ceph/src/boost/boost/beast/core/detail/clamp.hpp

   1 //
   2 // Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9
  10 #ifndef BOOST_BEAST_CORE_DETAIL_CLAMP_HPP
  11 #define BOOST_BEAST_CORE_DETAIL_CLAMP_HPP
  12
  13 #include <cstdlib>
  14 #include <limits>
  15 #include <type_traits>
  16
  17 namespace boost {
  18 namespace beast {
  19 namespace detail {
  20
  21 template<class UInt>
  22 static
  23 std::size_t
  24 clamp(UInt x)
  25 {
  26     if(x >= (std::numeric_limits<std::size_t>::max)())
  27         return (std::numeric_limits<std::size_t>::max)();
  28     return static_cast<std::size_t>(x);
  29 }
  30
  31 template<class UInt>
  32 static
  33 std::size_t
  34 clamp(UInt x, std::size_t limit)
  35 {
  36     if(x >= limit)
  37         return limit;
  38     return static_cast<std::size_t>(x);
  39 }
  40
  41 // return `true` if x + y > z, which are unsigned
  42 template<
  43     class U1, class U2, class U3>
  44 constexpr
  45 bool
  46 sum_exceeds(U1 x, U2 y, U3 z)
  47 {
  48     static_assert(
  49         std::is_unsigned<U1>::value &&
  50         std::is_unsigned<U2>::value &&
  51         std::is_unsigned<U3>::value, "");
  52     return y > z || x > z - y;
  53 }
  54
  55 } // detail
  56 } // beast
  57 } // boost
  58
  59 #endif