delete the random number generator
DELETE
include/vcpkg/base/rng.h
-#pragma once
-
-#include <cstdint>
-#include <limits>
-#include <random>
-
-namespace vcpkg::Rng {
-
- namespace detail {
- template <class T>
- constexpr std::size_t bitsize = sizeof(T) * CHAR_BITS;
-
- template <class T>
- constexpr bool is_valid_shift(int k) {
- return 0 <= k && k <= bitsize<T>;
- }
-
- // precondition: 0 <= k < bitsize<T>
- template <class T>
- constexpr T ror(T x, int k) {
- if (k == 0) {
- return x;
- }
- return (x >> k) | (x << (bitsize<T> - k));
- }
-
- // precondition: 0 <= k < bitsize<T>
- template <class T>
- constexpr T rol(T x, int k) {
- if (k == 0) {
- return x;
- }
- return (x << k) | (x >> (bitsize<T> - k));
- }
-
- // there _is_ a way to do this generally, but I don't know how to
- template <class UIntType, int e>
- struct XoshiroJumpTable;
-
- template <>
- struct XoshiroJumpTable<std::uint64_t, 128> {
- constexpr static std::uint64_t value[4] = {
- 0x180ec6d33cfd0aba, 0xd5a61266f0c9392c, 0xa9582618e03fc9aa, 0x39abdc4529b1661c
- };
- };
- }
-
- /*
- NOTE(ubsan): taken from the xoshiro paper
- initialized from random_device by default
- actual code is copied from wikipedia, since I wrote that code
- */
- struct splitmix {
- splitmix() noexcept;
-
- constexpr splitmix(std::uint64_t seed) noexcept
- : state(seed) {}
-
- constexpr std::uint64_t operator()() noexcept {
- state += 0x9E3779B97F4A7C15;
-
- std::uint64_t result = state;
- result = (result ^ (result >> 30)) * 0xBF58476D1CE4E5B9;
- result = (result ^ (result >> 27)) * 0x94D049BB133111EB;
-
- return result ^ (result >> 31);
- }
-
- constexpr std::uint64_t max() const noexcept {
- return std::numeric_limits<std::uint64_t>::max();
- }
-
- constexpr std::uint64_t min() const noexcept {
- return std::numeric_limits<std::uint64_t>::min();
- }
-
- template <class T>
- constexpr void fill(T* first, T* last) {
- constexpr auto mask =
- static_cast<std::uint64_t>(std::numeric_limits<T>::max());
-
- const auto remaining =
- (last - first) % (sizeof(std::uint64_t) / sizeof(T));
-
- for (auto it = first; it != last - remaining;) {
- const auto item = (*this)();
- for (
- int shift = 0;
- shift < 64;
- shift += detail::bitsize<T>, ++it
- ) {
- *it = static_cast<T>((item >> shift) & mask);
- }
- }
-
- if (remaining == 0) return;
-
- int shift = 0;
- const auto item = (*this)();
- for (auto it = last - remaining;
- it != last;
- shift += detail::bitsize<T>, ++it
- ) {
- *it = static_cast<T>((item >> shift) & mask);
- }
- }
-
- private:
- std::uint64_t state;
- };
-
- template <class UIntType, int S, int R, int T>
- struct starstar_scrambler {
- constexpr static UIntType scramble(UIntType n) noexcept {
- return detail::rol(n * S, R) * T;
- }
- };
-
- // Sebastian Vigna's xorshift-based xoshiro engine
- // fast and really good
- // uses the splitmix to initialize state
- template <class UIntType, class Scrambler, int A, int B>
- struct xoshiro_engine {
- static_assert(detail::is_valid_shift<UIntType>(A));
- static_assert(detail::is_valid_shift<UIntType>(B));
- static_assert(std::is_unsigned_v<UIntType>);
-
- // splitmix will be initialized with random_device
- xoshiro_engine() noexcept {
- splitmix sm{};
-
- sm.fill(&state[0], &state[4]);
- }
-
- constexpr xoshiro_engine(std::uint64_t seed) noexcept : state() {
- splitmix sm{seed};
-
- sm.fill(&state[0], &state[4]);
- }
-
- constexpr UIntType operator()() noexcept {
- const UIntType result = Scrambler::scramble(state[0]);
-
- const UIntType t = state[1] << A;
-
- state[2] ^= state[0];
- state[3] ^= state[1];
- state[1] ^= state[2];
- state[0] ^= state[3];
-
- state[2] ^= t;
- state[3] ^= detail::rol(state[3], B);
-
- return result;
- }
-
- constexpr UIntType max() const noexcept {
- return std::numeric_limits<UIntType>::max();
- }
-
- constexpr std::uint64_t min() const noexcept {
- return std::numeric_limits<UIntType>::min();
- }
-
- // quickly jump ahead 2^e steps
- // takes 4 * bitsize<UIntType> rng next operations
- template <int e>
- constexpr void discard_e() noexcept {
- using JT = detail::XoshiroJumpTable<UIntType, e>;
-
- UIntType s[4] = {};
- for (const auto& jump : JT::value) {
- for (std::size_t i = 0; i < bitsize<UIntType>; ++i) {
- if ((jump >> i) & 1) {
- s[0] ^= state[0];
- s[1] ^= state[1];
- s[2] ^= state[2];
- s[3] ^= state[3];
- }
- (*this)();
- }
- }
-
- state[0] = s[0];
- state[1] = s[1];
- state[2] = s[2];
- state[3] = s[3];
- }
- private:
- // rotate left
- UIntType state[4];
- };
-
- using xoshiro256ss = xoshiro_engine<
- std::uint64_t,
- starstar_scrambler<std::uint64_t, 5, 7, 9>,
- 17,
- 45>;
-}

DELETE
src/vcpkg/base/rng.cpp
-#include <base/rng.h>
-
-namespace vcpkg::Rng {
- namespace {
- std::random_device system_entropy{};
- }
-
- splitmix::splitmix() {
- std::uint64_t top_half = system_entropy();
- std::uint64_t bottom_half = system_entropy();
-
- state = (top_half << 32) | bottom_half;
- }
-}

delete the random number generator