NAME
Vcdiff::OpenVcdiff - open-vcdiff backend for Vcdiff
SYNOPSIS
use Vcdiff::OpenVcdiff;
my $delta = Vcdiff::OpenVcdiff::diff($source, $target);
my $target2 = Vcdiff::OpenVcdiff::patch($source, $delta);
## $target2 eq $target
This module is a backend to the Vcdiff module and isn't usually used
directly.
DESCRIPTION
This module uses Alien::OpenVcdiff which is a module that configures,
builds, and installs Google's <open-vcdiff> library.
The alien package installs the "vcdiff" binary for your convenience but
this module uses the "libvcdenc.so" and "libvcddec.so" shared libraries
so that the diffing computation is done in-process instead of forking
processes.
PROS
* Apache licensed
* open-vcdiff has a really cool feature that lets you re-use "hashed
dictionaries" for multiple diff operations (but this module doesn't
expose that yet).
CONS
* Even with the streaming API "open-vcdiff" has a hard upper-limit of
2G file sizes and the default (which this module hasn't changed) is
64M so be warned.
* If the source argument is a file handle, Vcdiff::OpenVcdiff will try
to mmap(2) the entire file into memory with Sys::Mmap. As well as
adding a dependency, this means that source files must be able to
fit in your address space. Because of the file size limitation
described above, this shouldn't be an issue. See the "STREAMING API"
section of Vcdiff for more details.
* The Alien::OpenVcdiff dependency takes a long time to compile
compared to Vcdiff::Xdelta3 although it's not a completely fair
comparison because the alien module also runs open-vcdiff's
test-suite (which is good).
* The library writes to standard error in the event of errors and I
don't believe there is any way to silence these messages.
SEE ALSO
<Vcdiff-OpenVcdiff github repo>
Vcdiff
Alien::OpenVcdiff
<Official open-vcdiff website>
AUTHOR
Doug Hoyte, "<
[email protected]>"
COPYRIGHT & LICENSE
Copyright 2013 Doug Hoyte.
This module is licensed under the same terms as perl itself.
