| /* |
| * linux/lib/string.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| /* |
| * stupid library routines.. The optimized versions should generally be found |
| * as inline code in <asm-xx/string.h> |
| * |
| * These are buggy as well.. |
| * |
| * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de> |
| * - Added strsep() which will replace strtok() soon (because strsep() is |
| * reentrant and should be faster). Use only strsep() in new code, please. |
| * |
| * * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>, |
| * Matthew Hawkins <matt@mh.dropbear.id.au> |
| * - Kissed strtok() goodbye |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/string.h> |
| #include <linux/ctype.h> |
| #include <linux/kernel.h> |
| #include <linux/export.h> |
| #include <linux/bug.h> |
| #include <linux/errno.h> |
| |
| #include <asm/byteorder.h> |
| #include <asm/word-at-a-time.h> |
| #include <asm/page.h> |
| |
| #ifndef __HAVE_ARCH_STRNCASECMP |
| /** |
| * strncasecmp - Case insensitive, length-limited string comparison |
| * @s1: One string |
| * @s2: The other string |
| * @len: the maximum number of characters to compare |
| */ |
| int strncasecmp(const char *s1, const char *s2, size_t len) |
| { |
| /* Yes, Virginia, it had better be unsigned */ |
| unsigned char c1, c2; |
| |
| if (!len) |
| return 0; |
| |
| do { |
| c1 = *s1++; |
| c2 = *s2++; |
| if (!c1 || !c2) |
| break; |
| if (c1 == c2) |
| continue; |
| c1 = tolower(c1); |
| c2 = tolower(c2); |
| if (c1 != c2) |
| break; |
| } while (--len); |
| return (int)c1 - (int)c2; |
| } |
| EXPORT_SYMBOL(strncasecmp); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCASECMP |
| int strcasecmp(const char *s1, const char *s2) |
| { |
| int c1, c2; |
| |
| do { |
| c1 = tolower(*s1++); |
| c2 = tolower(*s2++); |
| } while (c1 == c2 && c1 != 0); |
| return c1 - c2; |
| } |
| EXPORT_SYMBOL(strcasecmp); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCPY |
| /** |
| * strcpy - Copy a %NUL terminated string |
| * @dest: Where to copy the string to |
| * @src: Where to copy the string from |
| */ |
| #undef strcpy |
| char *strcpy(char *dest, const char *src) |
| { |
| char *tmp = dest; |
| |
| while ((*dest++ = *src++) != '\0') |
| /* nothing */; |
| return tmp; |
| } |
| EXPORT_SYMBOL(strcpy); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRNCPY |
| /** |
| * strncpy - Copy a length-limited, C-string |
| * @dest: Where to copy the string to |
| * @src: Where to copy the string from |
| * @count: The maximum number of bytes to copy |
| * |
| * The result is not %NUL-terminated if the source exceeds |
| * @count bytes. |
| * |
| * In the case where the length of @src is less than that of |
| * count, the remainder of @dest will be padded with %NUL. |
| * |
| */ |
| char *strncpy(char *dest, const char *src, size_t count) |
| { |
| char *tmp = dest; |
| |
| while (count) { |
| if ((*tmp = *src) != 0) |
| src++; |
| tmp++; |
| count--; |
| } |
| return dest; |
| } |
| EXPORT_SYMBOL(strncpy); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRLCPY |
| /** |
| * strlcpy - Copy a C-string into a sized buffer |
| * @dest: Where to copy the string to |
| * @src: Where to copy the string from |
| * @size: size of destination buffer |
| * |
| * Compatible with *BSD: the result is always a valid |
| * NUL-terminated string that fits in the buffer (unless, |
| * of course, the buffer size is zero). It does not pad |
| * out the result like strncpy() does. |
| */ |
| size_t strlcpy(char *dest, const char *src, size_t size) |
| { |
| size_t ret = strlen(src); |
| |
| if (size) { |
| size_t len = (ret >= size) ? size - 1 : ret; |
| memcpy(dest, src, len); |
| dest[len] = '\0'; |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(strlcpy); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRSCPY |
| /** |
| * strscpy - Copy a C-string into a sized buffer |
| * @dest: Where to copy the string to |
| * @src: Where to copy the string from |
| * @count: Size of destination buffer |
| * |
| * Copy the string, or as much of it as fits, into the dest buffer. |
