---
name: "bitmap_bitremap"
section: "9"
platform: "linux"
package: "linux-manual-4.9"
version: "4.9.228-1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/bitmap_bitremap"
---

# bitmap\_bitremap(9)

Apply map defined by a pair of bitmaps to a single bit

## NAME

bitmap\_bitremap - Apply map defined by a pair of bitmaps to a single bit

## SYNOPSIS

**int bitmap\_bitremap(int** *oldbit***, const unsigned long \*** *old***, const unsigned long \*** *new***, int** *bits***);**

## ARGUMENTS

*oldbit*

bit position to be mapped

*old*

defines domain of map

*new*

defines range of map

*bits*

number of bits in each of these bitmaps

## DESCRIPTION

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.

The positions of unset bits in *old* are mapped to themselves (the identify map).

Apply the above specified mapping to bit position *oldbit*, returning the new bit position.

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 *oldbit* is 5, then this routine returns 13.

## COPYRIGHT