blob: e96421ab9a9a0a1a8ddd4496e32789acdc4b0749 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/lib/string.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7/*
8 * stupid library routines.. The optimized versions should generally be found
9 * as inline code in <asm-xx/string.h>
10 *
11 * These are buggy as well..
12 *
13 * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
14 * - Added strsep() which will replace strtok() soon (because strsep() is
15 * reentrant and should be faster). Use only strsep() in new code, please.
16 *
17 * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>,
18 * Matthew Hawkins <matt@mh.dropbear.id.au>
19 * - Kissed strtok() goodbye
20 */
21
22#include <linux/types.h>
23#include <linux/string.h>
24#include <linux/ctype.h>
25#include <linux/module.h>
26
27#ifndef __HAVE_ARCH_STRNICMP
28/**
29 * strnicmp - Case insensitive, length-limited string comparison
30 * @s1: One string
31 * @s2: The other string
32 * @len: the maximum number of characters to compare
33 */
34int strnicmp(const char *s1, const char *s2, size_t len)
35{
36 /* Yes, Virginia, it had better be unsigned */
37 unsigned char c1, c2;
38
Jesper Juhl850b9242005-10-30 15:02:13 -080039 c1 = c2 = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 if (len) {
41 do {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080042 c1 = *s1;
43 c2 = *s2;
44 s1++;
45 s2++;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 if (!c1)
47 break;
48 if (!c2)
49 break;
50 if (c1 == c2)
51 continue;
52 c1 = tolower(c1);
53 c2 = tolower(c2);
54 if (c1 != c2)
55 break;
56 } while (--len);
57 }
58 return (int)c1 - (int)c2;
59}
Linus Torvalds1da177e2005-04-16 15:20:36 -070060EXPORT_SYMBOL(strnicmp);
61#endif
62
David S. Millerded220b2007-03-29 01:18:42 -070063#ifndef __HAVE_ARCH_STRCASECMP
64int strcasecmp(const char *s1, const char *s2)
65{
66 int c1, c2;
67
68 do {
69 c1 = tolower(*s1++);
70 c2 = tolower(*s2++);
71 } while (c1 == c2 && c1 != 0);
72 return c1 - c2;
73}
74EXPORT_SYMBOL(strcasecmp);
75#endif
76
77#ifndef __HAVE_ARCH_STRNCASECMP
78int strncasecmp(const char *s1, const char *s2, size_t n)
79{
80 int c1, c2;
81
82 do {
83 c1 = tolower(*s1++);
84 c2 = tolower(*s2++);
85 } while ((--n > 0) && c1 == c2 && c1 != 0);
86 return c1 - c2;
87}
88EXPORT_SYMBOL(strncasecmp);
89#endif
90
Linus Torvalds1da177e2005-04-16 15:20:36 -070091#ifndef __HAVE_ARCH_STRCPY
92/**
93 * strcpy - Copy a %NUL terminated string
94 * @dest: Where to copy the string to
95 * @src: Where to copy the string from
96 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -070097#undef strcpy
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080098char *strcpy(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -070099{
100 char *tmp = dest;
101
102 while ((*dest++ = *src++) != '\0')
103 /* nothing */;
104 return tmp;
105}
106EXPORT_SYMBOL(strcpy);
107#endif
108
109#ifndef __HAVE_ARCH_STRNCPY
110/**
111 * strncpy - Copy a length-limited, %NUL-terminated string
112 * @dest: Where to copy the string to
113 * @src: Where to copy the string from
114 * @count: The maximum number of bytes to copy
115 *
116 * The result is not %NUL-terminated if the source exceeds
117 * @count bytes.
walter harms25279522005-05-05 16:16:20 -0700118 *
119 * In the case where the length of @src is less than that of
120 * count, the remainder of @dest will be padded with %NUL.
