glibc/sysdeps/generic/strlen.c
Ulrich Drepper 9a0a462ceb Update.
1997-09-11 04:36  Ulrich Drepper  <drepper@cygnus.com>

	* db2/db_int.h: Define __set_errno if not yet available.
	* db2/btree/bt_rec.c: Use __set_errno to set errno value.
	* db2/clib/getlong.c: Likewise.
	* db2/db185/db185.c: Likewise.
	* db2/db185/db185_int.h: Likewise.
	* db2/dbm/dbm.c: Likewise.
	* db2/lock/lock_deadlock.c: Likewise.
	* db2/log/log_archive.c: Likewise.

	* elf/dl-profile.c: Implement mcount function.

	* gmon/gmon.c: Use __profil not profil because of namespace pollution.
	* gmon/mcount.c: Remove BSD kernel code.
	Use compare&swap instruction if possible to change state variable.
	Optimize frompc folding.
	* gmon/sys/gmon.h (struct gmonparam): Change state field to long int.
	* sysdeps/i386/i486/atomicity.h: New file.
	* sysdeps/stub/atomicity.h: New file.
	* sysdeps/mach/hurd/profil.c: Define function as __profil and make
	profil weak alias.
	* sysdeps/posix/profil.c: Likewise.

	* string/bits/string2.h: New file.
	* include/bits/string2.h: New file.
	* string/Makefile (routines): Add mempcpy.
	(tests): Add inl-tester.
	Remove _D__NO_STRING_INLINES from CFLAGS-* variables.
	* sysdeps/generic/mempcpy.c: New file.
	* sysdeps/generic/memccpy.c: Undef function name to enable definition
	as macro.
	* sysdeps/generic/memchr.c: Likewise.
	* sysdeps/generic/memcmp.c: Likewise.
	* sysdeps/generic/memmem.c: Likewise.
	* sysdeps/generic/memmove.c: Likewise.
	* sysdeps/generic/strcat.c: Likewise.
	* sysdeps/generic/strchr.c: Likewise.
	* sysdeps/generic/strcmp.c: Likewise.
	* sysdeps/generic/strcpy.c: Likewise.
	* sysdeps/generic/strcspn.c: Likewise.
	* sysdeps/generic/strlen.c: Likewise.
	* sysdeps/generic/strncat.c: Likewise.
	* sysdeps/generic/strncmp.c: Likewise.
	* sysdeps/generic/strncpy.c: Likewise.
	* sysdeps/generic/strpbrk.c: Likewise.
	* sysdeps/generic/strrchr.c: Likewise.
	* sysdeps/generic/strsep.c: Likewise.
	* sysdeps/generic/strspn.c: Likewise.
	* sysdeps/generic/strstr.c: Likewise.
	* sysdeps/generic/strtok.c: Likewise.
	* sysdeps/generic/strtok_r.c: Likewise.
	* sysdeps/i386/memset.c: Likewise.
	* sysdeps/i386/bits/string.h: Correct a few types and constraints.
	* sysdeps/i386/i486/bits/string.h: Heavy rewrites and optimizations.
	* string/stratcliff.c: Undefine __USE_STRING_INLINES.
	* string/tst-strlen.c: Likewise.
	* string/string.h: Add prototype for mempcpy.  Include bits/string2.h
	header always if optimizing.
	* intl/dcgettext.c: Don't unconditionally define stpcpy, only if not
	yet defined.
	* intl/l10nflist.c: Likewise.

	* string/tester.c: Add copyright and make little cleanups.

	* inet/test_ifindex.c: Change type of ni variable to unsigned int.

	* locale/programs/ld-ctype.c (struct locale_ctype_t): Change type
	of fields map_collection_max and map_collection_act to size_t.

	* nss/libnss_files.map: Group entries.

	* posix/unistd.h: Add prototype for __setpgid and __profil.

	* sysdeps/generic/crypt.h: Declare __crypt_r.

	* sysdeps/i386/bits/select.h: Fix fatal bugs, use correct casts now.

