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author | Roland McGrath <roland@gnu.org> | 1995-09-17 20:23:15 +0000 |
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committer | Roland McGrath <roland@gnu.org> | 1995-09-17 20:23:15 +0000 |
commit | 60478656fad8d8a487e9bc52d025f69767c3262b (patch) | |
tree | 0ae0836023f1c2f80064e7611f91d19c482208d9 /sysdeps/generic/strstr.c | |
parent | 9fd18b6c1b397e1af82a0b544f10f946c73864b6 (diff) | |
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Sat Sep 16 17:47:19 1995 Ulrich Drepper <drepper@ipd.info.uni-karlsruhe.de>
* elf/elf.h (AT_GID): Fix typo: Read -> Real.
* misc/efgvt_r.c: New file. Reentrant version of [efg]cvt functions.
* misc/efgcvt.c: Rewrite to use reentrant functions.
* misc/hsearch_r.c: New file. Reentrant version of functions from
hsearch family.
* misc/hsearch.c, misc/tsearch.c: New files.
* misc/Makefile (routines): Add efgcvt_r, hsearch_r, hsearch, tsearch.
* posix/unistd.h (ttyname_r): Add prototype for new function.
* stdlib/drand48_r.c, stdlib/erand48_r.c, stdlib/jrand48_r.c,
stdlib/lrand48_r.c, stdlib/mrand48_r.c, stdlib/nrand48_r.c,
stdlib/seed48_r.c, stdlib/srand48_r.c, stdlib/lcong48_r.c,
stdlib/drand48-iter.c: New files implementing reentrant versions
of functions from drand48 family.
* stdlib/seed48.c, stdlib/drand48.c, stdlib/erand48.c,
stdlib/jrand48.c, stdlib/lrand48.c, stdlib/mrand48.c,
stdlib/nrand48.c, stdlib/srand48.c, stdlib/lcong48.c:
Rewrite to use reentrant versions.
* stdlib/a64l.c, stdlib/l64a.c: New files. Implement a64l()
and l64a() functions from SysV library.
* stdlib/Makefile (routines): Add drand48_r, erand48_r, lrand48_r,
nrand48_r, mrand48_r, jrand48_r, srand48_r, seed48_r, lcong48_r,
drand48-iter, a64l, l64a.
* stdlib/stdlib.h: Declare them.
* stdlib/random_r.c: New file. Reentrant version of functions
from random family.
* stdlib/stdlib.h: Declare them.
* stdlib/random.c: Rewrite to use reentrant functions.
* string/strerror_r.c: New file. Reentrant version.
* string/strerror.c: Change for new _strerror_internal form.
* string/Makefile (routines): Add strerror_r.
* sysdeps/generic/dl-sysdep.c (_dl_sysdep_start): Set default
value of user_entry to `_start'.
Close AT_ENTRY case with `break'.
* sysdeps/generic/strstr.c: New and much faster implementation
by Stephen R. van den Berg.
* sysdeps/generic/_strerror.c: _strerror_internal now takes
three argument and has and explicit buffer length.
* sysdeps/mach/_strerror.c: Change for new interface with three
arguments.
* stdio/perror.c, stdio/vfprintf.c: Callers changed.
* sysdeps/mach/hurd/ttyname_r.c: New file. Reentrant version.
* sysdeps/posix/ttyname_r.c: New file. Reentrant version.
* sysdeps/stub/ttyname_r: New file. Define as dummy function.
* sysdeps/posix/utimes.c: Include <utime.h> for prototype.
(utimes): First parameter to utime must be file, not path.
* sysdeps/posix/sysconf.c (__sysconf): Test for CLK_TCK in case
_SC_CLK_TCK and return it when available.
Test for STREAM_MAX in case _SC_STREAM_MAX and return it when
available.
Add case for _SC_2_LOCALEDEF which is now available.
* posix/sys/types.h [__USE_SVID] (key_t): New type.
