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CommitLineData
1da177e4
LT
1/*
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
a11d2b64
AGR
39 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);
1da177e4
LT
54 return (int)c1 - (int)c2;
55}
1da177e4
LT
56EXPORT_SYMBOL(strnicmp);
57#endif
58
ded220bd
DM
59#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
1da177e4
LT
87#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 */
0c28130b 93#undef strcpy
51a0f0f6 94char *strcpy(char *dest, const char *src)
1da177e4
LT
95{
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.
25279526 114 *
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 *
1da177e4 118 */
51a0f0f6 119char *strncpy(char *dest, const char *src, size_t count)
1da177e4
LT
120{
121 char *tmp = dest;
122
123 while (count) {
51a0f0f6
JJ
124 if ((*tmp = *src) != 0)
125 src++;
1da177e4
LT
126 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) {
51a0f0f6 151 size_t len = (ret >= size) ? size - 1 : ret;
1da177e4
LT
152 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 */
0c28130b 166#undef strcat
51a0f0f6 167char *strcat(char *dest, const char *src)
1da177e4
LT
168{
169 char *tmp = dest;
170
171 while (*dest)
172 dest++;
173 while ((*dest++ = *src++) != '\0')
174 ;
1da177e4
LT
175 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 *
72fd4a35 187 * Note that in contrast to strncpy(), strncat() ensures the result is
1da177e4
LT
188 * terminated.
189 */
51a0f0f6 190char *strncat(char *dest, const char *src, size_t count)
1da177e4
LT
191{
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 }
1da177e4
LT
204 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 */
0c28130b 242#undef strcmp
51a0f0f6 243int strcmp(const char *cs, const char *ct)
1da177e4 244{
a414f01a 245 unsigned char c1, c2;
1da177e4
LT
246
247 while (1) {
a414f01a
LT
248 c1 = *cs++;
249 c2 = *ct++;
250 if (c1 != c2)
251 return c1 < c2 ? -1 : 1;
252 if (!c1)
1da177e4
LT
253 break;
254 }
a414f01a 255 return 0;
1da177e4
LT
256}
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 */
51a0f0f6 267int strncmp(const char *cs, const char *ct, size_t count)
1da177e4 268{
a414f01a 269 unsigned char c1, c2;
1da177e4
LT
270
271 while (count) {
a414f01a
LT
272 c1 = *cs++;
273 c2 = *ct++;
274 if (c1 != c2)
275 return c1 < c2 ? -1 : 1;
276 if (!c1)
1da177e4
LT
277 break;
278 count--;
279 }
a414f01a 280 return 0;
1da177e4
LT
281}
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 */
51a0f0f6 291char *strchr(const char *s, int c)
1da177e4 292{
51a0f0f6 293 for (; *s != (char)c; ++s)
1da177e4
LT
294 if (*s == '\0')
295 return NULL;
51a0f0f6 296 return (char *)s;
1da177e4
LT
297}
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 */
51a0f0f6 307char *strrchr(const char *s, int c)
1da177e4
LT
308{
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)
51a0f0f6
JJ
329 if (*s == (char)c)
330 return (char *)s;
1da177e4
LT
331 return NULL;
332}
333EXPORT_SYMBOL(strnchr);
334#endif
335
f653398c 336/**
a6cd13f3
RD
337 * skip_spaces - Removes leading whitespace from @str.
338 * @str: The string to be stripped.
f653398c 339 *
a6cd13f3 340 * Returns a pointer to the first non-whitespace character in @str.
f653398c
AGR
341 */
342char *skip_spaces(const char *str)
343{
344 while (isspace(*str))
345 ++str;
346 return (char *)str;
347}
348EXPORT_SYMBOL(skip_spaces);
349
481fad48 350/**
ca54cb8c 351 * strim - Removes leading and trailing whitespace from @s.