	* sysdeps/i386/fpu/bits/mathinline.h (isgreater, isgreaterequal,
	isless, islessequal, islessgreater, isunordered): Optimize a bit.

	* sysdeps/stub/ftruncate.c: Include missing header for prototype.
	* sysdeps/stub/getdents.c: Likewise.
	* sysdeps/stub/reboot.c: Likewise.
	* sysdeps/stub/swapon.c: Likewise.
	* sysdeps/stub/syscall.c: Likewise.
	* sysdeps/stub/ualarm.c: Likewise.
	* sysdeps/stub/usleep.c: Likewise.

	* sysdeps/unix/sysv/linux/if_index.c: Don't compile or use opensock
	if SIOGIFINDEX and SIOGIFNAME are not defined.

	* sysdeps/unix/sysv/linux/net/if.h: Add IFF_PORTSEL and IFF_AUTOMEDIA
	according to recent kernel changes.

1997-09-10 21:32  Klaus Espenlaub  <kespenla@student.informatik.uni-ulm.de>

	* Makeconfig: Use $(have-initfini) instead of $(elf) to figure out
	the installed name of the startup code.
	(common-generated): Add version.mk.
	* Makefile (distclean-1): Add glibcbug.
	* Makerules: Replace -lgcc by $(gnulib).
	* catgets/Makefile (generated): Add xmalloc.o.
	* csu/Makefile (generated): Replace align.h and end.h by defs.h to
	match the generated file.
	* manual/Makefile (mostlyclean): Add stub-manual and stamp.o.
	(realclean): Changed to remove chapters-incl[12].
	* po/Makefile (realclean): New rule to remove the generated .mo files.
	* time/Makefile: Only include zonefile dependencies if $(no_deps) is
	not true to avoid make clean failure when directory time doesn't exist
	yet.
	(generated): Add tzselect.

	* stdio/fgets.c (fgets): Add casts to reduce gcc warning noise.
	* stdio/internals.c (flushbuf): Likewise.
	* stdio/linewrap.c (lwupdate): Likewise.
	* stdio/memstream.c (enlarge_buffer): Likewise.
	* stdio-common/vfscanf.c (_IO_vfscanf): Likewise.
	* time/tzset.c (compute_change): Likewise.
	* misc/init-misc.c (__init_misc): Only declare static if HAVE_GNU_LD
	is defined.
	* sysdeps/posix/pipestream.c (FUNC): Change to generate ANSI C style
	functions.
	* sysdeps/stub/init-posix.c: Likewise.
	* sysdeps/stub/profil.c: Likewise.
	* munch-tmpl.c (__libc_init): Convert to ANSI C style declaration to
	reduce gcc warning noise.
	* stdio/glue.c (_filbuf, _flsbuf): Likewise.
	* stdio/obstream.c (grow, seek, input, init_obstream): Likewise.
	* stdio/vasprintf.c (enlarge_buffer): Likewise.
	* sysdeps/generic/sysd-stdio.c (__stdio_read, __stdio_write,
	__stdio_seek, __stdio_close, __stdio_fileno, __stdio_open,
	__stdio_reopen): Likewise.
	* sysdeps/posix/defs.c (_cleanup): Likewise.
	* time/offtime.c (__offtime): Add cast.

	* posix/getopt.c: Don't use text_set_element if not defined.

	* configure.in: Provide a check for underscores before user labels
	that works even when the compiler used for building doesn't work
	(like when there is no C library).  Use the old way if the compiler
	works.

1997-09-10 05:08  David S. Miller  <davem@caip.rutgers.edu>

	* sysdeps/unix/sysv/linux/sparc/bits/ioctls.h: The TC* ioctls use
	'T' not 't' on SparcLinux.
	* sysdeps/unix/sysv/linux/sparc/bits/termios.h: tcflag_t is 32 bits.

	* sysdeps/unix/sysv/linux/sparc/sparc64/longjmp.S: Add aliases for
	_longjmp and siglongjmp.

