* [committed] libstdc++: Refactor seed sequence constraints in <random>
@ 2022-10-04 16:46 Jonathan Wakely
0 siblings, 0 replies; only message in thread
From: Jonathan Wakely @ 2022-10-04 16:46 UTC (permalink / raw)
To: libstdc++, gcc-patches
Tested powerpc64le-linux. Pushed to trunk.
-- >8 --
Every use of _If_seed_seq in <random> and <ext/random> uses it with
enable_if. We can just move the enable_if into the helper alias instead
of repeating it everywhere.
libstdc++-v3/ChangeLog:
* include/bits/random.h (__is_seed_seq): Replace with ...
(_If_seed_seq_for): ... this.
* include/ext/random: Adjust to use _If_seed_seq_for.
---
libstdc++-v3/include/bits/random.h | 39 ++++++++++++++++++------------
libstdc++-v3/include/ext/random | 6 ++---
2 files changed, 27 insertions(+), 18 deletions(-)
diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index 3e6eb9de7d9..28b37a9e5a5 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -198,16 +198,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Engine& _M_g;
};
+ // Detect whether a template argument _Sseq is a valid seed sequence for
+ // a random number engine _Engine with result type _Res.
+ // Used to constrain _Engine::_Engine(_Sseq&) and _Engine::seed(_Sseq&)
+ // as required by [rand.eng.general].
+
template<typename _Sseq>
using __seed_seq_generate_t = decltype(
std::declval<_Sseq&>().generate(std::declval<uint_least32_t*>(),
std::declval<uint_least32_t*>()));
- // Detect whether _Sseq is a valid seed sequence for
- // a random number engine _Engine with result type _Res.
template<typename _Sseq, typename _Engine, typename _Res,
typename _GenerateCheck = __seed_seq_generate_t<_Sseq>>
- using __is_seed_seq = __and_<
+ using _If_seed_seq_for = _Require<
__not_<is_same<__remove_cvref_t<_Sseq>, _Engine>>,
is_unsigned<typename _Sseq::result_type>,
__not_<is_convertible<_Sseq, _Res>>
@@ -263,8 +266,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
"template argument substituting __m out of bounds");
template<typename _Sseq>
- using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
- _Sseq, linear_congruential_engine, _UIntType>::value>::type;
+ using _If_seed_seq
+ = __detail::_If_seed_seq_for<_Sseq, linear_congruential_engine,
+ _UIntType>;
public:
/** The type of the generated random value. */
@@ -502,8 +506,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
"template argument substituting __f out of bound");
template<typename _Sseq>
- using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
- _Sseq, mersenne_twister_engine, _UIntType>::value>::type;
+ using _If_seed_seq
+ = __detail::_If_seed_seq_for<_Sseq, mersenne_twister_engine,
+ _UIntType>;
public:
/** The type of the generated random value. */
@@ -702,8 +707,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
"template argument substituting __w out of bounds");
template<typename _Sseq>
- using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
- _Sseq, subtract_with_carry_engine, _UIntType>::value>::type;
+ using _If_seed_seq
+ = __detail::_If_seed_seq_for<_Sseq, subtract_with_carry_engine,
+ _UIntType>;
public:
/** The type of the generated random value. */
@@ -894,8 +900,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef typename _RandomNumberEngine::result_type result_type;
template<typename _Sseq>
- using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
- _Sseq, discard_block_engine, result_type>::value>::type;
+ using _If_seed_seq
+ = __detail::_If_seed_seq_for<_Sseq, discard_block_engine,
+ result_type>;
// parameter values
static constexpr size_t block_size = __p;
@@ -1113,8 +1120,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
"template argument substituting __w out of bounds");
template<typename _Sseq>
- using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
- _Sseq, independent_bits_engine, _UIntType>::value>::type;
+ using _If_seed_seq
+ = __detail::_If_seed_seq_for<_Sseq, independent_bits_engine,
+ _UIntType>;
public:
/** The type of the generated random value. */
@@ -1336,8 +1344,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
typedef typename _RandomNumberEngine::result_type result_type;
template<typename _Sseq>
- using _If_seed_seq = typename enable_if<__detail::__is_seed_seq<
- _Sseq, shuffle_order_engine, result_type>::value>::type;
+ using _If_seed_seq
+ = __detail::_If_seed_seq_for<_Sseq, shuffle_order_engine,
+ result_type>;
static constexpr size_t table_size = __k;
diff --git a/libstdc++-v3/include/ext/random b/libstdc++-v3/include/ext/random
index 4cc0e25e025..406b12b5d23 100644
--- a/libstdc++-v3/include/ext/random
+++ b/libstdc++-v3/include/ext/random
@@ -89,9 +89,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Sseq>
using _If_seed_seq
- = typename std::enable_if<std::__detail::__is_seed_seq<
- _Sseq, simd_fast_mersenne_twister_engine, result_type>::value
- >::type;
+ = std::__detail::_If_seed_seq_for<_Sseq,
+ simd_fast_mersenne_twister_engine,
+ result_type>;
public:
static constexpr size_t state_size = _M_nstate * (16
--
2.37.3
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