glibc/sysdeps/generic/strchrnul.c
Ulrich Drepper c4563d2d66 Update.
1999-04-28  Ulrich Drepper  <drepper@cygnus.com>

	* argp/argp-ba.c (argp_program_bug_address): Don't initialize with 0.
	* argp/argp-parse.c (_argp_hang): Likewise.
	* argp/argp-pv.c (argp_program_version): Likewise.
	* argp/argp-pvh.c (argp_program_version_hook): Likewise.
	* inet/ether_hton.c (ether_hton, startp): Likewise.
	* inet/ether_ntoh.c (ether_ntoh, startp): Likewise.
	* inet/getnetgrent_r.c (setup, startp): Likewise.
	* intl/loadmsgcat.c (_nl_msg_cat_cntr): Likewise.
	* intl/localealias.c (string_space, string_space_act, string_space_max,
	nmap, maxmap): Likewise.
	* libio/iopopen.c (proc_file_chain): Likewise.
	* libio/oldiopopen.c (old_proc_file_chain): Likewise.
	* locale/lc-collate.c (__collate_table, __collate_extra,
	__collate_element_hash, __collate_element_strings,
	__collate_element_values): Likewise.
	* malloc/mcheck.c (mcheck_used): Likewise.
	* malloc/mtrace.c (added_atexit_handler): Likewise.
	* malloc/set-freeres.c (already_called): Likewise.
	* misc/getpass.c (getpass) [buf, bufsize]: Likewise.
	* misc/syslog.c (LogStat, LogTag): Likewise.
	* nss/XXX-lookup.c (DATABASE_NAME_SYMBOL): Likewise.
	* nss/getXXbyYY_r.c (startp): Likewise.
	* posix/getopt.c (optarg, __getopt_initialized): Likewise.
	* posix/regex.c (init_syntax_once) [done]: Likewise.
	(debug): Likewise.
	* string/strfry.c (init): Likewise.
	* sunrpc/svc_run.c (svc_top): Likewise.
	* posix/euidaccess.c (have_ids): Likewise.
	* sysdeps/unix/sysv/linux/poll.c (must_emulate): Likewise.
	* sysdeps/unix/sysv/linux/ttyname.c (__ttyname, namelen): Likewise.
	* time/getdate.c (getdate_err): Likewise.
	* time/tzfile.c (transitions, type_idxs, types, zone_names, leaps):
	Likewise.
	* time/tzset.c (old_tz, is_initialized): Likewise.

	* inet/getnameinfo.c (nrl_domainname): Rewrite to allow initialization
	of static data with zero.
	* signal/allocrtsig.c (init): Likewise.

	* string/Makefile (routines): Add strchrnul.
	* string/Versions [GLIBC_2.1.1]: Add strchrnul.
	* string/string.c: Add strchrnul prototype.
	* include/string.h: Add __strchrnul prototype.
	* sysdeps/generic/strchrnul.c: New file.
	* sysdeps/i386/strchrnul.S: New file.
	* sysdeps/i386/bits/string.c: Add strchrnul optimization.
	* sysdeps/i386/i486/bits/string.c: Likewise.
	* argp/argp-help.c (argp_args_usage): Use __strchrnul.
	* inet/ether_line.c (ether_line): Likewise.
	* nscd/nscd_conf.c (nscd_parse_file): Likewise.
	* nss/nsswitch.c (nss_parse_file): Likewise.
	* posix/execvp.c (execvp): Likewise.
	* posix/fnmatch.c (internal_fnmatch): Likewise.
	* resolv/res_hconf.c (_res_hconv_init): Likewise.
	* resolv/res_init.c (res_init): Likewise.
	* stdlib/fmtmsg.c (init): Likewise.
	* stdlib/getsubopt.c (getsubopt): Likewise.

	* catgets/catgets.c (catopen): Only allocate one memory block.
	(catclose): Only one free call necessary.

	* catgets/open_catalog.c (__open_catalog): Simplify handling of
	file descriptor.

	* ctype/ctype-extn.c: Make __toascii_l and __isascii_l alias instead
	of real functions.  Simplify _tolower and _toupper.

	* grp/initgroups.c (compat_call): Remove unnecessary use of pointer
	variable.

	* iconv/gconv.h (struct gconv_info): Change data element from pointer
	to array of size 0.
	* iconv/gconv_open.c (__gconv_open): Allocate structures accordingly.
	* iconv/gconv_close.c (__gconv_close): Don't free data.

	* iconv/gconv_conf.c (add_alias): Avoid searching in tree twice to
	insert new alias.

	* iconv/gconv_db.c (add_derivation): More efficient copying.  Check
	for error while inserting in tree.