1997-09-09  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* libio/stdio.h: Add format attributes to the extra printf and
	scanf like functions.
	* stdio/stdio.h: Likewise.

1997-09-09  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* nis/nss_nisplus/nisplus-network.c (_nss_nisplus_getnetbyaddr_r):
	Print tablename_val, not tablename_len.

	* nis/nss_nisplus/nisplus-ethers.c (_nss_nisplus_getntohost_r):
	Use sprintf instead of sprintf, the string always fits.
	* nis/nss_nisplus/nisplus-hosts.c (_nss_nisplus_gethostbyaddr_r):
	Likewise.
	* nis/nss_nisplus/nisplus-network.c (_nss_nisplus_getnetbyaddr_r):
	Likewise.
	* nis/nss_nisplus/nisplus-proto.c
	(_nss_nisplus_getprotobynumber_r): Likewise.
	* nis/nss_nisplus/nisplus-rpc.c (_nss_nisplus_getrpcbynumber_r):
	Likewise.
	* nis/nss_nisplus/nisplus-service.c
	(_nss_nisplus_getservbynumber_r): Likewise.

	* nis/nss_nisplus/nisplus-alias.c (_nss_create_tablename): Use
	__stpcpy, __stpncpy and __strdup instead of public names.
	* nis/nss_nisplus/nisplus-ethers.c (_nss_create_tablename):
	Likewise.
	* nis/nss_nisplus/nisplus-grp.c (_nss_create_tablename): Likewise.
	* nis/nss_nisplus/nisplus-hosts.c (_nss_create_tablename):
	Likewise.
	* nis/nss_nisplus/nisplus-netgrp.c (_nss_nisplus_parse_netgroup):
	Likewise.
	* nis/nss_nisplus/nisplus-network.c (_nss_nisplus_parse_netent):
	Likewise.
	(_nss_create_tablename): Likewise.
	* nis/nss_nisplus/nisplus-proto.c (_nss_nisplus_parse_protoent):
	Likewise.
	(_nss_create_tablename): Likewise.
	* nis/nss_nisplus/nisplus-pwd.c (_nss_create_tablename):
	Likewise.
	* nis/nss_nisplus/nisplus-rpc.c (_nss_nisplus_parse_rpcent):
	Likewise.
	(_nss_create_tablename): Likewise.
	* nis/nss_nisplus/nisplus-service.c (_nss_nisplus_parse_servent):
	Likewise.
	(_nss_create_tablename): Likewise.
	* nis/nss_nisplus/nisplus-spwd.c (_nss_create_tablename):
	Likewise.

	* libc.map: Export __stpcpy and __strdup.

1997-09-09  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* math/Makefile (CFLAGS-test-float.c, CFLAGS-test-double.c,
	CFLAGS-test-ldouble.c): Pass -ffloat-store to avoid excessive
	precision.

1997-09-09  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* include/rpc/auth_des.h: New file.

1997-09-09  Paul Eggert  <eggert@twinsun.com>

	* time/mktime.c (__mktime_internal): Declare sec_requested even if
	!LEAP_SECONDS_POSSIBLE, since it's needed at the end when checking
	for time_t overflow.

1997-09-09 22:11  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/posix/getcwd.c: Correct test for too small buffer.
	Reported by Erik Troan <ewt@redhat.com>.

	* elf/dl-close.c: Include <bits/libc-lock.h>, not <libc-lock.h>.
	* elf/dl-open.c: Likewise.

1997-09-07 17:09  Richard Henderson  <rth@cygnus.com>

	* sysdeps/alpha/Makefile: Kill setjmp_aux.
	* sysdeps/alpha/bits/setjmp.h: Rewrite in terms of an array.
	* sysdeps/alpha/__longjmp.c: Remove.
	* sysdeps/alpha/setjmp_aux.c: Remove.
	* sysdeps/alpha/__longjmp.S: New file.
	* sysdeps/alpha/bsd-_setjmp.S: Stub out.
	* sysdeps/alpha/bsd-setjmp.S: Likewise.
	* sysdeps/alpha/setjmp.S: Do the work; don't call __setjmp_aux.
	Move _setjmp and setjmp from bsd-*.S.

