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-rw-r--r--absl/random/benchmarks.cc4
-rw-r--r--absl/random/internal/fast_uniform_bits.h52
-rw-r--r--absl/random/internal/fast_uniform_bits_test.cc155
-rw-r--r--absl/strings/str_format.h2
-rw-r--r--absl/types/internal/variant.h48
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<uint32_t, 32>); \
+ absl::random_internal::FastUniformBits<uint32_t>); \
BENCHMARK_TEMPLATE(BM_Dist, Engine, \
- absl::random_internal::FastUniformBits<uint64_t, 64>); \
+ absl::random_internal::FastUniformBits<uint64_t>); \
BENCHMARK_TEMPLATE(BM_Dist, Engine, std::uniform_int_distribution<int32_t>); \
BENCHMARK_TEMPLATE(BM_Dist, Engine, std::uniform_int_distribution<int64_t>); \
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 <typename UIntType = uint64_t,
- size_t Width = std::numeric_limits<UIntType>::digits>
+template <typename UIntType = uint64_t>
class FastUniformBits {
static_assert(std::is_unsigned<UIntType>::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<UIntType>::digits,
- "Class-template FastUniformBits<> Width argument must be <= "
- "width of UIntType.");
-
- static constexpr bool kIsMaxWidth =
- (kWidth >= std::numeric_limits<UIntType>::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<UIntType>::digits;
public:
using result_type = UIntType;
static constexpr result_type(min)() { return 0; }
static constexpr result_type(max)() {
- return kIsMaxWidth ? (std::numeric_limits<result_type>::max)()
- : constexpr_mask(kWidth);
+ return (std::numeric_limits<result_type>::max)();
}
template <typename URBG>
@@ -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 <typename UIntType, size_t Width, typename URBG>
+template <typename UIntType, typename URBG>
class FastUniformBitsLoopingConstants {
private:
- static constexpr size_t kWidth = Width;
+ static constexpr size_t kWidth = std::numeric_limits<UIntType>::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 <typename UIntType, size_t Width>
+template <typename UIntType>
template <typename URBG>
-typename FastUniformBits<UIntType, Width>::result_type
-FastUniformBits<UIntType, Width>::operator()(
+typename FastUniformBits<UIntType>::result_type
+FastUniformBits<UIntType>::operator()(
URBG& g) { // NOLINT(runtime/references)
using constants = FastUniformBitsURBGConstants<URBG>;
return Generate(
g, std::integral_constant<bool, constants::kRangeMask >= (max)()>{});
}
-template <typename UIntType, size_t Width>
+template <typename UIntType>
template <typename URBG>
-typename URBG::result_type FastUniformBits<UIntType, Width>::Variate(
+typename URBG::result_type FastUniformBits<UIntType>::Variate(
URBG& g) { // NOLINT(runtime/references)
using constants = FastUniformBitsURBGConstants<URBG>;
if (constants::kPowerOfTwo) {
@@ -256,10 +238,10 @@ typename URBG::result_type FastUniformBits<UIntType, Width>::Variate(
return u;
}
-template <typename UIntType, size_t Width>
+template <typename UIntType>
template <typename URBG>
-typename FastUniformBits<UIntType, Width>::result_type
-FastUniformBits<UIntType, Width>::Generate(
+typename FastUniformBits<UIntType>::result_type
+FastUniformBits<UIntType>::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<UIntType, Width>::Generate(
return Variate(g) & (max)();
}
-template <typename UIntType, size_t Width>
+template <typename UIntType>
template <typename URBG>
-typename FastUniformBits<UIntType, Width>::result_type
-FastUniformBits<UIntType, Width>::Generate(
+typename FastUniformBits<UIntType>::result_type
+FastUniformBits<UIntType>::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<UIntType, Width>::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<UIntType, Width, URBG>;
