bitmap_remap — Apply map defined by a pair of bitmaps to another bitmap
void bitmap_remap ( | unsigned long * | dst, |
| const unsigned long * | src, | |
| const unsigned long * | old, | |
| const unsigned long * | new, | |
| int | bits); |
dstremapped result
srcsubset to be remapped
olddefines domain of map
newdefines range of map
bitsnumber of bits in each of these bitmaps
Let old and new define a mapping of bit positions, such that
whatever position is held by the n-th set bit in old is mapped
to the n-th set bit in new. In the more general case, allowing
for the possibility that the weight 'w' of new is less than the
weight of old, map the position of the n-th set bit in old to
the position of the m-th set bit in new, where m == n % w.
If either of the old and new bitmaps are empty, or if src and
dst point to the same location, then this routine copies src
to dst.
The positions of unset bits in old are mapped to themselves
(the identify map).
Apply the above specified mapping to src, placing the result in
dst, clearing any bits previously set in dst.
For example, lets say that old has bits 4 through 7 set, and
new has bits 12 through 15 set. This defines the mapping of bit
position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
bit positions unchanged. So if say src comes into this routine
with bits 1, 5 and 7 set, then dst should leave with bits 1,
13 and 15 set.