blob: 11df54325fb8bce63c92b626a85dcbb3cbfb6e97 [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
André Goddard Rosaa11d2b62010-03-05 13:43:11 -080039 if (!len)
40 return 0;
41
42 do {
43 c1 = *s1++;
44 c2 = *s2++;
45 if (!c1 || !c2)
46 break;
47 if (c1 == c2)
48 continue;
49 c1 = tolower(c1);
50 c2 = tolower(c2);
51 if (c1 != c2)
52 break;
53 } while (--len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 return (int)c1 - (int)c2;
55}
Linus Torvalds1da177e2005-04-16 15:20:36 -070056EXPORT_SYMBOL(strnicmp);
57#endif
58
David S. Millerded220b2007-03-29 01:18:42 -070059#ifndef __HAVE_ARCH_STRCASECMP
60int strcasecmp(const char *s1, const char *s2)
61{
62 int c1, c2;
63
64 do {
65 c1 = tolower(*s1++);
66 c2 = tolower(*s2++);
67 } while (c1 == c2 && c1 != 0);
68 return c1 - c2;
69}
70EXPORT_SYMBOL(strcasecmp);
71#endif
72
73#ifndef __HAVE_ARCH_STRNCASECMP
74int strncasecmp(const char *s1, const char *s2, size_t n)
75{
76 int c1, c2;
77
78 do {
79 c1 = tolower(*s1++);
80 c2 = tolower(*s2++);
81 } while ((--n > 0) && c1 == c2 && c1 != 0);
82 return c1 - c2;
83}
84EXPORT_SYMBOL(strncasecmp);
85#endif
86
Linus Torvalds1da177e2005-04-16 15:20:36 -070087#ifndef __HAVE_ARCH_STRCPY
88/**
89 * strcpy - Copy a %NUL terminated string
90 * @dest: Where to copy the string to
91 * @src: Where to copy the string from
92 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -070093#undef strcpy
Jesper Juhl51a0f0f2005-10-30 15:02:11 -080094char *strcpy(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095{
96 char *tmp = dest;
97
98 while ((*dest++ = *src++) != '\0')
99 /* nothing */;
100 return tmp;
101}
102EXPORT_SYMBOL(strcpy);
103#endif
104
105#ifndef __HAVE_ARCH_STRNCPY
106/**
107 * strncpy - Copy a length-limited, %NUL-terminated string
108 * @dest: Where to copy the string to
109 * @src: Where to copy the string from
110 * @count: The maximum number of bytes to copy
111 *
112 * The result is not %NUL-terminated if the source exceeds
113 * @count bytes.
walter harms25279522005-05-05 16:16:20 -0700114 *
115 * In the case where the length of @src is less than that of
116 * count, the remainder of @dest will be padded with %NUL.
117 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800119char *strncpy(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120{
121 char *tmp = dest;
122
123 while (count) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800124 if ((*tmp = *src) != 0)
125 src++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 tmp++;
127 count--;
128 }
129 return dest;
130}
131EXPORT_SYMBOL(strncpy);
132#endif
133
134#ifndef __HAVE_ARCH_STRLCPY
135/**
136 * strlcpy - Copy a %NUL terminated string into a sized buffer
137 * @dest: Where to copy the string to
138 * @src: Where to copy the string from
139 * @size: size of destination buffer
140 *
141 * Compatible with *BSD: the result is always a valid
142 * NUL-terminated string that fits in the buffer (unless,
143 * of course, the buffer size is zero). It does not pad
144 * out the result like strncpy() does.