1997-09-06  20:20  Ulrich Drepper  <drepper@cygnus.com>

	* include/rpc/auth.h: New file.
	* include/rpc/auth_unix.h: New file.

1997-09-06  Paul Eggert  <eggert@twinsun.com>

	Fix gmtime so that it reports leap seconds when TZ
	indicates that leap seconds are desired.

	* time/gmtime.c (<stddef.h>): Remove unnecessary include.
	(gmtime): Put after gmtime_r, to help the compiler inline.
	(__tz_convert): New decl.
	(gmtime_r): Use __tz_convert instead of __offtime,
	so that leap seconds are handled correctly.

	* time/localtime.c (<errno.h>, <libc-lock.h>): Remove includes that
	are now unnecessary.
	(__tzset_internal, __tz_compute, __tzfile_compute, __use_tzfile,
	__tzset_lock): Remove extern decls that are now unnecessary.
	(localtime_internal): Moved to __tz_convert in tzset.c.
	so that localtime and gmtime can both use it easily.
	(localtime): Put after localtime_r, to help the compiler inline.
	(localtime_r): Use __tz_convert instead of localtime_internal.

	* time/strftime.c (__tz_compute): Remove unused (and now incorrect)
	decl.

	* time/tzfile.c (__tzfile_compute): New arg USE_LOCALTIME.

	* time/tzset.c (<errno.h>): Include.
	(_tmbuf): New decl.
	(__tzfile_compute): New function.
	(tz_compute): Renamed from __tz_compute.  No longer extern.
	Remove redundant call to tzset_internal.
	(tzset_internal): Renamed from __tzset_internal.  No longer extern.
	(tzset_lock): Renamed from __tzset_lock.  No longer extern.
	(__tz_convert): New function, containing functionality of old
	localtime_internal function, plus locking and optional UTC.

1997-09-06  Paul Eggert  <eggert@twinsun.com>

	* time/tzfile.c (__tzfile_read): Don't read a file if TZ is the empty
	string, just use UTC without leap seconds.  This is for compatibility
	with the Olson code.

1997-09-06  Paul Eggert  <eggert@twinsun.com>

	* time/tzset.c (__tzname_max): Lock tz data structures before
	invoking tzset_internal.

	* time/tzfile.c: Define compute_tzname_max statically.

1997-09-07 10:57  Thorsten Kukuk  <kukuk@vt.uni-paderborn.de>

	* nis/nis_call.c: Remove not longer necessary HAVE_SECURE_RPC ifdefs.
	* nis/nis_intern.h: Likewise.
	* nis/nss_nis/nis-publickey.c: Likewise.
	* nis/nss_nisplus/nisplus-publickey.c: Likewise.
	* nis/ypclnt.c: Likewise.

	* sunrpc/auth_des.c: Don't dereference NULL pointer,
	initialize ad->ad_timediff.

	* sunrpc/auth_none.c: Don't define our own prototypes, use the one
	from the header files.
	* sunrpc/auth_unix.c: Likewise.
	* sunrpc/clnt_raw.c: Likewise.
	* sunrpc/clnt_tcp.c: Likewise.
	* sunrpc/rpc_cmsg.c: Likewise.

	* sunrpc/key_call.c: Fix signal handling.

	* sunrpc/openchild.c: Don't use /bin/sh to start /usr/etc/keyenvoy,
	or we will get a deadlock with NIS+.

	* sunrpc/rpc/auth.h: Add prototype for xdr_opaque_auth, don't define
	HAVE_SECURE_RPC.

1997-09-07 15:51  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/i386/bits/select.h [__GNUC__] (__FD_ZERO, __FD_SET, __FD_CLR,
	__FD_ISSET): Use correct casts to address array correctly.
	Reported by urbanw@cs.umu.se.

