Using Memory Conversions for C++

The following code demonstrates how to implement memory conversions:

// include the LEAD Multimedia TOOLKIT header 
#include "ltmm.h" 
 
#include "resource.h" 
#include <tchar.h> 
#include <stdio.h> 
#include <assert.h> 
 
HINSTANCE g_hInstance; // application instance handle 
IltmmConvert* g_pConvert; // convert object's interface pointer 
 
// user defined message id used for conversion events 
#define WM_CONVERTNOTIFY (WM_USER + 1000)  
 
// 
// ConvertDlgProc 
// starts the conversion process and provides status feedback 
// 
// controls:  
// IDC_CONVERTSTATUS - static control used for status messages 
// IDC_CONVERTPROGRESS - static control used for conversion progress 
// IDC_USERABORT - button control used to abort the conversion or exit the dialog 
 
BOOL CALLBACK ConvertDlgProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)  
{ 
   TCHAR sz[256];  
   BSTR bstr1;  
   BSTR bstr2;  
   HRESULT hr;  
   long state;  
   long type;  
 
   switch (msg)  
   { 
   case WM_INITDIALOG:  
      // assign the notification window 
      g_pConvert->SetNotifyWindow((long) hwnd, WM_CONVERTNOTIFY);  
       
      // set the abort button text 
      SetDlgItemText(hwnd, IDC_USERABORT, _T("Abort")); 
    
      // start the conversion 
      hr = g_pConvert->StartConvert(); 
 
      if(FAILED(hr))  
      { 
         _stprintf(sz, _T("conversion error 0x%.8X"), lParam);  
         SetDlgItemText(hwnd, IDC_CONVERTSTATUS, sz);  
         UpdateWindow(GetDlgItem(hwnd, IDC_CONVERTSTATUS));  
         SetDlgItemText(hwnd, IDC_USERABORT, _T("Exit")); 
         MessageBeep(0);  
      } 
      return TRUE;  
      break;  
   case WM_DESTROY:  
      // reset the notification window 
      g_pConvert->SetNotifyWindow((long) NULL, 0);  
#ifdef _DEBUG 
   { 
      long state, err, pc;  
      TCHAR sz[1024];  
       
      // get the current state 
      g_pConvert->get_State(&state);  
       
      // get the current state 
      g_pConvert->get_ConvertError(&err);  
 
      // get the amount converted 
      g_pConvert->get_PercentComplete(&pc);  
       
      _stprintf(sz, _T("state = %d, error = 0x%.8X, complete = %d%%"), state, err, pc);  
      MessageBox(NULL, sz, _T("debug"), MB_OK);  
   } 
#endif 
    
