In some cases it may be desirable for latency reasons to forcefully
flush the queue even if it results in suboptimal compression. In our
case the queue might contain up to almost 4 bytes, which need an EOB
and a switch to literal mode, followed by 4 bytes to encode an empty
message. This means that each call can add 5 extra bytes in the ouput
stream. And the flush may also result in the header being produced for
the first time, which can amount to 2 or 10 bytes (zlib or gzip). In
the worst case, a total of 19 bytes may be emitted at once upon a flush
with 31 pending bits and a gzip header.
This is libslz upstream commit cf8c4668e4b4216e930b56338847d8d46a6bfda9.
stdint.h is not as portable as inttypes.h. It doesn't exist at least
on AIX 5.1 and Solaris 7, while inttypes.h is present there and does
include stdint.h on platforms supporting it.
This is equivalent to libslz upstream commit e36710a ("slz: use
inttypes.h instead of stdint.h")
As we now embed the library we don't need to support the older 1.0 API
any more, so we can remove the explicit calls to slz_make_crc_table()
and slz_prepare_dist_table().
SLZ is rarely packaged by distros and there have been complaints about
the CPU and memory usage of ZLIB, leading to some suggestions to better
address the issue by simply integrating SLZ into the tree (just 3 files).
See discussions below:
https://www.mail-archive.com/haproxy@formilux.org/msg38037.htmlhttps://www.mail-archive.com/haproxy@formilux.org/msg40079.htmlhttps://www.mail-archive.com/haproxy@formilux.org/msg40365.html
This patch does just this, after minor adjustments to these files:
- tables.h was renamed to slz-tables.h
- tables.h had the precomputed tables removed since not used here
- slz.c uses includes <import/slz*> instead of "slz*.h"
The slz commit imported here was b06c172 ("slz: avoid a build warning
with -Wimplicit-fallthrough"). No other change was performed either to
SLZ nor to haproxy at this point so that this operation may be replicated
if needed for a future version.
