From bc524d70253a4ab2fe40c3ca3e5666e267c0a4d1 Mon Sep 17 00:00:00 2001
From: Lexi Winter <lexi@le-fay.org>
Date: Sun, 29 Jun 2025 19:25:29 +0100
Subject: import catch2 3.8.1

---
 .../internal/catch_random_number_generator.cpp     | 70 ++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/catch2/internal/catch_random_number_generator.cpp

(limited to 'src/catch2/internal/catch_random_number_generator.cpp')

diff --git a/src/catch2/internal/catch_random_number_generator.cpp b/src/catch2/internal/catch_random_number_generator.cpp
new file mode 100644
index 0000000..c88cd8f
--- /dev/null
+++ b/src/catch2/internal/catch_random_number_generator.cpp
@@ -0,0 +1,70 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#include <catch2/internal/catch_random_number_generator.hpp>
+
+namespace Catch {
+
+namespace {
+
+#if defined(_MSC_VER)
+#pragma warning(push)
+#pragma warning(disable:4146) // we negate uint32 during the rotate
+#endif
+        // Safe rotr implementation thanks to John Regehr
+        uint32_t rotate_right(uint32_t val, uint32_t count) {
+            const uint32_t mask = 31;
+            count &= mask;
+            return (val >> count) | (val << (-count & mask));
+        }
+
+#if defined(_MSC_VER)
+#pragma warning(pop)
+#endif
+
+}
+
+
+    SimplePcg32::SimplePcg32(result_type seed_) {
+        seed(seed_);
+    }
+
+
+    void SimplePcg32::seed(result_type seed_) {
+        m_state = 0;
+        (*this)();
+        m_state += seed_;
+        (*this)();
+    }
+
+    void SimplePcg32::discard(uint64_t skip) {
+        // We could implement this to run in O(log n) steps, but this
+        // should suffice for our use case.
+        for (uint64_t s = 0; s < skip; ++s) {
+            static_cast<void>((*this)());
+        }
+    }
+
+    SimplePcg32::result_type SimplePcg32::operator()() {
+        // prepare the output value
+        const uint32_t xorshifted = static_cast<uint32_t>(((m_state >> 18u) ^ m_state) >> 27u);
+        const auto output = rotate_right(xorshifted, static_cast<uint32_t>(m_state >> 59u));
+
+        // advance state
+        m_state = m_state * 6364136223846793005ULL + s_inc;
+
+        return output;
+    }
+
+    bool operator==(SimplePcg32 const& lhs, SimplePcg32 const& rhs) {
+        return lhs.m_state == rhs.m_state;
+    }
+
+    bool operator!=(SimplePcg32 const& lhs, SimplePcg32 const& rhs) {
+        return lhs.m_state != rhs.m_state;
+    }
+}
-- 
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