      break;  
   case WM_COMMAND:  
      switch (LOWORD(wParam))  
      { 
      case IDC_USERABORT:  
         // user abort... stop conversion 
         g_pConvert->get_State(&state);  
         if(state == ltmmConvert_State_Running)  
            g_pConvert->StopConvert(); 
         else 
         { 
            g_pConvert->get_ConvertError((long*) &hr);  
            EndDialog(hwnd, (long) hr);  
         } 
         return TRUE;  
         break;  
      } 
      break;  
   case WM_CONVERTNOTIFY:  
      switch(wParam)  
      { 
      case ltmmConvert_Notify_Started:  
         // indicate conversion has started 
         g_pConvert->get_SourceType(&type);  
         switch(type)  
         { 
         case ltmmConvert_Source_File:  
            g_pConvert->get_SourceFile(&bstr1);  
            break;  
         case ltmmConvert_Source_HGlobal:  
            bstr1 = SysAllocString(L"[hglobal]");  
            break;  
         case ltmmConvert_Source_Array:  
            bstr1 = SysAllocString(L"[array]");  
            break;  
         case ltmmConvert_Source_Object:  
            bstr1 = SysAllocString(L"[object]");  
            break;  
         } 
         g_pConvert->get_TargetType(&type);  
         switch(type)  
         { 
         case ltmmConvert_Target_File:  
            g_pConvert->get_TargetFile(&bstr2);  
            break;  
         case ltmmConvert_Target_Array:  
            bstr2 = SysAllocString(L"[array]");  
            break;  
         case ltmmConvert_Target_Object:  
            bstr2 = SysAllocString(L"[object]");  
            break;  
         } 
         _stprintf(sz, _T("recompressing '%ls' to '%ls'..."), bstr1, bstr2);  
         SysFreeString(bstr1);  
         SysFreeString(bstr2);  
         SetDlgItemText(hwnd, IDC_CONVERTSTATUS, sz);  
         UpdateWindow(GetDlgItem(hwnd, IDC_CONVERTSTATUS));  
         break;  
      case ltmmConvert_Notify_Complete:  
         // indicate an conversion complete 
         _stprintf(sz, _T("conversion complete")); 
         SetDlgItemText(hwnd, IDC_CONVERTSTATUS, sz);  
         UpdateWindow(GetDlgItem(hwnd, IDC_CONVERTSTATUS));  
         SetDlgItemText(hwnd, IDC_USERABORT, _T("Exit")); 
         break;  
      case ltmmConvert_Notify_ErrorAbort:  
         // indicate an error 
         _stprintf(sz, _T("conversion error 0x%.8X"), lParam);  
         SetDlgItemText(hwnd, IDC_CONVERTSTATUS, sz);  
         UpdateWindow(GetDlgItem(hwnd, IDC_CONVERTSTATUS));  
         SetDlgItemText(hwnd, IDC_USERABORT, _T("Exit")); 
         MessageBeep(0);  
         break;  
      case ltmmConvert_Notify_UserAbort:  
         // indicate user abort 
         _stprintf(sz, _T("conversion aborted\n")); 
         SetDlgItemText(hwnd, IDC_CONVERTSTATUS, sz);  
         UpdateWindow(GetDlgItem(hwnd, IDC_CONVERTSTATUS));  
         SetDlgItemText(hwnd, IDC_USERABORT, _T("Exit")); 
         MessageBeep(0);  
         break;  
      case ltmmConvert_Notify_Progress:  
         // indicate conversion progress 
         _stprintf(sz, _T("%3d%% complete"), lParam);  
         SetDlgItemText(hwnd, IDC_CONVERTPROGRESS, sz);  
         UpdateWindow(GetDlgItem(hwnd, IDC_CONVERTPROGRESS));  
         break;  
      } 
      return TRUE;  
      break;  
   } 
   return FALSE;  
} 
 
// 
// SetAVIRecompression 
// sets up LEAD video compression, MP3 audio compression, and AVI file output 
// 
// hwndParent = parent window for compressor property dialog boxes 
// 
HRESULT SetAVIRecompression(HWND hwndParent)  
{ 
   IltmmCompressors* pCompressors;  
   long index;  
   VARIANT_BOOL f;  
   BSTR bstr;  
 
   // select the LEAD video compressor 
   g_pConvert->get_VideoCompressors(&pCompressors);  
   bstr = SysAllocString(L"@device:sw:{33D9A760-90C8-11D0-BD43-00A0C911CE86}\\LEAD MCMP/MJPEG Codec (2.0)"); 
   pCompressors->Find(bstr, &index);  
   SysFreeString(bstr);  
 
   if(index < 0)  
   { 
      // compressor isn't registered 
      pCompressors->Release(); 
      return E_FAIL;  
   } 
   pCompressors->put_Selection(index);  
   pCompressors->Release(); 
    
   // select the MP3 audio video compressor 
   g_pConvert->get_AudioCompressors(&pCompressors);  
   bstr = SysAllocString(L"@device:cm:{33D9A761-90C8-11D0-BD43-00A0C911CE86}\\85MPEG Layer-3"); 
   pCompressors->Find(bstr, &index);  
   SysFreeString(bstr);  
   if(index < 0)  
   { 
      // compressor isn't registered 
      pCompressors->Release(); 
      return E_FAIL;  
   } 
   pCompressors->put_Selection(index);  
   pCompressors->Release(); 
 
   // set output format to AVI 
   g_pConvert->put_TargetFormat(ltmmConvert_TargetFormat_Avi);  
 
#ifdef _DEBUG 
   { 
      long v; 
      g_pConvert->get_TargetFormat(&v); 
      assert(v == ltmmConvert_TargetFormat_Avi); 
   } 
#endif 
   // set video compressor properties 
   g_pConvert->HasDialog(ltmmConvert_Dlg_VideoCompressor, &f);  
   if(f)  
      g_pConvert->ShowDialog(ltmmConvert_Dlg_VideoCompressor, (long) hwndParent);  
    
