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git.proxmox.com Git - mirror_ubuntu-jammy-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/module.h>
27 #ifndef __HAVE_ARCH_STRNICMP
29 * strnicmp - Case insensitive, length-limited string comparison
31 * @s2: The other string
32 * @len: the maximum number of characters to compare
34 int strnicmp(const char *s1
, const char *s2
, size_t len
)
36 /* Yes, Virginia, it had better be unsigned */
58 return (int)c1
- (int)c2
;
60 EXPORT_SYMBOL(strnicmp
);
63 #ifndef __HAVE_ARCH_STRCASECMP
64 int strcasecmp(const char *s1
, const char *s2
)
71 } while (c1
== c2
&& c1
!= 0);
74 EXPORT_SYMBOL(strcasecmp
);
77 #ifndef __HAVE_ARCH_STRNCASECMP
78 int strncasecmp(const char *s1
, const char *s2
, size_t n
)
85 } while ((--n
> 0) && c1
== c2
&& c1
!= 0);
88 EXPORT_SYMBOL(strncasecmp
);
91 #ifndef __HAVE_ARCH_STRCPY
93 * strcpy - Copy a %NUL terminated string
94 * @dest: Where to copy the string to
95 * @src: Where to copy the string from
98 char *strcpy(char *dest
, const char *src
)
102 while ((*dest
++ = *src
++) != '\0')
106 EXPORT_SYMBOL(strcpy
);
109 #ifndef __HAVE_ARCH_STRNCPY
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
116 * The result is not %NUL-terminated if the source exceeds
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.
123 char *strncpy(char *dest
, const char *src
, size_t count
)
128 if ((*tmp
= *src
) != 0)
135 EXPORT_SYMBOL(strncpy
);
138 #ifndef __HAVE_ARCH_STRLCPY
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
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.
150 size_t strlcpy(char *dest
, const char *src
, size_t size
)
152 size_t ret
= strlen(src
);
155 size_t len
= (ret
>= size
) ? size
- 1 : ret
;
156 memcpy(dest
, src
, len
);
161 EXPORT_SYMBOL(strlcpy
);
164 #ifndef __HAVE_ARCH_STRCAT
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
171 char *strcat(char *dest
, const char *src
)
177 while ((*dest
++ = *src
++) != '\0')
181 EXPORT_SYMBOL(strcat
);
184 #ifndef __HAVE_ARCH_STRNCAT
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
191 * Note that in contrast to strncpy(), strncat() ensures the result is
194 char *strncat(char *dest
, const char *src
, size_t count
)
201 while ((*dest
++ = *src
++) != 0) {
210 EXPORT_SYMBOL(strncat
);
213 #ifndef __HAVE_ARCH_STRLCAT
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.
220 size_t strlcat(char *dest
, const char *src
, size_t count
)
222 size_t dsize
= strlen(dest
);
223 size_t len
= strlen(src
);
224 size_t res
= dsize
+ len
;
226 /* This would be a bug */
227 BUG_ON(dsize
>= count
);
233 memcpy(dest
, src
, len
);
237 EXPORT_SYMBOL(strlcat
);
240 #ifndef __HAVE_ARCH_STRCMP
242 * strcmp - Compare two strings
244 * @ct: Another string
247 int strcmp(const char *cs
, const char *ct
)
252 if ((__res
= *cs
- *ct
++) != 0 || !*cs
++)
257 EXPORT_SYMBOL(strcmp
);
260 #ifndef __HAVE_ARCH_STRNCMP
262 * strncmp - Compare two length-limited strings
264 * @ct: Another string
265 * @count: The maximum number of bytes to compare
267 int strncmp(const char *cs
, const char *ct
, size_t count
)
269 signed char __res
= 0;
272 if ((__res
= *cs
- *ct
++) != 0 || !*cs
++)
278 EXPORT_SYMBOL(strncmp
);
281 #ifndef __HAVE_ARCH_STRCHR
283 * strchr - Find the first occurrence of a character in a string
284 * @s: The string to be searched
285 * @c: The character to search for
287 char *strchr(const char *s
, int c
)
289 for (; *s
!= (char)c
; ++s
)
294 EXPORT_SYMBOL(strchr
);
297 #ifndef __HAVE_ARCH_STRRCHR
299 * strrchr - Find the last occurrence of a character in a string
300 * @s: The string to be searched
301 * @c: The character to search for
303 char *strrchr(const char *s
, int c
)
305 const char *p
= s
+ strlen(s
);
312 EXPORT_SYMBOL(strrchr
);
315 #ifndef __HAVE_ARCH_STRNCHR
317 * strnchr - Find a character in a length limited string
318 * @s: The string to be searched
319 * @count: The number of characters to be searched
320 * @c: The character to search for
322 char *strnchr(const char *s
, size_t count
, int c
)
324 for (; count
-- && *s
!= '\0'; ++s
)
329 EXPORT_SYMBOL(strnchr
);
333 * strstrip - Removes leading and trailing whitespace from @s.