145 */
146size_t strlcpy(char *dest, const char *src, size_t size)
147{
148 size_t ret = strlen(src);
149
150 if (size) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800151 size_t len = (ret >= size) ? size - 1 : ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 memcpy(dest, src, len);
153 dest[len] = '\0';
154 }
155 return ret;
156}
157EXPORT_SYMBOL(strlcpy);
158#endif
159
160#ifndef __HAVE_ARCH_STRCAT
161/**
162 * strcat - Append one %NUL-terminated string to another
163 * @dest: The string to be appended to
164 * @src: The string to append to it
165 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700166#undef strcat
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800167char *strcat(char *dest, const char *src)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168{
169 char *tmp = dest;
170
171 while (*dest)
172 dest++;
173 while ((*dest++ = *src++) != '\0')
174 ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 return tmp;
176}
177EXPORT_SYMBOL(strcat);
178#endif
179
180#ifndef __HAVE_ARCH_STRNCAT
181/**
182 * strncat - Append a length-limited, %NUL-terminated string to another
183 * @dest: The string to be appended to
184 * @src: The string to append to it
185 * @count: The maximum numbers of bytes to copy
186 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800187 * Note that in contrast to strncpy(), strncat() ensures the result is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 * terminated.
189 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800190char *strncat(char *dest, const char *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
192 char *tmp = dest;
193
194 if (count) {
195 while (*dest)
196 dest++;
197 while ((*dest++ = *src++) != 0) {
198 if (--count == 0) {
199 *dest = '\0';
200 break;
201 }
202 }
203 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 return tmp;
205}
206EXPORT_SYMBOL(strncat);
207#endif
208
209#ifndef __HAVE_ARCH_STRLCAT
210/**
211 * strlcat - Append a length-limited, %NUL-terminated string to another
212 * @dest: The string to be appended to
213 * @src: The string to append to it
214 * @count: The size of the destination buffer.
215 */
216size_t strlcat(char *dest, const char *src, size_t count)
217{
218 size_t dsize = strlen(dest);
219 size_t len = strlen(src);
220 size_t res = dsize + len;
221
222 /* This would be a bug */
223 BUG_ON(dsize >= count);
224
225 dest += dsize;
226 count -= dsize;
227 if (len >= count)
228 len = count-1;
229 memcpy(dest, src, len);
230 dest[len] = 0;
231 return res;
232}
233EXPORT_SYMBOL(strlcat);
234#endif
235
236#ifndef __HAVE_ARCH_STRCMP
237/**
238 * strcmp - Compare two strings
239 * @cs: One string
240 * @ct: Another string
241 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700242#undef strcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800243int strcmp(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
Linus Torvaldsa414f012009-11-18 22:31:52 +0100245 unsigned char c1, c2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
247 while (1) {
Linus Torvaldsa414f012009-11-18 22:31:52 +0100248 c1 = *cs++;
249 c2 = *ct++;
250 if (c1 != c2)
251 return c1 < c2 ? -1 : 1;
252 if (!c1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 break;
254 }
Linus Torvaldsa414f012009-11-18 22:31:52 +0100255 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256}
257EXPORT_SYMBOL(strcmp);
258#endif
259
260#ifndef __HAVE_ARCH_STRNCMP
261/**
262 * strncmp - Compare two length-limited strings
263 * @cs: One string
264 * @ct: Another string
265 * @count: The maximum number of bytes to compare
266 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800267int strncmp(const char *cs, const char *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268{
Linus Torvaldsa414f012009-11-18 22:31:52 +0100269 unsigned char c1, c2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
271 while (count) {
Linus Torvaldsa414f012009-11-18 22:31:52 +0100272 c1 = *cs++;
273 c2 = *ct++;
274 if (c1 != c2)
275 return c1 < c2 ? -1 : 1;
276 if (!c1)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 break;
278 count--;
279 }
Linus Torvaldsa414f012009-11-18 22:31:52 +0100280 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281}
282EXPORT_SYMBOL(strncmp);
283#endif
284
285#ifndef __HAVE_ARCH_STRCHR
286/**
287 * strchr - Find the first occurrence of a character in a string
288 * @s: The string to be searched
289 * @c: The character to search for
290 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800291char *strchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800293 for (; *s != (char)c; ++s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294 if (*s == '\0')
295 return NULL;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800296 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297}
298EXPORT_SYMBOL(strchr);
299#endif
300
301#ifndef __HAVE_ARCH_STRRCHR
302/**
303 * strrchr - Find the last occurrence of a character in a string
304 * @s: The string to be searched
305 * @c: The character to search for
306 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800307char *strrchr(const char *s, int c)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308{
309 const char *p = s + strlen(s);
310 do {
311 if (*p == (char)c)
312 return (char *)p;
313 } while (--p >= s);
314 return NULL;
315}
316EXPORT_SYMBOL(strrchr);
317#endif
318
319#ifndef __HAVE_ARCH_STRNCHR
320/**
321 * strnchr - Find a character in a length limited string
322 * @s: The string to be searched
323 * @count: The number of characters to be searched
324 * @c: The character to search for
325 */
326char *strnchr(const char *s, size_t count, int c)
327{
328 for (; count-- && *s != '\0'; ++s)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800329 if (*s == (char)c)
330 return (char *)s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 return NULL;
332}
333EXPORT_SYMBOL(strnchr);
334#endif
335
Pekka Enberg481fad42006-06-23 02:05:44 -0700336/**
Randy Dunlapa6cd13f2009-12-21 14:37:22 -0800337 * skip_spaces - Removes leading whitespace from @str.