1997-09-07 05:07  Ulrich Drepper  <drepper@cygnus.com>

	* elf/dl-close.c: Include <bits/libc-lock.h>, not <libc-lock.h>.
	* elf/dl-open.c: Likewise.
	* sysdeps/i386/memset.c: Undefine memset in case the header with the
	optimized functions is included.
	Patches by NIIBE Yutaka <gniibe@mri.co.jp>.

	* sysdeps/i386/bits/string.h [__PIC__] (strcspn, strspn, strpbrk,
	strsep): Use register for second parameter.
	* sysdeps/i386/i486/bits/string.h: Likewise.
	Reported by NIIBE Yutaka <gniibe@mri.co.jp>.

1997-09-03 09:48  Geoff Keating  <geoffk@ozemail.com.au>

	* math/libm-test.c: Change various tolerances to match what the
	tested routines can actually provide.

	* math/Makefile: Add new tests.
	* math/atest-sincos.c: New file.
	* math/atest-exp.c: New file.

	* csu/Makefile: Give initfini.s and initfiniS.s their own
	CFLAGS-* macros so they can be overridden.
	* sysdeps/powerpc/Makefile [subdir=csu]: Override flags for
	initfiniS.s to use -fpic instead of -fPIC, because the sed script
	breaks otherwise.

	* sysdeps/powerpc/Makefile [build-shared]: Use -fpic not -fPIC for
	efficiency.

	* sysdeps/powerpc/dl-machine.h (ELF_MACHINE_RUNTIME_TRAMPOLINE):
	Don't use register 0, to let _mcount be in a shared object.

	* sysdeps/powerpc/dl-machine.h: Use full sentences in comments.
	Generally clean up.  Suppress some code we don't need when relocating
	ld.so.
	* sysdeps/powerpc/test-arith.c: Change loop indices to size_t when
	appropriate to suppress gcc warning.
	* resolv/res_send.c: Suppress warning.
	* sunrpc/xdr_sizeof.c: Suppress warning.

	* FAQ: Add ppc-linux.
	* manual/maint.texi: Add ppc-linux.  Explain that gcc can't build it
	yet.

	* sysdeps/unix/sysv/linux/powerpc/profil-counter.h: Correct for
	current kernels.

1997-08-15 07:45  Geoff Keating  <geoffk@ozemail.com.au>

	* stdlib/fmtmsg.c: Use two parameters for __libc_once_define.
	* sysdeps/i386/machine-gmon.h: Correct typo.

	* sysdeps/unix/sysv/linux/powerpc/bits/mman.h: Change to match
	kernel.

	* sysdeps/generic/dl-sysdep.c: Add hook for bizzare PPC argument hack.
	* sysdeps/unix/sysv/linux/powerpc/dl-sysdep.c: Rewrite to use
	sysdeps/linux/dl-sysdep.c.

	* sysdeps/powerpc/Makefile [subdir=gmon]: Compile ppc-mcount.
	* sysdeps/powerpc/machine-gmon.h: Use ppc-mcount.
	* sysdeps/powerpc/ppc-mcount: New file.

