Re: [Qemu-devel] [PATCH v2 11/12] block/dmg: support bzip2 block entry types

[John Snow <jsnow@redhat.com>]

On 01/06/2015 12:48 PM, Peter Wu wrote:
> This patch adds support for bzip2-compressed block entries as introduced
> with OS X 10.4 (source: https://en.wikipedia.org/wiki/Apple_Disk_Image).
>
> It was tested against a 5.2G "OS X Yosemite" installation image which
> stores the BLXX block in the XML property list (instead of resource
> forks) and has over 5k chunks.
>
> New configure entries are added (--enable-bzip2 / --disable-bzip2) to
> control inclusion of bzip2 functionality (which requires linking against
> libbz2). The help message suggests that this option is needed for DMG
> files, but the tests are generic enough that other parts of QEMU can use
> bzip2 if needed.
>
> The identifiers are based on http://newosxbook.com/DMG.html.
>
> The decompression routines are based on the zlib case, but as there is
> no way to reset the decompression state (unlike zlib), memory is
> allocated and deallocated for every decompression. This should not be
> problematic as the decompression takes most of the time and as blocks
> are typically about/over 1 MiB in size, only one allocation is done
> every 2000 sectors.
>
> Signed-off-by: Peter Wu <peter@lekensteyn.nl>
> ---
>   v2: split block type check into a different patch ("[PATCH v2 10/12]
>       block/dmg: factor out block type check").
>       Add BZIP2_LIBS instead of polluting libs_softmmu with -lbz2 (which
>       would also end up in fsdev/virtfs-proxy-helper).
>       Fix unused variable warning with --disable-bzip2.
> ---
>   block/Makefile.objs |  1 +
>   block/dmg.c         | 43 ++++++++++++++++++++++++++++++++++++++++++-
>   configure           | 31 +++++++++++++++++++++++++++++++
>   3 files changed, 74 insertions(+), 1 deletion(-)
>

[snip]

Reviewed-by: John Snow <jsnow@redhat.com>