Re: generic strncpy - off-by-one error

[Erik Andersen <andersen@codepoet.org>]

On Tue Aug 12, 2003 at 10:18:21PM -0400, Albert Cahalan wrote:
> You're all wrong. This is some kind of programming
> test for sure!
> 
> Let us imagine that glibc has a correct version.
> By exhaustive testing, I found a version that works.
> Here it is, along with the test code:
> 
> //////////////////////////////////////////////////////
> #define _GNU_SOURCE
> #include <string.h>
> #include <stdlib.h>
> #include <stdio.h>
> 
> // first correct implementation!
> char * strncpy_good(char *dest, const char *src, size_t count){
>   char *tmp = dest;
>   memset(dest,'\0',count);
>   while (count-- && (*tmp++ = *src++))
>     ;
>   return dest;
> }

char *strncpy(char * s1, const char * s2, size_t n)
{
    register char *s = s1;
    while (n) {
	if ((*s = *s2) != 0) s2++;
	++s;
	--n;
    }
    return s1;
}

 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
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