From 44efe96dfca674a17b45ca53fc77fb69f1e29bf4 Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Tue, 9 Jul 2019 07:37:37 -0700 Subject: Export of internal Abseil changes. -- 9c4ef32276054fba6a116c01cd4b3fd278f59ece by Andy Soffer : Remove support for unused arbitrary-width output in FastUniformBits. Width should be inferred from the requested return UIntType. PiperOrigin-RevId: 257189319 -- e3326329d02171a301cc3d6ae617ed448472b728 by Abseil Team : Update comments to make clear that absl::Format(std::string *, ...) appends to the provided string. PiperOrigin-RevId: 257058043 -- e2096b06d714fba3ea2c885d670a42efd872765c by Xiaoyi Zhang : Fix compilation error on MSVC 2017. The root cause seems to be a compiler bug in VS 2017 about pack expansion with multiple parameter packs, specifically `MakeVisitationMatrixImpl::Run` is triggering compiler error "error C3528: 'BoundIndices': the number of elements in this pack expansion does not match the number of elements in 'EndIndices'". Work around this issue by using only one parameter pack `CurrIndices` in `MakeVisitationMatrixImpl::Run`. PiperOrigin-RevId: 257040381 -- 9ab75ff27b2513583fffc1233e6568aa96be36f7 by Matt Calabrese : Internal change. PiperOrigin-RevId: 257039041 GitOrigin-RevId: 9c4ef32276054fba6a116c01cd4b3fd278f59ece Change-Id: I5f708bb03aff93948502394a413260af2a8a273b --- absl/random/benchmarks.cc | 4 +- absl/random/internal/fast_uniform_bits.h | 52 +++------ absl/random/internal/fast_uniform_bits_test.cc | 155 ------------------------- absl/strings/str_format.h | 2 +- absl/types/internal/variant.h | 48 +++++--- 5 files changed, 50 insertions(+), 211 deletions(-) diff --git a/absl/random/benchmarks.cc b/absl/random/benchmarks.cc index 8e6d889e..265d54d7 100644 --- a/absl/random/benchmarks.cc +++ b/absl/random/benchmarks.cc @@ -257,9 +257,9 @@ void BM_Thread(benchmark::State& state) { BENCHMARK_TEMPLATE(BM_ShuffleReuse, Engine, 100); \ BENCHMARK_TEMPLATE(BM_ShuffleReuse, Engine, 1000); \ BENCHMARK_TEMPLATE(BM_Dist, Engine, \ - absl::random_internal::FastUniformBits); \ + absl::random_internal::FastUniformBits); \ BENCHMARK_TEMPLATE(BM_Dist, Engine, \ - absl::random_internal::FastUniformBits); \ + absl::random_internal::FastUniformBits); \ BENCHMARK_TEMPLATE(BM_Dist, Engine, std::uniform_int_distribution); \ BENCHMARK_TEMPLATE(BM_Dist, Engine, std::uniform_int_distribution); \ BENCHMARK_TEMPLATE(BM_Dist, Engine, \ diff --git a/absl/random/internal/fast_uniform_bits.h b/absl/random/internal/fast_uniform_bits.h index 23eabbc8..184a2708 100644 --- a/absl/random/internal/fast_uniform_bits.h +++ b/absl/random/internal/fast_uniform_bits.h @@ -38,14 +38,12 @@ constexpr typename URBG::result_type constexpr_range() { // from a type which conforms to the [rand.req.urbg] concept. // Parameterized by: // `UIntType`: the result (output) type -// `Width`: binary output width // // The std::independent_bits_engine [rand.adapt.ibits] adaptor can be // instantiated from an existing generator through a copy or a move. It does // not, however, facilitate the production of pseudorandom bits from an un-owned // generator that will outlive the std::independent_bits_engine instance. -template ::digits> +template class FastUniformBits { static_assert(std::is_unsigned::value, "Class-template FastUniformBits<> must be parameterized using " @@ -53,29 +51,14 @@ class FastUniformBits { // `kWidth` is the width, in binary digits, of the output. By default it is // the number of binary digits in the `result_type`. - static constexpr size_t kWidth = Width; - static_assert(kWidth > 0, - "Class-template FastUniformBits<> Width argument must be > 0"); - - static_assert(kWidth <= std::numeric_limits::digits, - "Class-template FastUniformBits<> Width argument must be <= " - "width of UIntType."); - - static constexpr bool kIsMaxWidth = - (kWidth >= std::numeric_limits::digits); - - // Computes a mask of `n` bits for the `UIntType`. - static constexpr UIntType constexpr_mask(size_t n) { - return (UIntType(1) << n) - 1; - } + static constexpr size_t kWidth = std::numeric_limits::digits; public: using result_type = UIntType; static constexpr result_type(min)() { return 0; } static constexpr result_type(max)() { - return kIsMaxWidth ? (std::numeric_limits::max)() - : constexpr_mask(kWidth); + return (std::numeric_limits::max)(); } template @@ -166,7 +149,6 @@ class FastUniformBitsURBGConstants { // URBG::result_type values are combined into an output_value. // Parameterized by the FastUniformBits parameters: // `UIntType`: output type. -// `Width`: binary output width, // `URNG`: The underlying UniformRandomNumberGenerator. // // The looping constants describe the sets of loop counters and mask values @@ -177,10 +159,10 @@ class FastUniformBitsURBGConstants { // bit per variate. // // See [rand.adapt.ibits] for more details on the use of these constants. -template +template class FastUniformBitsLoopingConstants { private: - static constexpr size_t kWidth = Width; + static constexpr size_t kWidth = std::numeric_limits::digits; using urbg_result_type = typename URBG::result_type; using uint_result_type = UIntType; @@ -229,19 +211,19 @@ class FastUniformBitsLoopingConstants { "Class-template FastUniformBitsLoopingConstants::kW0 too small."); }; -template +template template -typename FastUniformBits::result_type -FastUniformBits::operator()( +typename FastUniformBits::result_type +FastUniformBits::operator()( URBG& g) { // NOLINT(runtime/references) using constants = FastUniformBitsURBGConstants; return Generate( g, std::integral_constant= (max)()>{}); } -template +template template -typename URBG::result_type FastUniformBits::Variate( +typename URBG::result_type FastUniformBits::Variate( URBG& g) { // NOLINT(runtime/references) using constants = FastUniformBitsURBGConstants; if (constants::kPowerOfTwo) { @@ -256,10 +238,10 @@ typename URBG::result_type FastUniformBits::Variate( return u; } -template +template template -typename FastUniformBits::result_type -FastUniformBits::Generate( +typename FastUniformBits::result_type +FastUniformBits::Generate( URBG& g, // NOLINT(runtime/references) std::true_type /* avoid_looping */) { // The width of the result_type is less than than the width of the random bits @@ -268,10 +250,10 @@ FastUniformBits::Generate( return Variate(g) & (max)(); } -template +template template -typename FastUniformBits::result_type -FastUniformBits::Generate( +typename FastUniformBits::result_type +FastUniformBits::Generate( URBG& g, // NOLINT(runtime/references) std::false_type /* avoid_looping */) { // The width of the result_type is wider than the number of random bits @@ -279,7 +261,7 @@ FastUniformBits::Generate( // using a shift and mask. The constants type generates the parameters used // ensure that the bits are distributed across all the invocations of the // underlying URNG. - using constants = FastUniformBitsLoopingConstants; + using constants = FastUniformBitsLoopingConstants; result_type s = 0; for (size_t n = 0; n < constants::kN0; ++n) { diff --git a/absl/random/internal/fast_uniform_bits_test.cc b/absl/random/internal/fast_uniform_bits_test.cc index f4b9cd5f..18377944 100644 --- a/absl/random/internal/fast_uniform_bits_test.cc +++ b/absl/random/internal/fast_uniform_bits_test.cc @@ -45,57 +45,6 @@ TYPED_TEST(FastUniformBitsTypedTest, BasicTest) { } } -TEST(FastUniformBitsTest, TypeBoundaries32) { - // Tests that FastUniformBits can adapt to 32-bit boundaries. - absl::random_internal::FastUniformBits a; - absl::random_internal::FastUniformBits b; - absl::random_internal::FastUniformBits c; - - { - std::mt19937 gen; // 32-bit - a(gen); - b(gen); - c(gen); - } - - { - std::mt19937_64 gen; // 64-bit - a(gen); - b(gen); - c(gen); - } -} - -TEST(FastUniformBitsTest, TypeBoundaries64) { - // Tests that FastUniformBits can adapt to 64-bit