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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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602 lines
12 KiB
C
602 lines
12 KiB
C
![]() |
/*
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* linux/lib/string.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* stupid library routines.. The optimized versions should generally be found
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* as inline code in <asm-xx/string.h>
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*
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* These are buggy as well..
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*
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* * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
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* - Added strsep() which will replace strtok() soon (because strsep() is
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* reentrant and should be faster). Use only strsep() in new code, please.
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*
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* * Sat Feb 09 2002, Jason Thomas <jason@topic.com.au>,
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* Matthew Hawkins <matt@mh.dropbear.id.au>
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* - Kissed strtok() goodbye
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/ctype.h>
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#include <linux/module.h>
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#ifndef __HAVE_ARCH_STRNICMP
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/**
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* strnicmp - Case insensitive, length-limited string comparison
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* @s1: One string
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* @s2: The other string
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* @len: the maximum number of characters to compare
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*/
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int strnicmp(const char *s1, const char *s2, size_t len)
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{
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/* Yes, Virginia, it had better be unsigned */
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unsigned char c1, c2;
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c1 = 0; c2 = 0;
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if (len) {
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do {
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c1 = *s1; c2 = *s2;
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s1++; s2++;
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if (!c1)
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break;
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if (!c2)
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break;
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if (c1 == c2)
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continue;
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c1 = tolower(c1);
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c2 = tolower(c2);
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if (c1 != c2)
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break;
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} while (--len);
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}
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return (int)c1 - (int)c2;
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}
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EXPORT_SYMBOL(strnicmp);
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#endif
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#ifndef __HAVE_ARCH_STRCPY
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/**
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* strcpy - Copy a %NUL terminated string
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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*/
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char * strcpy(char * dest,const char *src)
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{
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char *tmp = dest;
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while ((*dest++ = *src++) != '\0')
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/* nothing */;
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return tmp;
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}
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EXPORT_SYMBOL(strcpy);
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#endif
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#ifndef __HAVE_ARCH_STRNCPY
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/**
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* strncpy - Copy a length-limited, %NUL-terminated string
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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* @count: The maximum number of bytes to copy
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*
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* The result is not %NUL-terminated if the source exceeds
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* @count bytes.
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*/
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char * strncpy(char * dest,const char *src,size_t count)
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{
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char *tmp = dest;
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while (count) {
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if ((*tmp = *src) != 0) src++;
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tmp++;
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count--;
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}
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return dest;
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}
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EXPORT_SYMBOL(strncpy);
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#endif
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#ifndef __HAVE_ARCH_STRLCPY
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/**
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* strlcpy - Copy a %NUL terminated string into a sized buffer
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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* @size: size of destination buffer
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*
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* Compatible with *BSD: the result is always a valid
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* NUL-terminated string that fits in the buffer (unless,
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* of course, the buffer size is zero). It does not pad
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* out the result like strncpy() does.
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*/
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size_t strlcpy(char *dest, const char *src, size_t size)
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{
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size_t ret = strlen(src);
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if (size) {
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size_t len = (ret >= size) ? size-1 : ret;
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memcpy(dest, src, len);
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dest[len] = '\0';
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}
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return ret;
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}
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EXPORT_SYMBOL(strlcpy);
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#endif
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#ifndef __HAVE_ARCH_STRCAT
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/**
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* strcat - Append one %NUL-terminated string to another
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* @dest: The string to be appended to
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* @src: The string to append to it
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*/
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char * strcat(char * dest, const char * src)
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{
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char *tmp = dest;
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while (*dest)
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dest++;
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while ((*dest++ = *src++) != '\0')
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;
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return tmp;
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}
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EXPORT_SYMBOL(strcat);
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#endif
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#ifndef __HAVE_ARCH_STRNCAT
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/**
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* strncat - Append a length-limited, %NUL-terminated string to another
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* @dest: The string to be appended to
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* @src: The string to append to it
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* @count: The maximum numbers of bytes to copy
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*
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* Note that in contrast to strncpy, strncat ensures the result is
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* terminated.
