//////////////////////////////////////////////////////////////////////////////
// MFC Tip #8 -- Vision X Software -- http://www.visionx.com/mfcpro
// Finding a File Association in the Registry
//
// This source code is provided for instructional purposes, and is released
// to the public domain. No claim of ownership is made. Use it at your own
// risk. No warranties are expressed or implied. The resulting program may
// not be fully functional. No animals were used to test this code.
//////////////////////////////////////////////////////////////////////////////


/////////////////////////////////////////////////////////////////////////////
// GetRegistryExe
// Returns the full executable file & path name that will open a document
// with a given extension.

void GetRegistryExe (LPCSTR szInput, LPSTR szOut, UINT uiOutSize)
{
    szOut[0] = 0;

    // Copy input extension to our extension.
    // Make sure it begins with '.'
    char szExt[16];
    szExt[0] = 0;
    if (szInput[0] != '.')
        lstrcpy(szExt, ".");
    lstrcat(szExt, szInput);

    // Get title of program assoc with this extension.
    char szName[256];
    GetRegistryEntry(szExt, "", szName, sizeof(szName));
    if (szName[0] == 0) return;

    // Get corresponding exe filename.
    lstrcat(szName, "\\shell\\open\\command");
    GetRegistryEntry(szName, "", szOut, uiOutSize);
    if (szOut[0] == 0) return;

    // Remove everything after the first "%" char
    // in case there's a %1, %2, or other param.
    char *pChar = strchr(szOut, '%');
    if (pChar)
    {
        for (--pChar  ;  pChar > szOut && *pChar != ' '  ;  --pChar)
            ;
        *pChar = 0;
    }
}


/////////////////////////////////////////////////////////////////////////////
// GetRegistryEntry
// Fetches an HKEY_CLASSES_ROOT registry entry for a given path and value.

void GetRegistryEntry (LPCSTR szInPath, LPCSTR szInValue, LPSTR szOut, UINT uiOutSize)
{
    szOut[0] = 0;
    HKEY hKey;
    if (RegOpenKey(HKEY_CLASSES_ROOT, szInPath, &hKey) == ERROR_SUCCESS)
    {
        LONG lSize = (LONG) uiOutSize;
        RegQueryValue(hKey, szInValue, szOut, &lSize);
        RegCloseKey(hKey);
    }
}