338 * @str: The string to be stripped.
André Goddard Rosaf6533982009-12-14 18:01:04 -0800339 *
Randy Dunlapa6cd13f2009-12-21 14:37:22 -0800340 * Returns a pointer to the first non-whitespace character in @str.
André Goddard Rosaf6533982009-12-14 18:01:04 -0800341 */
342char *skip_spaces(const char *str)
343{
344 while (isspace(*str))
345 ++str;
346 return (char *)str;
347}
348EXPORT_SYMBOL(skip_spaces);
349
350/**
KOSAKI Motohiroca54cb82009-12-14 18:01:15 -0800351 * strim - Removes leading and trailing whitespace from @s.
Pekka Enberg481fad42006-06-23 02:05:44 -0700352 * @s: The string to be stripped.
353 *
354 * Note that the first trailing whitespace is replaced with a %NUL-terminator
355 * in the given string @s. Returns a pointer to the first non-whitespace
356 * character in @s.
357 */
KOSAKI Motohiroca54cb82009-12-14 18:01:15 -0800358char *strim(char *s)
Pekka Enberg481fad42006-06-23 02:05:44 -0700359{
360 size_t size;
361 char *end;
362
André Goddard Rosa84c95c92009-12-14 18:01:04 -0800363 s = skip_spaces(s);
Pekka Enberg481fad42006-06-23 02:05:44 -0700364 size = strlen(s);
Pekka Enberg481fad42006-06-23 02:05:44 -0700365 if (!size)
366 return s;
367
368 end = s + size - 1;
Michael Holzheu6e6d9fa2006-10-28 10:38:47 -0700369 while (end >= s && isspace(*end))
Pekka Enberg481fad42006-06-23 02:05:44 -0700370 end--;
371 *(end + 1) = '\0';
372
André Goddard Rosa84c95c92009-12-14 18:01:04 -0800373 return s;
Pekka Enberg481fad42006-06-23 02:05:44 -0700374}
KOSAKI Motohiroca54cb82009-12-14 18:01:15 -0800375EXPORT_SYMBOL(strim);
Pekka Enberg481fad42006-06-23 02:05:44 -0700376
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377#ifndef __HAVE_ARCH_STRLEN
378/**
379 * strlen - Find the length of a string
380 * @s: The string to be sized
381 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800382size_t strlen(const char *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383{
384 const char *sc;
385
386 for (sc = s; *sc != '\0'; ++sc)
387 /* nothing */;
388 return sc - s;
389}
390EXPORT_SYMBOL(strlen);
391#endif
392
393#ifndef __HAVE_ARCH_STRNLEN
394/**
395 * strnlen - Find the length of a length-limited string
396 * @s: The string to be sized
397 * @count: The maximum number of bytes to search
398 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800399size_t strnlen(const char *s, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400{
401 const char *sc;
402
403 for (sc = s; count-- && *sc != '\0'; ++sc)
404 /* nothing */;
405 return sc - s;
406}
407EXPORT_SYMBOL(strnlen);
408#endif
409
410#ifndef __HAVE_ARCH_STRSPN
411/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800412 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 * @s: The string to be searched
414 * @accept: The string to search for
415 */
416size_t strspn(const char *s, const char *accept)
417{
418 const char *p;
419 const char *a;
420 size_t count = 0;
421
422 for (p = s; *p != '\0'; ++p) {
423 for (a = accept; *a != '\0'; ++a) {
424 if (*p == *a)
425 break;
426 }
427 if (*a == '\0')
428 return count;
429 ++count;
430 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 return count;
432}
433
434EXPORT_SYMBOL(strspn);
435#endif
436
Kyle McMartin8833d322006-04-10 22:53:57 -0700437#ifndef __HAVE_ARCH_STRCSPN
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -0800439 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 * @s: The string to be searched
441 * @reject: The string to avoid
442 */