| * The routine returns the number of characters copied (not including |
| * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough. |
| * The behavior is undefined if the string buffers overlap. |
| * The destination buffer is always NUL terminated, unless it's zero-sized. |
| * |
| * Preferred to strlcpy() since the API doesn't require reading memory |
| * from the src string beyond the specified "count" bytes, and since |
| * the return value is easier to error-check than strlcpy()'s. |
| * In addition, the implementation is robust to the string changing out |
| * from underneath it, unlike the current strlcpy() implementation. |
| * |
| * Preferred to strncpy() since it always returns a valid string, and |
| * doesn't unnecessarily force the tail of the destination buffer to be |
| * zeroed. If the zeroing is desired, it's likely cleaner to use strscpy() |
| * with an overflow test, then just memset() the tail of the dest buffer. |
| */ |
| ssize_t strscpy(char *dest, const char *src, size_t count) |
| { |
| const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; |
| size_t max = count; |
| long res = 0; |
| |
| if (count == 0) |
| return -E2BIG; |
| |
| #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS |
| /* |
| * If src is unaligned, don't cross a page boundary, |
| * since we don't know if the next page is mapped. |
| */ |
| if ((long)src & (sizeof(long) - 1)) { |
| size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)); |
| if (limit < max) |
| max = limit; |
| } |
| #else |
| /* If src or dest is unaligned, don't do word-at-a-time. */ |
| if (((long) dest | (long) src) & (sizeof(long) - 1)) |
| max = 0; |
| #endif |
| |
| while (max >= sizeof(unsigned long)) { |
| unsigned long c, data; |
| |
| c = *(unsigned long *)(src+res); |
| if (has_zero(c, &data, &constants)) { |
| data = prep_zero_mask(c, data, &constants); |
| data = create_zero_mask(data); |
| *(unsigned long *)(dest+res) = c & zero_bytemask(data); |
| return res + find_zero(data); |
| } |
| *(unsigned long *)(dest+res) = c; |
| res += sizeof(unsigned long); |
| count -= sizeof(unsigned long); |
| max -= sizeof(unsigned long); |
| } |
| |
| while (count) { |
| char c; |
| |
| c = src[res]; |
| dest[res] = c; |
| if (!c) |
| return res; |
| res++; |
| count--; |
| } |
| |
| /* Hit buffer length without finding a NUL; force NUL-termination. */ |
| if (res) |
| dest[res-1] = '\0'; |
| |
| return -E2BIG; |
| } |
| EXPORT_SYMBOL(strscpy); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCAT |
| /** |
| * strcat - Append one %NUL-terminated string to another |
| * @dest: The string to be appended to |
| * @src: The string to append to it |
| */ |
| #undef strcat |
| char *strcat(char *dest, const char *src) |
| { |
| char *tmp = dest; |
| |
| while (*dest) |
| dest++; |
| while ((*dest++ = *src++) != '\0') |
| ; |
| return tmp; |
| } |
| EXPORT_SYMBOL(strcat); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRNCAT |
| /** |
| * strncat - Append a length-limited, C-string to another |
| * @dest: The string to be appended to |
| * @src: The string to append to it |
| * @count: The maximum numbers of bytes to copy |
| * |
| * Note that in contrast to strncpy(), strncat() ensures the result is |
| * terminated. |
| */ |
| char *strncat(char *dest, const char *src, size_t count) |
| { |
| char *tmp = dest; |
| |
| if (count) { |
| while (*dest) |
| dest++; |
| while ((*dest++ = *src++) != 0) { |
| if (--count == 0) { |
| *dest = '\0'; |
| break; |
| } |
| } |
| } |
| return tmp; |
| } |
| EXPORT_SYMBOL(strncat); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRLCAT |
| /** |
| * strlcat - Append a length-limited, C-string to another |
| * @dest: The string to be appended to |
| * @src: The string to append to it |
| * @count: The size of the destination buffer. |
| */ |
| size_t strlcat(char *dest, const char *src, size_t count) |
| { |
| size_t dsize = strlen(dest); |
| size_t len = strlen(src); |
| size_t res = dsize + len; |
| |
| /* This would be a bug */ |