	* include/time.h: Pretty print.

	* inet/ruserpass.c: Rewrite use of toktab to avoid string pointers
	in table and lots of relocations.
	* posix/regex.c (regerror): Rewrite use of re_error_msgid to avoid
	string pointers in table and lots of relocations.

	* intl/finddomain.c: Remove definition of strchr macro.

	* io/ftw.c (nftw_arr, ftw_arr): Make const.

	* locale/loadlocale.c (_nl_load_locale): Optimize string copying.

	* locale/localeinfo.h (_nl_category_names): Change into an array with
	fixed width char string elements.
	* locale/setlocale.c (_nl_category_names): Likewise.
	(_nl_current): Make global.
	* locale/nl_langinfo.c (nldata): Removed.  Use _nl_current now.

	* malloc/Makefile (distribute): Add stackinfo.h.
	* sysdeps/generic/stackinfo.h: New file.
	* sysdeps/i386/stackinfo.h: New file.
	* posix/execl.c: Use stackinfo.h in optimizing alloca use.
	* posix/execle.c: Likewise.
	* posix/execlp.c: Likewise.

	* nis/nis_table.c (__create_ib_request): Always use realloc.

	* posix/execvp.c (execute): Rename to script_execute and keep only
	code to execute using shell.
	(execvp): Call execv directly and only fall back on script_execute.

	* resolv/inet_net_pton.c (inet_net_pton_ipv4): Remove digits define
	and always use xdigits instead.

	* resolv/res_init.c (res_init): Use rawmemchr instead of strchr
	where appropriate.

	* stdlib/fpioconst.h (__tens): New declaration.
	(struct mp_power): Remove array, add arrayoff element.
	* stdlib/fpioconst.c: Replace definitions of _ten_p* arrays by one
	__tens array and add in _fpioconst_pow10 offsets into __tens.
	* stdio-common/printf_fp.c: Rewrite to use new __tens array.
	* stdlib/strtod.c: Likewise.

	* stdlib/a64l.c (a64l_table): Avoid unnecessary elements.

	* stdlib/exit.c: Rewrite to use __exit_funcs being as sign for end
	of the list.
	* stdlib/atexit.c (__exit_funcs): Don't initialize.

	* stdlib/fmtmsg.c (keywords): Make name element fixed width array.

	* sunrpc/clnt_perr.c: Rewrite clnt_sperrno and auth_errmsg to use
	a single and an array with offsets.

	* sunrpc/des_soft.c (partab): Make it const.

	* sunrpc/key_call.c (trytimeout, tottimeout): Make const.
	(__key_encryptsession_pk_LOCAL): Don't initialize with 0.
	(__key_decryptsession_pk_LOCAL): Likewise.
	(__key_gendes_LOCAL): Likewise.
	(MESSENGER): Mark const.
	(key_call_private_main): Don't initialize with 0.
	(use_keyenvoy): Don't initialize with 0.
	(key_call): Rewrite to reverse logic of use_doors variable.

	* sunrpc/netname.c (OPSYS): Define as array, not pointer.
	(startp): Don't initialize with zero.

	* sunrpc/openchild.c (_openchild): Make first argument const.

	* sunrpc/pmap_rmt.c (timeout): Mark const.
	* sunrpc/xcrypt.c (hex): Likewise.

	* sysdeps/unix/sysv/linux/getcwd.c: Rewrite to allow omitting
	initialization of global variables.
	* sysdeps/unix/sysv/linux/getpt.c: Likewise.
	* sysdeps/unix/sysv/linux/if_index.c: Likewise.
	* termios/tcgetsid.c: Likewise.

	* sysdeps/unix/sysv/linux/i386/dl-procinfo.h (x86_cap_flags): Change
	fxsr to osfxsr.

	* time/tzfile.c (__tzfile_read): Rewrite to allocate only one memory
	block.  Add function to free memory if wanted.
	* time/tzset.c (tzset_internal): Pass extra argument to __tzfile_read.

	* wcsmbs/wcsmbsload.c (to_wc, to_mb): Correct initializers.

