如何加速.xll 函数中的数组处理？

Question

I want to get equal speed of my function VLOOKUP2 and standard VLOOKUP in Excel. But getting an array of cells in my VLOOKUP2 function is already longer than the speed of the standard VLOOKUP function in Excel.

I watched examples from Excel 2013 XLL SDK (С) and found nothing useful for myself. I used two solutions:

1.Getting the OPER12 array using the Q parameter in the HelpRegister12 function

int WINAPI xlAutoOpen(void)
    {
        HelpRegister12(L"VLOOKUP2", L"QQQQ$"...)
    }

extern "C" __declspec(dllexport) LPXLOPER12  WINAPI VLOOKUP2(LPXLOPER12 XLOP1, LPXLOPER12 XLOP2, LPXLOPER12 XLOP3)
    {
    '''
    }

2.Getting the XLOPER12 array using the U parameter in the HelpRegister12 function

int WINAPI xlAutoOpen(void)
    {
        HelpRegister12(L"VLOOKUP2", L"UUUU$"...)
    }

extern "C" __declspec(dllexport) LPXLOPER12  WINAPI VLOOKUP2(LPXLOPER12 XLOP1, LPXLOPER12 XLOP2, LPXLOPER12 XLOP3)
    {
...
LPXLOPER12 FAR *ppxArg; // Pointer to the argument being processed 
ppxArg = &XLOP1;
XLOPER12 xMulti;        // Argument coerced to xltypeMulti 
...
if (xlretUncalced == Excel12(xlCoerce, &xMulti, 2,(LPXLOPER12) *ppxArg, TempInt12(xltypeMulti)))
            {
                //
                // That coerce might have failed due to an 
                // uncalced cell, in which case, we need to 
                // return immediately. Microsoft Excel will
                // call us again in a moment after that cell
                // has been calced.
                //
                return 0;
            }
...

    }

All two solutions are slower than the standard VLOOKUP function in Excel.

Is it possible to get a link to a separate array element (cell) without using the entire array and without using the Excel12 function (xlCoerce, ...)? for example for the second solution:

    LPXLOPER12 ppxArgTmp;
    ppxArgTmp = &(*ppxArg1)->val.array.lparray[x];

?

How to speed up getting an array? I don't need all the elements, I need the elements until the first match.

Why is the standard VLOOKUP function faster?

Answer 1

Regarding your question to access cells individually, yes it is possible, see below (arrays are row-major in excel):

int row = ppxArg1->val.array.rows ;
int col = ppxArg1->val.array.columns ;

 for (int r=0;r<row ;r++)
      for (int c=0;c<col;c++)
        LPXLOPER12 cell =   ppxArg1->val.array.lparray + ((r* col) + c); //access each cells