Index: uspace/lib/cpp/include/impl/ratio.hpp =================================================================== --- uspace/lib/cpp/include/impl/ratio.hpp (revision 408256727791e30d914ee6c6423be75fb9b1bb0f) +++ uspace/lib/cpp/include/impl/ratio.hpp (revision 408256727791e30d914ee6c6423be75fb9b1bb0f) @@ -0,0 +1,189 @@ +/* + * Copyright (c) 2017 Jaroslav Jindrak + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * - The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef LIBCPP_RATIO +#define LIBCPP_RATIO + +#include +#include + +namespace std +{ + namespace aux + { + template + struct gcd + { + static constexpr intmax_t value = gcd::value; + }; + + template + struct gcd + { + static constexpr intmax_t value = A; + }; + + template + inline constexpr intmax_t gcd_v = gcd::value; + + template + struct abs + { + static constexpr intmax_t value = (A > 0 ? A : -A); + }; + + template + inline constexpr intmax_t abs_v = abs::value; + + template + struct sign + { + static constexpr intmax_t value = (A == 0 ? 0: (A > 0 ? 1 : -1)); + }; + + template + inline constexpr intmax_t sign_v = sign::value; + + // Not used here, but in , better to keep them together. + template + struct lcm + { + static constexpr intmax_t value = abs_v / gcd_v; + }; + + template + inline constexpr intmax_t lcm_v = lcm::value; + } + + /** + * 20.11.3, class template ratio: + */ + + template + class ratio + { + public: + static_assert(D != 0, "ratio with denominator == 0"); + + static constexpr intmax_t num = aux::sign_v * aux::sign_v + * aux::abs_v / aux::gcd_v; + + static constexpr intmax_t den = aux::abs_v / aux::gcd_v; + + using type = ratio; + }; + + /** + * 20.11.4, ratio arithmetic: + */ + + template + using ratio_add = typename ratio< + R1::num * R2::den + R2::num * R1::den, + R1::den * R2::den + >::type; + + template + using ratio_subtract = typename ratio< + R1::num * R2::den - R2::num * R1::den, + R1::den * R2::den + >::type; + + template + using ratio_multiply = typename ratio< + R1::num * R2::num, + R1::den * R2::den + >::type; + + template + using ratio_divide = typename ratio< + R1::num * R2::den, + R1::den * R2::num + >::type; + + /** + * 20.11.5, ratio comparison: + */ + + template + struct ratio_equal: integral_constant< + bool, (R1::num == R2::num) && (R1::den == R2::den) + > + { /* DUMMY BODY */ }; + + template + struct ratio_not_equal: integral_constant::value> + { /* DUMMY BODY */ }; + + template + struct ratio_less: integral_constant< + bool, R1::num * R2::den < R2::num * R1::den + > + { /* DUMMY BODY */ }; + + template + struct ratio_less_equal: integral_constant::value> + { /* DUMMY BODY */ }; + + template + struct ratio_greater: integral_constant::value> + { /* DUMMY BODY */ }; + + template + struct ratio_greater_equal: integral_constant::value> + { /* DUMMY BODY */ }; + + /** + * 20.11.6, convenience SI typedefs: + */ + + // TODO: yocto/zepto and yotta/zetta should not be defined if intmax_t is too small + + /* using yocto = ratio<1, 1'000'000'000'000'000'000'000'000>; */ + /* using zepto = ratio<1, 1'000'000'000'000'000'000'000>; */ + using atto = ratio<1, 1'000'000'000'000'000'000>; + using femto = ratio<1, 1'000'000'000'000'000>; + using pico = ratio<1, 1'000'000'000'000>; + using nano = ratio<1, 1'000'000'000>; + using micro = ratio<1, 1'000'000>; + using milli = ratio<1, 1'000>; + using centi = ratio<1, 100>; + using deci = ratio<1, 10>; + using deca = ratio< 10, 1>; + using hecto = ratio< 100, 1>; + using kilo = ratio< 1'000, 1>; + using mega = ratio< 1'000'000, 1>; + using giga = ratio< 1'000'000'000, 1>; + using tera = ratio< 1'000'000'000'000, 1>; + using peta = ratio< 1'000'000'000'000'000, 1>; + using exa = ratio< 1'000'000'000'000'000'000, 1>; + /* using zetta = ratio< 1'000'000'000'000'000'000'000, 1>; */ + /* using yotta = ratio<1'000'000'000'000'000'000'000'000, 1>; */ +} + +#endif