443size_t strcspn(const char *s, const char *reject)
444{
445 const char *p;
446 const char *r;
447 size_t count = 0;
448
449 for (p = s; *p != '\0'; ++p) {
450 for (r = reject; *r != '\0'; ++r) {
451 if (*p == *r)
452 return count;
453 }
454 ++count;
455 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 return count;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800457}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458EXPORT_SYMBOL(strcspn);
Kyle McMartin8833d322006-04-10 22:53:57 -0700459#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
461#ifndef __HAVE_ARCH_STRPBRK
462/**
463 * strpbrk - Find the first occurrence of a set of characters
464 * @cs: The string to be searched
465 * @ct: The characters to search for
466 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800467char *strpbrk(const char *cs, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800469 const char *sc1, *sc2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800471 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
472 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 if (*sc1 == *sc2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800474 return (char *)sc1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 }
476 }
477 return NULL;
478}
Kyle McMartin894b5772006-04-10 22:53:56 -0700479EXPORT_SYMBOL(strpbrk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480#endif
481
482#ifndef __HAVE_ARCH_STRSEP
483/**
484 * strsep - Split a string into tokens
485 * @s: The string to be searched
486 * @ct: The characters to search for
487 *
488 * strsep() updates @s to point after the token, ready for the next call.
489 *
490 * It returns empty tokens, too, behaving exactly like the libc function
491 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
492 * Same semantics, slimmer shape. ;)
493 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800494char *strsep(char **s, const char *ct)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800496 char *sbegin = *s;
497 char *end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
499 if (sbegin == NULL)
500 return NULL;
501
502 end = strpbrk(sbegin, ct);
503 if (end)
504 *end++ = '\0';
505 *s = end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 return sbegin;
507}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508EXPORT_SYMBOL(strsep);
509#endif
510
David Brownell34990cf2008-05-01 04:34:42 -0700511/**
512 * sysfs_streq - return true if strings are equal, modulo trailing newline
513 * @s1: one string
514 * @s2: another string
515 *
516 * This routine returns true iff two strings are equal, treating both
517 * NUL and newline-then-NUL as equivalent string terminations. It's
518 * geared for use with sysfs input strings, which generally terminate
519 * with newlines but are compared against values without newlines.
520 */
521bool sysfs_streq(const char *s1, const char *s2)
522{
523 while (*s1 && *s1 == *s2) {
524 s1++;
525 s2++;
526 }
527
528 if (*s1 == *s2)
529 return true;
530 if (!*s1 && *s2 == '\n' && !s2[1])
531 return true;
532 if (*s1 == '\n' && !s1[1] && !*s2)
533 return true;
534 return false;
535}
536EXPORT_SYMBOL(sysfs_streq);
537
Jonathan Camerond0f1fed2011-04-19 12:43:45 +0100538/**
539 * strtobool - convert common user inputs into boolean values
540 * @s: input string
541 * @res: result
542 *
543 * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
544 * Otherwise it will return -EINVAL. Value pointed to by res is
545 * updated upon finding a match.