   // set audio compressor properties 
   g_pConvert->HasDialog(ltmmConvert_Dlg_AudioCompressor, &f);  
   if(f)  
      g_pConvert->ShowDialog(ltmmConvert_Dlg_AudioCompressor, (long) hwndParent);  
 
   return S_OK;  
} 
 
// 
// RecompressArray 
// recompresses array to array using the LEAD video and MP3 audio compressors 
// 
// 1. the source file is preloaded into a source array 
// 2. the source array is recompressed to a target array 
// 3. the target array is written to the target file 
// 
// pszSource = source file path 
// pszTarget = target file path 
// 
HRESULT RecompressArray(LPCTSTR pszSource, LPCTSTR pszTarget)  
{ 
   HRESULT hr;  
   HANDLE hfile;    
   DWORD size, cb;  
   void* buffer;  
   VARIANT var;  
   SAFEARRAY* psaSource;  
   SAFEARRAY* psaTarget;  
 
   // open the source file 
   hfile = CreateFile(pszSource, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);  
   if(hfile == INVALID_HANDLE_VALUE)  
      return E_FAIL;  
 
   // allocate same-sized SAFEARRAY 
   size = GetFileSize(hfile, NULL);  
    
   psaSource = SafeArrayCreateVector(VT_UI1, 0, size);  
   if(!psaSource)  
   { 
      CloseHandle(hfile);  
      return E_OUTOFMEMORY;  
   } 
 
   // read entire source into array 
   SafeArrayAccessData(psaSource, (void**) &buffer);  
   if(!ReadFile(hfile, buffer, size, &cb, NULL) || cb != size)  
   { 
      SafeArrayUnaccessData(psaSource);  
      CloseHandle(hfile);  
      SafeArrayDestroy(psaSource);  
      return E_FAIL;  
   } 
   SafeArrayUnaccessData(psaSource);  
 
   // close file 
   CloseHandle(hfile);  
       
   // assign the source array 
   VariantInit(&var);  
   V_VT(&var) = (VT_ARRAY | VT_UI1);  
   V_ARRAY(&var) = psaSource;  
    
   hr = g_pConvert->put_SourceArray(var);  
   if(FAILED(hr))  
   { 
      SafeArrayDestroy(psaSource);  
      return hr;  
   } 
 
#ifdef _DEBUG 
   { 
      VARIANT var; 
      VariantInit(&var); 
      g_pConvert->get_SourceArray(&var); 
      assert(var.vt == (VT_ARRAY | VT_UI1)); 
   } 
#endif 
   // create the target array 
   psaTarget = SafeArrayCreateVector(VT_UI1, 0, 0);  
   if(!psaTarget)  
   { 
      g_pConvert->ResetSource(); 
      SafeArrayDestroy(psaSource);  
      return E_OUTOFMEMORY;  
   } 
 
   // assign the target array 
   VariantInit(&var);  
   V_VT(&var) = (VT_ARRAY | VT_UI1);  
   V_ARRAY(&var) = psaTarget;  
    
   hr = g_pConvert->put_TargetArray(var);  
   if(FAILED(hr))  
   { 
      g_pConvert->ResetSource(); 
      SafeArrayDestroy(psaSource);  
      SafeArrayDestroy(psaTarget);  
      return hr;  
   } 
 
#ifdef _DEBUG 
   { 
      VARIANT var; 
      VariantInit(&var); 
      g_pConvert->get_TargetArray(&var); 
      assert(var.vt == (VT_ARRAY | VT_UI1)); 
   } 
#endif 
   // setup AVI recompression 
   hr = SetAVIRecompression(NULL);  
   if(FAILED(hr))  
   { 
      g_pConvert->ResetTarget(); 
      g_pConvert->ResetSource(); 
      SafeArrayDestroy(psaSource);  
      SafeArrayDestroy(psaTarget);  
      return hr;  
   } 
 
   // do conversion 
   hr = (HRESULT) DialogBox(g_hInstance, (LPCTSTR)IDD_CONVERTDLG, NULL, ConvertDlgProc);  
    
   // kill the convert objects interest in the arrays 
   g_pConvert->ResetTarget(); 
   g_pConvert->ResetSource(); 
 
   // don't need the source anymore 
   SafeArrayDestroy(psaSource);  
 
   // return if the conversion failed 
   if(FAILED(hr))  
   { 
      SafeArrayDestroy(psaTarget);  
      return hr;  
   } 
    
   // write the output to file 
   hfile = CreateFile(pszTarget, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, 0, NULL);  
   if(hfile == INVALID_HANDLE_VALUE)  
   { 
      SafeArrayDestroy(psaTarget);  
      return E_FAIL;  
   } 
   SafeArrayAccessData(psaTarget, (void**) &buffer);  
   if(!WriteFile(hfile, buffer, psaTarget->rgsabound[0].cElements, &cb, NULL) || cb != psaTarget->rgsabound[0].cElements)  
   { 
      SafeArrayUnaccessData(psaTarget);  
      CloseHandle(hfile);  
      SafeArrayDestroy(psaTarget);  
      return E_FAIL;  
   } 
   SafeArrayUnaccessData(psaTarget);  
   CloseHandle(hfile);  
 
