An issue ran into by hyperlaunch was the need to use the gzip decompressor
multiple times. The current implementation fails when reused due to tainting of
decompressor state from a previous usage. This series seeks to colocate the
gzip unit files under a single directory similar to the other decompression
algorithms.  To enable the refactoring of the state tracking, the code is then
cleaned up in line with Xen coding style.

Changes in v3:
- patch "xen/gzip: Drop huffman code table tracking" was merged
- patch "xen/gzip: Remove custom memory allocator" was merged
- patch "xen/gzip: Drop unused define checks" was merged
- move of the decompressor state into struct was broken up to ease review
- expanded macros that were either only used once or obsfucated the logic
- adjusted variable types as needed to be more appropriate for their usage

Changes in v2:
- patch "xen/gzip: Colocate gunzip code files" was merged
- dropped ifdef chunks that are never enabled
- addressed formatting changes missed in v1
- replaced custom memory allocator with xalloc_bytes()
- renamed gzip_data to gzip_state
- moved gzip_state to being dynamically allocated
- changed crc table to the explicit size of uint32_t 
- instead of moving huffman tracking into state, dropped altogether


Daniel P. Smith (8):
  gzip: clean up comments and fix code alignment
  gzip: refactor and expand macros
  gzip: refactor the gunzip window into common state
  gzip: move window pointer into gunzip state
  gzip: move input buffer handling into gunzip state
  gzip: move output buffer into gunzip state
  gzip: move bitbuffer into gunzip state
  gzip: move crc state into gunzip state

 xen/common/gzip/gunzip.c  |  84 ++--
 xen/common/gzip/inflate.c | 948 +++++++++++++++++++-------------------
 2 files changed, 516 insertions(+), 516 deletions(-)

-- 
2.30.2

On 4/24/24 12:34, Daniel P. Smith wrote:
> An issue ran into by hyperlaunch was the need to use the gzip decompressor
> multiple times. The current implementation fails when reused due to tainting of
> decompressor state from a previous usage. This series seeks to colocate the
> gzip unit files under a single directory similar to the other decompression
> algorithms.  To enable the refactoring of the state tracking, the code is then
> cleaned up in line with Xen coding style.
> 

Forgot to add this comment to the cover letter.

Concern was raised about taking updates from original source to the 
code. In this case the original source is from the Linux kernel, which 
can be found in lib/inflate.c, and added to Xen in 2009. The last time 
there was a logic change to that code in the Linux kernel was in 2008, 
before it was added to Xen. Since then, it has only been updated for 
changes made to included headers. If fact, as far as I can see, while 
the file is still in place, nothing uses it. For zlib decompression, 
three is a new lib/zlib_deflate code base that is used. The scope of 
this work is not to completely fix/replace zlib decompression for Xen, 
but to stabilize it to allow hyperlaunch to decompress more than one 
zlib compressed kernel.

V/r,
Daniel P. Smith