	The following are mostly changes to allow profiling:
	* sysdeps/powerpc/add_n.S: Added.
	* sysdeps/powerpc/add_n.s: Removed.
	* sysdeps/powerpc/addmul_1.S: Added.
	* sysdeps/powerpc/addmul_1.s: Removed.
	* sysdeps/powerpc/bsd-_setjmp.S: Use JUMPTARGET macro.
	* sysdeps/powerpc/bsd-setjmp.S: Use JUMPTARGET macro.
	* sysdeps/powerpc/lshift.S: Added.
	* sysdeps/powerpc/lshift.s: Removed.
	* sysdeps/powerpc/memset.S: Added.
	* sysdeps/powerpc/memset.s: Removed.
	* sysdeps/powerpc/mul_1.S: Added.
	* sysdeps/powerpc/mul_1.s: Removed.
	* sysdeps/powerpc/rshift.S: Added.
	* sysdeps/powerpc/rshift.s: Removed.
	* sysdeps/powerpc/s_copysign.S: Use ENTRY, END, weak_alias macros.
	* sysdeps/powerpc/s_fabs.S: Use ENTRY, END, weak_alias macros.
	* sysdeps/powerpc/setjmp.S: Use JUMPTARGET macro.
	* sysdeps/powerpc/strchr.S: Added.
	* sysdeps/powerpc/strchr.s: Removed.
	* sysdeps/powerpc/strcmp.S: Added.
	* sysdeps/powerpc/strcmp.s: Removed.
	* sysdeps/powerpc/strlen.S: Added.
	* sysdeps/powerpc/strlen.s: Removed.
	* sysdeps/powerpc/sub_n.S: Added.
	* sysdeps/powerpc/sub_n.s: Removed.
	* sysdeps/powerpc/submul_1.S: Added.
	* sysdeps/powerpc/submul_1.s: Removed.
	* sysdeps/unix/sysv/linux/powerpc/_exit.S: Removed.
	* sysdeps/unix/sysv/linux/powerpc/brk.S: Added.
	* sysdeps/unix/sysv/linux/powerpc/brk.c: Removed.
	* sysdeps/unix/sysv/linux/powerpc/clone.S: Use new macros. Fix
	various bugs. Document that it isn't tested.
	* sysdeps/unix/sysv/linux/powerpc/sigreturn.S: Make look like
	sysdeps/unix/_exit.S.
	* sysdeps/unix/sysv/linux/powerpc/socket.S: Use new macros.
	* sysdeps/unix/sysv/linux/powerpc/syscall.S: Use new macros.
	* sysdeps/unix/sysv/linux/powerpc/sysdep.h: Define some new macros
	to make assembler (possibly) more portable, allow profiling, etc.
1997-09-11 12:09:10 +00:00

150 lines
4.9 KiB
C

/* Copyright (C) 1991, 1993, 1997 Free Software Foundation, Inc.
Written by Torbjorn Granlund (tege@sics.se),
with help from Dan Sahlin (dan@sics.se);
commentary by Jim Blandy (jimb@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 strlen
/* Return the length of the null-terminated string STR. Scan for
the null terminator quickly by testing four bytes at a time. */
size_t
strlen (str)
const char *str;
{
const char *char_ptr;
const unsigned long int *longword_ptr;
unsigned long int longword, magic_bits, himagic, lomagic;
/* 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 = str; ((unsigned long int) char_ptr
& (sizeof (longword) - 1)) != 0;
++char_ptr)
if (*char_ptr == '\0')
return char_ptr - str;
/* 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. */
magic_bits = 0x7efefeffL;
himagic = 0x80808080L;
lomagic = 0x01010101L;
if (sizeof (longword) > 4)
{
/* 64-bit version of the magic. */
magic_bits = (0x7efefefeL << 32) | 0xfefefeffL;
himagic = (himagic << 32) | himagic;
lomagic = (lomagic << 32) | lomagic;
}
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. */
longword = *longword_ptr++;
if (
#if 0
/* Add MAGIC_BITS to LONGWORD. */
(((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)
#else
((longword - lomagic) & himagic)
#endif
!= 0)
{
/* Which of the bytes was the zero? If none of them were, it was
a misfire; continue the search. */
const char *cp = (const char *) (longword_ptr - 1);
if (cp[0] == 0)
return cp - str;
if (cp[1] == 0)
return cp - str + 1;
if (cp[2] == 0)
return cp - str + 2;
if (cp[3] == 0)
return cp - str + 3;
if (sizeof (longword) > 4)
{
if (cp[4] == 0)
return cp - str + 4;
if (cp[5] == 0)
return cp - str + 5;
if (cp[6] == 0)
return cp - str + 6;
if (cp[7] == 0)
return cp - str + 7;
}
}
}
}