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authorVincent Ambo <mail@tazj.in>2022-02-07T23·05+0300
committerclbot <clbot@tvl.fyi>2022-02-07T23·09+0000
commit5aa5d282eac56a21e74611c1cdbaa97bb5db2dca (patch)
tree8cc5dce8157a1470ff76719dd15d65f648a05522 /third_party/abseil_cpp/absl/random/internal/pcg_engine.h
parenta25675804c4f429fab5ee5201fe25e89865dfd13 (diff)
chore(3p/abseil_cpp): unvendor abseil_cpp r/3786
we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>
Diffstat (limited to 'third_party/abseil_cpp/absl/random/internal/pcg_engine.h')
-rw-r--r--third_party/abseil_cpp/absl/random/internal/pcg_engine.h307
1 files changed, 0 insertions, 307 deletions
diff --git a/third_party/abseil_cpp/absl/random/internal/pcg_engine.h b/third_party/abseil_cpp/absl/random/internal/pcg_engine.h
deleted file mode 100644
index 53c23fe1b492..000000000000
--- a/third_party/abseil_cpp/absl/random/internal/pcg_engine.h
+++ /dev/null
@@ -1,307 +0,0 @@
-// Copyright 2018 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef ABSL_RANDOM_INTERNAL_PCG_ENGINE_H_
-#define ABSL_RANDOM_INTERNAL_PCG_ENGINE_H_
-
-#include <type_traits>
-
-#include "absl/base/config.h"
-#include "absl/meta/type_traits.h"
-#include "absl/numeric/int128.h"
-#include "absl/random/internal/fastmath.h"
-#include "absl/random/internal/iostream_state_saver.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace random_internal {
-
-// pcg_engine is a simplified implementation of Melissa O'Neil's PCG engine in
-// C++.  PCG combines a linear congruential generator (LCG) with output state
-// mixing functions to generate each random variate.  pcg_engine supports only a
-// single sequence (oneseq), and does not support streams.
-//
-// pcg_engine is parameterized by two types:
-//   Params, which provides the multiplier and increment values;
-//   Mix, which mixes the state into the result.
-//
-template <typename Params, typename Mix>
-class pcg_engine {
-  static_assert(std::is_same<typename Params::state_type,
-                             typename Mix::state_type>::value,
-                "Class-template absl::pcg_engine must be parameterized by "
-                "Params and Mix with identical state_type");
-
-  static_assert(std::is_unsigned<typename Mix::result_type>::value,
-                "Class-template absl::pcg_engine must be parameterized by "
-                "an unsigned Mix::result_type");
-
-  using params_type = Params;
-  using mix_type = Mix;
-  using state_type = typename Mix::state_type;
-
- public:
-  // C++11 URBG interface:
-  using result_type = typename Mix::result_type;
-
-  static constexpr result_type(min)() {
-    return (std::numeric_limits<result_type>::min)();
-  }
-
-  static constexpr result_type(max)() {
-    return (std::numeric_limits<result_type>::max)();
-  }
-
-  explicit pcg_engine(uint64_t seed_value = 0) { seed(seed_value); }
-
-  template <class SeedSequence,
-            typename = typename absl::enable_if_t<
-                !std::is_same<SeedSequence, pcg_engine>::value>>
-  explicit pcg_engine(SeedSequence&& seq) {
-    seed(seq);
-  }
-
-  pcg_engine(const pcg_engine&) = default;
-  pcg_engine& operator=(const pcg_engine&) = default;
-  pcg_engine(pcg_engine&&) = default;
-  pcg_engine& operator=(pcg_engine&&) = default;
-
-  result_type operator()() {
-    // Advance the LCG state, always using the new value to generate the output.