481fad48
PE
352 * @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 */
ca54cb8c 358char *strim(char *s)
481fad48
PE
359{
360 size_t size;
361 char *end;
362
363 size = strlen(s);
481fad48
PE
364 if (!size)
365 return s;
366
367 end = s + size - 1;
6e6d9fa6 368 while (end >= s && isspace(*end))
481fad48
PE
369 end--;
370 *(end + 1) = '\0';
371
66f6958e 372 return skip_spaces(s);
481fad48 373}
ca54cb8c 374EXPORT_SYMBOL(strim);
481fad48 375
1da177e4
LT
376#ifndef __HAVE_ARCH_STRLEN
377/**
378 * strlen - Find the length of a string
379 * @s: The string to be sized
380 */
51a0f0f6 381size_t strlen(const char *s)
1da177e4
LT
382{
383 const char *sc;
384
385 for (sc = s; *sc != '\0'; ++sc)
386 /* nothing */;
387 return sc - s;
388}
389EXPORT_SYMBOL(strlen);
390#endif
391
392#ifndef __HAVE_ARCH_STRNLEN
393/**
394 * strnlen - Find the length of a length-limited string
395 * @s: The string to be sized
396 * @count: The maximum number of bytes to search
397 */
51a0f0f6 398size_t strnlen(const char *s, size_t count)
1da177e4
LT
399{
400 const char *sc;
401
402 for (sc = s; count-- && *sc != '\0'; ++sc)
403 /* nothing */;
404 return sc - s;
405}
406EXPORT_SYMBOL(strnlen);
407#endif
408
409#ifndef __HAVE_ARCH_STRSPN
410/**
72fd4a35 411 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
1da177e4
LT
412 * @s: The string to be searched
413 * @accept: The string to search for
414 */
415size_t strspn(const char *s, const char *accept)
416{
417 const char *p;
418 const char *a;
419 size_t count = 0;
420
421 for (p = s; *p != '\0'; ++p) {
422 for (a = accept; *a != '\0'; ++a) {
423 if (*p == *a)
424 break;
425 }
426 if (*a == '\0')
427 return count;
428 ++count;
429 }
1da177e4
LT
430 return count;
431}
432
433EXPORT_SYMBOL(strspn);
434#endif
435
8833d328 436#ifndef __HAVE_ARCH_STRCSPN
1da177e4 437/**
72fd4a35 438 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
1da177e4
LT
439 * @s: The string to be searched
440 * @reject: The string to avoid
441 */
442size_t strcspn(const char *s, const char *reject)
443{
444 const char *p;
445 const char *r;
446 size_t count = 0;
447
448 for (p = s; *p != '\0'; ++p) {
449 for (r = reject; *r != '\0'; ++r) {
450 if (*p == *r)
451 return count;
452 }
453 ++count;
454 }
1da177e4 455 return count;
51a0f0f6 456}
1da177e4 457EXPORT_SYMBOL(strcspn);
8833d328 458#endif
1da177e4
LT
459
460#ifndef __HAVE_ARCH_STRPBRK
461/**
462 * strpbrk - Find the first occurrence of a set of characters
463 * @cs: The string to be searched
464 * @ct: The characters to search for
465 */
51a0f0f6 466char *strpbrk(const char *cs, const char *ct)
1da177e4 467{
51a0f0f6 468 const char *sc1, *sc2;
1da177e4 469
51a0f0f6
JJ
470 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
471 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
1da177e4 472 if (*sc1 == *sc2)
51a0f0f6 473 return (char *)sc1;
1da177e4
LT
474 }
475 }
476 return NULL;
477}
894b5779 478EXPORT_SYMBOL(strpbrk);
1da177e4
LT
479#endif
480
481#ifndef __HAVE_ARCH_STRSEP
482/**
483 * strsep - Split a string into tokens
484 * @s: The string to be searched
485 * @ct: The characters to search for
486 *
487 * strsep() updates @s to point after the token, ready for the next call.
488 *
489 * It returns empty tokens, too, behaving exactly like the libc function
490 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
491 * Same semantics, slimmer shape. ;)
492 */
51a0f0f6 493char *strsep(char **s, const char *ct)
1da177e4 494{
51a0f0f6
JJ
495 char *sbegin = *s;
496 char *end;
1da177e4
LT
497
498 if (sbegin == NULL)
499 return NULL;
500
501 end = strpbrk(sbegin, ct);
502 if (end)
503 *end++ = '\0';
504 *s = end;
1da177e4
LT
505 return sbegin;
506}
1da177e4
LT
507EXPORT_SYMBOL(strsep);
508#endif
509
34990cf7
DB
510/**
511 * sysfs_streq - return true if strings are equal, modulo trailing newline
512 * @s1: one string
513 * @s2: another string
514 *
515 * This routine returns true iff two strings are equal, treating both
516 * NUL and newline-then-NUL as equivalent string terminations. It's
517 * geared for use with sysfs input strings, which generally terminate
518 * with newlines but are compared against values without newlines.
