bitmap_ord_to_pos (9) - Linux Manuals
bitmap_ord_to_pos: find position of n-th set bit in bitmap
bitmap_ord_to_pos - find position of n-th set bit in bitmap
unsigned int bitmap_ord_to_pos(const unsigned long
* buf, unsigned int ord, unsigned int nbits);
- pointer to bitmap
- ordinal bit position (n-th set bit, n >= 0)
- number of valid bit positions in buf
Map the ordinal offset of bit ord in buf to its position in buf. Value of ord should be in range 0 <= ord < weight(buf). If ord >= weight(buf), returns nbits.
If for example, just bits 4 through 7 are set in buf, then ord values 0 through 3 will get mapped to 4 through 7, respectively, and all other ord values returns nbits. When ord value 3 gets mapped to (returns) pos value 7 in this example, that means that the 3rd set bit (starting with 0th) is at position 7 in buf.