C++ Class for fb_database_crypt_callback

This class can be compiled with Visual C++ and be used with C++Builder which lacks proper Template support.

Because we are using a global thread-local variable for legacy callback into the Firebird client we must make sure only one firebird client dll is loaded and that dll must be gds32.dll

Class:

CryptKey key;

typedef ISC_STATUS(__stdcall *p_fb_database_crypt_callback)(ISC_STATUS*, void*);

extern "C"
int __declspec(dllexport) SetKey1(char *szkey, int len )
{
    ICryptKeyCallback* cb = &key;
    HMODULE hGDS32 = NULL;
    p_fb_database_crypt_callback pSetCallback = NULL;

    strncpy_s(szKey, szkey, len);
    szKey[len] = NULL;

    try
    {
        ISC_STATUS status;
        ISC_STATUS statusArray[20];

        hGDS32 = LoadLibraryA("gds32.dll");
        if(hGDS32==NULL)
            return -2;

        pSetCallback = (p_fb_database_crypt_callback)GetProcAddress(hGDS32, "fb_database_crypt_callback");
        if (pSetCallback == NULL)
            throw "GetProcAddress error";

        status = pSetCallback(statusArray, (void*)cb);
        char szMsg[64],szRet[16];

        //strcpy_s(szMsg, "fb_database_crypt_callback returned ");
        //_itoa_s(status, szRet, 10);
        //strcat_s(szMsg,szRet);
        //MessageBoxA(NULL, szMsg, "SetColor", MB_OK);

        FreeLibrary(hGDS32);

        return (int)status;
    }
    catch (...)
    {
        if(hGDS32) FreeLibrary(hGDS32);
        return -1;
    }
}