334 * @s: The string to be stripped.
336 * Note that the first trailing whitespace is replaced with a %NUL-terminator
337 * in the given string @s. Returns a pointer to the first non-whitespace
340 char *strstrip(char *s
)
351 while (end
>= s
&& isspace(*end
))
355 while (*s
&& isspace(*s
))
360 EXPORT_SYMBOL(strstrip
);
362 #ifndef __HAVE_ARCH_STRLEN
364 * strlen - Find the length of a string
365 * @s: The string to be sized
367 size_t strlen(const char *s
)
371 for (sc
= s
; *sc
!= '\0'; ++sc
)
375 EXPORT_SYMBOL(strlen
);
378 #ifndef __HAVE_ARCH_STRNLEN
380 * strnlen - Find the length of a length-limited string
381 * @s: The string to be sized
382 * @count: The maximum number of bytes to search
384 size_t strnlen(const char *s
, size_t count
)
388 for (sc
= s
; count
-- && *sc
!= '\0'; ++sc
)
392 EXPORT_SYMBOL(strnlen
);
395 #ifndef __HAVE_ARCH_STRSPN
397 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
398 * @s: The string to be searched
399 * @accept: The string to search for
401 size_t strspn(const char *s
, const char *accept
)
407 for (p
= s
; *p
!= '\0'; ++p
) {
408 for (a
= accept
; *a
!= '\0'; ++a
) {
419 EXPORT_SYMBOL(strspn
);
422 #ifndef __HAVE_ARCH_STRCSPN
424 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
425 * @s: The string to be searched
426 * @reject: The string to avoid
428 size_t strcspn(const char *s
, const char *reject
)
434 for (p
= s
; *p
!= '\0'; ++p
) {
435 for (r
= reject
; *r
!= '\0'; ++r
) {
443 EXPORT_SYMBOL(strcspn
);
446 #ifndef __HAVE_ARCH_STRPBRK
448 * strpbrk - Find the first occurrence of a set of characters
449 * @cs: The string to be searched
450 * @ct: The characters to search for
452 char *strpbrk(const char *cs
, const char *ct
)
454 const char *sc1
, *sc2
;
456 for (sc1
= cs
; *sc1
!= '\0'; ++sc1
) {
457 for (sc2
= ct
; *sc2
!= '\0'; ++sc2
) {
464 EXPORT_SYMBOL(strpbrk
);
467 #ifndef __HAVE_ARCH_STRSEP
469 * strsep - Split a string into tokens
470 * @s: The string to be searched
471 * @ct: The characters to search for
473 * strsep() updates @s to point after the token, ready for the next call.
