]>
git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - lib/string.c
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 #ifndef __HAVE_ARCH_STRNCASECMP
32 * strncasecmp - Case insensitive, length-limited string comparison
34 * @s2: The other string
35 * @len: the maximum number of characters to compare
37 int strncasecmp(const char *s1
, const char *s2
, size_t len
)
39 /* Yes, Virginia, it had better be unsigned */
57 return (int)c1
- (int)c2
;
59 EXPORT_SYMBOL(strncasecmp
);
61 #ifndef __HAVE_ARCH_STRNICMP
63 int strnicmp(const char *s1
, const char *s2
, size_t len
)
65 return strncasecmp(s1
, s2
, len
);
67 EXPORT_SYMBOL(strnicmp
);
70 #ifndef __HAVE_ARCH_STRCASECMP
71 int strcasecmp(const char *s1
, const char *s2
)
78 } while (c1
== c2
&& c1
!= 0);
81 EXPORT_SYMBOL(strcasecmp
);
84 #ifndef __HAVE_ARCH_STRCPY
86 * strcpy - Copy a %NUL terminated string
87 * @dest: Where to copy the string to
88 * @src: Where to copy the string from
91 char *strcpy(char *dest
, const char *src
)
95 while ((*dest
++ = *src
++) != '\0')
99 EXPORT_SYMBOL(strcpy
);
102 #ifndef __HAVE_ARCH_STRNCPY
104 * strncpy - Copy a length-limited, C-string
105 * @dest: Where to copy the string to
106 * @src: Where to copy the string from
107 * @count: The maximum number of bytes to copy
109 * The result is not %NUL-terminated if the source exceeds
112 * In the case where the length of @src is less than that of
113 * count, the remainder of @dest will be padded with %NUL.
116 char *strncpy(char *dest
, const char *src
, size_t count
)
121 if ((*tmp
= *src
) != 0)
128 EXPORT_SYMBOL(strncpy
);
131 #ifndef __HAVE_ARCH_STRLCPY
133 * strlcpy - Copy a C-string into a sized buffer
134 * @dest: Where to copy the string to
135 * @src: Where to copy the string from
136 * @size: size of destination buffer
138 * Compatible with *BSD: the result is always a valid
139 * NUL-terminated string that fits in the buffer (unless,
140 * of course, the buffer size is zero). It does not pad
141 * out the result like strncpy() does.
143 size_t strlcpy(char *dest
, const char *src
, size_t size
)
145 size_t ret
= strlen(src
);
148 size_t len
= (ret
>= size
) ? size
- 1 : ret
;
149 memcpy(dest
, src
, len
);
154 EXPORT_SYMBOL(strlcpy
);
157 #ifndef __HAVE_ARCH_STRCAT
159 * strcat - Append one %NUL-terminated string to another
160 * @dest: The string to be appended to
161 * @src: The string to append to it
164 char *strcat(char *dest
, const char *src
)
170 while ((*dest
++ = *src
++) != '\0')
174 EXPORT_SYMBOL(strcat
);
177 #ifndef __HAVE_ARCH_STRNCAT
179 * strncat - Append a length-limited, C-string to another
180 * @dest: The string to be appended to
181 * @src: The string to append to it
182 * @count: The maximum numbers of bytes to copy
184 * Note that in contrast to strncpy(), strncat() ensures the result is
187 char *strncat(char *dest
, const char *src
, size_t count
)
194 while ((*dest
++ = *src
++) != 0) {
203 EXPORT_SYMBOL(strncat
);
206 #ifndef __HAVE_ARCH_STRLCAT
208 * strlcat - Append a length-limited, C-string to another
209 * @dest: The string to be appended to
210 * @src: The string to append to it
211 * @count: The size of the destination buffer.
213 size_t strlcat(char *dest
, const char *src
, size_t count
)
215 size_t dsize
= strlen(dest
);
216 size_t len
= strlen(src
);
217 size_t res
= dsize
+ len
;
219 /* This would be a bug */
220 BUG_ON(dsize
>= count
);
226 memcpy(dest
, src
, len
);
230 EXPORT_SYMBOL(strlcat
);
233 #ifndef __HAVE_ARCH_STRCMP
235 * strcmp - Compare two strings
237 * @ct: Another string
240 int strcmp(const char *cs
, const char *ct
)
242 unsigned char c1
, c2
;
248 return c1
< c2
? -1 : 1;
254 EXPORT_SYMBOL(strcmp
);
257 #ifndef __HAVE_ARCH_STRNCMP
259 * strncmp - Compare two length-limited strings
261 * @ct: Another string
262 * @count: The maximum number of bytes to compare
264 int strncmp(const char *cs
, const char *ct
, size_t count
)
266 unsigned char c1
, c2
;
272 return c1
< c2
? -1 : 1;
279 EXPORT_SYMBOL(strncmp
);
282 #ifndef __HAVE_ARCH_STRCHR
284 * strchr - Find the first occurrence of a character in a string
285 * @s: The string to be searched
286 * @c: The character to search for
288 char *strchr(const char *s
, int c
)
290 for (; *s
!= (char)c
; ++s
)
295 EXPORT_SYMBOL(strchr
);
298 #ifndef __HAVE_ARCH_STRCHRNUL
300 * strchrnul - Find and return a character in a string, or end of string
301 * @s: The string to be searched
302 * @c: The character to search for
304 * Returns pointer to first occurrence of 'c' in s. If c is not found, then
305 * return a pointer to the null byte at the end of s.