-    state_ = lcg(state_);
-    return Mix{}(state_);
-  }
-
-  void seed(uint64_t seed_value = 0) {
-    state_type tmp = seed_value;
-    state_ = lcg(tmp + Params::increment());
-  }
-
-  template <class SeedSequence>
-  typename absl::enable_if_t<
-      !std::is_convertible<SeedSequence, uint64_t>::value, void>
-  seed(SeedSequence&& seq) {
-    reseed(seq);
-  }
-
-  void discard(uint64_t count) { state_ = advance(state_, count); }
-
-  bool operator==(const pcg_engine& other) const {
-    return state_ == other.state_;
-  }
-
-  bool operator!=(const pcg_engine& other) const { return !(*this == other); }
-
-  template <class CharT, class Traits>
-  friend typename absl::enable_if_t<(sizeof(state_type) == 16),
-                                    std::basic_ostream<CharT, Traits>&>
-  operator<<(
-      std::basic_ostream<CharT, Traits>& os,  // NOLINT(runtime/references)
-      const pcg_engine& engine) {
-    auto saver = random_internal::make_ostream_state_saver(os);
-    random_internal::stream_u128_helper<state_type> helper;
-    helper.write(pcg_engine::params_type::multiplier(), os);
-    os << os.fill();
-    helper.write(pcg_engine::params_type::increment(), os);
-    os << os.fill();
-    helper.write(engine.state_, os);
-    return os;
-  }
-
-  template <class CharT, class Traits>
-  friend typename absl::enable_if_t<(sizeof(state_type) <= 8),
-                                    std::basic_ostream<CharT, Traits>&>
-  operator<<(
-      std::basic_ostream<CharT, Traits>& os,  // NOLINT(runtime/references)
-      const pcg_engine& engine) {
-    auto saver = random_internal::make_ostream_state_saver(os);
-    os << pcg_engine::params_type::multiplier() << os.fill();
-    os << pcg_engine::params_type::increment() << os.fill();
-    os << engine.state_;
-    return os;
-  }
-
-  template <class CharT, class Traits>
-  friend typename absl::enable_if_t<(sizeof(state_type) == 16),
-                                    std::basic_istream<CharT, Traits>&>
-  operator>>(
-      std::basic_istream<CharT, Traits>& is,  // NOLINT(runtime/references)
-      pcg_engine& engine) {                   // NOLINT(runtime/references)
-    random_internal::stream_u128_helper<state_type> helper;
-    auto mult = helper.read(is);
-    auto inc = helper.read(is);
-    auto tmp = helper.read(is);
-    if (mult != pcg_engine::params_type::multiplier() ||
-        inc != pcg_engine::params_type::increment()) {
-      // signal failure by setting the failbit.
-      is.setstate(is.rdstate() | std::ios_base::failbit);
-    }
-    if (!is.fail()) {
-      engine.state_ = tmp;
-    }
-    return is;
-  }
-
-  template <class CharT, class Traits>
-  friend typename absl::enable_if_t<(sizeof(state_type) <= 8),
-                                    std::basic_istream<CharT, Traits>&>
-  operator>>(
-      std::basic_istream<CharT, Traits>& is,  // NOLINT(runtime/references)
-      pcg_engine& engine) {                   // NOLINT(runtime/references)
-    state_type mult{}, inc{}, tmp{};
-    is >> mult >> inc >> tmp;
-    if (mult != pcg_engine::params_type::multiplier() ||
-        inc != pcg_engine::params_type::increment()) {
-      // signal failure by setting the failbit.
-      is.setstate(is.rdstate() | std::ios_base::failbit);
-    }
-    if (!is.fail()) {
-      engine.state_ = tmp;
-    }
-    return is;
-  }
-
- private:
-  state_type state_;
-
-  // Returns the linear-congruential generator next state.
-  static inline constexpr state_type lcg(state_type s) {
-    return s * Params::multiplier() + Params::increment();
-  }
-
-  // Returns the linear-congruential arbitrary seek state.
-  inline state_type advance(state_type s, uint64_t n) const {
-    state_type mult = Params::multiplier();
-    state_type inc = Params::increment();
-    state_type m = 1;
-    state_type i = 0;
-    while (n > 0) {
-      if (n & 1) {
-        m *= mult;
-        i = i * mult + inc;
-      }
-      inc = (mult + 1) * inc;
-      mult *= mult;
-      n >>= 1;
-    }
-    return m * s + i;
-  }
-
-  template <class SeedSequence>
-  void reseed(SeedSequence& seq) {
-    using sequence_result_type = typename SeedSequence::result_type;
-    constexpr size_t kBufferSize =
-        sizeof(state_type) / sizeof(sequence_result_type);
-    sequence_result_type buffer[kBufferSize];
-    seq.generate(std::begin(buffer), std::end(buffer));
-    // Convert the seed output to a single state value.
