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- /*
- * Created by Martin on 30/08/2017.
- *
- * Distributed under the Boost Software License, Version 1.0. (See accompanying
- * file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- */
- #include "catch_random_number_generator.h"
- #include "catch_context.h"
- #include "catch_run_context.h"
- #include "catch_interfaces_config.h"
- 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, 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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