pin
Furer Alexander27-Jan-04 2:35
Furer Alexander27-Jan-04 2:35 
GeneralRe: yes, but Pin
David Crow27-Jan-04 6:51
David Crow27-Jan-04 6:51 
GeneralRe: yes, but Pin
dlgproc27-Jan-04 7:29
dlgproc27-Jan-04 7:29 
GeneralRe: yes, but Pin
CPAVG23-Feb-05 21:24
CPAVG23-Feb-05 21:24 

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