* sysvipc/Makefile, sysvipc/ftok.c, sysvipc/sys/ipc.h,
sysvipc/sys/msg.h, sysvipc/sys/sem.h, sysvipc/sys/shm.h,
sysdeps/stub/sys/msq_buf.h, sysdeps/stub/sys/sem_buf.h,
sysdeps/stub/sys/shm_buf.h, sysdeps/stub/sys/ipc_buf.h,
sysdeps/stub/semctl.c, sysdeps/stub/semget.c, sysdeps/stub/semop.c,
sysdeps/stub/shmat.c, sysdeps/stub/shmctl.c, sysdeps/stub/shmdt.c,
sysdeps/stub/shmget.c, sysdeps/stub/msgctl.c, sysdeps/stub/msgget.c,
sysdeps/stub/msgrcv.c, sysdeps/stub/msgsnd.c: New files.
Add implementation of System V IPC.
Diffstat (limited to 'sysdeps/generic/strstr.c')
-rw-r--r-- | sysdeps/generic/strstr.c | 119 |
1 files changed, 90 insertions, 29 deletions
diff --git a/sysdeps/generic/strstr.c b/sysdeps/generic/strstr.c index 06681de931..9c0e8183b5 100644 --- a/sysdeps/generic/strstr.c +++ b/sysdeps/generic/strstr.c @@ -1,4 +1,4 @@ -/* Copyright (C) 1991, 1992 Free Software Foundation, Inc. +/* Copyright (C) 1994 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -16,41 +16,102 @@ License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ -#include <ansidecl.h> -#include <stddef.h> +/* + * My personal strstr() implementation that beats most other algorithms. + * Until someone tells me otherwise, I assume that this is the + * fastest implementation of strstr() in C. + * I deliberately chose not to comment it. You should have at least + * as much fun trying to understand it, as I had to write it :-). + * + * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */ + #include <string.h> +#include <sys/types.h> + +typedef unsigned chartype; -/* Return the first ocurrence of NEEDLE in HAYSTACK. */ char * -DEFUN(strstr, (haystack, needle), - CONST char *CONST haystack AND - CONST char *CONST needle) +strstr (phaystack, pneedle) + const char *phaystack; + const char *pneedle; { - register CONST char *CONST needle_end = strchr(needle, '\0'); - register CONST char *CONST haystack_end = strchr(haystack, '\0'); - register CONST size_t needle_len = needle_end - needle; - register CONST size_t needle_last = needle_len - 1; - register CONST char *begin; - - if (needle_len == 0) - return (char *) haystack; /* ANSI 4.11.5.7, line 25. */ - if ((size_t) (haystack_end - haystack) < needle_len) - return NULL; - - for (begin = &haystack[needle_last]; begin < haystack_end; ++begin) - { - register CONST char *n = &needle[needle_last]; - register CONST char *h = begin; + register const unsigned char *haystack, *needle; + register chartype b, c; + + haystack = (const unsigned char *) phaystack; + needle = (const unsigned char *) pneedle; + b = *needle; + if (b != '\0') + { + haystack--; /* possible ANSI violation */ do - if (*h != *n) - goto loop; /* continue for loop */ - while (--n >= needle && --h >= haystack); + { + c = *++haystack; + if (c == '\0') + goto ret0; + } + while (c != b); - return (char *) h; + c = *++needle; + if (c == '\0') + goto foundneedle; + ++needle; + goto jin; - loop:; - } + for (;;) + { + register chartype a; + register const unsigned char *rhaystack, *rneedle; + + do + { + a = *++haystack; + if (a == '\0') + goto ret0; + if (a == b) + break; + a = *++haystack; + if (a == '\0') + goto ret0; +shloop: } + while (a != b); - return NULL; +jin: a = *++haystack; + if (a == '\0') + goto ret0; + + if (a != c) + goto shloop; + + rhaystack = haystack-- + 1; + rneedle = needle; + a = *rneedle; + + if (*rhaystack == a) + do + { + if (a == '\0') + goto foundneedle; + ++rhaystack; + a = *++needle; + if (*rhaystack != a) + break; + if (a == '\0') + goto foundneedle; + ++rhaystack; + a = *++needle; + } + while (*rhaystack == a); + + needle = rneedle; /* took the register-poor aproach */ + + if (a == '\0') + break; + } + } +foundneedle: + return (char*) haystack; +ret0: + return 0; } |