[PATCH 0/4] erofs-utils: add DEFLATE compression support

[Gao Xiang]

Hi folks,

This is the EROFS DEFLATE support which I've been working on these
months, mainly implementing DEFLATE fixed-sized output approach.

DEFLATE is a popular generic-purpose compression algorithm for a quite
long time (many advanced formats like zlib, gzip, zip, png are all
based on that), which is made of LZ77 as wells as Huffman code, fully
documented as RFC1951 and quite easy to understand.  DEFLATE encoder
and decoder are also easy to be implemented and they generally have
fairly small code size and runtime memory consumption.

In addition, there are several hardware on-market DEFLATE accelerators
as well, such as (s390) DFLTCC, (Intel) IAA/QAT, (HiSilicon) ZIP
accelerator, etc.  Therefore, it's useful to support DEFLATE in order
to use these for async I/Os and get benefits from these later.

As usual, some numbers of enwik8 and silesia.tar are available below:

Commandline option: -zdeflate,9 (to match mksquashfs default level)
Sliding window size: 32768

enwik8:
 ____________________________
|  file system  |    size    |
|_______________|____________|
|___ enwik8 ____|_100000000__|
|_ squashfs_4k _|__46325760__|
|_ squashfs_8k _|__43618304__|
|__ erofs_4k ___|__43073536__| (erofs default)
| squashfs_16k _|__41406464__|
|__ erofs_8k ___|__40873984__|
|__ erofs_16k __|__38998016__|
| squashfs_64k _|__38109184__|
| squashfs_128k |__37306368__| (squashfs default)
|__ erofs_64k __|__37142528__|

silesia.tar (much similar to enwik8 so I omit some):
 ____________________________
|  file system  |    size    |
|_______________|____________|
|_ silesia.tar _|_211957760__|
|_ squashfs_4k _|__86884352__|
|_ squashfs_8k _|__81125376__|
|__ erofs_4k ___|__78970880__| (erofs default)
|__ erofs_8k ___|__74768384__|
| squashfs_64k _|__70447104__|
| squashfs_128k |__69079040__| (squashfs default)
|__ erofs_64k __|__68640768__|

Thanks,
Gao Xiang

Gao Xiang (4):
  erofs-utils: switch to effective unaligned access
  erofs-utils: add a built-in DEFLATE compressor
  erofs-utils: fuse: add DEFLATE algorithm support
  erofs-utils: mkfs: add DEFLATE algorithm support

 configure.ac             |   45 ++
 dump/Makefile.am         |    3 +-
 fsck/Makefile.am         |    6 +-
 fuse/Makefile.am         |    2 +-
 include/erofs/defs.h     |   24 +-
 include/erofs/internal.h |    2 -
 include/erofs_fs.h       |    7 +
 lib/Makefile.am          |    2 +
 lib/compress.c           |   24 +
 lib/compressor.c         |    1 +
 lib/compressor.h         |    1 +
 lib/compressor_deflate.c |   77 +++
 lib/decompress.c         |  147 +++++
 lib/dedupe.c             |   23 +-
 lib/kite_deflate.c       | 1267 ++++++++++++++++++++++++++++++++++++++
 15 files changed, 1618 insertions(+), 13 deletions(-)
 create mode 100644 lib/compressor_deflate.c
 create mode 100644 lib/kite_deflate.c

-- 
2.24.4