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Fix a couple of bugs in linear_congruential_engine::seed. Regression test added.

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@182421 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Howard Hinnant 2013-05-21 21:05:12 +00:00
parent a71a952634
commit 8f72d5ce16
2 changed files with 11 additions and 3 deletions
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6
include/random
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@ -1835,7 +1835,7 @@ public:
// types // types
typedef _UIntType result_type; typedef _UIntType result_type;
private: //private:
result_type __x_; result_type __x_;
static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0); static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
@ -1880,7 +1880,7 @@ public:
seed(_Sseq& __q) seed(_Sseq& __q)
{__seed(__q, integral_constant<unsigned, {__seed(__q, integral_constant<unsigned,
1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32 1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
: (__m-1) / 0x100000000ull)>());} : (__m > 0x100000000ull))>());}
// generating functions // generating functions
_LIBCPP_INLINE_VISIBILITY _LIBCPP_INLINE_VISIBILITY
@ -1969,7 +1969,7 @@ linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
uint32_t __ar[__k+3]; uint32_t __ar[__k+3];
__q.generate(__ar, __ar + __k + 3); __q.generate(__ar, __ar + __k + 3);
result_type __s = static_cast<result_type>((__ar[3] + result_type __s = static_cast<result_type>((__ar[3] +
(uint64_t)__ar[4] << 32) % __m); ((uint64_t)__ar[4] << 32)) % __m);
__x_ = __c == 0 && __s == 0 ? result_type(1) : __s; __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
} }

8
test/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
View File

@ -28,4 +28,12 @@ int main()
e1.seed(sseq); e1.seed(sseq);
assert(e1 == e2); assert(e1 == e2);
} }
{
unsigned a[] = {3, 5, 7, 9, 11};
std::seed_seq sseq(a, a+5);
typedef std::linear_congruential_engine<unsigned long long, 1, 1, 0x200000001ULL> E;
E e1(4309005589);
E e2(sseq);
assert(e1 == e2);
}
} }