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opnsense-src/include
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Ed Schouten 2747eff128 Replace implementation of hsearch() by one that scales. 
Traditionally the hcreate() function creates a hash table that uses
chaining, using a fixed user-provided size. The problem with this
approach is that this often either wastes memory (table too big) or
yields bad performance (table too small). For applications it may not
always be easy to estimate the right hash table size. A fixed number
only increases performance compared to a linked list by a constant
factor.

This problem can be solved easily by dynamically resizing the hash
table. If the size of the hash table is at least doubled, this has no
negative on the running time complexity. If a dynamically sized hash
table is used, we can also switch to using open addressing instead of
chaining, which has the advantage of just using a single allocation for
the entire table, instead of allocating many small objects.

Finally, a problem with the existing implementation is that its
deterministic algorithm for hashing makes it possible to come up with
fixed patterns to trigger an excessive number of collisions. We can
easily solve this by using FNV-1a as a hashing algorithm in combination
with a randomly generated offset basis.

Measurements have shown that this implementation is about 20-25% faster
than the existing implementation (even if the existing implementation is
given an excessive number of buckets). Though it allocates more memory
through malloc() than the old implementation (between 4-8 pointers per
used entry instead of 3), process memory use is similar to the old
implementation as if the estimated size was underestimated by a factor
10. This is due to the fact that malloc() needs to perform less
bookkeeping.