boundaries. - absl::random_internal::FastUniformBits a; - absl::random_internal::FastUniformBits b; - absl::random_internal::FastUniformBits c; - absl::random_internal::FastUniformBits d; - absl::random_internal::FastUniformBits e; - absl::random_internal::FastUniformBits f; - - { - std::mt19937 gen; // 32-bit - a(gen); - b(gen); - c(gen); - d(gen); - e(gen); - f(gen); - } - - { - std::mt19937_64 gen; // 64-bit - a(gen); - b(gen); - c(gen); - d(gen); - e(gen); - f(gen); - } -} - class UrngOddbits { public: using result_type = uint8_t; @@ -135,18 +84,6 @@ TEST(FastUniformBitsTest, FastUniformBitsDetails) { static_assert(constants::kRangeMask == 0x0f, "constants::kRangeMask == false"); } - { - using looping = FastUniformBitsLoopingConstants; - // To get 31 bits from a 4-bit generator, issue 8 calls and extract 4 bits - // per call on all except the first. - static_assert(looping::kN0 == 1, "looping::kN0"); - static_assert(looping::kW0 == 3, "looping::kW0"); - static_assert(looping::kM0 == 0x7, "looping::kM0"); - // (The second set of calls, kN1, will not do anything.) - static_assert(looping::kN1 == 8, "looping::kN1"); - static_assert(looping::kW1 == 4, "looping::kW1"); - static_assert(looping::kM1 == 0xf, "looping::kM1"); - } // ~7-bit URBG { @@ -158,31 +95,6 @@ TEST(FastUniformBitsTest, FastUniformBitsDetails) { static_assert(constants::kRangeMask == 0x7f, "constants::kRangeMask == 0x7f"); } - { - using looping = FastUniformBitsLoopingConstants; - // To get 60 bits from a 7-bit generator, issue 10 calls and extract 6 bits - // per call, discarding the excess entropy. - static_assert(looping::kN0 == 10, "looping::kN0"); - static_assert(looping::kW0 == 6, "looping::kW0"); - static_assert(looping::kM0 == 0x3f, "looping::kM0"); - // (The second set of calls, kN1, will not do anything.) - static_assert(looping::kN1 == 10, "looping::kN1"); - static_assert(looping::kW1 == 7, "looping::kW1"); - static_assert(looping::kM1 == 0x7f, "looping::kM1"); - } - { - using looping = FastUniformBitsLoopingConstants; - // To get 63 bits from a 7-bit generator, issue 10 calls--the same as we - // would issue for 60 bits--however this time we use two groups. The first - // group (kN0) will issue 7 calls, extracting 6 bits per call. - static_assert(looping::kN0 == 7, "looping::kN0"); - static_assert(looping::kW0 == 6, "looping::kW0"); - static_assert(looping::kM0 == 0x3f, "looping::kM0"); - // The second group (kN1) will issue 3 calls, extracting 7 bits per call. - static_assert(looping::kN1 == 10, "looping::kN1"); - static_assert(looping::kW1 == 7, "looping::kW1"); - static_assert(looping::kM1 == 0x7f, "looping::kM1"); - } } TEST(FastUniformBitsTest, Urng4_VariousOutputs) { @@ -192,33 +104,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) { Urng32bits urng32; // 8-bit types - { - absl::random_internal::FastUniformBits fast1; - EXPECT_EQ(0x1, fast1(urng4)); - EXPECT_EQ(0x1, fast1(urng32)); - } - { - absl::random_internal::FastUniformBits fast2; - EXPECT_EQ(0x1, fast2(urng4)); - EXPECT_EQ(0x1, fast2(urng32)); - } - - { - absl::random_internal::FastUniformBits fast4; - EXPECT_EQ(0x1, fast4(urng4)); - EXPECT_EQ(0x1, fast4(urng32)); - } - { - absl::random_internal::FastUniformBits fast6; - EXPECT_EQ(0x9, fast6(urng4)); // b001001 (2x3) - EXPECT_EQ(0x1, fast6(urng32)); - } - { - absl::random_internal::FastUniformBits fast7; - EXPECT_EQ(0x9, fast7(urng4)); // b00001001 (1x4 + 1x3) - EXPECT_EQ(0x1, fast7(urng32)); - } - { absl::random_internal::FastUniformBits fast8; EXPECT_EQ(0x11, fast8(urng4)); @@ -226,22 +111,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) { } // 16-bit types - { - absl::random_internal::FastUniformBits fast10; - EXPECT_EQ(0x91, fast10(urng4)); // b 0010010001 (2x3 + 1x4) - EXPECT_EQ(0x1, fast10(urng32)); - } - { - absl::random_internal::FastUniformBits fast11; - EXPECT_EQ(0x111, fast11(urng4)); - EXPECT_EQ(0x1, fast11(urng32)); - } - { - absl::random_internal::FastUniformBits