/*
   *  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_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
  
  #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
  
  /**
   * 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);
  
  #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;
  	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