| BUG_ON(dsize >= count); |
| |
| dest += dsize; |
| count -= dsize; |
| if (len >= count) |
| len = count-1; |
| memcpy(dest, src, len); |
| dest[len] = 0; |
| return res; |
| } |
| EXPORT_SYMBOL(strlcat); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCMP |
| /** |
| * strcmp - Compare two strings |
| * @cs: One string |
| * @ct: Another string |
| */ |
| #undef strcmp |
| int strcmp(const char *cs, const char *ct) |
| { |
| unsigned char c1, c2; |
| |
| while (1) { |
| c1 = *cs++; |
| c2 = *ct++; |
| if (c1 != c2) |
| return c1 < c2 ? -1 : 1; |
| if (!c1) |
| break; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(strcmp); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRNCMP |
| /** |
| * strncmp - Compare two length-limited strings |
| * @cs: One string |
| * @ct: Another string |
| * @count: The maximum number of bytes to compare |
| */ |
| int strncmp(const char *cs, const char *ct, size_t count) |
| { |
| unsigned char c1, c2; |
| |
| while (count) { |
| c1 = *cs++; |
| c2 = *ct++; |
| if (c1 != c2) |
| return c1 < c2 ? -1 : 1; |
| if (!c1) |
| break; |
| count--; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(strncmp); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCHR |
| /** |
| * strchr - Find the first occurrence of a character in a string |
| * @s: The string to be searched |
| * @c: The character to search for |
| */ |
| char *strchr(const char *s, int c) |
| { |
| for (; *s != (char)c; ++s) |
| if (*s == '\0') |
| return NULL; |
| return (char *)s; |
| } |
| EXPORT_SYMBOL(strchr); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCHRNUL |
| /** |
| * strchrnul - Find and return a character in a string, or end of string |
| * @s: The string to be searched |
| * @c: The character to search for |
| * |
| * Returns pointer to first occurrence of 'c' in s. If c is not found, then |
| * return a pointer to the null byte at the end of s. |
| */ |
| char *strchrnul(const char *s, int c) |
| { |
| while (*s && *s != (char)c) |
| s++; |
| return (char *)s; |
| } |
| EXPORT_SYMBOL(strchrnul); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRRCHR |
| /** |
| * strrchr - Find the last occurrence of a character in a string |
| * @s: The string to be searched |
| * @c: The character to search for |
| */ |
| char *strrchr(const char *s, int c) |
| { |
| const char *last = NULL; |
| do { |
| if (*s == (char)c) |
| last = s; |
| } while (*s++); |
| return (char *)last; |
| } |
| EXPORT_SYMBOL(strrchr); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRNCHR |
| /** |
| * strnchr - Find a character in a length limited string |
| * @s: The string to be searched |
| * @count: The number of characters to be searched |
| * @c: The character to search for |
| */ |
| char *strnchr(const char *s, size_t count, int c) |
| { |
| for (; count-- && *s != '\0'; ++s) |
| if (*s == (char)c) |
| return (char *)s; |
| return NULL; |
| } |
| EXPORT_SYMBOL(strnchr); |
| #endif |
| |
| /** |
| * skip_spaces - Removes leading whitespace from @str. |
| * @str: The string to be stripped. |
| * |
| * Returns a pointer to the first non-whitespace character in @str. |
| */ |
| char *skip_spaces(const char *str) |
| { |
| while (isspace(*str)) |
| ++str; |
| return (char *)str; |
| } |
| EXPORT_SYMBOL(skip_spaces); |
| |
| /** |
| * strim - Removes leading and trailing whitespace from @s. |
| * @s: The string to be stripped. |
| * |
| * Note that the first trailing whitespace is replaced with a %NUL-terminator |
| * in the given string @s. Returns a pointer to the first non-whitespace |
| * character in @s. |
| */ |
| char *strim(char *s) |
| { |
| size_t size; |
| char *end; |
| |
| size = strlen(s); |
| if (!size) |
| return s; |
| |
| end = s + size - 1; |
| while (end >= s && isspace(*end)) |
| end--; |
| *(end + 1) = '\0'; |
| |
| return skip_spaces(s); |
| } |
| EXPORT_SYMBOL(strim); |
| |
| #ifndef __HAVE_ARCH_STRLEN |
| /** |
| * strlen - Find the length of a string |
| * @s: The string to be sized |
| */ |
| size_t strlen(const char *s) |
| { |
| const char *sc; |
| |
