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 if (has_zero(c, &data, &constants)) {
207 data = prep_zero_mask(c, data, &constants);
208 data = create_zero_mask(data);
209 *(unsigned long *)(dest+res) = c & zero_bytemask(data);
210 return res + find_zero(data);
212 *(unsigned long *)(dest+res) = c;
213 res += sizeof(unsigned long);
214 count -= sizeof(unsigned long);
215 max -= sizeof(unsigned long);
229 /* Hit buffer length without finding a NUL; force NUL-termination. */
235 EXPORT_SYMBOL(strscpy);
238 #ifndef __HAVE_ARCH_STRCAT
240 * strcat - Append one %NUL-terminated string to another
241 * @dest: The string to be appended to
242 * @src: The string to append to it
245 char *strcat(char *dest, const char *src)
251 while ((*dest++ = *src++) != '\0')
255 EXPORT_SYMBOL(strcat);
258 #ifndef __HAVE_ARCH_STRNCAT
260 * strncat - Append a length-limited, C-string to another
261 * @dest: The string to be appended to
262 * @src: The string to append to it
263 * @count: The maximum numbers of bytes to copy
265 * Note that in contrast to strncpy(), strncat() ensures the result is
268 char *strncat(char *dest, const char *src, size_t count)
275 while ((*dest++ = *src++) != 0) {
284 EXPORT_SYMBOL(strncat);
287 #ifndef __HAVE_ARCH_STRLCAT
289 * strlcat - Append a length-limited, C-string to another
290 * @dest: The string to be appended to
291 * @src: The string to append to it
292 * @count: The size of the destination buffer.
294 size_t strlcat(char *dest, const char *src, size_t count)
296 size_t dsize = strlen(dest);
297 size_t len = strlen(src);
298 size_t res = dsize + len;
300 /* This would be a bug */
301 BUG_ON(dsize >= count);
307 memcpy(dest, src, len);
311 EXPORT_SYMBOL(strlcat);
314 #ifndef __HAVE_ARCH_STRCMP
316 * strcmp - Compare two strings
318 * @ct: Another string
321 int strcmp(const char *cs, const char *ct)
323 unsigned char c1, c2;
329 return c1 < c2 ? -1 : 1;
335 EXPORT_SYMBOL(strcmp);
338 #ifndef __HAVE_ARCH_STRNCMP
340 * strncmp - Compare two length-limited strings
342 * @ct: Another string
343 * @count: The maximum number of bytes to compare
345 int strncmp(const char *cs, const char *ct, size_t count)
347 unsigned char c1, c2;
353 return c1 < c2 ? -1 : 1;
360 EXPORT_SYMBOL(strncmp);
363 #ifndef __HAVE_ARCH_STRCHR
365 * strchr - Find the first occurrence of a character in a string
366 * @s: The string to be searched
367 * @c: The character to search for
369 char *strchr(const char *s, int c)
371 for (; *s != (char)c; ++s)
376 EXPORT_SYMBOL(strchr);
379 #ifndef __HAVE_ARCH_STRCHRNUL
381 * strchrnul - Find and return a character in a string, or end of string
382 * @s: The string to be searched
383 * @c: The character to search for
385 * Returns pointer to first occurrence of 'c' in s. If c is not found, then
386 * return a pointer to the null byte at the end of s.
388 char *strchrnul(const char *s, int c)
390 while (*s && *s != (char)c)
394 EXPORT_SYMBOL(strchrnul);
397 #ifndef __HAVE_ARCH_STRRCHR
399 * strrchr - Find the last occurrence of a character in a string
400 * @s: The string to be searched
401 * @c: The character to search for
403 char *strrchr(const char *s, int c)
405 const char *last = NULL;
412 EXPORT_SYMBOL(strrchr);
415 #ifndef __HAVE_ARCH_STRNCHR
417 * strnchr - Find a character in a length limited string
418 * @s: The string to be searched
419 * @count: The number of characters to be searched
420 * @c: The character to search for
422 char *strnchr(const char *s, size_t count, int c)
424 for (; count-- && *s != '\0'; ++s)
429 EXPORT_SYMBOL(strnchr);
433 * skip_spaces - Removes leading whitespace from @str.
434 * @str: The string to be stripped.
436 * Returns a pointer to the first non-whitespace character in @str.
438 char *skip_spaces(const char *str)
440 while (isspace(*str))
444 EXPORT_SYMBOL(skip_spaces);
447 * strim - Removes leading and trailing whitespace from @s.
448 * @s: The string to be stripped.
