Subject: [Boost-commit] svn:boost r77212 - in sandbox/fixed_point: boost/fixed_point libs/fixed_point/example
From: vicente.botet_at_[hidden]
Date: 2012-03-04 07:33:56
Author: viboes
Date: 2012-03-04 07:33:55 EST (Sun, 04 Mar 2012)
New Revision: 77212
URL: http://svn.boost.org/trac/boost/changeset/77212
Log:
FixedPoint: Use integer max type to avoid overflows while rounding
Text files modified:
sandbox/fixed_point/boost/fixed_point/number.hpp | 63 +++++++++++++++++++++++++++++----------
sandbox/fixed_point/libs/fixed_point/example/ex_xx.cpp | 30 +++++++++++++++++++
2 files changed, 77 insertions(+), 16 deletions(-)
Modified: sandbox/fixed_point/boost/fixed_point/number.hpp
==============================================================================
--- sandbox/fixed_point/boost/fixed_point/number.hpp (original)
+++ sandbox/fixed_point/boost/fixed_point/number.hpp 2012-03-04 07:33:55 EST (Sun, 04 Mar 2012)
@@ -29,6 +29,7 @@
#include <boost/integer/static_log2.hpp>
#include <boost/ratio/detail/mpl/abs.hpp>
#include <limits>
+#include <boost/integer_traits.hpp>
#include <boost/config.hpp>
//#include <boost/fixed_point/config.hpp>
@@ -75,6 +76,19 @@
typename shift_impl<UT,Bits,P>::result_type shift(UT v) {
return shift_impl<UT,Bits,P>::apply(v);
}
+ template <bool IsSigned>
+ struct max_type;
+ template <>
+ struct max_type<true>
+ {
+ typedef boost::intmax_t type;
+ };
+ template <>
+ struct max_type<false>
+ {
+ typedef boost::uintmax_t type;
+ };
+
}
struct positive_overflow {};
@@ -90,9 +104,15 @@
template <typename From, typename To>
static typename To::underlying_type round(From const& rhs)
{
- BOOST_STATIC_CONSTEXPR typename To::underlying_type d = To::resolution_exp-From::resolution_exp;
-
- return typename To::underlying_type(rhs.count()) >> d;
+ BOOST_STATIC_CONSTEXPR boost::uintmax_t d = To::resolution_exp-From::resolution_exp;
+ typedef typename detail::max_type<is_signed<typename To::underlying_type>::value>::type tmp_type;
+ BOOST_STATIC_ASSERT(d<(8*sizeof(tmp_type)));
+ //BOOST_MPL_ASSERT_MSG(d<(8*sizeof(tmp_type)), OVERFLOW, (mpl::int_<8*sizeof(tmp_type)>, mpl::int_<d>));
+
+ tmp_type res = tmp_type(rhs.count()) >> d;
+ BOOST_ASSERT(res<=To::max_index);
+ BOOST_ASSERT(res>=To::min_index);
+ return res;
}
template <typename To, typename From>
static typename To::underlying_type round_divide(From const& lhs, From const& rhs)
@@ -116,11 +136,18 @@
template <typename From, typename To>
static typename To::underlying_type round(From const& rhs)
{
- BOOST_STATIC_CONSTEXPR typename To::underlying_type d = To::resolution_exp-From::resolution_exp;
+ BOOST_STATIC_CONSTEXPR boost::uintmax_t d = To::resolution_exp-From::resolution_exp;
+ typedef typename detail::max_type<is_signed<typename To::underlying_type>::value>::type tmp_type;
+ BOOST_STATIC_ASSERT(d<(8*sizeof(tmp_type)));
+
typename To::underlying_type m(((rhs.count()>0)?rhs.count():-rhs.count()));
typename To::underlying_type s(((rhs.count()>0)?+1:-1));
- return s * (m >> d);
+ tmp_type res = s * (m >> d);
+ BOOST_ASSERT(res<=To::max_index);
+ BOOST_ASSERT(res>=To::min_index);
+ return res;
+ ;
}
template <typename To, typename From>
static typename To::underlying_type round_divide(From const& lhs, From const& rhs)
@@ -135,11 +162,19 @@
template <typename From, typename To>
static typename To::underlying_type round(From const& rhs)
{
- BOOST_STATIC_CONSTEXPR typename To::underlying_type d = To::resolution_exp-From::resolution_exp;
- typename To::underlying_type w = (1<<d)-1;
- typename To::underlying_type i = rhs.count();
-
- return (i+w) >> d;
+ BOOST_STATIC_CONSTEXPR boost::uintmax_t d = To::resolution_exp-From::resolution_exp;
+ typedef typename detail::max_type<is_signed<typename To::underlying_type>::value>::type tmp_type;
+ BOOST_STATIC_ASSERT(d<(8*sizeof(tmp_type)));
+
+ BOOST_STATIC_CONSTEXPR tmp_type w = (1<<d)-1;
+ tmp_type i = rhs.count();
+
+ BOOST_ASSERT(i<=(integer_traits<tmp_type>::const_max-w));
+
+ tmp_type res = (i+w) >> d;
+ BOOST_ASSERT(res<=To::max_index);