+ using constants = FastUniformBitsLoopingConstants<UIntType, URBG>;
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<uint32_t, 1> a;
- absl::random_internal::FastUniformBits<uint32_t, 31> b;
- absl::random_internal::FastUniformBits<uint32_t, 32> 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<uint64_t, 1> a;
- absl::random_internal::FastUniformBits<uint64_t, 31> b;
- absl::random_internal::FastUniformBits<uint64_t, 32> c;
- absl::random_internal::FastUniformBits<uint64_t, 33> d;
- absl::random_internal::FastUniformBits<uint64_t, 63> e;
- absl::random_internal::FastUniformBits<uint64_t, 64> 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<uint32_t, 31, Urng4bits>;
- // 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<uint64_t, 60, UrngOddbits>;
- // 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<uint64_t, 63, UrngOddbits>;
- // 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) {
@@ -193,33 +105,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) {
// 8-bit types
{
- absl::random_internal::FastUniformBits<uint8_t, 1> fast1;
- EXPECT_EQ(0x1, fast1(urng4));
- EXPECT_EQ(0x1, fast1(urng32));
- }
- {
- absl::random_internal::FastUniformBits<uint8_t, 2> fast2;
- EXPECT_EQ(0x1, fast2(urng4));
- EXPECT_EQ(0x1, fast2(urng32));
- }
-
- {
- absl::random_internal::FastUniformBits<uint8_t, 4> fast4;
- EXPECT_EQ(0x1, fast4(urng4));
- EXPECT_EQ(0x1, fast4(urng32));
- }
- {
- absl::random_internal::FastUniformBits<uint8_t, 6> fast6;
- EXPECT_EQ(0x9, fast6(urng4)); // b001001 (2x3)
- EXPECT_EQ(0x1, fast6(urng32));
- }
- {
- absl::random_internal::FastUniformBits<uint8_t, 6> fast7;
- EXPECT_EQ(0x9, fast7(urng4)); // b00001001 (1x4 + 1x3)
- EXPECT_EQ(0x1, fast7(urng32));
- }
-
- {
absl::random_internal::FastUniformBits<uint8_t> fast8;
EXPECT_EQ(0x11, fast8(urng4));
EXPECT_EQ(0x1, fast8(urng32));
@@ -227,22 +112,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) {
// 16-bit types
{
- absl::random_internal::FastUniformBits<uint16_t, 10> fast10;
- EXPECT_EQ(0x91, fast10(urng4)); // b 0010010001 (2x3 + 1x4)
- EXPECT_EQ(0x1, fast10(urng32));
- }
- {
- absl::random_internal::FastUniformBits<uint16_t, 11> fast11;
- EXPECT_EQ(0x111, fast11(urng4));
- EXPECT_EQ(0x1, fast11(urng32));
- }
- {
- absl::random_internal::FastUniformBits<uint16_t, 12> fast12;
- EXPECT_EQ(0x111, fast12(urng4));
- EXPECT_EQ(0x1, fast12(urng32));
- }
-
- {
absl::random_internal::FastUniformBits<uint16_t> fast16;
EXPECT_EQ(0x1111, fast16(urng4));
EXPECT_EQ(0x1, fast16(urng32));
@@ -250,17 +119,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) {
// 32-bit types
{
- absl::random_internal::FastUniformBits<uint32_t, 21> fast21;
- EXPECT_EQ(0x49111, fast21(urng4)); // b 001001001 000100010001 (3x3 + 3x4)
- EXPECT_EQ(0x1, fast21(urng32));
- }
- {
- absl::random_internal::FastUniformBits<uint32_t, 24> fast24;
- EXPECT_EQ(0x111111, fast24(urng4));
- EXPECT_EQ(0x1, fast24(urng32));
- }
-
- {
absl::random_internal::FastUniformBits<uint32_t> fast32;
EXPECT_EQ(0x11111111, fast32(urng4));
EXPECT_EQ(0x1, fast32(urng32));
@@ -268,19 +126,6 @@ TEST(FastUniformBitsTest, Urng4_VariousOutputs) {
// 64-bit types
{
- absl::random_internal::FastUniformBits<uint64_t, 5> fast5;
- EXPECT_EQ(0x9, fast5(urng4));
- EXPECT_EQ(0x1, fast5(urng32));
- }
-
- {
- absl::random_internal::FastUniformBits<uint64_t, 48> fast48;
- EXPECT_EQ(0x111111111111, fast48(urng4));
- // computes in 2 steps, should be 24 << 24
- EXPECT_EQ(0x000001000001, fast48(urng32));
- }
-
- {
absl::random_internal::FastUniformBits<uint64_t> fast64;
EXPECT_EQ(0x1111111111111111, fast64(urng4));
EXPECT_EQ(0x0000000100000001, fast64(urng32));
