From 43493b56df7c8f7aab02256ab7f65135d4dd1d4c Mon Sep 17 00:00:00 2001
From: Nicole Mazzuca <t-nimaz@microsoft.com>
Date: Wed, 10 Jul 2019 15:18:44 -0700
Subject: delete the random number generator

---
 toolsrc/include/vcpkg/base/rng.h | 199 ---------------------------------------
 1 file changed, 199 deletions(-)
 delete mode 100644 toolsrc/include/vcpkg/base/rng.h

(limited to 'toolsrc/include')

diff --git a/toolsrc/include/vcpkg/base/rng.h b/toolsrc/include/vcpkg/base/rng.h
deleted file mode 100644
index 4a0411f64..000000000
--- a/toolsrc/include/vcpkg/base/rng.h
+++ /dev/null
@@ -1,199 +0,0 @@
-#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>;
-}
-- 
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