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*/
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char * strncat(char *dest, const char *src, size_t count)
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{
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char *tmp = dest;
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if (count) {
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while (*dest)
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dest++;
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while ((*dest++ = *src++) != 0) {
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if (--count == 0) {
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*dest = '\0';
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break;
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}
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}
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}
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return tmp;
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}
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EXPORT_SYMBOL(strncat);
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#endif
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#ifndef __HAVE_ARCH_STRLCAT
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/**
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* strlcat - Append a length-limited, %NUL-terminated string to another
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* @dest: The string to be appended to
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* @src: The string to append to it
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* @count: The size of the destination buffer.
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*/
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size_t strlcat(char *dest, const char *src, size_t count)
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{
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size_t dsize = strlen(dest);
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size_t len = strlen(src);
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size_t res = dsize + len;
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/* This would be a bug */
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BUG_ON(dsize >= count);
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dest += dsize;
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count -= dsize;
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if (len >= count)
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len = count-1;
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memcpy(dest, src, len);
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dest[len] = 0;
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return res;
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}
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EXPORT_SYMBOL(strlcat);
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#endif
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#ifndef __HAVE_ARCH_STRCMP
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/**
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* strcmp - Compare two strings
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* @cs: One string
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* @ct: Another string
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*/
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int strcmp(const char * cs,const char * ct)
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{
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register signed char __res;
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while (1) {
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if ((__res = *cs - *ct++) != 0 || !*cs++)
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break;
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}
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return __res;
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}
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EXPORT_SYMBOL(strcmp);
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#endif
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#ifndef __HAVE_ARCH_STRNCMP
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/**
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* strncmp - Compare two length-limited strings
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* @cs: One string
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* @ct: Another string
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* @count: The maximum number of bytes to compare
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*/
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int strncmp(const char * cs,const char * ct,size_t count)
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{
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register signed char __res = 0;
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while (count) {
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if ((__res = *cs - *ct++) != 0 || !*cs++)
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break;
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count--;
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}
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return __res;
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}
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EXPORT_SYMBOL(strncmp);
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#endif
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#ifndef __HAVE_ARCH_STRCHR
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/**
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* strchr - Find the first occurrence of a character in a string
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* @s: The string to be searched
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* @c: The character to search for
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*/
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char * strchr(const char * s, int c)
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{
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for(; *s != (char) c; ++s)
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if (*s == '\0')
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return NULL;
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return (char *) s;
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}
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EXPORT_SYMBOL(strchr);
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#endif
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#ifndef __HAVE_ARCH_STRRCHR
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/**
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* strrchr - Find the last occurrence of a character in a string
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* @s: The string to be searched
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* @c: The character to search for
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*/
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char * strrchr(const char * s, int c)
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{
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const char *p = s + strlen(s);
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do {
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if (*p == (char)c)
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return (char *)p;
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} while (--p >= s);
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return NULL;
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}
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EXPORT_SYMBOL(strrchr);
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#endif
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#ifndef __HAVE_ARCH_STRNCHR
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/**
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* strnchr - Find a character in a length limited string
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* @s: The string to be searched
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* @count: The number of characters to be searched
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* @c: The character to search for
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*/
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char *strnchr(const char *s, size_t count, int c)
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{
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for (; count-- && *s != '\0'; ++s)
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if (*s == (char) c)
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return (char *) s;
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return NULL;
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}
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EXPORT_SYMBOL(strnchr);
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#endif
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#ifndef __HAVE_ARCH_STRLEN
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/**
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* strlen - Find the length of a string
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* @s: The string to be sized
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*/
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size_t strlen(const char * s)
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{
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const char *sc;
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for (sc = s; *sc != '\0'; ++sc)
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/* nothing */;
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return sc - s;
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}
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EXPORT_SYMBOL(strlen);
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#endif
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#ifndef __HAVE_ARCH_STRNLEN
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/**
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* strnlen - Find the length of a length-limited string
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* @s: The string to be sized
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* @count: The maximum number of bytes to search