+ BOOST_ASSERT(res>=To::min_index);
+ return res;
}
template <typename To, typename From>
static typename To::underlying_type round_divide(From const& lhs, From const& rhs)
@@ -899,13 +934,10 @@
BOOST_CONSTEXPR To operator()(const From& rhs) const
{
- std::cout << __FILE__ << "[" <<__LINE__<<"] "<< int(rhs.count()) <<std::endl;
// Overflow
underlying_type indx(((rhs.count()) >> (P2-P1)));
- std::cout << __FILE__ << "[" <<__LINE__<<"] "<< int(indx) <<std::endl;
if (rhs.count() > (typename From::underlying_type(To::max_index)<<(P2-P1)))
{
- std::cout << __FILE__ << "[" <<__LINE__<<"] "<< int(typename From::underlying_type(To::max_index)<<(P2-P1)) <<std::endl;
return To(index(OP2::template on_positive_overflow<To,underlying_type>(indx)));
}
if (rhs.count() < (typename From::underlying_type(To::min_index)<<(P2-P1)))
@@ -1457,7 +1489,7 @@
else
{
signed_number tmp=
- divide<signed_number<Range, Resolution, RP, Overflow, Optimization>>(*this,
+ divide<signed_number<Range, Resolution, RP, Overflow, Optimization> >(*this,
signed_number<-N+1, -N, Rounding, Overflow, Optimization>(index(1)));
value_ = tmp.count();
}
@@ -1747,7 +1779,7 @@
else
{
unsigned_number tmp=
- divide<unsigned_number<Range, Resolution, RP, Overflow, Optimization>>(*this,
+ divide<unsigned_number<Range, Resolution, RP, Overflow, Optimization> >(*this,
unsigned_number<-N+1, -N, Rounding, Overflow, Optimization>(index(1)));
value_ = tmp.count();
}
@@ -2378,7 +2410,6 @@
template <typename To, typename From>
To number_cast(From const& f)
{
- //std::cout << __FILE__ << "[" <<__LINE__<<"] "<< f.count() <<std::endl;
return fixed_point::detail::number_cast<From, To>()(f);
}
}
Modified: sandbox/fixed_point/libs/fixed_point/example/ex_xx.cpp
==============================================================================
--- sandbox/fixed_point/libs/fixed_point/example/ex_xx.cpp (original)
+++ sandbox/fixed_point/libs/fixed_point/example/ex_xx.cpp 2012-03-04 07:33:55 EST (Sun, 04 Mar 2012)
@@ -60,18 +60,41 @@
BOOST_TEST(n.count()==1);
}
{
+ unsigned_number<1,-32> n1((index(1)));
+ unsigned_number<64,31,round::negative> n2(n1);
+ std::cout << int(n2.count()) << std::endl;
+ BOOST_TEST(n2.count()==0);
+ }
+ {
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
+ unsigned_number<8,0> n1((index(255)));
+ unsigned_number<8,0,round::negative> n2(n1);
+ BOOST_TEST(n2.count()==255);
+ }
+ {
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
+ signed_number<9,-1> n1((index(-254)));
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
+ signed_number<7,0,round::negative> n2(n1);
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
+ BOOST_TEST(n2.count()==-127);
+ }
+ {
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
unsigned_number<2,-2> n1((index(1)));
unsigned_number<2,-2,round::negative> n2(n1);
BOOST_TEST(n1.count()==1);
BOOST_TEST(n2.count()==1);
}
{
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-2> n1((index(1)));
signed_number<2,-2,round::negative> n2(n1);
BOOST_TEST(n1.count()==1);
BOOST_TEST(n2.count()==1);
}
{
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-2> n1((index(1)));
signed_number<2,-2,round::negative> n2;
n2=n1;
@@ -170,6 +193,7 @@
BOOST_TEST(n2.count()==1);
}
{
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-3> n1((index(-1)));
signed_number<2,-2,round::negative> n2(n1);
BOOST_TEST(n1.count()==-1);
@@ -177,14 +201,20 @@
BOOST_TEST(n2.count()==-1);
}
{
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-3> n1((index(-1)));
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-2,round::positive> n2(n1);
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
std::cout << int(n2.count()) << std::endl;
BOOST_TEST(n2.count()==0);
}
{
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-3> n1((index(-1)));
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
signed_number<2,-2,round::truncated> n2(n1);
+ std::cout << __FILE__ << "[" <<__LINE__<<"]"<<std::endl;
std::cout << int(n2.count()) << std::endl;
BOOST_TEST(n2.count()==0);
}