Re: [PATCH V2 1/2] lib/string: add memrchr function

[Andy Shevchenko]

On Thu, Feb 14, 2019 at 02:02:37PM +0800, Xiang Xiao wrote:
> Here is the detailed description for memrchr:
> 
> void *memrchr(const void *s, int c, size_t n);
> 
> The memrchr() function is like the memchr() function, except
> that it searches backward from the end of the n bytes pointed
> to by s instead of forward from the beginning.
> 
> The memrchr() functions return a pointer to the matching byte
> or NULL if the character does not occur in the given memory
> area.

> +void *memrchr(const void *s, int c, size_t n)
> +{
> +	const unsigned char *p = s + n;
> +
> +	while (n-- != 0) {

Simple:

	while (n--) {

> +		if ((unsigned char)c == *--p)
> +			return (void *)p;
> +	}
> +	return NULL;
> +}

-- 
With Best Regards,
Andy Shevchenko