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ARROW-2578: [Plasma] Use mersenne twister to generate random number #2039

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pcmoritz wants to merge 8 commits into from
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ARROW-2578: [Plasma] Use mersenne twister to generate random number #2039

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cd95cf1
use mersenne twister to generate random number
pcmoritz May 14, 2018
841a67f
fix linting
pcmoritz May 14, 2018
62d412f
fix on older versions of macOS
pcmoritz May 14, 2018
f60bd99
more valgrind fixes
pcmoritz May 14, 2018
83740b5
update
pcmoritz May 14, 2018
beb5bab
update
pcmoritz May 14, 2018
be4bb84
fix
pcmoritz May 14, 2018
21d0e3f
fixes
pcmoritz May 14, 2018
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12 changes: 10 additions & 2 deletions cpp/src/plasma/common.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,8 @@

#include "plasma/common.h"

#include <limits>
#include <mutex>
#include <random>

#include "plasma/plasma_generated.h"
Expand All @@ -28,9 +30,15 @@ using arrow::Status;
UniqueID UniqueID::from_random() {
UniqueID id;
uint8_t* data = id.mutable_data();
std::random_device engine;
// NOTE(pcm): The right way to do this is to have one std::mt19937 per
// thread (using the thread_local keyword), but that's not supported on
// older versions of macOS (see https://stackoverflow.com/a/29929949)
static std::mutex mutex;
std::lock_guard<std::mutex> lock(mutex);
static std::mt19937 generator;
std::uniform_int_distribution<uint32_t> dist(0, std::numeric_limits<uint8_t>::max());
for (int i = 0; i < kUniqueIDSize; i++) {
data[i] = static_cast<uint8_t>(engine());
data[i] = static_cast<uint8_t>(dist(generator));
}
return id;
}
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4 changes: 2 additions & 2 deletions cpp/src/plasma/test/client_tests.cc
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Expand Up @@ -51,8 +51,8 @@ class TestPlasmaStore : public ::testing::Test {
// TODO(pcm): At the moment, stdout of the test gets mixed up with
// stdout of the object store. Consider changing that.
void SetUp() {
std::mt19937 rng;
rng.seed(std::random_device()());
uint64_t seed = std::chrono::high_resolution_clock::now().time_since_epoch().count();
std::mt19937 rng(static_cast<uint32_t>(seed));
std::string store_index = std::to_string(rng());
store_socket_name_ = "/tmp/store" + store_index;

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