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 <class Op, class... Vs>
using VisitIndicesResultT = typename VisitIndicesResultImpl<Op, Vs...>::type;
template <class ReturnType, class FunctionObject, class EndIndices,
- std::size_t... BoundIndices>
+ class BoundIndices>
struct MakeVisitationMatrix;
template <class ReturnType, class FunctionObject, std::size_t... Indices>
@@ -218,7 +218,7 @@ constexpr ReturnType call_with_indices(FunctionObject&& function) {
template <class ReturnType, class FunctionObject, std::size_t... BoundIndices>
struct MakeVisitationMatrix<ReturnType, FunctionObject, index_sequence<>,
- BoundIndices...> {
+ index_sequence<BoundIndices...>> {
using ResultType = ReturnType (*)(FunctionObject&&);
static constexpr ResultType Run() {
return &call_with_indices<ReturnType, FunctionObject,
@@ -226,24 +226,34 @@ struct MakeVisitationMatrix<ReturnType, FunctionObject, index_sequence<>,
}
};
+template <typename Is, std::size_t J>
+struct AppendToIndexSequence;
+
+template <typename Is, std::size_t J>
+using AppendToIndexSequenceT = typename AppendToIndexSequence<Is, J>::type;
+
+template <std::size_t... Is, std::size_t J>
+struct AppendToIndexSequence<index_sequence<Is...>, J> {
+ using type = index_sequence<Is..., J>;
+};
+
template <class ReturnType, class FunctionObject, class EndIndices,
- class CurrIndices, std::size_t... BoundIndices>
+ class CurrIndices, class BoundIndices>
struct MakeVisitationMatrixImpl;
-template <class ReturnType, class FunctionObject, std::size_t... EndIndices,
- std::size_t... CurrIndices, std::size_t... BoundIndices>
-struct MakeVisitationMatrixImpl<
- ReturnType, FunctionObject, index_sequence<EndIndices...>,
- index_sequence<CurrIndices...>, BoundIndices...> {
+template <class ReturnType, class FunctionObject, class EndIndices,
+ std::size_t... CurrIndices, class BoundIndices>
+struct MakeVisitationMatrixImpl<ReturnType, FunctionObject, EndIndices,
+ index_sequence<CurrIndices...>, BoundIndices> {
using ResultType = SimpleArray<
- typename MakeVisitationMatrix<ReturnType, FunctionObject,
- index_sequence<EndIndices...>>::ResultType,
+ typename MakeVisitationMatrix<ReturnType, FunctionObject, EndIndices,
+ index_sequence<>>::ResultType,
sizeof...(CurrIndices)>;
static constexpr ResultType Run() {
- return {{MakeVisitationMatrix<ReturnType, FunctionObject,
- index_sequence<EndIndices...>,
- BoundIndices..., CurrIndices>::Run()...}};
+ return {{MakeVisitationMatrix<
+ ReturnType, FunctionObject, EndIndices,
+ AppendToIndexSequenceT<BoundIndices, CurrIndices>>::Run()...}};
}
};
@@ -251,10 +261,11 @@ template <class ReturnType, class FunctionObject, std::size_t HeadEndIndex,
std::size_t... TailEndIndices, std::size_t... BoundIndices>
struct MakeVisitationMatrix<ReturnType, FunctionObject,
index_sequence<HeadEndIndex, TailEndIndices...>,
- BoundIndices...>
- : MakeVisitationMatrixImpl<
- ReturnType, FunctionObject, index_sequence<TailEndIndices...>,
- absl::make_index_sequence<HeadEndIndex>, BoundIndices...> {};
+ index_sequence<BoundIndices...>>
+ : MakeVisitationMatrixImpl<ReturnType, FunctionObject,
+ index_sequence<TailEndIndices...>,
+ absl::make_index_sequence<HeadEndIndex>,
+ index_sequence<BoundIndices...>> {};
struct UnreachableSwitchCase {
template <class Op>
@@ -423,7 +434,8 @@ struct VisitIndicesFallback {
static VisitIndicesResultT<Op, SizeT...> Run(Op&& op, SizeT... indices) {
return AccessSimpleArray(
MakeVisitationMatrix<VisitIndicesResultT<Op, SizeT...>, Op,
- index_sequence<(EndIndices + 1)...>>::Run(),
+ index_sequence<(EndIndices + 1)...>,
+ index_sequence<>>::Run(),
(indices + 1)...)(absl::forward<Op>(op));
}
};
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-17 19:56:08 +0000