The various hpack files are self-contained, but hpack-tbl was one of
those showing difficulties when pools were added because that began
to add quite some dependencies. Now when built in standalone mode,
it still uses the bare minimum pool definitions and doesn't require
to know the prototypes anymore when only the structures are needed.
Thus the files were moved verbatim except for hpack-tbl which was
split between types and prototypes.
Fortunately that file wasn't made dependent upon haproxy since it was
integrated, better isolate it before it's too late. Its dependency on
api.h was the result of the change from config.h, which in turn wasn't
correct. It was changed back to stddef.h for size_t and sys/types.h for
ssize_t. The recently added reference to MAX() was changed as it was
placed only to avoid a zero length in the non-free-standing version and
was causing a build warning in the hpack encoder.
The only leftovers were the unused compiler.h file and the LICENSE file
which is already mentioned in each and every ebtree file header.
A few build paths were updated in the contrib/ directory not to mention
this directory anymore, and all its occurrences were dropped from the
main makefile. From now on no other include path but include/ will be
needed anymore to build any file.
As reported in oss-fuzz issue 22388, the contrib/hpack code doesn't
build anymore for now. Thanks to previous patch we can now just define
HPACK_STANDALONE in the few files which include hpack-tbl.h and we can
declare a dummy pool to hold the DHT size. This is enough to make the
code work again outside of the haproxy process. It was successfully
tested using:
$ echo 82 84 87 90 | ./decode
I found on an (old) AIX 5.1 machine that stdint.h didn't exist while
inttypes.h which is expected to include it does exist and provides the
desired functionalities.
As explained here, stdint being just a subset of inttypes for use in
freestanding environments, it's probably always OK to switch to inttypes
instead:
https://pubs.opengroup.org/onlinepubs/009696799/basedefs/stdint.h.html
Also it's even clearer here in the autoconf doc :
https://www.gnu.org/software/autoconf/manual/autoconf-2.61/html_node/Header-Portability.html
"The C99 standard says that inttypes.h includes stdint.h, so there's
no need to include stdint.h separately in a standard environment.
Some implementations have inttypes.h but not stdint.h (e.g., Solaris
7), but we don't know of any implementation that has stdint.h but not
inttypes.h"
This generates the tables and indexes which will be used by the HPACK
encoder. The headers are sorted by length, then by statistical frequency,
then by direction (preference for responses), then by name, then by index.
The purpose is to speed up their lookup.