307 char *strchrnul(const char *s
, int c
)
309 while (*s
&& *s
!= (char)c
)
313 EXPORT_SYMBOL(strchrnul
);
316 #ifndef __HAVE_ARCH_STRRCHR
318 * strrchr - Find the last occurrence of a character in a string
319 * @s: The string to be searched
320 * @c: The character to search for
322 char *strrchr(const char *s
, int c
)
324 const char *p
= s
+ strlen(s
);
331 EXPORT_SYMBOL(strrchr
);
334 #ifndef __HAVE_ARCH_STRNCHR
336 * strnchr - Find a character in a length limited string
337 * @s: The string to be searched
338 * @count: The number of characters to be searched
339 * @c: The character to search for
341 char *strnchr(const char *s
, size_t count
, int c
)
343 for (; count
-- && *s
!= '\0'; ++s
)
348 EXPORT_SYMBOL(strnchr
);
352 * skip_spaces - Removes leading whitespace from @str.
353 * @str: The string to be stripped.
355 * Returns a pointer to the first non-whitespace character in @str.
357 char *skip_spaces(const char *str
)
359 while (isspace(*str
))
363 EXPORT_SYMBOL(skip_spaces
);
366 * strim - Removes leading and trailing whitespace from @s.
367 * @s: The string to be stripped.
369 * Note that the first trailing whitespace is replaced with a %NUL-terminator
370 * in the given string @s. Returns a pointer to the first non-whitespace
383 while (end
>= s
&& isspace(*end
))
387 return skip_spaces(s
);
389 EXPORT_SYMBOL(strim
);
391 #ifndef __HAVE_ARCH_STRLEN
393 * strlen - Find the length of a string
394 * @s: The string to be sized
396 size_t strlen(const char *s
)
400 for (sc
= s
; *sc
!= '\0'; ++sc
)
404 EXPORT_SYMBOL(strlen
);
407 #ifndef __HAVE_ARCH_STRNLEN
409 * strnlen - Find the length of a length-limited string
410 * @s: The string to be sized
411 * @count: The maximum number of bytes to search
413 size_t strnlen(const char *s
, size_t count
)
417 for (sc
= s
; count
-- && *sc
!= '\0'; ++sc
)
421 EXPORT_SYMBOL(strnlen
);
424 #ifndef __HAVE_ARCH_STRSPN
426 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
427 * @s: The string to be searched
428 * @accept: The string to search for
430 size_t strspn(const char *s
, const char *accept
)
436 for (p
= s
; *p
!= '\0'; ++p
) {
437 for (a
= accept
; *a
!= '\0'; ++a
) {
448 EXPORT_SYMBOL(strspn
);
451 #ifndef __HAVE_ARCH_STRCSPN
453 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
454 * @s: The string to be searched
455 * @reject: The string to avoid
457 size_t strcspn(const char *s
, const char *reject
)
463 for (p
= s
; *p
!= '\0'; ++p
) {
464 for (r
= reject
; *r
!= '\0'; ++r
) {
472 EXPORT_SYMBOL(strcspn
);
475 #ifndef __HAVE_ARCH_STRPBRK
477 * strpbrk - Find the first occurrence of a set of characters
478 * @cs: The string to be searched
479 * @ct: The characters to search for
481 char *strpbrk(const char *cs
, const char *ct
)
483 const char *sc1
, *sc2
;
485 for (sc1
= cs
; *sc1
!= '\0'; ++sc1
) {
486 for (sc2
= ct
; *sc2
!= '\0'; ++sc2
) {
493 EXPORT_SYMBOL(strpbrk
);
496 #ifndef __HAVE_ARCH_STRSEP
498 * strsep - Split a string into tokens
499 * @s: The string to be searched
500 * @ct: The characters to search for
502 * strsep() updates @s to point after the token, ready for the next call.
504 * It returns empty tokens, too, behaving exactly like the libc function
505 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
506 * Same semantics, slimmer shape. ;)
508 char *strsep(char **s
, const char *ct
)
516 end
= strpbrk(sbegin
, ct
);
522 EXPORT_SYMBOL(strsep
);
526 * sysfs_streq - return true if strings are equal, modulo trailing newline
528 * @s2: another string
530 * This routine returns true iff two strings are equal, treating both
531 * NUL and newline-then-NUL as equivalent string terminations. It's
532 * geared for use with sysfs input strings, which generally terminate
533 * with newlines but are compared against values without newlines.