121 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800123char *strncpy(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 char *tmp = dest;
126
127 while (count) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800128 if ((*tmp = *src) != 0)
129 src++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 tmp++;
131 count--;
132 }
133 return dest;
134}
135EXPORT_SYMBOL(strncpy);
136#endif
137
138#ifndef __HAVE_ARCH_STRLCPY
139/**
140 * strlcpy - Copy a %NUL terminated string into a sized buffer
141 * @dest: Where to copy the string to
142 * @src: Where to copy the string from
143 * @size: size of destination buffer
144 *
145 * Compatible with *BSD: the result is always a valid
146 * NUL-terminated string that fits in the buffer (unless,
147 * of course, the buffer size is zero). It does not pad
148 * out the result like strncpy() does.
149 */
150size_t strlcpy(char *dest, const char *src, size_t size)
151{
152 size_t ret = strlen(src);
153
154 if (size) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800155 size_t len = (ret >= size) ? size - 1 : ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 memcpy(dest, src, len);
157 dest[len] = '\0';
158 }
159 return ret;
160}
161EXPORT_SYMBOL(strlcpy);
162#endif
163
164#ifndef __HAVE_ARCH_STRCAT
165/**
166 * strcat - Append one %NUL-terminated string to another
167 * @dest: The string to be appended to
168 * @src: The string to append to it
169 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700170#undef strcat
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800171char *strcat(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172{
173 char *tmp = dest;
174
175 while (*dest)
176 dest++;
177 while ((*dest++ = *src++) != '\0')
178 ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 return tmp;
180}
181EXPORT_SYMBOL(strcat);
182#endif
183
184#ifndef __HAVE_ARCH_STRNCAT
185/**
186 * strncat - Append a length-limited, %NUL-terminated string to another
187 * @dest: The string to be appended to
188 * @src: The string to append to it
189 * @count: The maximum numbers of bytes to copy
190 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800191 * Note that in contrast to strncpy(), strncat() ensures the result is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 * terminated.
193 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800194char *strncat(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195{
196 char *tmp = dest;
197
198 if (count) {
199 while (*dest)
200 dest++;
201 while ((*dest++ = *src++) != 0) {
202 if (--count == 0) {
203 *dest = '\0';
204 break;
205 }
206 }
207 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 return tmp;
209}
210EXPORT_SYMBOL(strncat);
211#endif
212
213#ifndef __HAVE_ARCH_STRLCAT
214/**
215 * strlcat - Append a length-limited, %NUL-terminated string to another
216 * @dest: The string to be appended to
217 * @src: The string to append to it
218 * @count: The size of the destination buffer.
219 */
220size_t strlcat(char *dest, const char *src, size_t count)
221{
222 size_t dsize = strlen(dest);
223 size_t len = strlen(src);
224 size_t res = dsize + len;
225
226 /* This would be a bug */
227 BUG_ON(dsize >= count);
228
229 dest += dsize;
230 count -= dsize;
231 if (len >= count)
232 len = count-1;
233 memcpy(dest, src, len);
234 dest[len] = 0;
235 return res;
236}
237EXPORT_SYMBOL(strlcat);
238#endif
239
240#ifndef __HAVE_ARCH_STRCMP
241/**
242 * strcmp - Compare two strings
243 * @cs: One string
244 * @ct: Another string
245 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700246#undef strcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800247int strcmp(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248{
Linus Torvaldsa414f012009-11-18 22:31:52 +0100249 unsigned char c1, c2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250
251 while (1) {
Linus Torvaldsa414f012009-11-18 22:31:52 +0100252 c1 = *cs++;
253 c2 = *ct++;
254 if (c1 != c2)
255 return c1 < c2 ? -1 : 1;
256 if (!c1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 break;
258 }
Linus Torvaldsa414f012009-11-18 22:31:52 +0100259 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260}
261EXPORT_SYMBOL(strcmp);
262#endif
263
264#ifndef __HAVE_ARCH_STRNCMP
265/**
266 * strncmp - Compare two length-limited strings
267 * @cs: One string
268 * @ct: Another string
269 * @count: The maximum number of bytes to compare