475 * It returns empty tokens, too, behaving exactly like the libc function
476 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
477 * Same semantics, slimmer shape. ;)
479 char *strsep(char **s
, const char *ct
)
487 end
= strpbrk(sbegin
, ct
);
493 EXPORT_SYMBOL(strsep
);
497 * sysfs_streq - return true if strings are equal, modulo trailing newline
499 * @s2: another string
501 * This routine returns true iff two strings are equal, treating both
502 * NUL and newline-then-NUL as equivalent string terminations. It's
503 * geared for use with sysfs input strings, which generally terminate
504 * with newlines but are compared against values without newlines.
506 bool sysfs_streq(const char *s1
, const char *s2
)
508 while (*s1
&& *s1
== *s2
) {
515 if (!*s1
&& *s2
== '\n' && !s2
[1])
517 if (*s1
== '\n' && !s1
[1] && !*s2
)
521 EXPORT_SYMBOL(sysfs_streq
);
523 #ifndef __HAVE_ARCH_MEMSET
525 * memset - Fill a region of memory with the given value
526 * @s: Pointer to the start of the area.
527 * @c: The byte to fill the area with
528 * @count: The size of the area.
530 * Do not use memset() to access IO space, use memset_io() instead.
532 void *memset(void *s
, int c
, size_t count
)
540 EXPORT_SYMBOL(memset
);
543 #ifndef __HAVE_ARCH_MEMCPY
545 * memcpy - Copy one area of memory to another
546 * @dest: Where to copy to
547 * @src: Where to copy from
548 * @count: The size of the area.
550 * You should not use this function to access IO space, use memcpy_toio()
551 * or memcpy_fromio() instead.
553 void *memcpy(void *dest
, const void *src
, size_t count
)
562 EXPORT_SYMBOL(memcpy
);
565 #ifndef __HAVE_ARCH_MEMMOVE
567 * memmove - Copy one area of memory to another
568 * @dest: Where to copy to
569 * @src: Where to copy from
570 * @count: The size of the area.
572 * Unlike memcpy(), memmove() copes with overlapping areas.
574 void *memmove(void *dest
, const void *src
, size_t count
)
594 EXPORT_SYMBOL(memmove
);
597 #ifndef __HAVE_ARCH_MEMCMP
599 * memcmp - Compare two areas of memory
600 * @cs: One area of memory
601 * @ct: Another area of memory
602 * @count: The size of the area.
605 int memcmp(const void *cs
, const void *ct
, size_t count
)
607 const unsigned char *su1
, *su2
;
610 for (su1
= cs
, su2
= ct
; 0 < count
; ++su1
, ++su2
, count
--)
611 if ((res
= *su1
- *su2
) != 0)
615 EXPORT_SYMBOL(memcmp
);
618 #ifndef __HAVE_ARCH_MEMSCAN
620 * memscan - Find a character in an area of memory.
621 * @addr: The memory area
622 * @c: The byte to search for
623 * @size: The size of the area.
625 * returns the address of the first occurrence of @c, or 1 byte past
626 * the area if @c is not found
628 void *memscan(void *addr
, int c
, size_t size
)
630 unsigned char *p
= addr
;
640 EXPORT_SYMBOL(memscan
);
643 #ifndef __HAVE_ARCH_STRSTR
645 * strstr - Find the first substring in a %NUL terminated string
646 * @s1: The string to be searched
647 * @s2: The string to search for
649 char *strstr(const char *s1
, const char *s2
)
659 if (!memcmp(s1
, s2
, l2
))
665 EXPORT_SYMBOL(strstr
);
668 #ifndef __HAVE_ARCH_MEMCHR
670 * memchr - Find a character in an area of memory.
671 * @s: The memory area
672 * @c: The byte to search for
673 * @n: The size of the area.
675 * returns the address of the first occurrence of @c, or %NULL
678 void *memchr(const void *s
, int c
, size_t n
)
680 const unsigned char *p
= s
;
682 if ((unsigned char)c
== *p
++) {
683 return (void *)(p
- 1);
688 EXPORT_SYMBOL(memchr
);