Question

Is there a simple way to convert a bitmask in to an array index?

ie. If i’ve got an enum

a = 0x01, b = 0x02, c = 0x04, d = 0x08, e = 0x10,  etc 

and I want to store releated data in an array, is there a simple way such that i can convert a to 0, b to 1, c to 2. etc?

Many thanks

Answer 1

r =   ln base 2  and programmatically,  unsigned int v=yourEnumValue; unsigned r = 0;  while (v >>= 1)  {    r++; }  r is your answer