	* wcsmbs/wmemset.c: Little code optimization.
1999-04-28 23:13:52 +00:00

167 lines
5.8 KiB
C

/* Copyright (C) 1991, 93, 94, 95, 96, 97, 99 Free Software Foundation, Inc.
Based on strlen implementation by Torbjorn Granlund (tege@sics.se),
with help from Dan Sahlin (dan@sics.se) and
bug fix and commentary by Jim Blandy (jimb@ai.mit.edu);
adaptation to strchr suggested by Dick Karpinski (dick@cca.ucsf.edu),
and implemented by Roland McGrath (roland@ai.mit.edu).
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <string.h>
#undef __strchrnul
#undef strchrnul
/* Find the first occurrence of C in S or the final NUL byte. */
char *
__strchrnul (s, c)
const char *s;
int c;
{
const unsigned char *char_ptr;
const unsigned long int *longword_ptr;
unsigned long int longword, magic_bits, charmask;
c = (unsigned char) c;
/* Handle the first few characters by reading one character at a time.
Do this until CHAR_PTR is aligned on a longword boundary. */
for (char_ptr = s; ((unsigned long int) char_ptr
& (sizeof (longword) - 1)) != 0;
++char_ptr)
if (*char_ptr == c || *char_ptr == '\0')
return (void *) char_ptr;
/* All these elucidatory comments refer to 4-byte longwords,
but the theory applies equally well to 8-byte longwords. */
longword_ptr = (unsigned long int *) char_ptr;
/* Bits 31, 24, 16, and 8 of this number are zero. Call these bits
the "holes." Note that there is a hole just to the left of
each byte, with an extra at the end:
bits: 01111110 11111110 11111110 11111111
bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
The 1-bits make sure that carries propagate to the next 0-bit.
The 0-bits provide holes for carries to fall into. */
switch (sizeof (longword))
{
case 4: magic_bits = 0x7efefeffL; break;
case 8: magic_bits = ((0x7efefefeL << 16) << 16) | 0xfefefeffL; break;
default:
abort ();
}
/* Set up a longword, each of whose bytes is C. */
charmask = c | (c << 8);
charmask |= charmask << 16;
if (sizeof (longword) > 4)
/* Do the shift in two steps to avoid a warning if long has 32 bits. */
charmask |= (charmask << 16) << 16;
if (sizeof (longword) > 8)
abort ();
/* Instead of the traditional loop which tests each character,
we will test a longword at a time. The tricky part is testing
if *any of the four* bytes in the longword in question are zero. */
for (;;)
{
/* We tentatively exit the loop if adding MAGIC_BITS to
LONGWORD fails to change any of the hole bits of LONGWORD.
1) Is this safe? Will it catch all the zero bytes?
Suppose there is a byte with all zeros. Any carry bits
propagating from its left will fall into the hole at its
least significant bit and stop. Since there will be no
carry from its most significant bit, the LSB of the
byte to the left will be unchanged, and the zero will be
detected.
2) Is this worthwhile? Will it ignore everything except
zero bytes? Suppose every byte of LONGWORD has a bit set
somewhere. There will be a carry into bit 8. If bit 8
is set, this will carry into bit 16. If bit 8 is clear,
one of bits 9-15 must be set, so there will be a carry
into bit 16. Similarly, there will be a carry into bit
24. If one of bits 24-30 is set, there will be a carry
into bit 31, so all of the hole bits will be changed.
The one misfire occurs when bits 24-30 are clear and bit
31 is set; in this case, the hole at bit 31 is not
changed. If we had access to the processor carry flag,
we could close this loophole by putting the fourth hole
at bit 32!
So it ignores everything except 128's, when they're aligned
properly.
3) But wait! Aren't we looking for C as well as zero?
Good point. So what we do is XOR LONGWORD with a longword,
each of whose bytes is C. This turns each byte that is C
into a zero. */
longword = *longword_ptr++;
/* Add MAGIC_BITS to LONGWORD. */
if ((((longword + magic_bits)
/* Set those bits that were unchanged by the addition. */
^ ~longword)
/* Look at only the hole bits. If any of the hole bits
are unchanged, most likely one of the bytes was a
zero. */
& ~magic_bits) != 0 ||
/* That caught zeroes. Now test for C. */
((((longword ^ charmask) + magic_bits) ^ ~(longword ^ charmask))
& ~magic_bits) != 0)
{
/* Which of the bytes was C or zero?
If none of them were, it was a misfire; continue the search. */
const unsigned char *cp = (const unsigned char *) (longword_ptr - 1);
if (*cp == c || *cp == '\0')
return (char *) cp;
if (*++cp == c || *cp == '\0')
return (char *) cp;
if (*++cp == c || *cp == '\0')
return (char *) cp;
if (*++cp == c || *cp == '\0')
return (char *) cp;
if (sizeof (longword) > 4)
{
if (*++cp == c || *cp == '\0')
return (char *) cp;
if (*++cp == c || *cp == '\0')
return (char *) cp;
if (*++cp == c || *cp == '\0')
return (char *) cp;
if (*++cp == c || *cp == '\0')
return (char *) cp;
}
}
}
/* This should never happen. */
return NULL;
}
weak_alias (__strchrnul, strchrnul)