546 */
547int strtobool(const char *s, bool *res)
548{
549 switch (s[0]) {
550 case 'y':
551 case 'Y':
552 case '1':
553 *res = true;
554 break;
555 case 'n':
556 case 'N':
557 case '0':
558 *res = false;
559 break;
560 default:
561 return -EINVAL;
562 }
563 return 0;
564}
565EXPORT_SYMBOL(strtobool);
566
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567#ifndef __HAVE_ARCH_MEMSET
568/**
569 * memset - Fill a region of memory with the given value
570 * @s: Pointer to the start of the area.
571 * @c: The byte to fill the area with
572 * @count: The size of the area.
573 *
574 * Do not use memset() to access IO space, use memset_io() instead.
575 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800576void *memset(void *s, int c, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577{
Jesper Juhl850b9242005-10-30 15:02:13 -0800578 char *xs = s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579
580 while (count--)
581 *xs++ = c;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 return s;
583}
584EXPORT_SYMBOL(memset);
585#endif
586
587#ifndef __HAVE_ARCH_MEMCPY
588/**
589 * memcpy - Copy one area of memory to another
590 * @dest: Where to copy to
591 * @src: Where to copy from
592 * @count: The size of the area.
593 *
594 * You should not use this function to access IO space, use memcpy_toio()
595 * or memcpy_fromio() instead.
596 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800597void *memcpy(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598{
Jesper Juhl850b9242005-10-30 15:02:13 -0800599 char *tmp = dest;
Jan-Benedict Glaw4c416ab2006-04-10 22:54:09 -0700600 const char *s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601
602 while (count--)
603 *tmp++ = *s++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 return dest;
605}
606EXPORT_SYMBOL(memcpy);
607#endif
608
609#ifndef __HAVE_ARCH_MEMMOVE
610/**
611 * memmove - Copy one area of memory to another
612 * @dest: Where to copy to
613 * @src: Where to copy from
614 * @count: The size of the area.
615 *
616 * Unlike memcpy(), memmove() copes with overlapping areas.
617 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800618void *memmove(void *dest, const void *src, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619{
Paul Jackson82da2c32005-10-30 15:03:19 -0800620 char *tmp;
621 const char *s;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622
623 if (dest <= src) {
Jesper Juhl850b9242005-10-30 15:02:13 -0800624 tmp = dest;
625 s = src;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 while (count--)
627 *tmp++ = *s++;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800628 } else {
Jesper Juhl850b9242005-10-30 15:02:13 -0800629 tmp = dest;
630 tmp += count;
631 s = src;
632 s += count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 while (count--)
634 *--tmp = *--s;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800635 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 return dest;
637}
638EXPORT_SYMBOL(memmove);
639#endif
640
641#ifndef __HAVE_ARCH_MEMCMP
642/**
643 * memcmp - Compare two areas of memory
644 * @cs: One area of memory
645 * @ct: Another area of memory
646 * @count: The size of the area.
647 */
Paolo 'Blaisorblade' Giarrusso0c281302005-05-05 16:15:17 -0700648#undef memcmp
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800649int memcmp(const void *cs, const void *ct, size_t count)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650{
651 const unsigned char *su1, *su2;
652 int res = 0;
653
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800654 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 if ((res = *su1 - *su2) != 0)
656 break;
657 return res;
658}
659EXPORT_SYMBOL(memcmp);
660#endif
661
662#ifndef __HAVE_ARCH_MEMSCAN
663/**
664 * memscan - Find a character in an area of memory.
665 * @addr: The memory area
666 * @c: The byte to search for
667 * @size: The size of the area.
