ceph/src/boost/libs/safe_numerics/test/test_constexpr.cpp

   1 //  Copyright (c) 2014 Robert Ramey
   2 //
   3 // Distributed under the Boost Software License, Version 1.0. (See
   4 // accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Test constexpr operations on literals
   8
   9 #include <iostream>
  10
  11 #include <boost/safe_numerics/safe_integer_literal.hpp>
  12 #include <boost/safe_numerics/native.hpp>
  13 #include <boost/safe_numerics/exception.hpp>
  14
  15 using namespace boost::safe_numerics;
  16
  17 template<std::uintmax_t N>
  18 using compile_time_value = safe_unsigned_literal<N, native, loose_trap_policy>;
  19
  20 int main(){
  21     constexpr const compile_time_value<1000> x;
  22     constexpr const compile_time_value<1> y;
  23
  24     // should compile and execute without problem
  25     std::cout << x << '\n';
  26
  27     // all the following statements should compile
  28     constexpr auto x_plus_y = x + y;
  29     static_assert(1001 == x_plus_y, "1001 == x + y");
  30
  31     constexpr auto x_minus_y = x - y;
  32     static_assert(999 == x_minus_y, "999 == x - y");
  33
  34     constexpr auto x_times_y = x * y;
  35     static_assert(1000 == x_times_y, "1000 == x * y");
  36
  37     constexpr auto x_and_y = x & y;
  38     static_assert(0 == x_and_y, "0 == x & y");
  39
  40     constexpr auto x_or_y = x | y;
  41     static_assert(1001 == x_or_y, "1001 == x | y");
  42
  43     constexpr auto x_xor_y = x ^ y;
  44     static_assert(1001 == x_xor_y, "1001 == x ^ y");
  45
  46     constexpr auto x_divided_by_y = x / y;
  47     static_assert(1000 == x_divided_by_y, "1000 == x / y");
  48
  49     constexpr auto x_mod_y = x % y;
  50     static_assert(0 == x_mod_y, "0 == x % y");
  51
  52     // this should fail compilation since a positive unsigned number
  53     // can't be converted to a negative value of the same type
  54     constexpr auto minus_x = -x;
  55
  56     // should compile OK since the negative inverse of a zero is still zero
  57     constexpr const compile_time_value<0> x0;
  58     constexpr auto minus_x0 = -x0; // should compile OK
  59     static_assert(0 == minus_x0, "0 == -x where x == 0");
  60
  61     constexpr auto not_x = ~x;
  62
  63     return 0;
  64 }