270 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800271int strncmp(const char *cs, const char *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272{
Linus Torvaldsa414f012009-11-18 22:31:52 +0100273 unsigned char c1, c2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275 while (count) {
Linus Torvaldsa414f012009-11-18 22:31:52 +0100276 c1 = *cs++;
277 c2 = *ct++;
278 if (c1 != c2)
279 return c1 < c2 ? -1 : 1;
280 if (!c1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 break;
282 count--;
283 }
Linus Torvaldsa414f012009-11-18 22:31:52 +0100284 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285}
286EXPORT_SYMBOL(strncmp);
287#endif
288
289#ifndef __HAVE_ARCH_STRCHR
290/**
291 * strchr - Find the first occurrence of a character in a string
292 * @s: The string to be searched
293 * @c: The character to search for
294 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800295char *strchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800297 for (; *s != (char)c; ++s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298 if (*s == '\0')
299 return NULL;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800300 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301}
302EXPORT_SYMBOL(strchr);
303#endif
304
305#ifndef __HAVE_ARCH_STRRCHR
306/**
307 * strrchr - Find the last occurrence of a character in a string
308 * @s: The string to be searched
309 * @c: The character to search for
310 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800311char *strrchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312{
313 const char *p = s + strlen(s);
314 do {
315 if (*p == (char)c)
316 return (char *)p;
317 } while (--p >= s);
318 return NULL;
319}
320EXPORT_SYMBOL(strrchr);
321#endif
322
323#ifndef __HAVE_ARCH_STRNCHR
324/**
325 * strnchr - Find a character in a length limited string
326 * @s: The string to be searched
327 * @count: The number of characters to be searched
328 * @c: The character to search for
329 */
330char *strnchr(const char *s, size_t count, int c)
331{
332 for (; count-- && *s != '\0'; ++s)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800333 if (*s == (char)c)
334 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 return NULL;
336}
337EXPORT_SYMBOL(strnchr);
338#endif
339
Pekka Enberg481fad42006-06-23 02:05:44 -0700340/**
341 * strstrip - Removes leading and trailing whitespace from @s.
342 * @s: The string to be stripped.
343 *
344 * Note that the first trailing whitespace is replaced with a %NUL-terminator
345 * in the given string @s. Returns a pointer to the first non-whitespace
346 * character in @s.
347 */
348char *strstrip(char *s)
349{
350 size_t size;
351 char *end;
352
353 size = strlen(s);
354
355 if (!size)
356 return s;
357
358 end = s + size - 1;
Michael Holzheu6e6d9fa2006-10-28 10:38:47 -0700359 while (end >= s && isspace(*end))
Pekka Enberg481fad42006-06-23 02:05:44 -0700360 end--;
361 *(end + 1) = '\0';
362
363 while (*s && isspace(*s))
364 s++;
365
366 return s;
367}
368EXPORT_SYMBOL(strstrip);
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370#ifndef __HAVE_ARCH_STRLEN
371/**
372 * strlen - Find the length of a string
373 * @s: The string to be sized
374 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800375size_t strlen(const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376{
377 const char *sc;
378
379 for (sc = s; *sc != '\0'; ++sc)
380 /* nothing */;
381 return sc - s;
382}
383EXPORT_SYMBOL(strlen);
384#endif
385
386#ifndef __HAVE_ARCH_STRNLEN
387/**
388 * strnlen - Find the length of a length-limited string
389 * @s: The string to be sized
390 * @count: The maximum number of bytes to search
391 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800392size_t strnlen(const char *s, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393{
394 const char *sc;
395
396 for (sc = s; count-- && *sc != '\0'; ++sc)
397 /* nothing */;
398 return sc - s;
399}
400EXPORT_SYMBOL(strnlen);
401#endif
402
403#ifndef __HAVE_ARCH_STRSPN
404/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800405 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 * @s: The string to be searched
407 * @accept: The string to search for
408 */
409size_t strspn(const char *s, const char *accept)
410{
411 const char *p;
412 const char *a;
413 size_t count = 0;
414
415 for (p = s; *p != '\0'; ++p) {
416 for (a = accept; *a != '\0'; ++a) {
417 if (*p == *a)
418 break;
419 }
420 if (*a == '\0')
421 return count;
422 ++count;