535 bool sysfs_streq(const char *s1
, const char *s2
)
537 while (*s1
&& *s1
== *s2
) {
544 if (!*s1
&& *s2
== '\n' && !s2
[1])
546 if (*s1
== '\n' && !s1
[1] && !*s2
)
550 EXPORT_SYMBOL(sysfs_streq
);
553 * strtobool - convert common user inputs into boolean values
557 * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
558 * Otherwise it will return -EINVAL. Value pointed to by res is
559 * updated upon finding a match.
561 int strtobool(const char *s
, bool *res
)
579 EXPORT_SYMBOL(strtobool
);
581 #ifndef __HAVE_ARCH_MEMSET
583 * memset - Fill a region of memory with the given value
584 * @s: Pointer to the start of the area.
585 * @c: The byte to fill the area with
586 * @count: The size of the area.
588 * Do not use memset() to access IO space, use memset_io() instead.
590 void *memset(void *s
, int c
, size_t count
)
598 EXPORT_SYMBOL(memset
);
601 #ifndef __HAVE_ARCH_MEMCPY
603 * memcpy - Copy one area of memory to another
604 * @dest: Where to copy to
605 * @src: Where to copy from
606 * @count: The size of the area.
608 * You should not use this function to access IO space, use memcpy_toio()
609 * or memcpy_fromio() instead.
611 void *memcpy(void *dest
, const void *src
, size_t count
)
620 EXPORT_SYMBOL(memcpy
);
623 #ifndef __HAVE_ARCH_MEMMOVE
625 * memmove - Copy one area of memory to another
626 * @dest: Where to copy to
627 * @src: Where to copy from
628 * @count: The size of the area.
630 * Unlike memcpy(), memmove() copes with overlapping areas.
632 void *memmove(void *dest
, const void *src
, size_t count
)
652 EXPORT_SYMBOL(memmove
);
655 #ifndef __HAVE_ARCH_MEMCMP
657 * memcmp - Compare two areas of memory
658 * @cs: One area of memory
659 * @ct: Another area of memory
660 * @count: The size of the area.
663 __visible
int memcmp(const void *cs
, const void *ct
, size_t count
)
665 const unsigned char *su1
, *su2
;
668 for (su1
= cs
, su2
= ct
; 0 < count
; ++su1
, ++su2
, count
--)
669 if ((res
= *su1
- *su2
) != 0)
673 EXPORT_SYMBOL(memcmp
);
676 #ifndef __HAVE_ARCH_MEMSCAN
678 * memscan - Find a character in an area of memory.
679 * @addr: The memory area
680 * @c: The byte to search for
681 * @size: The size of the area.
683 * returns the address of the first occurrence of @c, or 1 byte past
684 * the area if @c is not found
686 void *memscan(void *addr
, int c
, size_t size
)
688 unsigned char *p
= addr
;
698 EXPORT_SYMBOL(memscan
);
701 #ifndef __HAVE_ARCH_STRSTR
703 * strstr - Find the first substring in a %NUL terminated string
704 * @s1: The string to be searched
705 * @s2: The string to search for
707 char *strstr(const char *s1
, const char *s2
)
717 if (!memcmp(s1
, s2
, l2
))
723 EXPORT_SYMBOL(strstr
);
726 #ifndef __HAVE_ARCH_STRNSTR
728 * strnstr - Find the first substring in a length-limited string
729 * @s1: The string to be searched
730 * @s2: The string to search for
731 * @len: the maximum number of characters to search
733 char *strnstr(const char *s1
, const char *s2
, size_t len
)
742 if (!memcmp(s1
, s2
, l2
))
748 EXPORT_SYMBOL(strnstr
);
751 #ifndef __HAVE_ARCH_MEMCHR
753 * memchr - Find a character in an area of memory.
754 * @s: The memory area
755 * @c: The byte to search for
756 * @n: The size of the area.
758 * returns the address of the first occurrence of @c, or %NULL
761 void *memchr(const void *s
, int c
, size_t n
)
763 const unsigned char *p
= s
;
765 if ((unsigned char)c
== *p
++) {
766 return (void *)(p
- 1);
771 EXPORT_SYMBOL(memchr
);
774 static void *check_bytes8(const u8
*start
, u8 value
, unsigned int bytes
)
778 return (void *)start
;
786 * memchr_inv - Find an unmatching character in an area of memory.
787 * @start: The memory area
788 * @c: Find a character other than c
789 * @bytes: The size of the area.
791 * returns the address of the first character other than @c, or %NULL
792 * if the whole buffer contains just @c.
794 void *memchr_inv(const void *start
, int c
, size_t bytes
)
798 unsigned int words
, prefix
;
801 return check_bytes8(start
, value
, bytes
);
804 #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
805 value64
*= 0x0101010101010101;
806 #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
807 value64
*= 0x01010101;
808 value64
|= value64
<< 32;
810 value64
|= value64
<< 8;
811 value64
|= value64
<< 16;
812 value64
|= value64
<< 32;
815 prefix
= (unsigned long)start
% 8;
820 r
= check_bytes8(start
, value
, prefix
);
830 if (*(u64
*)start
!= value64
)
831 return check_bytes8(start
, value
, 8);
836 return check_bytes8(start
, value
, bytes
% 8);
838 EXPORT_SYMBOL(memchr_inv
);