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[multiple changes] 

2008-07-05  Paolo Carlini  <paolo.carlini@oracle.com>

	* include/std/ratio: Prefer __INTMAX_MAX__ to INTMAX_MAX (INTMAX_MIN).

2008-07-05  Chris Fairles  <chris.fairles@gmail.com>

        * include/std/ratio: Documentation for std::ratio class. Add conditions 
        to ratio_less to prevent overflow.
        * testsuite/20_util/ratio/comparisons/comp2.cc: New.
        * testsuite/20_util/ratio/cons/cons_overflow.cc: Update dg-error line
        numbers.

From-SVN: r137504
This commit is contained in:
Paolo Carlini 2008-07-05 10:24:08 +00:00
parent 752929c698
commit ea31932d53
4 changed files with 110 additions and 11 deletions
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12
libstdc++-v3/ChangeLog
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@ -1,3 +1,15 @@
2008-07-05 Paolo Carlini <paolo.carlini@oracle.com>
* include/std/ratio: Prefer __INTMAX_MAX__ to INTMAX_MAX (INTMAX_MIN).
2008-07-05 Chris Fairles <chris.fairles@gmail.com>
* include/std/ratio: Documentation for std::ratio class. Add conditions
to ratio_less to prevent overflow.
* testsuite/20_util/ratio/comparisons/comp2.cc: New.
* testsuite/20_util/ratio/cons/cons_overflow.cc: Update dg-error line
numbers.
2008-07-04 Chris Fairles <chris.fairles@gmail.com>
* include/std/ratio: New, per N2661.

49
libstdc++-v3/include/std/ratio
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@ -96,10 +96,10 @@ namespace std
"overflow in multiplication");
static_assert(__a0 * __b1 + __b0 * __a1 < (__c >> 1),
"overflow in multiplication");
static_assert(__b0 * __a0 <= INTMAX_MAX,
static_assert(__b0 * __a0 <= __INTMAX_MAX__,
"overflow in multiplication");
static_assert((__a0 * __b1 + __b0 * __a1) * __c <=
INTMAX_MAX - __b0 * __a0, "overflow in multiplication");
__INTMAX_MAX__ - __b0 * __a0, "overflow in multiplication");
public:
static const intmax_t value = _Pn * _Qn;
@ -108,12 +108,12 @@ namespace std
// Helpers for __safe_add
template<intmax_t _Pn, intmax_t _Qn, bool>
struct __add_overflow_check_impl
: integral_constant<bool, (_Pn <= INTMAX_MAX - _Qn)>
: integral_constant<bool, (_Pn <= __INTMAX_MAX__ - _Qn)>
{ };
template<intmax_t _Pn, intmax_t _Qn>
struct __add_overflow_check_impl<_Pn, _Qn, false>
: integral_constant<bool, (_Pn >= -INTMAX_MAX - _Qn)>
: integral_constant<bool, (_Pn >= -__INTMAX_MAX__ - _Qn)>
{ };
template<intmax_t _Pn, intmax_t _Qn>
@ -130,12 +130,27 @@ namespace std
static const intmax_t value = _Pn + _Qn;
};
/**
* @brief Provides compile-time rational arithmetic.
*
* This class template represents any finite rational number with a
* numerator and denominator representable by compile-time constants of
* type intmax_t. The ratio is simplified when instantiated.
*
* For example:
* @code
* std::ratio<7,-21>::num == -1;
* std::ratio<7,-21>::den == 3;
* @endcode
*
*/
template<intmax_t _Num, intmax_t _Den = 1>
struct ratio
{
static_assert(_Den != 0, "denominator cannot be zero");
static_assert(_Num > INTMAX_MIN && _Den > INTMAX_MIN, "out of range");
static_assert(_Num >= -__INTMAX_MAX__ && _Den >= -__INTMAX_MAX__,
"out of range");
// Note: sign(N) * abs(N) == N
static const intmax_t num =
_Num * __static_sign<_Den>::value / __static_gcd<_Num, _Den>::value;
@ -211,10 +226,26 @@ namespace std
{ };
template<typename _R1, typename _R2>
struct ratio_less
struct __ratio_less_simple_impl
: integral_constant<bool,
(__safe_multiply<_R1::num, _R2::den>::value <
__safe_multiply<_R2::num, _R1::den>::value)>
(__safe_multiply<_R1::num, _R2::den>::value
< __safe_multiply<_R2::num, _R1::den>::value)>
{ };
// If the denominators are equal or the signs differ, we can just compare
// numerators, otherwise fallback to the simple cross-multiply method.
template<typename _R1, typename _R2>
struct __ratio_less_impl
: conditional<(_R1::den == _R2::den
|| (__static_sign<_R1::num>::value
!= __static_sign<_R2::num>::value)),
integral_constant<bool, (_R1::num < _R2::num)>,
__ratio_less_simple_impl<_R1, _R2>>::type
{ };
template<typename _R1, typename _R2>
struct ratio_less
: __ratio_less_impl<_R1, _R2>::type
{ };
template<typename _R1, typename _R2>

56
libstdc++-v3/testsuite/20_util/ratio/comparisons/comp2.cc Normal file
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@ -0,0 +1,56 @@
// { dg-options "-std=gnu++0x" }
// Copyright (C) 2008 Free Software Foundation
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this library; see the file COPYING. If not, write to
// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301, USA.
#include <ratio>
#include <testsuite_hooks.h>
#ifdef _GLIBCXX_USE_C99_STDINT_TR1
static const std::intmax_t M = INTMAX_MAX;
void
test01()
{
bool test __attribute__((unused)) = true;
//no overflow with same denominator
VERIFY(( std::ratio_less<std::ratio<M - 2, M>,
std::ratio<M - 1, M>>::value == 1 ) );
VERIFY(( std::ratio_less<std::ratio<M - 1, M>,
std::ratio<M - 2, M>>::value == 0 ) );
//no overflow if signs differ
VERIFY(( std::ratio_less<std::ratio<-M, M - 1>,
std::ratio<M - 1, M - 2>>::value == 1 ) );
VERIFY(( std::ratio_less<std::ratio<M - 1, M - 2>,
std::ratio<-M, M - 1>>::value == 0 ) );
}
#endif //_GLIBCXX_USE_C99_STDINT_TR1
int main()
{
#ifdef _GLIBCXX_USE_C99_STDINT_TR1
test01();
#endif
return 0;
}

4
libstdc++-v3/testsuite/20_util/ratio/cons/cons_overflow.cc
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@ -51,8 +51,8 @@ test04()
// { dg-error "instantiated from here" "" { target *-*-* } 36 }
// { dg-error "instantiated from here" "" { target *-*-* } 42 }
// { dg-error "instantiated from here" "" { target *-*-* } 48 }
// { dg-error "denominator cannot be zero" "" { target *-*-* } 136 }
// { dg-error "out of range" "" { target *-*-* } 137 }
// { dg-error "denominator cannot be zero" "" { target *-*-* } 150 }
// { dg-error "out of range" "" { target *-*-* } 151 }
// { dg-excess-errors "In instantiation of" }
#endif //_GLIBCXX_USE_C99_STDINT_TR1