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Re: [Qemu-devel] [libfdt][PATCH v2] implement strnlen for systems that n
From: |
Ian Lepore |
Subject: |
Re: [Qemu-devel] [libfdt][PATCH v2] implement strnlen for systems that need it |
Date: |
Sun, 22 Oct 2017 13:06:12 -0600 |
On Sun, 2017-10-22 at 10:41 -0400, Programmingkid wrote:
> >
> > On Oct 22, 2017, at 1:33 AM, David Gibson wrote:
> >
> > On Fri, Oct 20, 2017 at 04:44:58PM -0700, Richard Henderson wrote:
> > >
> > > On 10/20/2017 10:55 AM, John Arbuckle wrote:
> > > >
> > > > +static inline size_t strnlen(const char *string, size_t max_count)
> > > > +{
> > > > + size_t count;
> > > > + for (count = 0; count < max_count; count++) {
> > > > + if (string[count] == '\0') {
> > > > + break;
> > > > + }
> > > > + }
> > > > + return count;
> > > Not to nitpick, but
> > >
> > > const char *p = memchr(string, 0, max_count);
> > > return p ? max_count : p - string;
> > Richard's right, that's definitely a better implementation.
> His implementation is smaller, but this one is even smaller. Plus it uses the
> familiar strlen() function:
>
> size_t strnlen(const char *string, size_t max_count)
> {
> return strlen(string) < max_count ? strlen(string) : max_count;
> }
That is not a proper implementation of strnlen(), which is not supposed
to access any source-string bytes beyond max_count.
-- Ian
Re: [Qemu-devel] [libfdt][PATCH v2] implement strnlen for systems that need it, Peter Maydell, 2017/10/22