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The following commit(s) were added to refs/heads/main by this push:
new a58e66c PROTON-2396: Use random_device for seed initialization in
uuid.cpp
a58e66c is described below
commit a58e66ce3e42937a1b22e0c741834bc6eb0a9797
Author: Rakhi Kumari <[email protected]>
AuthorDate: Wed Nov 3 18:46:04 2021 +0530
PROTON-2396: Use random_device for seed initialization in uuid.cpp
Closes #340
---
cpp/src/uuid.cpp | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/cpp/src/uuid.cpp b/cpp/src/uuid.cpp
index ec3880c..150d6c8 100644
--- a/cpp/src/uuid.cpp
+++ b/cpp/src/uuid.cpp
@@ -22,10 +22,15 @@
#include "proton/uuid.hpp"
#include "proton/types_fwd.hpp"
+#include <algorithm>
+#include <chrono>
+#include <climits>
#include <cstdlib>
#include <ctime>
-#include <sstream>
+#include <functional>
#include <iomanip>
+#include <random>
+#include <sstream>
#if defined(_WIN32)
#include <process.h>
@@ -39,19 +44,19 @@ namespace proton {
namespace {
+thread_local std::independent_bits_engine<std::mt19937, CHAR_BIT, unsigned
int> engine = [] {
+ // A hash of time, PID and random_device to produce an unsigned integer
+ // for seeding the engine.
+ std::seed_seq seq{
+ (unsigned
long)std::chrono::system_clock::now().time_since_epoch().count(),
+ (unsigned long)GETPID(),
+ (unsigned long)std::random_device{}()};
-// Seed the random number generated once at startup.
-struct seed {
- seed() {
- // A hash of time and PID, time alone is a bad seed as programs started
- // within the same second will get the same seed.
- unsigned long secs = time(0);
- unsigned long pid = GETPID();
- std::srand(((secs*181)*((pid-83)*359))%104729);
- }
-} seed_;
+ return
+ std::independent_bits_engine<std::mt19937, CHAR_BIT, unsigned int>(seq);
+}();
-}
+} // namespace
uuid uuid::copy() {
uuid u;
@@ -70,12 +75,7 @@ uuid uuid::copy(const char* bytes) {
uuid uuid::random() {
uuid bytes;
- int r = std::rand();
- for (size_t i = 0; i < bytes.size(); ++i ) {
- bytes[i] = r & 0xFF;
- r >>= 8;
- if (!r) r = std::rand();
- }
+ std::generate(bytes.begin(), bytes.end(), std::ref(engine));
// From RFC4122, the version bits are set to 0100
bytes[6] = (bytes[6] & 0x0F) | 0x40;
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