From b005000525ab0a5116d21217c41fb1da5bd03796 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 6 May 2022 21:19:17 +0100 Subject: [PATCH] libstdc++: Fix deserialization for std::normal_distribution [PR105502] This fixes a regression in std::normal_distribution deserialization that caused the object to be left unchanged if the __state_avail value read from the stream was false. libstdc++-v3/ChangeLog: PR libstdc++/105502 * include/bits/random.tcc (operator>>(basic_istream&, normal_distribution&)): Update state when __state_avail is false. * testsuite/26_numerics/random/normal_distribution/operators/serialize.cc: Check that deserialized object equals serialized one. (cherry picked from commit 909ef4e2727ddc50a32d6ad379a1f1ccc1043c6a) --- libstdc++-v3/include/bits/random.tcc | 2 +- .../operators/serialize.cc | 36 ++++++++++++++++++- 2 files changed, 36 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/bits/random.tcc b/libstdc++-v3/include/bits/random.tcc index 0a299baedc5..0f758671f69 100644 --- a/libstdc++-v3/include/bits/random.tcc +++ b/libstdc++-v3/include/bits/random.tcc @@ -1941,7 +1941,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION bool __saved_avail; if (__is >> __mean >> __stddev >> __saved_avail) { - if (__saved_avail && (__is >> __x._M_saved)) + if (!__saved_avail || (__is >> __x._M_saved)) { __x._M_saved_available = __saved_avail; __x.param(typename normal_distribution<_RealType>:: diff --git a/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/serialize.cc b/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/serialize.cc index a65d4004161..8cc70886bc7 100644 --- a/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/serialize.cc +++ b/libstdc++-v3/testsuite/26_numerics/random/normal_distribution/operators/serialize.cc @@ -25,6 +25,7 @@ #include #include +#include void test01() @@ -37,10 +38,43 @@ test01() str << u; str >> v; + VERIFY( u == v ); +} + +void +test_pr105502() +{ + // PR libstdc++/105502 std::normal_distribution deserialization issue + std::stringstream str; + std::normal_distribution<> d{1, 2}, d2; + std::minstd_rand0 g; + str << d; + VERIFY( str ); + str >> d2; + VERIFY( str ); + VERIFY( d == d2 ); + + (void) d(g); // sets d._M_saved_available = true + str.str(""); + str.clear(); + str << d; + VERIFY( str ); + str >> d2; + VERIFY( str ); + VERIFY( d == d2 ); + + (void) d(g); // sets d._M_saved_available = false + str.str(""); + str.clear(); + str << d; + VERIFY( str ); + str >> d2; + VERIFY( str ); + VERIFY( d == d2 ); } int main() { test01(); - return 0; + test_pr105502(); } -- 2.31.1