boost_mirror/utility
1
0
Fork 0
mirror of https://github.com/boostorg/utility.git synced 2025-05-08 18:34:02 +00:00
Code Issues Packages Projects Releases Wiki Activity

Now statically selecting a test for signed numbers to avoid warnings with fancy

Browse Source 
compilers. Added commentary and additional dumping of traits data for tested
types.


[SVN r8746]
This commit is contained in:
Dave Abrahams 2001-01-24 01:40:22 +00:00
parent 6396fdb5ff
commit d9e0f80d50
1 changed files with 72 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

85
numeric_traits_test.cpp
View File

@ -7,6 +7,9 @@
// See http://www.boost.org for most recent version including documentation.
// Revision History
// 23 Jan 2001 Now statically selecting a test for signed numbers to avoid
// warnings with fancy compilers. Added commentary and
// additional dumping of traits data for tested types.
// 21 Jan 2001 Initial version (David Abrahams)
#include <boost/detail/numeric_traits.hpp>
@ -31,6 +34,7 @@
# define DECLARE_CLASS_CONST(type, init) enum { init }
#endif
// =================================================================================
// template class complement_traits<Number> --
//
// statically computes the max and min for 1s and 2s-complement binary
@ -118,6 +122,8 @@ struct complement_traits
DECLARE_CLASS_CONST(Number, min = (complement_traits_aux<Number, sizeof(Number)>::min));
};
// =================================================================================
// Support for streaming various numeric types in exactly the format I want. I
// needed this in addition to all the assertions so that I could see exactly
// what was going on.
@ -198,6 +204,7 @@ typename stream_as<T>::t2 stream_number(T x)
{
return promote<T>::from(x);
}
// =================================================================================
//
// Tests for built-in signed and unsigned types
@ -246,6 +253,56 @@ void test_aux(unsigned_tag, Number* = 0)
// Tests for signed numbers. The extra default Number parameter works around an
// MSVC bug.
struct out_of_range_tag {};
struct in_range_tag {};
// This test morsel gets executed for numbers whose difference will always be
// representable in intmax_t
template <class Number>
void signed_test(in_range_tag, Number* = 0)
{
BOOST_STATIC_ASSERT(boost::detail::is_signed<Number>::value);
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
const Number max = complement_traits<Number>::max;
const Number min = complement_traits<Number>::min;
difference_type d1 = boost::detail::numeric_distance(min, max);
difference_type d2 = boost::detail::numeric_distance(max, min);
std::cout << stream_number(min) << "->" << stream_number(max) << "==";
std::cout << std::dec << stream_number(d1) << "; ";
std::cout << std::hex << stream_number(max) << "->" << stream_number(min)
<< "==" << std::dec << stream_number(d2) << "..." << std::flush;
assert(d1 == difference_type(max) - difference_type(min));
assert(d2 == difference_type(min) - difference_type(max));
}
// This test morsel gets executed for numbers whose difference may exceed the
// capacity of intmax_t.
template <class Number>
void signed_test(out_of_range_tag, Number* = 0)
{
BOOST_STATIC_ASSERT(boost::detail::is_signed<Number>::value);
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
const Number max = complement_traits<Number>::max;
const Number min = complement_traits<Number>::min;
difference_type min_distance = complement_traits<difference_type>::min;
difference_type max_distance = complement_traits<difference_type>::max;
const Number n1 = Number(min + max_distance);
const Number n2 = Number(max + min_distance);
difference_type d1 = boost::detail::numeric_distance(min, n1);
difference_type d2 = boost::detail::numeric_distance(max, n2);
std::cout << stream_number(min) << "->" << stream_number(n1) << "==";
std::cout << std::dec << stream_number(d1) << "; ";
std::cout << std::hex << stream_number(max) << "->" << stream_number(n2)
<< "==" << std::dec << stream_number(d2) << "..." << std::flush;
assert(d1 == max_distance);
assert(d2 == min_distance);
}
template <class Number>
void test_aux(signed_tag, Number* = 0)
{
@ -266,19 +323,15 @@ void test_aux(signed_tag, Number* = 0)
<< stream_number(max) << "..." << std::flush;
std::cout << "difference_type = " << typeid(difference_type).name() << "..."
<< std::flush;
assert(min < max);
difference_type d1 = boost::detail::numeric_distance(min, max);
difference_type d2 = boost::detail::numeric_distance(max, min);
if (sizeof(Number) < sizeof(boost::intmax_t))
{
std::cout << stream_number(min) << "->" << stream_number(max) << "==";
std::cout << std::dec << stream_number(d1) << "; ";
std::cout << std::hex << stream_number(max) << "->" << stream_number(min)
<< "==" << std::dec << stream_number(d2) << "..." << std::flush;
assert(d1 == difference_type(max) - difference_type(min));
assert(d2 == difference_type(min) - difference_type(max));
}
typedef typename boost::detail::if_true<
(sizeof(Number) < sizeof(boost::intmax_t))>
::template then<
in_range_tag,
out_of_range_tag
>::type
range_tag;
signed_test<Number>(range_tag());
}
@ -287,7 +340,13 @@ void test_aux(signed_tag, Number* = 0)
template <class Number>
void test(Number* = 0)
{
std::cout << "testing " << typeid(Number).name() << "..." << std::flush;
std::cout << "testing " << typeid(Number).name() << ":\n"
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
<< "is_signed: " << (std::numeric_limits<Number>::is_signed ? "true\n" : "false\n")
<< "is_bounded: " << (std::numeric_limits<Number>::is_bounded ? "true\n" : "false\n")
<< "digits: " << std::numeric_limits<Number>::digits << "\n"
#endif
<< "..." << std::flush;
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
BOOST_STATIC_ASSERT(boost::detail::is_signed<difference_type>::value);