Reviewed by:	jilles, pfg
Obtained from:	https://github.com/NuxiNL/cloudlibc
Differential Revision:	https://reviews.freebsd.org/D4644
2015-12-27 07:50:11 +00:00
..
arpa Add META_MODE support. 2015-06-13 19:20:56 +00:00
gssapi Add META_MODE support. 2015-06-13 19:20:56 +00:00
protocols Add META_MODE support. 2015-06-13 19:20:56 +00:00
rpc Add META_MODE support. 2015-06-13 19:20:56 +00:00
rpcsvc Add META_MODE support. 2015-06-13 19:20:56 +00:00
xlocale Commit log from Dragonfly: 2015-10-13 20:43:49 +00:00
_ctype.h Commit log from Dragonfly: 2015-10-13 20:43:49 +00:00
a.out.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
ar.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
assert.h Don't define static_assert for C++. 2011-12-29 14:41:17 +00:00
bitstring.h
complex.h I'm happy to finally commit stephen@'s implementations of cacos, 2013-05-30 04:49:26 +00:00
cpio.h
ctype.h Commit log from Dragonfly: 2015-10-13 20:43:49 +00:00
db.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
dirent.h Fix some edge cases with rewinddir(): 2014-07-11 16:16:26 +00:00
dlfcn.h Implement fdlopen(3), an rtld interface to load shared object by file 2012-01-07 10:33:01 +00:00
elf-hints.h
elf.h Remove some OpenSolaris compatibility stuff now that we're doing it a 2007-11-28 22:09:12 +00:00
err.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
fmtmsg.h Fix a small typo. Fireware -> firmware. 2012-06-05 19:42:57 +00:00
fnmatch.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
fstab.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
fts.h Allow certain headers to be included more easily. 2013-05-21 21:20:10 +00:00
ftw.h
getopt.h Remove NetBSD Foundation clauses 3 & 4. They eliminated those clauses 2010-02-16 19:28:10 +00:00
glob.h - Add restrict keyword to glob(3) 2011-12-20 22:56:13 +00:00
grp.h include: Remove checks for __BSD_VISIBLE where redundant with __XSI_VISIBLE 2014-05-11 13:48:21 +00:00
gssapi.h Add a new extensible GSS-API layer which can support GSS-API plugins, 2005-12-29 14:40:22 +00:00
hesiod.h We don't use these files. 2014-08-09 20:03:40 +00:00
iconv.h Remove the const qualifier from iconv(3) to comply with POSIX: 2015-04-15 09:09:20 +00:00
ieeefp.h People porting FreeBSD to new architectures ought not have to 2011-10-21 06:41:46 +00:00
ifaddrs.h Allow certain headers to be included more easily. 2013-05-21 21:20:10 +00:00
inttypes.h Rename __wchar_t so it no longer conflicts with __wchar_t from clang 3.4 2014-04-01 14:46:11 +00:00
iso646.h Avoid accidental conflicts with C++ operator keywords. 2011-09-27 16:33:17 +00:00
kenv.h Fix prototype to match the code and documentation. 2005-11-24 07:20:26 +00:00
langinfo.h langinfo.h: Hide YESSTR and NOSTR in strict POSIX mode. 2014-04-19 12:38:01 +00:00
libgen.h Add basename_r(3) to complement basename(3). basename_r(3) which accepts 2009-10-06 14:05:57 +00:00
limits.h Merge from HEAD 2015-08-09 00:15:17 +00:00
link.h
locale.h Reapply 227753 (xlocale cleanup), plus some fixes so that it passes build 2012-03-04 15:31:13 +00:00
Makefile Move obscure lib/ installation of /usr/lib/include symlink to include/. 2015-12-04 03:18:02 +00:00
Makefile.depend new depends 2015-06-16 23:37:19 +00:00
malloc.h
malloc_np.h Use bool rather than _Bool for C++ compatibility. 2015-08-19 18:32:12 +00:00
memory.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
mk-osreldate.sh Stop building vers.c in include/ and only build the needed osreldate.h. 2015-11-25 19:10:59 +00:00
monetary.h Correctly expose xlocale functions if people include the headers in the wrong 2012-03-28 12:11:54 +00:00
mpool.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
mqueue.h POSIX requires sigevent to be visible after mqueue.h is included. 2012-09-10 05:12:45 +00:00
ndbm.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
netconfig.h
netdb.h addrinfo.ai_family is an address family, not a protocol family. 2015-12-20 15:18:50 +00:00
nl_types.h Remove NetBSD Foundation clauses 3 & 4. They eliminated those clauses 2010-02-16 19:28:10 +00:00
nlist.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
nss.h
nsswitch.h Add capability to use a db version of services. It is enabled by 2010-04-04 08:31:03 +00:00
paths.h Assume that the -f argument is /dev/gpioc0 if it is not passed. 2013-09-17 11:48:47 +00:00
printf.h The register_printf_render_std() function expects regular string. 2012-07-04 17:35:07 +00:00
proc_service.h Introduce a new proc service routine ps_linfo() to get LWP info. 2006-02-07 02:29:55 +00:00
pthread.h Make use of gcc attributes in some standard include headers. 2015-04-06 01:39:16 +00:00
pthread_np.h Introduce a non-portable function pthread_getthreadid_np(3) to retrieve 2011-02-07 21:26:46 +00:00
pwd.h Replace our version of the pwcache(3) API with NetBSD's implementation. 2012-10-19 12:44:22 +00:00
ranlib.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
readpassphrase.h Sync with OpenBSD, primarily better signal and terminal handling. 2010-11-13 10:38:06 +00:00
regex.h Replace __const by const in all non-contributed source code. 2011-12-13 13:32:56 +00:00
res_update.h Update our stub resolver to final version of libbind. 2014-08-12 12:36:06 +00:00
resolv.h resolver: preserve binary compatibility; reduce header pollution 2015-12-14 17:21:06 +00:00
runetype.h After r232498, programs built with -ansi or -std=c89 including <ctype.h> 2012-03-06 20:15:23 +00:00
search.h Replace implementation of hsearch() by one that scales. 2015-12-27 07:50:11 +00:00
semaphore.h Ensure #include <semaphore.h> is sufficient for using SEM_VALUE_MAX. 2015-01-31 16:39:26 +00:00
setjmp.h include: Remove checks for __BSD_VISIBLE where redundant with __XSI_VISIBLE 2014-05-11 13:48:21 +00:00
signal.h Make use of gcc attributes in some standard include headers. 2015-04-06 01:39:16 +00:00
spawn.h Remove __restrict keywords from array arguments to make GCC's -std=c99 work. 2008-06-19 07:30:32 +00:00
stab.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
stdalign.h Add <stdalign.h> and <stdnoreturn.h>. 2011-12-25 20:51:40 +00:00
stdbool.h Remove unneeded guard. 2011-12-25 20:15:41 +00:00
stddef.h Add guards to ptrdiff_t definition in include/stddef.h 2014-08-21 15:10:10 +00:00
stdio.h Add _flags2 per jhb@ suggestion since no room left in _flags. 2015-10-28 14:40:02 +00:00
stdlib.h Make use of GCC alloc_align attribute 2015-05-15 20:43:37 +00:00
stdnoreturn.h Simply disallow <stdnoreturn.h> to be used in combination with C++. 2012-01-03 23:05:23 +00:00
string.h include: Remove checks for __BSD_VISIBLE where redundant with __XSI_VISIBLE 2014-05-11 13:48:21 +00:00
stringlist.h Remove clause 3 and 4 from the license 2015-05-21 08:38:25 +00:00
strings.h Add explicit_bzero(3) and its kernel counterpart. 2014-10-07 04:54:11 +00:00
sysexits.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
tar.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
termios.h include: Remove checks for __BSD_VISIBLE where redundant with __XSI_VISIBLE 2014-05-11 13:48:21 +00:00
tgmath.h Roll back r271012 even more aggressively. 2014-09-05 05:36:32 +00:00
time.h Add CLOCK_PROCESS_CPUTIME_ID to <time.h>, to synchronize the CLOCK_* 2013-01-14 18:01:19 +00:00
timeconv.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
timers.h
ttyent.h Add a new flag to /etc/ttys: onifconsole. This is equivalent to "on" if the 2014-01-20 18:15:06 +00:00
uchar.h Fix <uchar.h> in for C++11. 2013-05-25 16:58:12 +00:00
ulimit.h
unistd.h Rename __sentinel to __null_sentinel 2015-11-05 14:55:58 +00:00
unwind.h Also the stop function should accept 64-bit exception class. 2010-09-30 03:16:35 +00:00
utime.h Remove the Berkeley clause 3's. 2010-02-16 19:39:50 +00:00
utmpx.h Implement <utmpx.h>. 2010-01-13 17:29:55 +00:00
uuid.h Add missing prototypes for uuid_enc,dec_le,be() functions. 2008-09-15 23:47:19 +00:00
varargs.h
wchar.h include: Remove checks for __BSD_VISIBLE where redundant with __XSI_VISIBLE 2014-05-11 13:48:21 +00:00
wctype.h Commit log from Dragonfly: 2015-10-13 20:43:49 +00:00
wordexp.h
xlocale.h Reapply 227753 (xlocale cleanup), plus some fixes so that it passes build 2012-03-04 15:31:13 +00:00