| for (sc = s; *sc != '\0'; ++sc) |
| /* nothing */; |
| return sc - s; |
| } |
| EXPORT_SYMBOL(strlen); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRNLEN |
| /** |
| * strnlen - Find the length of a length-limited string |
| * @s: The string to be sized |
| * @count: The maximum number of bytes to search |
| */ |
| size_t strnlen(const char *s, size_t count) |
| { |
| const char *sc; |
| |
| for (sc = s; count-- && *sc != '\0'; ++sc) |
| /* nothing */; |
| return sc - s; |
| } |
| EXPORT_SYMBOL(strnlen); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRSPN |
| /** |
| * strspn - Calculate the length of the initial substring of @s which only contain letters in @accept |
| * @s: The string to be searched |
| * @accept: The string to search for |
| */ |
| size_t strspn(const char *s, const char *accept) |
| { |
| const char *p; |
| const char *a; |
| size_t count = 0; |
| |
| for (p = s; *p != '\0'; ++p) { |
| for (a = accept; *a != '\0'; ++a) { |
| if (*p == *a) |
| break; |
| } |
| if (*a == '\0') |
| return count; |
| ++count; |
| } |
| return count; |
| } |
| |
| EXPORT_SYMBOL(strspn); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRCSPN |
| /** |
| * strcspn - Calculate the length of the initial substring of @s which does not contain letters in @reject |
| * @s: The string to be searched |
| * @reject: The string to avoid |
| */ |
| size_t strcspn(const char *s, const char *reject) |
| { |
| const char *p; |
| const char *r; |
| size_t count = 0; |
| |
| for (p = s; *p != '\0'; ++p) { |
| for (r = reject; *r != '\0'; ++r) { |
| if (*p == *r) |
| return count; |
| } |
| ++count; |
| } |
| return count; |
| } |
| EXPORT_SYMBOL(strcspn); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRPBRK |
| /** |
| * strpbrk - Find the first occurrence of a set of characters |
| * @cs: The string to be searched |
| * @ct: The characters to search for |
| */ |
| char *strpbrk(const char *cs, const char *ct) |
| { |
| const char *sc1, *sc2; |
| |
| for (sc1 = cs; *sc1 != '\0'; ++sc1) { |
| for (sc2 = ct; *sc2 != '\0'; ++sc2) { |
| if (*sc1 == *sc2) |
| return (char *)sc1; |
| } |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL(strpbrk); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRSEP |
| /** |
| * strsep - Split a string into tokens |
| * @s: The string to be searched |
| * @ct: The characters to search for |
| * |
| * strsep() updates @s to point after the token, ready for the next call. |
| * |
| * It returns empty tokens, too, behaving exactly like the libc function |
| * of that name. In fact, it was stolen from glibc2 and de-fancy-fied. |
| * Same semantics, slimmer shape. ;) |
| */ |
| char *strsep(char **s, const char *ct) |
| { |
| char *sbegin = *s; |
| char *end; |
| |
| if (sbegin == NULL) |
| return NULL; |
| |
| end = strpbrk(sbegin, ct); |
| if (end) |
| *end++ = '\0'; |
| *s = end; |
| return sbegin; |
| } |
| EXPORT_SYMBOL(strsep); |
| #endif |
| |
| /** |
| * sysfs_streq - return true if strings are equal, modulo trailing newline |
| * @s1: one string |
| * @s2: another string |
| * |
| * This routine returns true iff two strings are equal, treating both |
| * NUL and newline-then-NUL as equivalent string terminations. It's |
| * geared for use with sysfs input strings, which generally terminate |
| * with newlines but are compared against values without newlines. |
| */ |
| bool sysfs_streq(const char *s1, const char *s2) |
| { |
| while (*s1 && *s1 == *s2) { |
| s1++; |
| s2++; |
| } |
| |
| if (*s1 == *s2) |
| return true; |
| if (!*s1 && *s2 == '\n' && !s2[1]) |
| return true; |
| if (*s1 == '\n' && !s1[1] && !*s2) |
| return true; |
| return false; |
| } |
| EXPORT_SYMBOL(sysfs_streq); |
| |
| /** |
| * match_string - matches given string in an array |
| * @array: array of strings |
| * @n: number of strings in the array or -1 for NULL terminated arrays |
| * @string: string to match with |
| * |
| * Return: |
| * index of a @string in the @array if matches, or %-EINVAL otherwise. |
| */ |
| int match_string(const char * const *array, size_t n, const char *string) |
