220 32840 article Path: news.gmane.org!.POSTED!not-for-mail From: Mingxin Wang Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: The Proxies - A Language Feature Decoupling Implementations from Requirements of Polymorphism Date: Wed, 21 Jun 2017 20:02:35 -0700 (PDT) Lines: 124 Approved: news@gmane.org Message-ID: References: <8d79a013-fe0e-4fb6-8278-d438ae9b4c64@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_5523_222890770.1498100555430" X-Trace: blaine.gmane.org 1498100556 27353 195.159.176.226 (22 Jun 2017 03:02:36 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 22 Jun 2017 03:02:36 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDNMBNHJWIGBBTHGVTFAKGQE4OKPZ6A@isocpp.org Thu Jun 22 05:02:32 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pf0-f197.google.com ([209.85.192.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dNsO8-0006mw-Ay for gclcip-std-proposals@m.gmane.org; Thu, 22 Jun 2017 05:02:32 +0200 Original-Received: by mail-pf0-f197.google.com with SMTP id s65sf3755728pfi.14 for ; Wed, 21 Jun 2017 20:02:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=4zlsjiQ3U1VYkBTOX7DaZ9OLgPCtVIfZAgHoADlt/es=; b=nDlLpDA0jOisaBmYLng7p71NJga7CvnZx8wsy7iA5p97n4aLy+9qmkFbybbKnMBogy VxDVjf20l30ukMxTKcXGXCBs89MPhf6n3ZMzRXqrgYrXx8mfFqHPHvxPgxX2gSp+aJDp Fweh7Rf2fy6s1qyWxCRVvo0uYhEglg8Fd/ZSAVW/ulqlb23TlLPsH2fLlBD1SrcMGXfW E//ReyxxHcA7jLLAAv26XIqz5SjGHo3mZjjv7Dbq8TGWCsFtkvgmtNjPyLkTW9BX/2Fj /wpDf+SrEfKFjfwNCXom6G8P6PYJ4EbPJTVsXK59chRx2ApN7VCkgx/mZ2PexFgh6E3J BzVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=4zlsjiQ3U1VYkBTOX7DaZ9OLgPCtVIfZAgHoADlt/es=; b=bUulDsE3fUIMH+wZ8eKh8DdDr0TWKFKtscBfofBDB4QJEmO1lRjlzwNcn6KUGp4vtH 0sKcelTS00rgOkICGika/99VlyUsQ1DC8IIodXJzBqJfD4ycZlN4UFyEgnm+3+EHqC8E 0GiqZfG9Xf0nWSL9fqIdoLSaRFRkz00MOK+6yrffSUnSu6UaL2ibkNCp2UogJaQfEmwr bL801MnAoDWHJEhdWeZN48Ohz4t7COAhaGV367zAeSktctJL1m8Iq3de/sqXBugmVdyn coXmc1MEzzItNkf+aVAjsEJWA8tmyaWdtt+LVg1fSirgxxS6O0zgm9KPN/YjpAHXnTQI /uCw== X-Gm-Message-State: AKS2vOwXaQSIMneMqB59vT9JEGwJou5ROH2eiRiY8q30WZiRltvl3toc xUClc7HaPERyhE4Q X-Received: by 10.98.196.3 with SMTP id y3mr123688pff.23.1498100556917; Wed, 21 Jun 2017 20:02:36 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.23.40 with SMTP id i40ls640076ota.32.gmail; Wed, 21 Jun 2017 20:02:36 -0700 (PDT) X-Received: by 10.157.52.161 with SMTP id g30mr7233otc.17.1498100556010; Wed, 21 Jun 2017 20:02:36 -0700 (PDT) In-Reply-To: <8d79a013-fe0e-4fb6-8278-d438ae9b4c64@isocpp.org> X-Original-Sender: wmx16835vv@163.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:32840 Archived-At: ------=_Part_5523_222890770.1498100555430 Content-Type: multipart/alternative; boundary="----=_Part_5524_809515705.1498100555430" ------=_Part_5524_809515705.1498100555430 Content-Type: text/plain; charset="UTF-8" I designed another general wrapper type yesterday, which is intended for small and trivial types, as is shown below: template class TrivialWrapper { public: /* Constructors */ template TrivialWrapper(T&& data) requires !std::is_same>, TrivialWrapper>::value && std::is_trivial>>::value && (sizeof(std::remove_cv_t>) <= SIZE) { memcpy(data_.get(), &data, sizeof(std::remove_cv_t>)); } TrivialWrapper() = default; TrivialWrapper(const TrivialWrapper&) = default; TrivialWrapper(TrivialWrapper&&) = default; TrivialWrapper& operator=(const TrivialWrapper& rhs) = default; TrivialWrapper& operator=(TrivialWrapper&&) = default; /* Meets the Wrapper requirements */ void* get() { // The address of the wrapped object is calculated with a constant offset return data_.get(); } private: MemoryBlock data_; }; I am wondering if these design for wrappers (DeferredWrapper, DeepWrapper, SharedWrapper and TrivialWrapper) are adequate to be added to the standard (discard of naming). I am looking forward to your comments and suggestions! Thank you! Mingxin Wang -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/d6138434-59ef-42d7-82d8-f2934c6f3bfb%40isocpp.org. ------=_Part_5524_809515705.1498100555430 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I designed another general wrapper type yesterday, wh= ich is intended for small and trivial types, as is shown below:

template <std::size_t SIZE>= ;
class TrivialWrapper {
=C2=A0public:
=C2=A0= /* Constructors */
=C2=A0 template <= class T>
=C2=A0 TrivialWrapper(T&= & data) requires
=C2=A0 =C2=A0 =C2= =A0 !std::is_same<std::remove_cv_t<std::remove_reference_t<T>&g= t;, TrivialWrapper>::value &&
=C2=A0 =C2=A0 =C2=A0 std::is_trivial<std::remove_cv_t<std::remove_re= ference_t<T>>>::value &&
=C2=A0 =C2=A0 =C2=A0 (sizeof(std::remove_cv_t<std::remove_reference= _t<T>>) <=3D SIZE) {
=C2=A0 = =C2=A0 memcpy(data_.get(), &data, sizeof(std::remove_cv_t<std::remov= e_reference_t<T>>));
=C2=A0 }
=C2=A0 TrivialWrapper() =3D default;
=C2=A0 TrivialWrapper(const TrivialWrapper&a= mp;) =3D default;
=C2=A0 TrivialWrapper(= TrivialWrapper&&) =3D default;
<= br>
=C2=A0 TrivialWrapper& operator= =3D(const TrivialWrapper& rhs) =3D default;
=C2=A0 TrivialWrapper& operator=3D(TrivialWrapper&&) = =3D default;

=C2=A0 /* Meets the Wrapper requirements */
=C2=A0 void* get() {
= =C2=A0 =C2=A0 // The address of the wrapped object is calculated with a con= stant offset
=C2=A0 =C2=A0 return data_.= get();
=C2=A0 }

=C2=A0private:
=C2=A0 MemoryBlock<SIZE> data_;
};


I am wondering if these design for wrappers (DeferredWrapper, DeepWrapper= , SharedWrapper and TrivialWrapper) are adequate to be added to the standar= d (discard of naming).

I am looking forward to you= r comments and suggestions!

Thank you!
<= br>
Mingxin Wang

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/d6138434-59ef-42d7-82d8-f2934c6f3bfb= %40isocpp.org.
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