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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 <config.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <malloc.h>
/**
* 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;
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;
}
/**
* strcasecmp - Case insensitive string comparison
* @s1: One string
* @s2: The other string
*/
int strcasecmp(const char *s1, const char *s2)
{
return strncasecmp(s1, s2, -1U);
}
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_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.
*
* Return: strlen(src)
*/
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;
}
#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_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
* @size: The size of @dest
*
* 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
* write past @size like strncat() does.
*
* Return: min(strlen(dest), size) + strlen(src)
*/
size_t strlcat(char *dest, const char *src, size_t size)
{
size_t len = strnlen(dest, size);
return len + strlcpy(dest + len, src, size - len);
}
#endif
#ifndef __HAVE_ARCH_STRCMP
/**
* strcmp - Compare two strings
* @cs: One string
* @ct: Another string
*/
int strcmp(const char *cs, const char *ct)
{
int ret;
while (1) {
unsigned char a = *cs++;
unsigned char b = *ct++;
ret = a - b;
if (ret || !b)
break;
}
return ret;
}
#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)
{
int ret = 0;
while (count--) {
unsigned char a = *cs++;
unsigned char b = *ct++;
ret = a - b;
if (ret || !b)
break;
}
return ret;
}
#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
const char *strchrnul(const char *s, int c)
{
for (; *s != (char)c; ++s)
if (*s == '\0')
break;
return s;
}
#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_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;
}
#endif
#ifndef __HAVE_ARCH_STRDUP
char * strdup(const char *s)
{
char *new;
if ((s == NULL) ||
((new = malloc (strlen(s) + 1)) == NULL) ) {
return NULL;
}
strcpy (new, s);
return new;
}
char * strndup(const char *s, size_t n)
{
size_t len;
char *new;
if (s == NULL)
return NULL;
len = strlen(s);
if (n < len)
len = n;
new = malloc(len + 1);
if (new == NULL)
return NULL;
strncpy(new, s, len);
new[len] = '\0';
return new;
}
#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_STRSWAB
/**
* strswab - swap adjacent even and odd bytes in %NUL-terminated string
* s: address of the string
*
* returns the address of the swapped string or NULL on error. If
* string length is odd, last byte is untouched.
*/
char *strswab(const char *s)
{
char *p, *q;
if ((NULL == s) || ('\0' == *s)) {
return (NULL);
}
for (p=(char *)s, q=p+1; (*p != '\0') && (*q != '\0'); p+=2, q+=2) {
char tmp;
tmp = *p;
*p = *q;
*q = tmp;
}
return (char *) s;
}
#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.
*/
__used void * memset(void * s,int c,size_t count)
{
unsigned long *sl = (unsigned long *) s;
char *s8;
#if !CONFIG_IS_ENABLED(TINY_MEMSET)
unsigned long cl = 0;
int i;
/* do it one word at a time (32 bits or 64 bits) while possible */
if ( ((ulong)s & (sizeof(*sl) - 1)) == 0) {
for (i = 0; i < sizeof(*sl); i++) {
cl <<= 8;
cl |= c & 0xff;
}
while (count >= sizeof(*sl)) {
*sl++ = cl;
count -= sizeof(*sl);
}
}
#endif /* fill 8 bits at a time */
s8 = (char *)sl;
while (count--)
*s8++ = c;
return s;
}
#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.
*/
__used void * memcpy(void *dest, const void *src, size_t count)
{
unsigned long *dl = (unsigned long *)dest, *sl = (unsigned long *)src;
char *d8, *s8;
if (src == dest)
return dest;
/* while all data is aligned (common case), copy a word at a time */
if ( (((ulong)dest | (ulong)src) & (sizeof(*dl) - 1)) == 0) {
while (count >= sizeof(*dl)) {
*dl++ = *sl++;
count -= sizeof(*dl);
}
}
/* copy the reset one byte at a time */
d8 = (char *)dl;
s8 = (char *)sl;
while (count--)
*d8++ = *s8++;
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.
*/
__used void * memmove(void * dest,const void *src,size_t count)
{
char *tmp, *s;
if (dest <= src || (src + count) <= dest) {
/*
* Use the fast memcpy implementation (ARCH optimized or lib/string.c) when it is possible:
* - when dest is before src (assuming that memcpy is doing forward-copying)
* - when destination don't overlap the source buffer (src + count <= dest)
*
* WARNING: the first optimisation cause an issue, when __HAVE_ARCH_MEMCPY is defined,
* __HAVE_ARCH_MEMMOVE is not defined and if the memcpy ARCH-specific
* implementation is not doing a forward-copying.
*
* No issue today because memcpy is doing a forward-copying in lib/string.c and for ARM32
* architecture; no other arches use __HAVE_ARCH_MEMCPY without __HAVE_ARCH_MEMMOVE.
*/
memcpy(dest, src, count);
} 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.
*/
__used 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
char *memdup(const void *src, size_t len)
{
char *p;
p = malloc(len);
if (!p)
return NULL;
memcpy(p, src, len);
return p;
}
#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
#ifndef __HAVE_ARCH_MEMCHR_INV
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;
value64 |= value64 << 8;
value64 |= value64 << 16;
value64 |= value64 << 32;
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);
}
#endif