4 * Copyright (C) 1991, 1992 Linus Torvalds
8 * stupid library routines.. The optimized versions should generally be found
9 * as inline code in <asm-xx/string.h>
11 * These are buggy as well..
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.
17 * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>,
18 * Matthew Hawkins <matt@mh.dropbear.id.au>
19 * - Kissed strtok() goodbye
22 #include <linux/types.h>
23 #include <linux/string.h>
24 #include <linux/ctype.h>
25 #include <linux/kernel.h>
26 #include <linux/export.h>
27 #include <linux/bug.h>
28 #include <linux/errno.h>
30 #include <asm/byteorder.h>
31 #include <asm/word-at-a-time.h>
34 #ifndef __HAVE_ARCH_STRNCASECMP
36 * strncasecmp - Case insensitive, length-limited string comparison
38 * @s2: The other string
39 * @len: the maximum number of characters to compare
41 int strncasecmp(const char *s1
, const char *s2
, size_t len
)
43 /* Yes, Virginia, it had better be unsigned */
61 return (int)c1
- (int)c2
;
63 EXPORT_SYMBOL(strncasecmp
);
66 #ifndef __HAVE_ARCH_STRCASECMP
67 int strcasecmp(const char *s1
, const char *s2
)
74 } while (c1
== c2
&& c1
!= 0);
77 EXPORT_SYMBOL(strcasecmp
);
80 #ifndef __HAVE_ARCH_STRCPY
82 * strcpy - Copy a %NUL terminated string
83 * @dest: Where to copy the string to
84 * @src: Where to copy the string from
87 char *strcpy(char *dest
, const char *src
)
91 while ((*dest
++ = *src
++) != '\0')
95 EXPORT_SYMBOL(strcpy
);
98 #ifndef __HAVE_ARCH_STRNCPY
100 * strncpy - Copy a length-limited, C-string
101 * @dest: Where to copy the string to
102 * @src: Where to copy the string from
103 * @count: The maximum number of bytes to copy
105 * The result is not %NUL-terminated if the source exceeds
108 * In the case where the length of @src is less than that of
109 * count, the remainder of @dest will be padded with %NUL.
112 char *strncpy(char *dest
, const char *src
, size_t count
)
117 if ((*tmp
= *src
) != 0)
124 EXPORT_SYMBOL(strncpy
);
127 #ifndef __HAVE_ARCH_STRLCPY
129 * strlcpy - Copy a C-string into a sized buffer
130 * @dest: Where to copy the string to
131 * @src: Where to copy the string from
132 * @size: size of destination buffer
134 * Compatible with *BSD: the result is always a valid
135 * NUL-terminated string that fits in the buffer (unless,
136 * of course, the buffer size is zero). It does not pad
137 * out the result like strncpy() does.
139 size_t strlcpy(char *dest
, const char *src
, size_t size
)
141 size_t ret
= strlen(src
);
144 size_t len
= (ret
>= size
) ? size
- 1 : ret
;
145 memcpy(dest
, src
, len
);
150 EXPORT_SYMBOL(strlcpy
);
153 #ifndef __HAVE_ARCH_STRSCPY
155 * strscpy - Copy a C-string into a sized buffer
156 * @dest: Where to copy the string to
157 * @src: Where to copy the string from
158 * @count: Size of destination buffer
160 * Copy the string, or as much of it as fits, into the dest buffer.
161 * The routine returns the number of characters copied (not including
162 * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough.
163 * The behavior is undefined if the string buffers overlap.
164 * The destination buffer is always NUL terminated, unless it's zero-sized.
166 * Preferred to strlcpy() since the API doesn't require reading memory
167 * from the src string beyond the specified "count" bytes, and since
168 * the return value is easier to error-check than strlcpy()'s.
169 * In addition, the implementation is robust to the string changing out
170 * from underneath it, unlike the current strlcpy() implementation.
172 * Preferred to strncpy() since it always returns a valid string, and
173 * doesn't unnecessarily force the tail of the destination buffer to be
174 * zeroed. If the zeroing is desired, it's likely cleaner to use strscpy()
175 * with an overflow test, then just memset() the tail of the dest buffer.
177 ssize_t
strscpy(char *dest
, const char *src
, size_t count
)
179 const struct word_at_a_time constants
= WORD_AT_A_TIME_CONSTANTS
;
186 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
188 * If src is unaligned, don't cross a page boundary,
189 * since we don't know if the next page is mapped.