450 * Note that the first trailing whitespace is replaced with a %NUL-terminator
451 * in the given string @s. Returns a pointer to the first non-whitespace
464 while (end >= s && isspace(*end))
468 return skip_spaces(s);
470 EXPORT_SYMBOL(strim);
472 #ifndef __HAVE_ARCH_STRLEN
474 * strlen - Find the length of a string
475 * @s: The string to be sized
477 size_t strlen(const char *s)
481 for (sc = s; *sc != '\0'; ++sc)
485 EXPORT_SYMBOL(strlen);
488 #ifndef __HAVE_ARCH_STRNLEN
490 * strnlen - Find the length of a length-limited string
491 * @s: The string to be sized
492 * @count: The maximum number of bytes to search
494 size_t strnlen(const char *s, size_t count)
498 for (sc = s; count-- && *sc != '\0'; ++sc)
502 EXPORT_SYMBOL(strnlen);
505 #ifndef __HAVE_ARCH_STRSPN
507 * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept
508 * @s: The string to be searched
509 * @accept: The string to search for
511 size_t strspn(const char *s, const char *accept)
517 for (p = s; *p != '\0'; ++p) {
518 for (a = accept; *a != '\0'; ++a) {
529 EXPORT_SYMBOL(strspn);
532 #ifndef __HAVE_ARCH_STRCSPN
534 * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject
535 * @s: The string to be searched
536 * @reject: The string to avoid
538 size_t strcspn(const char *s, const char *reject)
544 for (p = s; *p != '\0'; ++p) {
545 for (r = reject; *r != '\0'; ++r) {
553 EXPORT_SYMBOL(strcspn);
556 #ifndef __HAVE_ARCH_STRPBRK
558 * strpbrk - Find the first occurrence of a set of characters
559 * @cs: The string to be searched
560 * @ct: The characters to search for
562 char *strpbrk(const char *cs, const char *ct)
564 const char *sc1, *sc2;
566 for (sc1 = cs; *sc1 != '\0'; ++sc1) {
567 for (sc2 = ct; *sc2 != '\0'; ++sc2) {
574 EXPORT_SYMBOL(strpbrk);
577 #ifndef __HAVE_ARCH_STRSEP
579 * strsep - Split a string into tokens
580 * @s: The string to be searched
581 * @ct: The characters to search for
583 * strsep() updates @s to point after the token, ready for the next call.
585 * It returns empty tokens, too, behaving exactly like the libc function
586 * of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
587 * Same semantics, slimmer shape. ;)
589 char *strsep(char **s, const char *ct)
597 end = strpbrk(sbegin, ct);
603 EXPORT_SYMBOL(strsep);
607 * sysfs_streq - return true if strings are equal, modulo trailing newline
609 * @s2: another string
611 * This routine returns true iff two strings are equal, treating both
612 * NUL and newline-then-NUL as equivalent string terminations. It's
613 * geared for use with sysfs input strings, which generally terminate
614 * with newlines but are compared against values without newlines.
616 bool sysfs_streq(const char *s1, const char *s2)
618 while (*s1 && *s1 == *s2) {
625 if (!*s1 && *s2 == '\n' && !s2[1])
627 if (*s1 == '\n' && !s1[1] && !*s2)
631 EXPORT_SYMBOL(sysfs_streq);
633 #ifndef __HAVE_ARCH_MEMSET
635 * memset - Fill a region of memory with the given value
636 * @s: Pointer to the start of the area.
637 * @c: The byte to fill the area with
638 * @count: The size of the area.
640 * Do not use memset() to access IO space, use memset_io() instead.
642 void *memset(void *s, int c, size_t count)
650 EXPORT_SYMBOL(memset);
654 * memzero_explicit - Fill a region of memory (e.g. sensitive
655 * keying data) with 0s.
656 * @s: Pointer to the start of the area.
657 * @count: The size of the area.
659 * Note: usually using memset() is just fine (!), but in cases
660 * where clearing out _local_ data at the end of a scope is
661 * necessary, memzero_explicit() should be used instead in
662 * order to prevent the compiler from optimising away zeroing.
664 * memzero_explicit() doesn't need an arch-specific version as
665 * it just invokes the one of memset() implicitly.
667 void memzero_explicit(void *s, size_t count)
672 EXPORT_SYMBOL(memzero_explicit);
674 #ifndef __HAVE_ARCH_MEMCPY
676 * memcpy - Copy one area of memory to another
677 * @dest: Where to copy to
678 * @src: Where to copy from
679 * @count: The size of the area.
681 * You should not use this function to access IO space, use memcpy_toio()
682 * or memcpy_fromio() instead.
