C language implementation of a non-recursive binary lookup algorithm (applicable to various types of data)

Using C language to implement a non-recursive binary lookup algorithm is not too difficult, but the requirements for a variety of data types general, the difficulty is somewhat increased.

C language has no function template, so the main use of void pointers and function pointers.

The specific code is as follows:

typedef int (*cmp_fun) (const void *key, const void *DST);
#define GET_DATA (arr, POS, size) (UINT8 *) (arr) + (POS) * (size)

void *bisearch (CONST void *ptable, UINT32 Cnt, UINT Size, VOID *key, Cmp_fun cmpfunc)
{
    INT32 Start, Mid, end;

    Start = 0;
    end = Cnt-1;
    
    if (Start > End) {return
        NULL;
    }
    While [start <= end] {
        Mid = (start + end)/2;
        if (Cmpfunc (Key, Get_data (ptable, Mid, Size) < 0) {end
            = Mid-1;
        }
        else if (Cmpfunc Key, Get_data (ptable, Mid, Size) > 0) {
            Start = Mid + 1;
        }
        else {return
            get_data (ptable, Mid, Size);
        }       
    }
    return NULL;
}