191 if ((long)src
& (sizeof(long) - 1)) {
192 size_t limit
= PAGE_SIZE
- ((long)src
& (PAGE_SIZE
- 1));
197 /* If src or dest is unaligned, don't do word-at-a-time. */
198 if (((long) dest
| (long) src
) & (sizeof(long) - 1))
202 while (max
>= sizeof(unsigned long)) {
203 unsigned long c
, data
;
205 c
= *(unsigned long *)(src
+res
);
206 *(unsigned long *)(dest
+res
) = c
;
207 if (has_zero(c
, &data
, &constants
)) {
208 data
= prep_zero_mask(c
, data
, &constants
);
209 data
= create_zero_mask(data
);
210 return res
+ find_zero(data
);
212 res
+= sizeof(unsigned long);
213 count
-= sizeof(unsigned long);
214 max
-= sizeof(unsigned long);
228 /* Hit buffer length without finding a NUL; force NUL-termination. */
234 EXPORT_SYMBOL(strscpy
);
237 #ifndef __HAVE_ARCH_STRCAT
239 * strcat - Append one %NUL-terminated string to another
240 * @dest: The string to be appended to
241 * @src: The string to append to it
244 char *strcat(char *dest
, const char *src
)
250 while ((*dest
++ = *src
++) != '\0')
254 EXPORT_SYMBOL(strcat
);
257 #ifndef __HAVE_ARCH_STRNCAT
259 * strncat - Append a length-limited, C-string to another
260 * @dest: The string to be appended to
261 * @src: The string to append to it
262 * @count: The maximum numbers of bytes to copy
264 * Note that in contrast to strncpy(), strncat() ensures the result is
267 char *strncat(char *dest
, const char *src
, size_t count
)
274 while ((*dest
++ = *src
++) != 0) {
283 EXPORT_SYMBOL(strncat
);
286 #ifndef __HAVE_ARCH_STRLCAT
288 * strlcat - Append a length-limited, C-string to another
289 * @dest: The string to be appended to
290 * @src: The string to append to it
291 * @count: The size of the destination buffer.
293 size_t strlcat(char *dest
, const char *src
, size_t count
)
295 size_t dsize
= strlen(dest
);
296 size_t len
= strlen(src
);
297 size_t res
= dsize
+ len
;
299 /* This would be a bug */
300 BUG_ON(dsize
>= count
);
306 memcpy(dest
, src
, len
);
310 EXPORT_SYMBOL(strlcat
);
313 #ifndef __HAVE_ARCH_STRCMP
315 * strcmp - Compare two strings
317 * @ct: Another string
320 int strcmp(const char *cs
, const char *ct
)
322 unsigned char c1
, c2
;
328 return c1
< c2
? -1 : 1;
334 EXPORT_SYMBOL(strcmp
);
337 #ifndef __HAVE_ARCH_STRNCMP
339 * strncmp - Compare two length-limited strings
341 * @ct: Another string
342 * @count: The maximum number of bytes to compare
344 int strncmp(const char *cs
, const char *ct
, size_t count
)
346 unsigned char c1
, c2
;
352 return c1
< c2
? -1 : 1;
359 EXPORT_SYMBOL(strncmp
);
362 #ifndef __HAVE_ARCH_STRCHR
364 * strchr - Find the first occurrence of a character in a string
365 * @s: The string to be searched
366 * @c: The character to search for
368 char *strchr(const char *s
, int c
)
370 for (; *s
!= (char)c
; ++s
)
375 EXPORT_SYMBOL(strchr
);
378 #ifndef __HAVE_ARCH_STRCHRNUL
380 * strchrnul - Find and return a character in a string, or end of string
381 * @s: The string to be searched
382 * @c: The character to search for
384 * Returns pointer to first occurrence of 'c' in s. If c is not found, then
385 * return a pointer to the null byte at the end of s.
387 char *strchrnul(const char *s
, int c
)
389 while (*s
&& *s
!= (char)c
)
393 EXPORT_SYMBOL(strchrnul
);
396 #ifndef __HAVE_ARCH_STRRCHR
398 * strrchr - Find the last occurrence of a character in a string
399 * @s: The string to be searched
400 * @c: The character to search for
402 char *strrchr(const char *s
, int c
)
404 const char *last
= NULL
;
411 EXPORT_SYMBOL(strrchr
);
414 #ifndef __HAVE_ARCH_STRNCHR
416 * strnchr - Find a character in a length limited string
417 * @s: The string to be searched
418 * @count: The number of characters to be searched
419 * @c: The character to search for
421 char *strnchr(const char *s
, size_t count
, int c
)
423 for (; count
-- && *s
!= '\0'; ++s
)
428 EXPORT_SYMBOL(strnchr
);
432 * skip_spaces - Removes leading whitespace from @str.
433 * @str: The string to be stripped.
435 * Returns a pointer to the first non-whitespace character in @str.
437 char *skip_spaces(const char *str
)
439 while (isspace(*str
))
443 EXPORT_SYMBOL(skip_spaces
);
446 * strim - Removes leading and trailing whitespace from @s.