519 */
520bool sysfs_streq(const char *s1, const char *s2)
521{
522 while (*s1 && *s1 == *s2) {
523 s1++;
524 s2++;
525 }
526
527 if (*s1 == *s2)
528 return true;
529 if (!*s1 && *s2 == '\n' && !s2[1])
530 return true;
531 if (*s1 == '\n' && !s1[1] && !*s2)
532 return true;
533 return false;
534}
535EXPORT_SYMBOL(sysfs_streq);
536
d0f1fed2
JC
537/**
538 * strtobool - convert common user inputs into boolean values
539 * @s: input string
540 * @res: result
541 *
542 * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
543 * Otherwise it will return -EINVAL. Value pointed to by res is
544 * updated upon finding a match.
545 */
546int strtobool(const char *s, bool *res)
547{
548 switch (s[0]) {
549 case 'y':
550 case 'Y':
551 case '1':
552 *res = true;
553 break;
554 case 'n':
555 case 'N':
556 case '0':
557 *res = false;
558 break;
559 default:
560 return -EINVAL;
561 }
562 return 0;
563}
564EXPORT_SYMBOL(strtobool);
565
1da177e4
LT
566#ifndef __HAVE_ARCH_MEMSET
567/**
568 * memset - Fill a region of memory with the given value
569 * @s: Pointer to the start of the area.
570 * @c: The byte to fill the area with
571 * @count: The size of the area.
572 *
573 * Do not use memset() to access IO space, use memset_io() instead.
574 */
51a0f0f6 575void *memset(void *s, int c, size_t count)
1da177e4 576{
850b9247 577 char *xs = s;
1da177e4
LT
578
579 while (count--)
580 *xs++ = c;
1da177e4
LT
581 return s;
582}
583EXPORT_SYMBOL(memset);
584#endif
585
586#ifndef __HAVE_ARCH_MEMCPY
587/**
588 * memcpy - Copy one area of memory to another
589 * @dest: Where to copy to
590 * @src: Where to copy from
591 * @count: The size of the area.
592 *
593 * You should not use this function to access IO space, use memcpy_toio()
594 * or memcpy_fromio() instead.
595 */
51a0f0f6 596void *memcpy(void *dest, const void *src, size_t count)
1da177e4 597{
850b9247 598 char *tmp = dest;
4c416ab7 599 const char *s = src;
1da177e4
LT
600
601 while (count--)
602 *tmp++ = *s++;
1da177e4
LT
603 return dest;
604}
605EXPORT_SYMBOL(memcpy);
606#endif
607
608#ifndef __HAVE_ARCH_MEMMOVE
609/**
610 * memmove - Copy one area of memory to another
611 * @dest: Where to copy to
612 * @src: Where to copy from
613 * @count: The size of the area.
614 *
615 * Unlike memcpy(), memmove() copes with overlapping areas.
616 */
51a0f0f6 617void *memmove(void *dest, const void *src, size_t count)
1da177e4 618{
82da2c37
PJ
619 char *tmp;
620 const char *s;
1da177e4
LT
621
622 if (dest <= src) {
850b9247
JJ
623 tmp = dest;
624 s = src;
1da177e4
LT
625 while (count--)
626 *tmp++ = *s++;
51a0f0f6 627 } else {
850b9247
JJ
628 tmp = dest;
629 tmp += count;
630 s = src;
631 s += count;
1da177e4
LT
632 while (count--)
633 *--tmp = *--s;
51a0f0f6 634 }
1da177e4
LT
635 return dest;
636}
637EXPORT_SYMBOL(memmove);
638#endif
639
640#ifndef __HAVE_ARCH_MEMCMP
641/**
642 * memcmp - Compare two areas of memory
643 * @cs: One area of memory
644 * @ct: Another area of memory
645 * @count: The size of the area.
646 */
0c28130b 647#undef memcmp
51a0f0f6 648int memcmp(const void *cs, const void *ct, size_t count)
1da177e4
LT
649{
650 const unsigned char *su1, *su2;
651 int res = 0;
652
51a0f0f6 653 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
1da177e4
LT
654 if ((res = *su1 - *su2) != 0)
655 break;
656 return res;
657}
658EXPORT_SYMBOL(memcmp);
659#endif
660
661#ifndef __HAVE_ARCH_MEMSCAN
662/**
663 * memscan - Find a character in an area of memory.
664 * @addr: The memory area
665 * @c: The byte to search for
666 * @size: The size of the area.