423 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 return count;
425}
426
427EXPORT_SYMBOL(strspn);
428#endif
429
Kyle McMartin8833d322006-04-10 22:53:57 -0700430#ifndef __HAVE_ARCH_STRCSPN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800432 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 * @s: The string to be searched
434 * @reject: The string to avoid
435 */
436size_t strcspn(const char *s, const char *reject)
437{
438 const char *p;
439 const char *r;
440 size_t count = 0;
441
442 for (p = s; *p != '\0'; ++p) {
443 for (r = reject; *r != '\0'; ++r) {
444 if (*p == *r)
445 return count;
446 }
447 ++count;
448 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 return count;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800450}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451EXPORT_SYMBOL(strcspn);
Kyle McMartin8833d322006-04-10 22:53:57 -0700452#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
454#ifndef __HAVE_ARCH_STRPBRK
455/**
456 * strpbrk - Find the first occurrence of a set of characters
457 * @cs: The string to be searched
458 * @ct: The characters to search for
459 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800460char *strpbrk(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800462 const char *sc1, *sc2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800464 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
465 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 if (*sc1 == *sc2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800467 return (char *)sc1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 }
469 }
470 return NULL;
471}
Kyle McMartin894b5772006-04-10 22:53:56 -0700472EXPORT_SYMBOL(strpbrk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473#endif
474
475#ifndef __HAVE_ARCH_STRSEP
476/**
477 * strsep - Split a string into tokens
478 * @s: The string to be searched
479 * @ct: The characters to search for
480 *
481 * strsep() updates @s to point after the token, ready for the next call.
482 *
483 * It returns empty tokens, too, behaving exactly like the libc function
484 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
485 * Same semantics, slimmer shape. ;)
486 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800487char *strsep(char **s, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800489 char *sbegin = *s;
490 char *end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491
492 if (sbegin == NULL)
493 return NULL;
494
495 end = strpbrk(sbegin, ct);
496 if (end)
497 *end++ = '\0';
498 *s = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 return sbegin;
500}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501EXPORT_SYMBOL(strsep);
502#endif
503
David Brownell34990cf2008-05-01 04:34:42 -0700504/**
505 * sysfs_streq - return true if strings are equal, modulo trailing newline
506 * @s1: one string
507 * @s2: another string
508 *
509 * This routine returns true iff two strings are equal, treating both
510 * NUL and newline-then-NUL as equivalent string terminations. It's
511 * geared for use with sysfs input strings, which generally terminate
512 * with newlines but are compared against values without newlines.
513 */
514bool sysfs_streq(const char *s1, const char *s2)
515{
516 while (*s1 && *s1 == *s2) {
517 s1++;
518 s2++;
519 }
520
521 if (*s1 == *s2)
522 return true;
523 if (!*s1 && *s2 == '\n' && !s2[1])
524 return true;
525 if (*s1 == '\n' && !s1[1] && !*s2)
526 return true;
527 return false;
528}
529EXPORT_SYMBOL(sysfs_streq);
530
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531#ifndef __HAVE_ARCH_MEMSET
532/**
533 * memset - Fill a region of memory with the given value
534 * @s: Pointer to the start of the area.
535 * @c: The byte to fill the area with
536 * @count: The size of the area.
537 *
538 * Do not use memset() to access IO space, use memset_io() instead.
539 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800540void *memset(void *s, int c, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541{
Jesper Juhl850b9242005-10-30 15:02:13 -0800542 char *xs = s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
544 while (count--)
545 *xs++ = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 return s;
547}
548EXPORT_SYMBOL(memset);
549#endif
550
551#ifndef __HAVE_ARCH_MEMCPY
552/**
553 * memcpy - Copy one area of memory to another
554 * @dest: Where to copy to
555 * @src: Where to copy from
556 * @count: The size of the area.