| { |
| int index; |
| const char *item; |
| |
| for (index = 0; index < n; index++) { |
| item = array[index]; |
| if (!item) |
| break; |
| if (!strcmp(item, string)) |
| return index; |
| } |
| |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(match_string); |
| |
| /** |
| * __sysfs_match_string - matches given string in an array |
| * @array: array of strings |
| * @n: number of strings in the array or -1 for NULL terminated arrays |
| * @str: string to match with |
| * |
| * Returns index of @str in the @array or -EINVAL, just like match_string(). |
| * Uses sysfs_streq instead of strcmp for matching. |
| */ |
| int __sysfs_match_string(const char * const *array, size_t n, const char *str) |
| { |
| const char *item; |
| int index; |
| |
| for (index = 0; index < n; index++) { |
| item = array[index]; |
| if (!item) |
| break; |
| if (sysfs_streq(item, str)) |
| return index; |
| } |
| |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(__sysfs_match_string); |
| |
| #ifndef __HAVE_ARCH_MEMSET |
| /** |
| * memset - Fill a region of memory with the given value |
| * @s: Pointer to the start of the area. |
| * @c: The byte to fill the area with |
| * @count: The size of the area. |
| * |
| * Do not use memset() to access IO space, use memset_io() instead. |
| */ |
| void *memset(void *s, int c, size_t count) |
| { |
| char *xs = s; |
| |
| while (count--) |
| *xs++ = c; |
| return s; |
| } |
| EXPORT_SYMBOL(memset); |
| #endif |
| |
| /** |
| * memzero_explicit - Fill a region of memory (e.g. sensitive |
| * keying data) with 0s. |
| * @s: Pointer to the start of the area. |
| * @count: The size of the area. |
| * |
| * Note: usually using memset() is just fine (!), but in cases |
| * where clearing out _local_ data at the end of a scope is |
| * necessary, memzero_explicit() should be used instead in |
| * order to prevent the compiler from optimising away zeroing. |
| * |
| * memzero_explicit() doesn't need an arch-specific version as |
| * it just invokes the one of memset() implicitly. |
| */ |
| void memzero_explicit(void *s, size_t count) |
| { |
| memset(s, 0, count); |
| barrier_data(s); |
| } |
| EXPORT_SYMBOL(memzero_explicit); |
| |
| #ifndef __HAVE_ARCH_MEMCPY |
| /** |
| * memcpy - Copy one area of memory to another |
| * @dest: Where to copy to |
| * @src: Where to copy from |
| * @count: The size of the area. |
| * |
| * You should not use this function to access IO space, use memcpy_toio() |
| * or memcpy_fromio() instead. |
| */ |
| void *memcpy(void *dest, const void *src, size_t count) |
| { |
| char *tmp = dest; |
| const char *s = src; |
| |
| while (count--) |
| *tmp++ = *s++; |
| return dest; |
| } |
| EXPORT_SYMBOL(memcpy); |
| #endif |
| |
| #ifndef __HAVE_ARCH_MEMMOVE |
| /** |
| * memmove - Copy one area of memory to another |
| * @dest: Where to copy to |
| * @src: Where to copy from |
| * @count: The size of the area. |
| * |
| * Unlike memcpy(), memmove() copes with overlapping areas. |
| */ |
| void *memmove(void *dest, const void *src, size_t count) |
| { |
| char *tmp; |
| const char *s; |
| |
| if (dest <= src) { |
| tmp = dest; |
| s = src; |
| while (count--) |
| *tmp++ = *s++; |
| } else { |
| tmp = dest; |
| tmp += count; |
| s = src; |
| s += count; |
| while (count--) |
| *--tmp = *--s; |
| } |
| return dest; |
| } |
| EXPORT_SYMBOL(memmove); |
| #endif |
| |
| #ifndef __HAVE_ARCH_MEMCMP |
| /** |
| * memcmp - Compare two areas of memory |
| * @cs: One area of memory |
| * @ct: Another area of memory |
| * @count: The size of the area. |
| */ |
| #undef memcmp |
| __visible int memcmp(const void *cs, const void *ct, size_t count) |
| { |
| const unsigned char *su1, *su2; |
| int res = 0; |
| |
| for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--) |
| if ((res = *su1 - *su2) != 0) |
| break; |
| return res; |
| } |
| EXPORT_SYMBOL(memcmp); |
| #endif |
| |
| #ifndef __HAVE_ARCH_MEMSCAN |
| /** |
| * memscan - Find a character in an area of memory. |
| * @addr: The memory area |
| * @c: The byte to search for |
