bitmap_pos_to_ord — find ordinal of set bit at given position in bitmap
int bitmap_pos_to_ord ( | const unsigned long * buf, |
| unsigned int pos, | |
unsigned int nbits); |
bufpointer to a bitmap
pos
a bit position in buf (0 <= pos < nbits)
nbits
number of valid bit positions in buf
Map the bit at position pos in buf (of length nbits) to the
ordinal of which set bit it is. If it is not set or if pos
is not a valid bit position, map to -1.
If for example, just bits 4 through 7 are set in buf, then pos
values 4 through 7 will get mapped to 0 through 3, respectively,
and other pos values will get mapped to -1. When pos value 7
gets mapped to (returns) ord value 3 in this example, that means
that bit 7 is the 3rd (starting with 0th) set bit in buf.
The bit positions 0 through bits are valid positions in buf.