jammy (1) nbdkit-swab-filter.1.gz

Provided by: nbdkit_1.24.1-2ubuntu4_amd64 bug

NAME
       nbdkit-swab-filter - nbdkit filter for swapping byte order


SYNOPSIS
        nbdkit --filter=swab PLUGIN [PLUGIN-ARGS...] [swab-bits=8|16|32|64]


DESCRIPTION
       "nbdkit-swab-filter" is a filter for nbdkit(1) which swaps bytes in the underlying plugin.

       One use for this is to read disk images which were formatted on the Atari Falcon, where the IDE
       controller is wired in reverse order.


EXAMPLE
   Swap bytes from a disk image
        nbdkit --filter=swab file file=disk.img

       The above command serves the disk image disk.img, swapping even and odd bytes:

        disk.img   0   1   2   3   4   5 ...
                     ╳       ╳       ╳
          output   1   0   3   2   5   4 ...

       This filter truncates the size of the plugin down to the alignment determined by swab-bits (since
       operating on an unaligned tail would be awkward).  If you need to round the image size up instead to
       access the last few bytes, combine this filter with nbdkit-truncate-filter(1); fortunately, sector-based
       disk images are already suitably sized.


PARAMETERS
       swab-bits=8
           This turns off the filter.

       swab-bits=16
           This is the default setting which swaps pairs of bytes.  This is suitable when reading and writing to
           Atari Falcon drives.

       swab-bits=32
           This swaps the endianness of each 4 byte word in the disk, ie:

             input    0   1   2   3   4   5   6   7

            output    3   2   1   0   7   6   5   4

       swab-bits=64
           This swaps the endianness of each 8 byte word in the disk, ie:

             input    0   1   2   3   4   5   6   7

            output    7   6   5   4   3   2   1   0

           This can be used to make nbdkit-pattern-plugin(1) little endian instead of big endian.


FILES
       $filterdir/nbdkit-swab-filter.so
           The filter.

           Use "nbdkit --dump-config" to find the location of $filterdir.


VERSION
       "nbdkit-swab-filter" first appeared in nbdkit 1.22.


SEE ALSO
       nbdkit(1), nbdkit-file-plugin(1), nbdkit-pattern-plugin(1), nbdkit-filter(3), nbdkit-truncate-filter(1).


AUTHORS
       François Revol


       Copyright (C) 2020 François Revol


LICENSE
       Redistribution and use in source and binary forms, with or without modification, are permitted provided
       that the following conditions are met:

       •   Redistributions of source code must retain the above copyright notice, this list of conditions and
           the following disclaimer.

       •   Redistributions in binary form must reproduce the above copyright notice, this list of conditions and
           the following disclaimer in the documentation and/or other materials provided with the distribution.

       •   Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote
           products derived from this software without specific prior written permission.

       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
       INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
       INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
       ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
       DAMAGE.