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*/
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size_t strnlen(const char * s, size_t count)
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{
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const char *sc;
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for (sc = s; count-- && *sc != '\0'; ++sc)
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/* nothing */;
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return sc - s;
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}
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EXPORT_SYMBOL(strnlen);
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#endif
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#ifndef __HAVE_ARCH_STRSPN
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/**
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* strspn - Calculate the length of the initial substring of @s which only
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* contain letters in @accept
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* @s: The string to be searched
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* @accept: The string to search for
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*/
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size_t strspn(const char *s, const char *accept)
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{
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const char *p;
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const char *a;
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size_t count = 0;
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for (p = s; *p != '\0'; ++p) {
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for (a = accept; *a != '\0'; ++a) {
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if (*p == *a)
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break;
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}
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if (*a == '\0')
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return count;
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++count;
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}
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return count;
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}
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EXPORT_SYMBOL(strspn);
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#endif
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/**
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* strcspn - Calculate the length of the initial substring of @s which does
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* not contain letters in @reject
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* @s: The string to be searched
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* @reject: The string to avoid
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*/
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size_t strcspn(const char *s, const char *reject)
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{
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const char *p;
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const char *r;
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size_t count = 0;
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for (p = s; *p != '\0'; ++p) {
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for (r = reject; *r != '\0'; ++r) {
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if (*p == *r)
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return count;
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}
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++count;
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}
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return count;
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}
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EXPORT_SYMBOL(strcspn);
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#ifndef __HAVE_ARCH_STRPBRK
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/**
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* strpbrk - Find the first occurrence of a set of characters
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* @cs: The string to be searched
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* @ct: The characters to search for
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*/
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char * strpbrk(const char * cs,const char * ct)
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{
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const char *sc1,*sc2;
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for( sc1 = cs; *sc1 != '\0'; ++sc1) {
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for( sc2 = ct; *sc2 != '\0'; ++sc2) {
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if (*sc1 == *sc2)
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return (char *) sc1;
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}
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}
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return NULL;
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}
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EXPORT_SYMBOL(strpbrk);
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#endif
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#ifndef __HAVE_ARCH_STRSEP
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/**
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* strsep - Split a string into tokens
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* @s: The string to be searched
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* @ct: The characters to search for
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*
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* strsep() updates @s to point after the token, ready for the next call.
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*
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* It returns empty tokens, too, behaving exactly like the libc function
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* of that name. In fact, it was stolen from glibc2 and de-fancy-fied.
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* Same semantics, slimmer shape. ;)
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*/
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char * strsep(char **s, const char *ct)
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{
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char *sbegin = *s, *end;
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if (sbegin == NULL)
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return NULL;
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end = strpbrk(sbegin, ct);
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if (end)
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*end++ = '\0';
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*s = end;
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return sbegin;
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}
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EXPORT_SYMBOL(strsep);
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#endif
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#ifndef __HAVE_ARCH_MEMSET
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/**
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* memset - Fill a region of memory with the given value
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* @s: Pointer to the start of the area.
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* @c: The byte to fill the area with
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* @count: The size of the area.
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*
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* Do not use memset() to access IO space, use memset_io() instead.
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*/
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void * memset(void * s,int c,size_t count)
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{
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char *xs = (char *) s;
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while (count--)
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*xs++ = c;
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return s;
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}
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EXPORT_SYMBOL(memset);
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#endif
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#ifndef __HAVE_ARCH_MEMCPY
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/**
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* memcpy - Copy one area of memory to another
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* @dest: Where to copy to
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* @src: Where to copy from
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* @count: The size of the area.
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*
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* You should not use this function to access IO space, use memcpy_toio()
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* or memcpy_fromio() instead.
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*/
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void * memcpy(void * dest,const void *src,size_t count)
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{
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char *tmp = (char *) dest, *s = (char *) src;
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while (count--)
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*tmp++ = *s++;
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return dest;
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}
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EXPORT_SYMBOL(memcpy);
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#endif
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#ifndef __HAVE_ARCH_MEMMOVE
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/**
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||
|
* 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.
|
||
|
*/
|
||
|
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
|