667 *
668 * returns the address of the first occurrence of @c, or 1 byte past
669 * the area if @c is not found
670 */
51a0f0f6 671void *memscan(void *addr, int c, size_t size)
1da177e4 672{
850b9247 673 unsigned char *p = addr;
1da177e4
LT
674
675 while (size) {
676 if (*p == c)
51a0f0f6 677 return (void *)p;
1da177e4
LT
678 p++;
679 size--;
680 }
51a0f0f6 681 return (void *)p;
1da177e4
LT
682}
683EXPORT_SYMBOL(memscan);
684#endif
685
686#ifndef __HAVE_ARCH_STRSTR
687/**
688 * strstr - Find the first substring in a %NUL terminated string
689 * @s1: The string to be searched
690 * @s2: The string to search for
691 */
51a0f0f6 692char *strstr(const char *s1, const char *s2)
1da177e4 693{
d5f1fb53 694 size_t l1, l2;
1da177e4
LT
695
696 l2 = strlen(s2);
697 if (!l2)
51a0f0f6 698 return (char *)s1;
1da177e4
LT
699 l1 = strlen(s1);
700 while (l1 >= l2) {
701 l1--;
51a0f0f6
JJ
702 if (!memcmp(s1, s2, l2))
703 return (char *)s1;
1da177e4
LT
704 s1++;
705 }
706 return NULL;
707}
708EXPORT_SYMBOL(strstr);
709#endif
710
d5f1fb53
LZ
711#ifndef __HAVE_ARCH_STRNSTR
712/**
713 * strnstr - Find the first substring in a length-limited string
714 * @s1: The string to be searched
715 * @s2: The string to search for
716 * @len: the maximum number of characters to search
717 */
718char *strnstr(const char *s1, const char *s2, size_t len)
719{
d6a2eedf 720 size_t l2;
d5f1fb53
LZ
721
722 l2 = strlen(s2);
723 if (!l2)
724 return (char *)s1;
d6a2eedf
AGR
725 while (len >= l2) {
726 len--;
d5f1fb53
LZ
727 if (!memcmp(s1, s2, l2))
728 return (char *)s1;
729 s1++;
730 }
731 return NULL;
732}
733EXPORT_SYMBOL(strnstr);
734#endif
735
1da177e4
LT
736#ifndef __HAVE_ARCH_MEMCHR
737/**
738 * memchr - Find a character in an area of memory.
739 * @s: The memory area
740 * @c: The byte to search for
741 * @n: The size of the area.
742 *
743 * returns the address of the first occurrence of @c, or %NULL
744 * if @c is not found
745 */
746void *memchr(const void *s, int c, size_t n)
747{
748 const unsigned char *p = s;
749 while (n-- != 0) {
750 if ((unsigned char)c == *p++) {
51a0f0f6 751 return (void *)(p - 1);
1da177e4
LT
752 }
753 }
754 return NULL;
755}
756EXPORT_SYMBOL(memchr);
757#endif
79824820
AM
758
759static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
760{
761 while (bytes) {
762 if (*start != value)
763 return (void *)start;
764 start++;
765 bytes--;
766 }
767 return NULL;
768}
769
770/**
771 * memchr_inv - Find an unmatching character in an area of memory.
772 * @start: The memory area
773 * @c: Find a character other than c
774 * @bytes: The size of the area.
775 *
776 * returns the address of the first character other than @c, or %NULL
777 * if the whole buffer contains just @c.
778 */
779void *memchr_inv(const void *start, int c, size_t bytes)
780{
781 u8 value = c;
782 u64 value64;
783 unsigned int words, prefix;
784
785 if (bytes <= 16)
786 return check_bytes8(start, value, bytes);
787
788 value64 = value | value << 8 | value << 16 | value << 24;
789 value64 = (value64 & 0xffffffff) | value64 << 32;
790 prefix = 8 - ((unsigned long)start) % 8;
791
792 if (prefix) {
793 u8 *r = check_bytes8(start, value, prefix);
794 if (r)
795 return r;
796 start += prefix;
797 bytes -= prefix;
798 }
799
800 words = bytes / 8;
801
802 while (words) {
803 if (*(u64 *)start != value64)
804 return check_bytes8(start, value, 8);
805 start += 8;
806 words--;
807 }
808
809 return check_bytes8(start, value, bytes % 8);
810}
811EXPORT_SYMBOL(memchr_inv);