-    state_type tmp = buffer[0];
-    for (size_t i = 1; i < kBufferSize; i++) {
-      tmp <<= (sizeof(sequence_result_type) * 8);
-      tmp |= buffer[i];
-    }
-    state_ = lcg(tmp + params_type::increment());
-  }
-};
-
-// Parameterized implementation of the PCG 128-bit oneseq state.
-// This provides state_type, multiplier, and increment for pcg_engine.
-template <uint64_t kMultA, uint64_t kMultB, uint64_t kIncA, uint64_t kIncB>
-class pcg128_params {
- public:
-#if ABSL_HAVE_INTRINSIC_INT128
-  using state_type = __uint128_t;
-  static inline constexpr state_type make_u128(uint64_t a, uint64_t b) {
-    return (static_cast<__uint128_t>(a) << 64) | b;
-  }
-#else
-  using state_type = absl::uint128;
-  static inline constexpr state_type make_u128(uint64_t a, uint64_t b) {
-    return absl::MakeUint128(a, b);
-  }
-#endif
-
-  static inline constexpr state_type multiplier() {
-    return make_u128(kMultA, kMultB);
-  }
-  static inline constexpr state_type increment() {
-    return make_u128(kIncA, kIncB);
-  }
-};
-
-// Implementation of the PCG xsl_rr_128_64 128-bit mixing function, which
-// accepts an input of state_type and mixes it into an output of result_type.
-struct pcg_xsl_rr_128_64 {
-#if ABSL_HAVE_INTRINSIC_INT128
-  using state_type = __uint128_t;
-#else
-  using state_type = absl::uint128;
-#endif
-  using result_type = uint64_t;
-
-  inline uint64_t operator()(state_type state) {
-    // This is equivalent to the xsl_rr_128_64 mixing function.
-#if ABSL_HAVE_INTRINSIC_INT128
-    uint64_t rotate = static_cast<uint64_t>(state >> 122u);
-    state ^= state >> 64;
-    uint64_t s = static_cast<uint64_t>(state);
-#else
-    uint64_t h = Uint128High64(state);
-    uint64_t rotate = h >> 58u;
-    uint64_t s = Uint128Low64(state) ^ h;
-#endif
-    return random_internal::rotr(s, rotate);
-  }
-};
-
-// Parameterized implementation of the PCG 64-bit oneseq state.
-// This provides state_type, multiplier, and increment for pcg_engine.
-template <uint64_t kMult, uint64_t kInc>
-class pcg64_params {
- public:
-  using state_type = uint64_t;
-  static inline constexpr state_type multiplier() { return kMult; }
-  static inline constexpr state_type increment() { return kInc; }
-};
-
-// Implementation of the PCG xsh_rr_64_32 64-bit mixing function, which accepts
-// an input of state_type and mixes it into an output of result_type.
-struct pcg_xsh_rr_64_32 {
-  using state_type = uint64_t;
-  using result_type = uint32_t;
-  inline uint32_t operator()(uint64_t state) {
-    return random_internal::rotr(
-        static_cast<uint32_t>(((state >> 18) ^ state) >> 27), state >> 59);
-  }
-};
-
-// Stable pcg_engine implementations:
-// This is a 64-bit generator using 128-bits of state.
-// The output sequence is equivalent to Melissa O'Neil's pcg64_oneseq.
-using pcg64_2018_engine = pcg_engine<
-    random_internal::pcg128_params<0x2360ed051fc65da4ull, 0x4385df649fccf645ull,
-                                   0x5851f42d4c957f2d, 0x14057b7ef767814f>,
-    random_internal::pcg_xsl_rr_128_64>;
-
-// This is a 32-bit generator using 64-bits of state.
-// This is equivalent to Melissa O'Neil's pcg32_oneseq.
-using pcg32_2018_engine = pcg_engine<
-    random_internal::pcg64_params<0x5851f42d4c957f2dull, 0x14057b7ef767814full>,
-    random_internal::pcg_xsh_rr_64_32>;
-
-}  // namespace random_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_RANDOM_INTERNAL_PCG_ENGINE_H_