| * @size: The size of the area. |
| * |
| * returns the address of the first occurrence of @c, or 1 byte past |
| * the area if @c is not found |
| */ |
| void *memscan(void *addr, int c, size_t size) |
| { |
| unsigned char *p = addr; |
| |
| while (size) { |
| if (*p == c) |
| return (void *)p; |
| p++; |
| size--; |
| } |
| return (void *)p; |
| } |
| EXPORT_SYMBOL(memscan); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRSTR |
| /** |
| * strstr - Find the first substring in a %NUL terminated string |
| * @s1: The string to be searched |
| * @s2: The string to search for |
| */ |
| char *strstr(const char *s1, const char *s2) |
| { |
| size_t l1, l2; |
| |
| l2 = strlen(s2); |
| if (!l2) |
| return (char *)s1; |
| l1 = strlen(s1); |
| while (l1 >= l2) { |
| l1--; |
| if (!memcmp(s1, s2, l2)) |
| return (char *)s1; |
| s1++; |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL(strstr); |
| #endif |
| |
| #ifndef __HAVE_ARCH_STRNSTR |
| /** |
| * strnstr - Find the first substring in a length-limited string |
| * @s1: The string to be searched |
| * @s2: The string to search for |
| * @len: the maximum number of characters to search |
| */ |
| char *strnstr(const char *s1, const char *s2, size_t len) |
| { |
| size_t l2; |
| |
| l2 = strlen(s2); |
| if (!l2) |
| return (char *)s1; |
| while (len >= l2) { |
| len--; |
| if (!memcmp(s1, s2, l2)) |
| return (char *)s1; |
| s1++; |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL(strnstr); |
| #endif |
| |
| #ifndef __HAVE_ARCH_MEMCHR |
| /** |
| * memchr - Find a character in an area of memory. |
| * @s: The memory area |
| * @c: The byte to search for |
| * @n: The size of the area. |
| * |
| * returns the address of the first occurrence of @c, or %NULL |
| * if @c is not found |
| */ |
| void *memchr(const void *s, int c, size_t n) |
| { |
| const unsigned char *p = s; |
| while (n-- != 0) { |
| if ((unsigned char)c == *p++) { |
| return (void *)(p - 1); |
| } |
| } |
| return NULL; |
| } |
| EXPORT_SYMBOL(memchr); |
| #endif |
| |
| static void *check_bytes8(const u8 *start, u8 value, unsigned int bytes) |
| { |
| while (bytes) { |
| if (*start != value) |
| return (void *)start; |
| start++; |
| bytes--; |
| } |
| return NULL; |
| } |
| |
| /** |
| * memchr_inv - Find an unmatching character in an area of memory. |
| * @start: The memory area |
| * @c: Find a character other than c |
| * @bytes: The size of the area. |
| * |
| * returns the address of the first character other than @c, or %NULL |
| * if the whole buffer contains just @c. |
| */ |
| void *memchr_inv(const void *start, int c, size_t bytes) |
| { |
| u8 value = c; |
| u64 value64; |
| unsigned int words, prefix; |
| |
| if (bytes <= 16) |
| return check_bytes8(start, value, bytes); |
| |
| value64 = value; |
| #if defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) && BITS_PER_LONG == 64 |
| value64 *= 0x0101010101010101ULL; |
| #elif defined(CONFIG_ARCH_HAS_FAST_MULTIPLIER) |
| value64 *= 0x01010101; |
| value64 |= value64 << 32; |
| #else |
| value64 |= value64 << 8; |
| value64 |= value64 << 16; |
| value64 |= value64 << 32; |
| #endif |
| |
| prefix = (unsigned long)start % 8; |
| if (prefix) { |
| u8 *r; |
| |
| prefix = 8 - prefix; |
| r = check_bytes8(start, value, prefix); |
| if (r) |
| return r; |
| start += prefix; |
| bytes -= prefix; |
| } |
| |
| words = bytes / 8; |
| |
| while (words) { |
| if (*(u64 *)start != value64) |
| return check_bytes8(start, value, 8); |
| start += 8; |
| words--; |
| } |
| |
| return check_bytes8(start, value, bytes % 8); |
| } |
| EXPORT_SYMBOL(memchr_inv); |
| |
| /** |
| * strreplace - Replace all occurrences of character in string. |
| * @s: The string to operate on. |
| * @old: The character being replaced. |
| * @new: The character @old is replaced with. |
| * |
| * Returns pointer to the nul byte at the end of @s. |
| */ |
| char *strreplace(char *s, char old, char new) |
| { |
| for (; *s; ++s) |
| if (*s == old) |
| *s = new; |
| return s; |
| } |
| EXPORT_SYMBOL(strreplace); |