447 * @s: The string to be stripped.
449 * Note that the first trailing whitespace is replaced with a %NUL-terminator
450 * in the given string @s. Returns a pointer to the first non-whitespace
463 while (end
>= s
&& isspace(*end
))
467 return skip_spaces(s
);
469 EXPORT_SYMBOL(strim
);
471 #ifndef __HAVE_ARCH_STRLEN
473 * strlen - Find the length of a string
474 * @s: The string to be sized
476 size_t strlen(const char *s
)
480 for (sc
= s
; *sc
!= '\0'; ++sc
)
484 EXPORT_SYMBOL(strlen
);
487 #ifndef __HAVE_ARCH_STRNLEN
489 * strnlen - Find the length of a length-limited string
490 * @s: The string to be sized
491 * @count: The maximum number of bytes to search
493 size_t strnlen(const char *s
, size_t count
)
497 for (sc
= s
; count
-- && *sc
!= '\0'; ++sc
)
501 EXPORT_SYMBOL(strnlen
);
504 #ifndef __HAVE_ARCH_STRSPN
506 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
507 * @s: The string to be searched
508 * @accept: The string to search for
510 size_t strspn(const char *s
, const char *accept
)
516 for (p
= s
; *p
!= '\0'; ++p
) {
517 for (a
= accept
; *a
!= '\0'; ++a
) {
528 EXPORT_SYMBOL(strspn
);
531 #ifndef __HAVE_ARCH_STRCSPN
533 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
534 * @s: The string to be searched
535 * @reject: The string to avoid
537 size_t strcspn(const char *s
, const char *reject
)
543 for (p
= s
; *p
!= '\0'; ++p
) {
544 for (r
= reject
; *r
!= '\0'; ++r
) {
552 EXPORT_SYMBOL(strcspn
);
555 #ifndef __HAVE_ARCH_STRPBRK
557 * strpbrk - Find the first occurrence of a set of characters
558 * @cs: The string to be searched
559 * @ct: The characters to search for
561 char *strpbrk(const char *cs
, const char *ct
)
563 const char *sc1
, *sc2
;
565 for (sc1
= cs
; *sc1
!= '\0'; ++sc1
) {
566 for (sc2
= ct
; *sc2
!= '\0'; ++sc2
) {
573 EXPORT_SYMBOL(strpbrk
);
576 #ifndef __HAVE_ARCH_STRSEP
578 * strsep - Split a string into tokens
579 * @s: The string to be searched
580 * @ct: The characters to search for
582 * strsep() updates @s to point after the token, ready for the next call.
584 * It returns empty tokens, too, behaving exactly like the libc function
585 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
586 * Same semantics, slimmer shape. ;)
588 char *strsep(char **s
, const char *ct
)
596 end
= strpbrk(sbegin
, ct
);
602 EXPORT_SYMBOL(strsep
);
606 * sysfs_streq - return true if strings are equal, modulo trailing newline
608 * @s2: another string
610 * This routine returns true iff two strings are equal, treating both
611 * NUL and newline-then-NUL as equivalent string terminations. It's
612 * geared for use with sysfs input strings, which generally terminate
613 * with newlines but are compared against values without newlines.
615 bool sysfs_streq(const char *s1
, const char *s2
)
617 while (*s1
&& *s1
== *s2
) {
624 if (!*s1
&& *s2
== '\n' && !s2
[1])
626 if (*s1
== '\n' && !s1
[1] && !*s2
)
630 EXPORT_SYMBOL(sysfs_streq
);
633 * strtobool - convert common user inputs into boolean values
637 * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
638 * Otherwise it will return -EINVAL. Value pointed to by res is
639 * updated upon finding a match.
641 int strtobool(const char *s
, bool *res
)
659 EXPORT_SYMBOL(strtobool
);
661 #ifndef __HAVE_ARCH_MEMSET
663 * memset - Fill a region of memory with the given value
664 * @s: Pointer to the start of the area.
665 * @c: The byte to fill the area with
666 * @count: The size of the area.
668 * Do not use memset() to access IO space, use memset_io() instead.
670 void *memset(void *s
, int c
, size_t count
)
678 EXPORT_SYMBOL(memset
);
682 * memzero_explicit - Fill a region of memory (e.g. sensitive
683 * keying data) with 0s.
684 * @s: Pointer to the start of the area.
685 * @count: The size of the area.
687 * Note: usually using memset() is just fine (!), but in cases
688 * where clearing out _local_ data at the end of a scope is
689 * necessary, memzero_explicit() should be used instead in
690 * order to prevent the compiler from optimising away zeroing.
692 * memzero_explicit() doesn't need an arch-specific version as
693 * it just invokes the one of memset() implicitly.
