From: Antoine Pelisse <apelisse@gmail.com>
Date: Sun, 10 Mar 2013 11:54:18 GMT
Subject: Re: [PATCH v2 3/6] match_basename: use strncmp instead of strcmp
Message-ID: <CALWbr2x6V6TB9g_nQCgG2r9L__a2wxG28Qi5KTXChHxj5JSQ8w@mail.gmail.com>
In-Reply-To: <CALWbr2wEJy0p2hcFK_rLtA98koeacE8rS2T=9P130GUFjWKc0Q@mail.gmail.com>

On Sun, Mar 10, 2013 at 12:43 PM, Antoine Pelisse <apelisse@gmail.com> wrote:
> On Sun, Mar 10, 2013 at 11:38 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>> glibc's C strncmp version does 4-byte comparison at a time when n >=4,
>> then fall back to 1-byte for the rest.
>
> Looking at this
> (http://fossies.org/dox/glibc-2.17/strncmp_8c_source.html), it's not
> exactly true.
>
> It would rather be while (n >= 4), manually unroll the loop.

By the way, if we know the length of the string, we could use memcmp.
This one is allowed to compare 4-bytes at a time (he doesn't care
about end of string). This is true because the value of the length
parameter is no longer "at most".