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/*

 *  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/module.h>

#ifndef __HAVE_ARCH_STRNICMP

/**

 * strnicmp - Case insensitive, length-limited string comparison

 * @s1: One string

 * @s2: The other string

 * @len: the maximum number of characters to compare

 */

int strnicmp(const char *s1, const char *s2, size_t len)

{

        /* Yes, Virginia, it had better be unsigned */

        unsigned char c1, c2;

        c1 = c2 = 0;

        if (len) {

                do {

                        c1 = *s1;

                        c2 = *s2;

                        s1++;

                        s2++;

                        if (!c1)

                                break;

                        if (!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(strnicmp);

#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_STRNCASECMP

int strncasecmp(const char *s1, const char *s2, size_t n)

{

        int c1, c2;

        do {

                c1 = tolower(*s1++);

                c2 = tolower(*s2++);

        } while ((--n > 0) && c1 == c2 && c1 != 0);

        return c1 - c2;

}

EXPORT_SYMBOL(strncasecmp);

#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, %NUL-terminated 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 %NUL terminated 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_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, %NUL-terminated 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, %NUL-terminated 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)

{

        signed char __res;

        while (1) {

                if ((__res = *cs - *ct++) != 0 || !*cs++)

                        break;

        }

        return __res;

}

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)

{

        signed char __res = 0;

        while (count) {

                if ((__res = *cs - *ct++) != 0 || !*cs++)

                        break;

                count--;

        }

        return __res;

}

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_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 *p = s + strlen(s);

       do {

           if (*p == (char)c)

               return (char *)p;

       } while (--p >= s);

       return NULL;

}

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

/**

 * strstrip - 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 *strstrip(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';

        while (*s && isspace(*s))

                s++;

        return s;

}

EXPORT_SYMBOL(strstrip);

#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

#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

#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

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)

{

        int 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_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