557 *
558 * You should not use this function to access IO space, use memcpy_toio()
559 * or memcpy_fromio() instead.
560 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800561void *memcpy(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562{
Jesper Juhl850b9242005-10-30 15:02:13 -0800563 char *tmp = dest;
Jan-Benedict Glaw4c416ab2006-04-10 22:54:09 -0700564 const char *s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565
566 while (count--)
567 *tmp++ = *s++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 return dest;
569}
570EXPORT_SYMBOL(memcpy);
571#endif
572
573#ifndef __HAVE_ARCH_MEMMOVE
574/**
575 * memmove - Copy one area of memory to another
576 * @dest: Where to copy to
577 * @src: Where to copy from
578 * @count: The size of the area.
579 *
580 * Unlike memcpy(), memmove() copes with overlapping areas.
581 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800582void *memmove(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583{
Paul Jackson82da2c32005-10-30 15:03:19 -0800584 char *tmp;
585 const char *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586
587 if (dest <= src) {
Jesper Juhl850b9242005-10-30 15:02:13 -0800588 tmp = dest;
589 s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 while (count--)
591 *tmp++ = *s++;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800592 } else {
Jesper Juhl850b9242005-10-30 15:02:13 -0800593 tmp = dest;
594 tmp += count;
595 s = src;
596 s += count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 while (count--)
598 *--tmp = *--s;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800599 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 return dest;
601}
602EXPORT_SYMBOL(memmove);
603#endif
604
605#ifndef __HAVE_ARCH_MEMCMP
606/**
607 * memcmp - Compare two areas of memory
608 * @cs: One area of memory
609 * @ct: Another area of memory
610 * @count: The size of the area.
611 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700612#undef memcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800613int memcmp(const void *cs, const void *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614{
615 const unsigned char *su1, *su2;
616 int res = 0;
617
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800618 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 if ((res = *su1 - *su2) != 0)
620 break;
621 return res;
622}
623EXPORT_SYMBOL(memcmp);
624#endif
625
626#ifndef __HAVE_ARCH_MEMSCAN
627/**
628 * memscan - Find a character in an area of memory.
629 * @addr: The memory area
630 * @c: The byte to search for
631 * @size: The size of the area.
632 *
633 * returns the address of the first occurrence of @c, or 1 byte past
634 * the area if @c is not found
635 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800636void *memscan(void *addr, int c, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637{
Jesper Juhl850b9242005-10-30 15:02:13 -0800638 unsigned char *p = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639
640 while (size) {
641 if (*p == c)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800642 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 p++;
644 size--;
645 }
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800646 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647}
648EXPORT_SYMBOL(memscan);
649#endif
650
651#ifndef __HAVE_ARCH_STRSTR
652/**
653 * strstr - Find the first substring in a %NUL terminated string
654 * @s1: The string to be searched
655 * @s2: The string to search for
656 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800657char *strstr(const char *s1, const char *s2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658{
659 int l1, l2;
660
661 l2 = strlen(s2);
662 if (!l2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800663 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 l1 = strlen(s1);
665 while (l1 >= l2) {
666 l1--;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800667 if (!memcmp(s1, s2, l2))
668 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 s1++;
670 }
671 return NULL;
672}
673EXPORT_SYMBOL(strstr);
674#endif
675
676#ifndef __HAVE_ARCH_MEMCHR
677/**
678 * memchr - Find a character in an area of memory.
679 * @s: The memory area
680 * @c: The byte to search for
681 * @n: The size of the area.
682 *
683 * returns the address of the first occurrence of @c, or %NULL
684 * if @c is not found
685 */
686void *memchr(const void *s, int c, size_t n)
687{
688 const unsigned char *p = s;
689 while (n-- != 0) {
690 if ((unsigned char)c == *p++) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800691 return (void *)(p - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 }
693 }
694 return NULL;
695}
696EXPORT_SYMBOL(memchr);
697#endif