*  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 = 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;

}

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)

{

register 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)

{

register 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, *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 = (char *) 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 = (char *) dest, *s = (char *) 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, *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;

}

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 = (unsigned char *) 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

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