fast12; - EXPECT_EQ(0x111, fast12(urng4)); - EXPECT_EQ(0x1, fast12(urng32)); - } - { absl::random_internal::FastUniformBits fast16; EXPECT_EQ(0x1111, fast16(urng4)); @@ -249,17 +118,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) { } // 32-bit types - { - absl::random_internal::FastUniformBits fast21; - EXPECT_EQ(0x49111, fast21(urng4)); // b 001001001 000100010001 (3x3 + 3x4) - EXPECT_EQ(0x1, fast21(urng32)); - } - { - absl::random_internal::FastUniformBits fast24; - EXPECT_EQ(0x111111, fast24(urng4)); - EXPECT_EQ(0x1, fast24(urng32)); - } - { absl::random_internal::FastUniformBits fast32; EXPECT_EQ(0x11111111, fast32(urng4)); @@ -267,19 +125,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) { } // 64-bit types - { - absl::random_internal::FastUniformBits fast5; - EXPECT_EQ(0x9, fast5(urng4)); - EXPECT_EQ(0x1, fast5(urng32)); - } - - { - absl::random_internal::FastUniformBits fast48; - EXPECT_EQ(0x111111111111, fast48(urng4)); - // computes in 2 steps, should be 24 << 24 - EXPECT_EQ(0x000001000001, fast48(urng32)); - } - { absl::random_internal::FastUniformBits fast64; EXPECT_EQ(0x1111111111111111, fast64(urng4)); diff --git a/absl/strings/str_format.h b/absl/strings/str_format.h index 0b93c288..607e2bca 100644 --- a/absl/strings/str_format.h +++ b/absl/strings/str_format.h @@ -449,7 +449,7 @@ class FormatRawSink { // additional arguments. // // By default, `std::string` and `std::ostream` are supported as destination -// objects. +// objects. If a `std::string` is used the formatted string is appended to it. // // `absl::Format()` is a generic version of `absl::StrFormat(), for custom // sinks. The format string, like format strings for `StrFormat()`, is checked diff --git a/absl/types/internal/variant.h b/absl/types/internal/variant.h index 85201b4a..19de2e13 100644 --- a/absl/types/internal/variant.h +++ b/absl/types/internal/variant.h @@ -204,7 +204,7 @@ template using VisitIndicesResultT = typename VisitIndicesResultImpl::type; template + class BoundIndices> struct MakeVisitationMatrix; template @@ -218,7 +218,7 @@ constexpr ReturnType call_with_indices(FunctionObject&& function) { template struct MakeVisitationMatrix, - BoundIndices...> { + index_sequence> { using ResultType = ReturnType (*)(FunctionObject&&); static constexpr ResultType Run() { return &call_with_indices, } }; +template +struct AppendToIndexSequence; + +template +using AppendToIndexSequenceT = typename AppendToIndexSequence::type; + +template +struct AppendToIndexSequence, J> { + using type = index_sequence; +}; + template + class CurrIndices, class BoundIndices> struct MakeVisitationMatrixImpl; -template -struct MakeVisitationMatrixImpl< - ReturnType, FunctionObject, index_sequence, - index_sequence, BoundIndices...> { +template +struct MakeVisitationMatrixImpl, BoundIndices> { using ResultType = SimpleArray< - typename MakeVisitationMatrix>::ResultType, + typename MakeVisitationMatrix>::ResultType, sizeof...(CurrIndices)>; static constexpr ResultType Run() { - return {{MakeVisitationMatrix, - BoundIndices..., CurrIndices>::Run()...}}; + return {{MakeVisitationMatrix< + ReturnType, FunctionObject, EndIndices, + AppendToIndexSequenceT>::Run()...}}; } }; @@ -251,10 +261,11 @@ template struct MakeVisitationMatrix, - BoundIndices...> - : MakeVisitationMatrixImpl< - ReturnType, FunctionObject, index_sequence, - absl::make_index_sequence, BoundIndices...> {}; + index_sequence> + : MakeVisitationMatrixImpl, + absl::make_index_sequence, + index_sequence> {}; struct UnreachableSwitchCase { template @@ -423,7 +434,8 @@ struct VisitIndicesFallback { static VisitIndicesResultT Run(Op&& op, SizeT... indices) { return AccessSimpleArray( MakeVisitationMatrix, Op, - index_sequence<(EndIndices + 1)...>>::Run(), + index_sequence<(EndIndices + 1)...>, + index_sequence<>>::Run(), (indices + 1)...)(absl::forward(op)); } }; -- cgit v1.2.3