695 void memzero_explicit(void *s
, size_t count
)
700 EXPORT_SYMBOL(memzero_explicit
);
702 #ifndef __HAVE_ARCH_MEMCPY
704 * memcpy - Copy one area of memory to another
705 * @dest: Where to copy to
706 * @src: Where to copy from
707 * @count: The size of the area.
709 * You should not use this function to access IO space, use memcpy_toio()
710 * or memcpy_fromio() instead.
712 void *memcpy(void *dest
, const void *src
, size_t count
)
721 EXPORT_SYMBOL(memcpy
);
724 #ifndef __HAVE_ARCH_MEMMOVE
726 * memmove - Copy one area of memory to another
727 * @dest: Where to copy to
728 * @src: Where to copy from
729 * @count: The size of the area.
731 * Unlike memcpy(), memmove() copes with overlapping areas.
733 void *memmove(void *dest
, const void *src
, size_t count
)
753 EXPORT_SYMBOL(memmove
);
756 #ifndef __HAVE_ARCH_MEMCMP
758 * memcmp - Compare two areas of memory
759 * @cs: One area of memory
760 * @ct: Another area of memory
761 * @count: The size of the area.
764 __visible
int memcmp(const void *cs
, const void *ct
, size_t count
)
766 const unsigned char *su1
, *su2
;
769 for (su1
= cs
, su2
= ct
; 0 < count
; ++su1
, ++su2
, count
--)
770 if ((res
= *su1
- *su2
) != 0)
774 EXPORT_SYMBOL(memcmp
);
777 #ifndef __HAVE_ARCH_MEMSCAN
779 * memscan - Find a character in an area of memory.
780 * @addr: The memory area
781 * @c: The byte to search for
782 * @size: The size of the area.
784 * returns the address of the first occurrence of @c, or 1 byte past
785 * the area if @c is not found
787 void *memscan(void *addr
, int c
, size_t size
)
789 unsigned char *p
= addr
;
799 EXPORT_SYMBOL(memscan
);
802 #ifndef __HAVE_ARCH_STRSTR
804 * strstr - Find the first substring in a %NUL terminated string
805 * @s1: The string to be searched
806 * @s2: The string to search for
808 char *strstr(const char *s1
, const char *s2
)
818 if (!memcmp(s1
, s2
, l2
))
824 EXPORT_SYMBOL(strstr
);
827 #ifndef __HAVE_ARCH_STRNSTR
829 * strnstr - Find the first substring in a length-limited string
830 * @s1: The string to be searched
831 * @s2: The string to search for
832 * @len: the maximum number of characters to search
834 char *strnstr(const char *s1
, const char *s2
, size_t len
)
843 if (!memcmp(s1
, s2
, l2
))
849 EXPORT_SYMBOL(strnstr
);
852 #ifndef __HAVE_ARCH_MEMCHR
854 * memchr - Find a character in an area of memory.
855 * @s: The memory area
856 * @c: The byte to search for
857 * @n: The size of the area.
859 * returns the address of the first occurrence of @c, or %NULL
862 void *memchr(const void *s
, int c
, size_t n
)
864 const unsigned char *p
= s
;
866 if ((unsigned char)c
== *p
++) {
867 return (void *)(p
- 1);
872 EXPORT_SYMBOL(memchr
);
875 static void *check_bytes8(const u8
*start
, u8 value
, unsigned int bytes
)
879 return (void *)start
;
887 * memchr_inv - Find an unmatching character in an area of memory.
888 * @start: The memory area
889 * @c: Find a character other than c
890 * @bytes: The size of the area.
892 * returns the address of the first character other than @c, or %NULL
893 * if the whole buffer contains just @c.
895 void *memchr_inv(const void *start
, int c
, size_t bytes
)
899 unsigned int words
, prefix
;
902 return check_bytes8(start
, value
, bytes
);
905 #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
906 value64
*= 0x0101010101010101;
907 #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
908 value64
*= 0x01010101;
909 value64
|= value64
<< 32;
911 value64
|= value64
<< 8;
912 value64
|= value64
<< 16;
913 value64
|= value64
<< 32;
916 prefix
= (unsigned long)start
% 8;
921 r
= check_bytes8(start
, value
, prefix
);
931 if (*(u64
*)start
!= value64
)
932 return check_bytes8(start
, value
, 8);
937 return check_bytes8(start
, value
, bytes
% 8);
939 EXPORT_SYMBOL(memchr_inv
);
942 * strreplace - Replace all occurrences of character in string.
943 * @s: The string to operate on.
944 * @old: The character being replaced.
945 * @new: The character @old is replaced with.
947 * Returns pointer to the nul byte at the end of @s.
949 char *strreplace(char *s
, char old
, char new)
956 EXPORT_SYMBOL(strreplace
);
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