220 32993 <4473c388-1bc0-24b3-b1f2-fc8bfc834df3@rrsd.com> article Path: news.gmane.org!.POSTED!not-for-mail From: Robert Ramey Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: safe integrals comparison Date: Wed, 28 Jun 2017 14:47:17 -0700 Lines: 182 Approved: news@gmane.org Message-ID: <4473c388-1bc0-24b3-b1f2-fc8bfc834df3@rrsd.com> References: <66f9bab2-7220-4bf1-afb7-77c5efa1bac3@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed X-Trace: blaine.gmane.org 1498686450 29763 195.159.176.226 (28 Jun 2017 21:47:30 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 28 Jun 2017 21:47:30 +0000 (UTC) User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDG73K7L6AIRB3WH2DFAKGQE7MME6MQ@isocpp.org Wed Jun 28 23:47:24 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yb0-f200.google.com ([209.85.213.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1dQKnz-0007Ml-D5 for gclcip-std-proposals@m.gmane.org; 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[172.20.107.195]) (using TLSv1 with cipher DHE-RSA-AES256-SHA) by 0.0.0.0:2500 (trex/5.9.7); Wed, 28 Jun 2017 21:47:21 +0000 X-MC-Relay: Neutral X-MailChannels-SenderId: wwwh2|x-authuser|ramey@rrsd.com X-MailChannels-Auth-Id: wwwh2 X-Soft-Spill: 52188fc148c40727_1498686440848_1212665696 X-MC-Loop-Signature: 1498686440848:1364179264 X-MC-Ingress-Time: 1498686440848 Original-Received: from ip68-6-126-194.sb.sd.cox.net ([68.6.126.194]:54755 helo=Roberts-Mac-mini.local) by clippers.accountservergroup.com with esmtpsa (TLSv1:DHE-RSA-AES128-SHA:128) (Exim 4.87) (envelope-from ) id 1dQKnv-0005Tp-2X for std-proposals@isocpp.org; Wed, 28 Jun 2017 14:47:19 -0700 Original-Newsgroups: gmane.comp.lang.c++.isocpp.proposals In-Reply-To: <66f9bab2-7220-4bf1-afb7-77c5efa1bac3@isocpp.org> Content-Language: en-US X-AuthUser: ramey@rrsd.com X-Original-Sender: ramey@rrsd.com X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of ramey@rrsd.com designates 23.83.222.31 as permitted sender) smtp.mailfrom=ramey@rrsd.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:32993 Archived-At: The following is what I use #ifndef BOOST_NUMERIC_SAFE_COMPARE_HPP #define BOOST_NUMERIC_SAFE_COMPARE_HPP // MS compatible compilers support #pragma once #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma once #endif // Copyright (c) 2012 Robert Ramey // // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) #include #include #include #include #include "safe_common.hpp" namespace boost { namespace numeric { namespace safe_compare { //////////////////////////////////////////////////// // safe comparison on primitive types namespace safe_compare_detail { template using make_unsigned = typename boost::mpl::if_c< //std::numeric_limits::is_signed, std::is_signed::value, std::make_unsigned, boost::mpl::identity >::type; // both arguments unsigned or signed template struct less_than { template constexpr static bool invoke(const T & t, const U & u){ return t < u; } }; // T unsigned, U signed template<> struct less_than { template constexpr static bool invoke(const T & t, const U & u){ return (u < 0) ? false : less_than::invoke( t, static_cast::type &>(u) ) ; } }; // T signed, U unsigned template<> struct less_than { template constexpr static bool invoke(const T & t, const U & u){ return (t < 0) ? true : less_than::invoke( static_cast::type &>(t), u ) ; } }; } // safe_compare_detail template constexpr bool less_than(const T & lhs, const U & rhs) { return safe_compare_detail::less_than< std::is_signed::value, std::is_signed::value >::template invoke(lhs, rhs); } template constexpr bool greater_than(const T & lhs, const U & rhs) { return less_than(rhs, lhs); } template constexpr bool less_than_equal(const T & lhs, const U & rhs) { return ! greater_than(lhs, rhs); } template constexpr bool greater_than_equal(const T & lhs, const U & rhs) { return ! less_than(lhs, rhs); } namespace safe_compare_detail { // both arguments unsigned or signed template struct equal { template constexpr static bool invoke(const T & t, const U & u){ return t == u; } }; // T unsigned, U signed template<> struct equal { template constexpr static bool invoke(const T & t, const U & u){ return (u < 0) ? false : equal::invoke( t, static_cast::type &>(u) ) ; } }; // T signed, U unsigned template<> struct equal { template constexpr static bool invoke(const T & t, const U & u){ return (t < 0) ? false : equal::invoke( static_cast::type &>(t), u ) ; } }; } // safe_compare_detail template constexpr bool equal(const T & lhs, const U & rhs) { return safe_compare_detail::equal< std::numeric_limits::is_signed, std::numeric_limits::is_signed >::template invoke(lhs, rhs); } template constexpr bool not_equal(const T & lhs, const U & rhs) { return ! safe_compare_detail::equal< std::numeric_limits::is_signed, std::numeric_limits::is_signed >::template invoke(lhs, rhs); } } // safe_compare } // numeric } // boost #endif // BOOST_NUMERIC_SAFE_COMPARE_HPP -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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