684 void *memcpy(void *dest, const void *src, size_t count)
693 EXPORT_SYMBOL(memcpy);
696 #ifndef __HAVE_ARCH_MEMMOVE
698 * memmove - Copy one area of memory to another
699 * @dest: Where to copy to
700 * @src: Where to copy from
701 * @count: The size of the area.
703 * Unlike memcpy(), memmove() copes with overlapping areas.
705 void *memmove(void *dest, const void *src, size_t count)
725 EXPORT_SYMBOL(memmove);
728 #ifndef __HAVE_ARCH_MEMCMP
730 * memcmp - Compare two areas of memory
731 * @cs: One area of memory
732 * @ct: Another area of memory
733 * @count: The size of the area.
736 __visible int memcmp(const void *cs, const void *ct, size_t count)
738 const unsigned char *su1, *su2;
741 for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
742 if ((res = *su1 - *su2) != 0)
746 EXPORT_SYMBOL(memcmp);
749 #ifndef __HAVE_ARCH_BCMP
751 * bcmp - returns 0 if and only if the buffers have identical contents.
752 * @a: pointer to first buffer.
753 * @b: pointer to second buffer.
754 * @len: size of buffers.
756 * The sign or magnitude of a non-zero return value has no particular
757 * meaning, and architectures may implement their own more efficient bcmp(). So
758 * while this particular implementation is a simple (tail) call to memcmp, do
759 * not rely on anything but whether the return value is zero or non-zero.
762 int bcmp(const void *a, const void *b, size_t len)
764 return memcmp(a, b, len);
769 #ifndef __HAVE_ARCH_MEMSCAN
771 * memscan - Find a character in an area of memory.
772 * @addr: The memory area
773 * @c: The byte to search for
774 * @size: The size of the area.
776 * returns the address of the first occurrence of @c, or 1 byte past
777 * the area if @c is not found
779 void *memscan(void *addr, int c, size_t size)
781 unsigned char *p = addr;
791 EXPORT_SYMBOL(memscan);
794 #ifndef __HAVE_ARCH_STRSTR
796 * strstr - Find the first substring in a %NUL terminated string
797 * @s1: The string to be searched
798 * @s2: The string to search for
800 char *strstr(const char *s1, const char *s2)
810 if (!memcmp(s1, s2, l2))
816 EXPORT_SYMBOL(strstr);
819 #ifndef __HAVE_ARCH_STRNSTR
821 * strnstr - Find the first substring in a length-limited string
822 * @s1: The string to be searched
823 * @s2: The string to search for
824 * @len: the maximum number of characters to search
826 char *strnstr(const char *s1, const char *s2, size_t len)
835 if (!memcmp(s1, s2, l2))
841 EXPORT_SYMBOL(strnstr);
844 #ifndef __HAVE_ARCH_MEMCHR
846 * memchr - Find a character in an area of memory.
847 * @s: The memory area
848 * @c: The byte to search for
849 * @n: The size of the area.
851 * returns the address of the first occurrence of @c, or %NULL
854 void *memchr(const void *s, int c, size_t n)
856 const unsigned char *p = s;
858 if ((unsigned char)c == *p++) {
859 return (void *)(p - 1);
864 EXPORT_SYMBOL(memchr);
867 static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes)
871 return (void *)start;
879 * memchr_inv - Find an unmatching character in an area of memory.
880 * @start: The memory area
881 * @c: Find a character other than c
882 * @bytes: The size of the area.
884 * returns the address of the first character other than @c, or %NULL
885 * if the whole buffer contains just @c.
887 void *memchr_inv(const void *start, int c, size_t bytes)
891 unsigned int words, prefix;
894 return check_bytes8(start, value, bytes);
897 #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64
898 value64 *= 0x0101010101010101ULL;
899 #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER)
900 value64 *= 0x01010101;
901 value64 |= value64 << 32;
903 value64 |= value64 << 8;
904 value64 |= value64 << 16;
905 value64 |= value64 << 32;
908 prefix = (unsigned long)start % 8;
913 r = check_bytes8(start, value, prefix);
923 if (*(u64 *)start != value64)
924 return check_bytes8(start, value, 8);
929 return check_bytes8(start, value, bytes % 8);
931 EXPORT_SYMBOL(memchr_inv);
934 * strreplace - Replace all occurrences of character in string.
935 * @s: The string to operate on.
936 * @old: The character being replaced.
937 * @new: The character @old is replaced with.
939 * Returns pointer to the nul byte at the end of @s.
941 char *strreplace(char *s, char old, char new)
948 EXPORT_SYMBOL(strreplace);