C字符串操作函数源码

 
#ifndef _PPC_BOOT_STRING_H_
#define _PPC_BOOT_STRING_H_
#include <stddef.h>
extern char *strcpy(char *dest, const char *src);
extern char *strncpy(char *dest, const char *src, size_t n);
extern char *strcat(char *dest, const char *src);
extern int strcmp(const char *s1, const char *s2);
extern size_t strlen(const char *s);
extern size_t strnlen(const char *s, size_t count);
extern void *memset(void *s, int c, size_t n);
extern void *memmove(void *dest, const void *src, unsigned long n);
extern void *memcpy(void *dest, const void *src, unsigned long n);
extern int memcmp(const void *s1, const void *s2, size_t n);
#endif    /* _PPC_BOOT_STRING_H_ */
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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.
*
* * 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