   SafeArrayDestroy(psaTarget);  
 
   return hr;  
} 
 
// 
// RecompressHGlobal 
// recompresses from global memory to a file using the LEAD video and MP3 audio compressors 
// 
// 1. the source file is preloaded into global memory 
// 2. the source memory is recompressed to the target file 
// 
// pszSource = source file path 
// pszTarget = target file path 
// 
HRESULT RecompressHGlobal(LPCTSTR pszSource, LPCTSTR pszTarget)  
{ 
   HRESULT hr;  
   HANDLE hfile;    
   BSTR bstr;  
   DWORD size, cb;  
   void* buffer;  
   HGLOBAL hglobal;  
#ifndef _UNICODE 
   WCHAR wsz[MAX_PATH];  
#endif 
 
   // open the source file 
   hfile = CreateFile(pszSource, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, 0, NULL);  
   if(hfile == INVALID_HANDLE_VALUE)  
      return E_FAIL;  
 
   // allocate same-sized buffer 
   size = GetFileSize(hfile, NULL);  
    
   hglobal = GlobalAlloc(GMEM_MOVEABLE, size);  
   if(!hglobal)  
   { 
      CloseHandle(hfile);  
      return E_OUTOFMEMORY;  
   } 
 
   // read entire source into buffer 
   buffer = GlobalLock(hglobal);  
   if(!ReadFile(hfile, buffer, size, &cb, NULL) || cb != size)  
   { 
      GlobalUnlock(hglobal);  
      CloseHandle(hfile);  
      GlobalFree(hglobal);  
      return E_FAIL;  
   } 
   GlobalUnlock(hglobal);  
 
   // close file 
   CloseHandle(hfile);  
       
   // assign the source buffer 
   hr = g_pConvert->put_SourceHGlobal((long) hglobal);  
   if(FAILED(hr))  
   { 
      GlobalFree(hglobal);  
      return hr;  
   } 
 
#ifdef _DEBUG 
   { 
      HGLOBAL hGlobal; 
      g_pConvert->get_SourceHGlobal((long*) &hGlobal); 
      assert(hGlobal != NULL); 
   } 
#endif 
   // set target file 
#ifdef _UNICODE 
   bstr = SysAllocString(pszTarget);  
#else 
   swprintf(wsz, L"%hs", pszTarget);  
   bstr = SysAllocString(wsz);  
#endif 
   hr = g_pConvert->put_TargetFile(bstr);  
   SysFreeString(bstr);  
   if(FAILED(hr))  
   { 
      g_pConvert->ResetSource(); 
      GlobalFree(hglobal);  
      return hr;  
   } 
   // setup AVI recompression 
   hr = SetAVIRecompression(NULL);  
   if(FAILED(hr))  
   { 
      g_pConvert->ResetSource(); 
      GlobalFree(hglobal);  
      return hr;  
   } 
 
   // do conversion 
   hr = (HRESULT) DialogBox(g_hInstance, (LPCTSTR)IDD_CONVERTDLG, NULL, ConvertDlgProc);  
    
   g_pConvert->ResetSource(); 
   GlobalFree(hglobal);  
 
   return hr;  
} 
 
int APIENTRY WinMain(HINSTANCE hInstance,  
                HINSTANCE hPrevInstance,  
                LPSTR      lpCmdLine,  
                int      nCmdShow)  
{ 
   HRESULT hr;  
    
   g_hInstance = hInstance;  
 
   // initialize COM library 
   hr = CoInitialize(NULL);  
   if(FAILED(hr))  
      goto error;  
 
   // create the convert object 
   hr = CoCreateInstance(CLSID_ltmmConvert, NULL, CLSCTX_INPROC_SERVER, IID_IltmmConvert, (void**) &g_pConvert);  
   if(FAILED(hr))  
      goto error;  
    
   hr = RecompressArray(MAKE_MEDIA_PATH("source.avi"), MAKE_MEDIA_PATH("target1.avi")); 
   if(FAILED(hr))  
      goto error;  
 
   hr = RecompressHGlobal(MAKE_MEDIA_PATH("source.avi"), MAKE_MEDIA_PATH("target2.avi")); 
   if(FAILED(hr))  
      goto error;  
 
error:  
   // cleanup 
   if(g_pConvert)  
      g_pConvert->Release(); 
 
   CoUninitialize(); 
    
   return 0;  
} 

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