Technique : les Patch Files sous C++ Builder

bool __fastcall TMMF::Execute()
{
    try
    {
        GetFile();
        GetSizeofFile();
        if (FMapFileOffset==0)
        FMapFileOffset=FFileSize;
        if (FBigger)
        FMapFileSizeLow=FFileSize+FMapFileOffset;
        else
        FMapFileSizeLow=FMapFileOffset;
        FMapFileSizeHigh=FFileSizeHigh;
        GetMapping();
        GetPtrAdresse();
        }
    catch (EOSError &E)
    {
        FErrorMsg=E.Message;
        return false;
        }
    return true;
    }

void __fastcall TMMF::GetMapping()
{
    FFileMap=CreateFileMapping(
        FFileHandle, // handle to file to map
        NULL, // optional security attributes
        PAGE_READWRITE, // protection for mapping object
        FMapFileSizeHigh, // high-order 32 bits of object size
        FMapFileSizeLow, // low-order 32 bits of object size
        NULL);
    if (!FFileMap)
    RaiseLastOSError();
   
}

bool __fastcall TForm1::GetFileSize(AnsiString FileName,long * Size)
{
long FileSize;
int FHandle=FileOpen(FileName,fmOpenRead);
if (FHandle!=-1)
{
    FileSize=FileSeek(FHandle,0,2);
    FileClose(FHandle);
    *Size= FileSize;
    return true;
    }
else return false;
}

void __fastcall TForm1::AdjustFileSize()
{
HANDLE FFileHandle;
FFileHandle=CreateFile(
    FoldFileName.c_str(), // pointer to name of the file
    GENERIC_READ|GENERIC_WRITE, // access (read-write) mode
    FILE_SHARE_READ|FILE_SHARE_WRITE,// share mode
    NULL, // pointer to security attributes
    OPEN_EXISTING, // how to create
    FILE_ATTRIBUTE_NORMAL, // file attributes
    NULL);

SetFilePointer(
    FFileHandle,
    FStreamSize,
    NULL,
    FILE_BEGIN);

SetEndOfFile(FFileHandle);
CloseHandle(FFileHandle);
}

bool __fastcall TForm1::PatchFile()
{
TMMF *oldMMF,*PatchMMF;
PatchMMF= new TMMF(FPatchFileName);
if (PatchMMF->Execute())
{
    FStreamSize=PatchMMF->FileSize;
    oldMMF= new TMMF(FoldFileName,FDiff,FPatchIsBigger);
    if (oldMMF->Execute())
    {
        memcpy(oldMMF->PtrMapping,PatchMMF->PtrMapping,FStreamSize);
        delete oldMMF;
        if (!FPatchIsBigger)AdjustFileSize();
        }
    else
    {
        MessageDlg(oldMMF->ErrorMessage, mtError, TMsgDlgButtons() << mbOK, 0);
        StatusBar1->Panels->Items[0]->Text ="Erreur lors de la copie ...";
        delete oldMMF;
        return false;
        }
    delete PatchMMF;
    }
else
{
    MessageDlg(PatchMMF->ErrorMessage, mtError, TMsgDlgButtons() << mbOK, 0);
    StatusBar1->Panels->Items[0]->Text ="Erreur lors du traitement ...";
    return false;
    }
return true;
}

void __fastcall TForm1::DisplayErrorMessage(AnsiString msgE)
{
MessageDlg(msgE, mtError, TMsgDlgButtons() << mbOK, 0);
StatusBar1->Panels->Items[0]->Text =msgE;
}

void __fastcall TForm1::ClearFields()
{
FPatchFileName="";
FoldFileName="";
edNewFile->Text="";
edOldFile->Text="";
}

bool __fastcall TForm1::IsBigger(long * size)
{
if (FSizePatchFile>FSizeOldFile)
{
    *size= FSizePatchFile-FSizeOldFile;
    return true;
    }
else
{
    *size=FSizePatchFile;
    return false;
    }
}

void __fastcall TForm1::OpenOlDfileExecute(TObject *Sender)
{
OpenDialog1->Title="Sélectionner le fichier à patcher";
if (OpenDialog1->Execute())
{
    edOldFile->Text=OpenDialog1->FileName;
    FoldFileName=OpenDialog1->FileName;
    StatusBar1->Panels->Items[0]->Text ="Sélectionner le Patch";
    }
}

void __fastcall TForm1::OpenPatchNameExecute(TObject *Sender)
{
OpenDialog1->Title="Sélectionner le Patch";
if (OpenDialog1->Execute())
{
    edNewFile->Text=OpenDialog1->FileName;
    FPatchFileName=OpenDialog1->FileName;
    StatusBar1->Panels->Items[0]->Text ="Presser la touche Make...";
    }
}

void __fastcall TForm1::AboutExecute(TObject *Sender)
{
    AboutBox->ShowModal();
    }

void __fastcall TForm1::CloseAppExecute(TObject *Sender)
{
    Close();
    }

void __fastcall TForm1::MakeExecute(TObject *Sender)
{
FPatchIsBigger=false;
if (!GetFileSize(FoldFileName,&FSizeOldFile))
{
    DisplayErrorMessage("Veuillez choisir un fichier valide");
    FPatchFileName="";
    FoldFileName="";
    return ;
    }
if (!GetFileSize(FPatchFileName,&FSizePatchFile))
{
    DisplayErrorMessage("Veuillez choisir un fichier valide");
    FPatchFileName="";
    FoldFileName="";
    return ;
    }
FPatchIsBigger=IsBigger(&FDiff);
if (PatchFile())
{
    AnsiString msg="Le fichier \r\n";
    msg+=FoldFileName;
    msg+="\r\na été mis a jour avec succès avec le patch suivant\r\n";
    msg+=FPatchFileName;
    MessageDlg(msg, mtInformation, TMsgDlgButtons() << mbOK, 0);
    StatusBar1->Panels->Items[0]->Text ="Opération terminée avec succès...";
    ClearFields();
    }
}