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authorRoland McGrath <roland@gnu.org>1995-09-17 20:23:15 +0000
committerRoland McGrath <roland@gnu.org>1995-09-17 20:23:15 +0000
commit60478656fad8d8a487e9bc52d025f69767c3262b (patch)
tree0ae0836023f1c2f80064e7611f91d19c482208d9 /sysdeps/generic/strstr.c
parent9fd18b6c1b397e1af82a0b544f10f946c73864b6 (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.c119
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;
}