Mercurial > hg > octave-kai > gnulib-hg
annotate lib/strstr.c @ 2020:989f1a5c1c0c
(strstr): Include config.h.
Add a `;' between shloop label and `}'.
| author | Jim Meyering <jim@meyering.net> |
|---|---|
| date | Fri, 19 Nov 1999 17:02:01 +0000 |
| parents | 38fd8f5d359d |
| children | 5994c6f939c5 |
| rev | line source |
|---|---|
|
2020
989f1a5c1c0c
(strstr): Include config.h.
Jim Meyering <jim@meyering.net>
parents:
1557
diff
changeset
|
1 /* Copyright (C) 1994, 1999 Free Software Foundation, Inc. |
| 656 | 2 This file is part of the GNU C Library. |
| 5 | 3 |
| 656 | 4 This program is free software; you can redistribute it and/or modify |
| 5 it under the terms of the GNU General Public License as published by | |
| 6 the Free Software Foundation; either version 2, or (at your option) | |
| 7 any later version. | |
| 8 | |
| 9 This program is distributed in the hope that it will be useful, | |
| 10 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 12 GNU General Public License for more details. | |
| 5 | 13 |
| 656 | 14 You should have received a copy of the GNU General Public License |
| 15 along with this program; if not, write to the Free Software | |
| 16 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ | |
| 5 | 17 |
| 656 | 18 /* |
| 19 * My personal strstr() implementation that beats most other algorithms. | |
| 20 * Until someone tells me otherwise, I assume that this is the | |
| 21 * fastest implementation of strstr() in C. | |
| 22 * I deliberately chose not to comment it. You should have at least | |
| 23 * as much fun trying to understand it, as I had to write it :-). | |
| 24 * | |
| 25 * Stephen R. van den Berg, berg@pool.informatik.rwth-aachen.de */ | |
| 5 | 26 |
|
2020
989f1a5c1c0c
(strstr): Include config.h.
Jim Meyering <jim@meyering.net>
parents:
1557
diff
changeset
|
27 #if HAVE_CONFIG_H |
|
989f1a5c1c0c
(strstr): Include config.h.
Jim Meyering <jim@meyering.net>
parents:
1557
diff
changeset
|
28 # include <config.h> |
|
989f1a5c1c0c
(strstr): Include config.h.
Jim Meyering <jim@meyering.net>
parents:
1557
diff
changeset
|
29 #endif |
|
989f1a5c1c0c
(strstr): Include config.h.
Jim Meyering <jim@meyering.net>
parents:
1557
diff
changeset
|
30 |
| 656 | 31 #include <string.h> |
| 32 #include <sys/types.h> | |
| 5 | 33 |
| 656 | 34 typedef unsigned chartype; |
| 5 | 35 |
| 36 char * | |
| 1557 | 37 strstr (const char *phaystack, const char *pneedle) |
| 5 | 38 { |
| 656 | 39 register const unsigned char *haystack, *needle; |
| 40 register chartype b, c; | |
| 41 | |
| 42 haystack = (const unsigned char *) phaystack; | |
| 43 needle = (const unsigned char *) pneedle; | |
| 44 | |
| 45 b = *needle; | |
| 46 if (b != '\0') | |
| 47 { | |
| 48 haystack--; /* possible ANSI violation */ | |
| 49 do | |
| 50 { | |
| 51 c = *++haystack; | |
| 52 if (c == '\0') | |
| 53 goto ret0; | |
| 54 } | |
| 55 while (c != b); | |
| 56 | |
| 57 c = *++needle; | |
| 58 if (c == '\0') | |
| 59 goto foundneedle; | |
| 60 ++needle; | |
| 61 goto jin; | |
| 62 | |
| 63 for (;;) | |
| 64 { | |
| 65 register chartype a; | |
| 66 register const unsigned char *rhaystack, *rneedle; | |
| 5 | 67 |
| 656 | 68 do |
| 69 { | |
| 70 a = *++haystack; | |
| 71 if (a == '\0') | |
| 72 goto ret0; | |
| 73 if (a == b) | |
| 74 break; | |
| 75 a = *++haystack; | |
| 76 if (a == '\0') | |
| 77 goto ret0; | |
|
2020
989f1a5c1c0c
(strstr): Include config.h.
Jim Meyering <jim@meyering.net>
parents:
1557
diff
changeset
|
78 shloop:; } |
| 656 | 79 while (a != b); |
| 80 | |
| 81 jin: a = *++haystack; | |
| 82 if (a == '\0') | |
| 83 goto ret0; | |
| 84 | |
| 85 if (a != c) | |
| 86 goto shloop; | |
| 87 | |
| 88 rhaystack = haystack-- + 1; | |
| 89 rneedle = needle; | |
| 90 a = *rneedle; | |
| 91 | |
| 92 if (*rhaystack == a) | |
| 93 do | |
| 94 { | |
| 95 if (a == '\0') | |
| 96 goto foundneedle; | |
| 97 ++rhaystack; | |
| 98 a = *++needle; | |
| 99 if (*rhaystack != a) | |
| 100 break; | |
| 101 if (a == '\0') | |
| 102 goto foundneedle; | |
| 103 ++rhaystack; | |
| 104 a = *++needle; | |
| 105 } | |
| 106 while (*rhaystack == a); | |
| 107 | |
| 108 needle = rneedle; /* took the register-poor aproach */ | |
| 109 | |
| 110 if (a == '\0') | |
| 111 break; | |
| 112 } | |
| 5 | 113 } |
| 656 | 114 foundneedle: |
| 115 return (char*) haystack; | |
| 116 ret0: | |
| 5 | 117 return 0; |
| 118 } |