• Kagamin <spam here.lot> Nov 27 2010
• Kagamin <spam here.lot> Nov 27 2010
• bearophile <bearophileHUGS lycos.com> Nov 27 2010
• =?UTF-8?B?IkrDqXLDtG1lIE0uIEJlcmdlciI=?= <jeberger free.fr> Nov 28 2010

Kagamin <spam here.lot> writes:

You need only match 3-char strings?
Try this hack

bool cmp3c(string a, string etalon) pure
{
  if(a.length!=3)return false;
  return *cast(short*)a.ptr==*cast(short*)b.ptr && a[2]==b[2];
}

Kagamin <spam here.lot> writes:

or

bool cmp3c(string a, string b) pure
{
  if(a.length!=3)return false;
  return *cast(char[3]*)a.ptr==*cast(char[3]*)b.ptr;
}

llvm.memcmp should rock with lengths known at compile time.

bearophile <bearophileHUGS lycos.com> writes:

Kagamin:

 You need only match 3-char strings?
 Try this hack


I agree there are are ways to speed up the code, probably the D #3 code is fast
enough. But while some things are better left to Phobos, comparing short
strings efficiently is the compiler's job, not mine (and I am not sure your
trick works in C99).

Bye,
bearophile

=?UTF-8?B?IkrDqXLDtG1lIE0uIEJlcmdlciI=?= <jeberger free.fr> writes:

Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Kagamin wrote:
 You need only match 3-char strings?
 Try this hack
=20
 bool cmp3c(string a, string etalon) pure
 {
   if(a.length!=3D3)return false;
   return *cast(short*)a.ptr=3D=3D*cast(short*)b.ptr && a[2]=3D=3Db[2];
 }



		Jerome
--=20
mailto:jeberger free.fr
http://jeberger.free.fr
Jabber: jeberger jabber.fr