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Make FastRandomContext support standard C++11 RNG interface

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This makes it possible to plug it into the various standard C++11 random
distribution algorithms and other functions like std::shuffle.
This commit is contained in:
Pieter Wuille 2018-03-20 19:10:39 -07:00
parent 4ba3d4f439
commit 1ec1602a45
2 changed files with 29 additions and 0 deletions
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7
src/random.h
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@ -11,6 +11,7 @@
#include <uint256.h> #include <uint256.h>
#include <stdint.h> #include <stdint.h>
#include <limits>
/* Seed OpenSSL PRNG with additional entropy data */ /* Seed OpenSSL PRNG with additional entropy data */
void RandAddSeed(); void RandAddSeed();
@ -121,6 +122,12 @@ public:
/** Generate a random boolean. */ /** Generate a random boolean. */
bool randbool() { return randbits(1); } bool randbool() { return randbits(1); }
// Compatibility with the C++11 UniformRandomBitGenerator concept
typedef uint64_t result_type;
static constexpr uint64_t min() { return 0; }
static constexpr uint64_t max() { return std::numeric_limits<uint64_t>::max(); }
inline uint64_t operator()() { return rand64(); }
}; };
/* Number of random bytes returned by GetOSRand. /* Number of random bytes returned by GetOSRand.

22
src/test/random_tests.cpp
View file

@ -8,6 +8,9 @@
#include <boost/test/unit_test.hpp> #include <boost/test/unit_test.hpp>
#include <random>
#include <algorithm>
BOOST_FIXTURE_TEST_SUITE(random_tests, BasicTestingSetup) BOOST_FIXTURE_TEST_SUITE(random_tests, BasicTestingSetup)
BOOST_AUTO_TEST_CASE(osrandom_tests) BOOST_AUTO_TEST_CASE(osrandom_tests)
@ -57,4 +60,23 @@ BOOST_AUTO_TEST_CASE(fastrandom_randbits)
} }
} }
/** Does-it-compile test for compatibility with standard C++11 RNG interface. */
BOOST_AUTO_TEST_CASE(stdrandom_test)
{
FastRandomContext ctx;
std::uniform_int_distribution<int> distribution(3, 9);
for (int i = 0; i < 100; ++i) {
int x = distribution(ctx);
BOOST_CHECK(x >= 3);
BOOST_CHECK(x <= 9);
std::vector<int> test{1,2,3,4,5,6,7,8,9,10};
std::shuffle(test.begin(), test.end(), ctx);
for (int j = 1; j <= 10; ++j) {
BOOST_CHECK(std::find(test.begin(), test.end(), j) != test.end());
}
}
}
BOOST_AUTO_TEST_SUITE_END() BOOST_AUTO_TEST_SUITE_END()