668 *
669 * returns the address of the first occurrence of @c, or 1 byte past
670 * the area if @c is not found
671 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800672void *memscan(void *addr, int c, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673{
Jesper Juhl850b9242005-10-30 15:02:13 -0800674 unsigned char *p = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
676 while (size) {
677 if (*p == c)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800678 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 p++;
680 size--;
681 }
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800682 return (void *)p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683}
684EXPORT_SYMBOL(memscan);
685#endif
686
687#ifndef __HAVE_ARCH_STRSTR
688/**
689 * strstr - Find the first substring in a %NUL terminated string
690 * @s1: The string to be searched
691 * @s2: The string to search for
692 */
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800693char *strstr(const char *s1, const char *s2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694{
Li Zefand5f1fb52010-01-14 10:53:55 +0800695 size_t l1, l2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696
697 l2 = strlen(s2);
698 if (!l2)
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800699 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 l1 = strlen(s1);
701 while (l1 >= l2) {
702 l1--;
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800703 if (!memcmp(s1, s2, l2))
704 return (char *)s1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 s1++;
706 }
707 return NULL;
708}
709EXPORT_SYMBOL(strstr);
710#endif
711
Li Zefand5f1fb52010-01-14 10:53:55 +0800712#ifndef __HAVE_ARCH_STRNSTR
713/**
714 * strnstr - Find the first substring in a length-limited string
715 * @s1: The string to be searched
716 * @s2: The string to search for
717 * @len: the maximum number of characters to search
718 */
719char *strnstr(const char *s1, const char *s2, size_t len)
720{
André Goddard Rosad6a2eed2010-03-05 13:43:12 -0800721 size_t l2;
Li Zefand5f1fb52010-01-14 10:53:55 +0800722
723 l2 = strlen(s2);
724 if (!l2)
725 return (char *)s1;
André Goddard Rosad6a2eed2010-03-05 13:43:12 -0800726 while (len >= l2) {
727 len--;
Li Zefand5f1fb52010-01-14 10:53:55 +0800728 if (!memcmp(s1, s2, l2))
729 return (char *)s1;
730 s1++;
731 }
732 return NULL;
733}
734EXPORT_SYMBOL(strnstr);
735#endif
736
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737#ifndef __HAVE_ARCH_MEMCHR
738/**
739 * memchr - Find a character in an area of memory.
740 * @s: The memory area
741 * @c: The byte to search for
742 * @n: The size of the area.
743 *
744 * returns the address of the first occurrence of @c, or %NULL
745 * if @c is not found
746 */
747void *memchr(const void *s, int c, size_t n)
748{
749 const unsigned char *p = s;
750 while (n-- != 0) {
751 if ((unsigned char)c == *p++) {
Jesper Juhl51a0f0f2005-10-30 15:02:11 -0800752 return (void *)(p - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 }
754 }
755 return NULL;
756}
757EXPORT_SYMBOL(memchr);
758#endif
Akinobu Mita798248202011-10-31 17:08:07 -0700759
760static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
761{
762 while (bytes) {
763 if (*start != value)
764 return (void *)start;
765 start++;
766 bytes--;
767 }
768 return NULL;
769}
770
771/**
772 * memchr_inv - Find an unmatching character in an area of memory.
773 * @start: The memory area
774 * @c: Find a character other than c
775 * @bytes: The size of the area.
776 *
777 * returns the address of the first character other than @c, or %NULL
778 * if the whole buffer contains just @c.
779 */
780void *memchr_inv(const void *start, int c, size_t bytes)
781{
782 u8 value = c;
783 u64 value64;
784 unsigned int words, prefix;
785
786 if (bytes <= 16)
787 return check_bytes8(start, value, bytes);
788
789 value64 = value | value << 8 | value << 16 | value << 24;
790 value64 = (value64 & 0xffffffff) | value64 << 32;
791 prefix = 8 - ((unsigned long)start) % 8;
792
793 if (prefix) {
794 u8 *r = check_bytes8(start, value, prefix);
795 if (r)
796 return r;
797 start += prefix;
798 bytes -= prefix;
799 }
800
801 words = bytes / 8;
802
803 while (words) {
804 if (*(u64 *)start != value64)
805 return check_bytes8(start, value, 8);
806 start += 8;
807 words--;
808 }
809
810 return check_bytes8(start, value, bytes % 8);
811}
812EXPORT_SYMBOL(memchr_inv);