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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.

 */

#include <linux/types.h>

#include <linux/string.h>

#include <linux/ctype.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 = 0;  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;

}

#endif

char * ___strtok;

#ifndef __HAVE_ARCH_STRCPY

/**

 * strcpy - Copy a %NUL terminated string

 * @dest: Where to copy the string to

 * @src: Where to copy the string from

 */

char * strcpy(char * dest,const char *src)

{

        char *tmp = dest;

        while ((*dest++ = *src++) != '\0')

                /* nothing */;

        return tmp;

}

#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

 *

 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.

 * However, the result is not %NUL-terminated if the source exceeds

 * @count bytes.

 */

char * strncpy(char * dest,const char *src,size_t count)

{

        char *tmp = dest;

        while (count-- && (*dest++ = *src++) != '\0')

                /* nothing */;

        return tmp;

}

#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

 */

char * strcat(char * dest, const char * src)

{

        char *tmp = dest;

        while (*dest)

                dest++;

        while ((*dest++ = *src++) != '\0')

                ;

        return tmp;

}

#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++)) {

                        if (--count == 0) {

                                *dest = '\0';

                                break;

                        }

                }

        }

        return tmp;

}

#endif

#ifndef __HAVE_ARCH_STRCMP

/**

 * strcmp - Compare two strings

 * @cs: One string

 * @ct: Another string

 */

int strcmp(const char * cs,const char * ct)

{

        register signed char __res;

        while (1) {

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

                        break;

        }

        return __res;

}

#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)

{

        register signed char __res = 0;

        while (count) {

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

                        break;

                count--;

        }

        return __res;

}

#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;

}

#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;

}

#endif

#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;

}

#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;

}

#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;

}

#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;

}

#endif

#ifndef __HAVE_ARCH_STRTOK

/**

 * strtok - Split a string into tokens

 * @s: The string to be searched

 * @ct: The characters to search for

 *

 * WARNING: strtok is deprecated, use strsep instead.

 */

char * strtok(char * s,const char * ct)

{

        char *sbegin, *send;

        sbegin  = s ? s : ___strtok;

        if (!sbegin) {

                return NULL;

        }

        sbegin += strspn(sbegin,ct);

        if (*sbegin == '\0') {

                ___strtok = NULL;

                return( NULL );

        }

        send = strpbrk( sbegin, ct);

        if (send && *send != '\0')

                *send++ = '\0';

        ___strtok = send;

        return (sbegin);

}

#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, *end;

        if (sbegin == NULL)

                return NULL;

        end = strpbrk(sbegin, ct);

        if (end)

                *end++ = '\0';

        *s = end;

        return sbegin;

}

#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 = (char *) s;

        while (count--)

                *xs++ = c;

        return s;

}

#endif

#ifndef __HAVE_ARCH_BCOPY

/**

 * bcopy - Copy one area of memory to another

 * @src: Where to copy from

 * @dest: Where to copy to

 * @count: The size of the area.

 *

 * Note that this is the same as memcpy(), with the arguments reversed.

 * memcpy() is the standard, bcopy() is a legacy BSD function.

 *

 * You should not use this function to access IO space, use memcpy_toio()

 * or memcpy_fromio() instead.

 */

char * bcopy(const char * src, char * dest, int count)

{

        char *tmp = dest;

        while (count--)

                *tmp++ = *src++;

        return dest;

}

#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 = (char *) dest, *s = (char *) src;

        while (count--)

                *tmp++ = *s++;

        return dest;

}

#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, *s;

        if (dest <= src) {

                tmp = (char *) dest;

                s = (char *) src;

                while (count--)

                        *tmp++ = *s++;

                }

        else {

                tmp = (char *) dest + count;

                s = (char *) src + count;

                while (count--)

                        *--tmp = *--s;

                }

        return dest;

}

#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.

 */

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;

}

#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 = (unsigned char *) addr;

        while (size) {

                if (*p == c)

                        return (void *) p;

                p++;

                size--;

        }

        return (void *) p;

}

#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;

}

#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;

}

#endif