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Export of internal Abseil changes

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--
a9ac6567c0933d786d68c10011e3f3ff9deedf89 by Greg Falcon <gfalcon@google.com>:

Add absl::FunctionRef, a type analogous to the proposed C++23 std::function_ref.

Like std::function, FunctionRef can be used to type-erase any callable (invokable) object.  However, FunctionRef works by reference: it does not store a copy of the type-erased object.  If the wrapped object is destroyed before the FunctionRef, the reference becomes dangling.

FunctionRef relates to std::function in much the same way that string_view relates to std::string.

Because of these limitations, FunctionRef is best used only as a function argument type, and only where the function will be invoked immediately (rather than saved for later use).  When `const std::function<...>&` is used in this way, `absl::FunctionRef<...>` is a better-performing replacement.

PiperOrigin-RevId: 275484044

--
1f7c4df3760f8b93e5a5baf40b070eca1d3f4c98 by Abseil Team <absl-team@google.com>:

Add FastHexToBufferZeroPad16() function for blazingly fast hex encoding of uint64_t.

PiperOrigin-RevId: 275420901

--
08d48ac004eba57cf2f1ada827181a2995f74807 by Abseil Team <absl-team@google.com>:

Avoid applying the workaround for MSVC's static initialization problems when using clang-cl.

PiperOrigin-RevId: 275366326

--
40be82bd2b34670b5458c0a72a0475086153c2d6 by Abseil Team <absl-team@google.com>:

Added comments to SimpleAtof()/SimpleAtod() that clarify that they
always use the "C" locale, unlike the standard functions strtod()
and strtof() referenced now in the comments.

PiperOrigin-RevId: 275355815

--
086779dacb3f6f2b3ab59947e94e79046bdb1fe1 by Jorg Brown <jorg@google.com>:

Move the hex conversion table used by escaping.cc into numbers.h so
that other parts of Abseil can more efficiently access it.

PiperOrigin-RevId: 275331251

--
3c4ed1b04e55d96a40cbe70fb70929ffbb0c0432 by Abseil Team <absl-team@google.com>:

Avoid applying the workaround for MSVC's static initialization problems when using clang-cl.

PiperOrigin-RevId: 275323858

--
56ceb58ab688c3761978308609b09a1ac2739c9a by Derek Mauro <dmauro@google.com>:

Add script for testing on Alpine Linux (for musl test coverage)

PiperOrigin-RevId: 275321244
GitOrigin-RevId: a9ac6567c0933d786d68c10011e3f3ff9deedf89
Change-Id: I39799fa03768ddb44f3166200c860e1da4461807
This commit is contained in:
Abseil Team 2019-10-18 09:06:29 -07:00 committed by Andy Soffer
parent a15364ce4d
commit e4c8d0eb8e
15 changed files with 887 additions and 40 deletions
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51
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load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
load(
"//absl:copts/configure_copts.bzl",
"ABSL_DEFAULT_COPTS",
"ABSL_DEFAULT_LINKOPTS",
"ABSL_TEST_COPTS",
)
package(default_visibility = ["//visibility:public"])
licenses(["notice"]) # Apache 2.0
cc_library(
name = "function_ref",
srcs = ["internal/function_ref.h"],
hdrs = ["function_ref.h"],
copts = ABSL_DEFAULT_COPTS,
linkopts = ABSL_DEFAULT_LINKOPTS,
deps = [
"//absl/base:base_internal",
"//absl/meta:type_traits",
],
)
cc_test(
name = "function_ref_test",
size = "small",
srcs = ["function_ref_test.cc"],
copts = ABSL_TEST_COPTS,
deps = [
":function_ref",
"//absl/container:test_instance_tracker",
"//absl/memory",
"@com_google_googletest//:gtest_main",
],
)
cc_test(
name = "function_ref_benchmark",
srcs = [
"function_ref_benchmark.cc",
],
copts = ABSL_TEST_COPTS,
tags = ["benchmark"],
visibility = ["//visibility:private"],
deps = [
":function_ref",
"//absl/base:core_headers",
"@com_github_google_benchmark//:benchmark_main",
],
)

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// Copyright 2019 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.
//
// -----------------------------------------------------------------------------
// File: function_ref.h
// -----------------------------------------------------------------------------
//
// This header file defines the `absl::FunctionRef` type for holding a
// non-owning reference to an object of any invocable type. This function
// reference is typically most useful as a type-erased argument type for
// accepting function types that neither take ownership nor copy the type; using
// the reference type in this case avoids a copy and an allocation. Best
// practices of other non-owning reference-like objects (such as
// `absl::string_view`) apply here.
//
// An `absl::FunctionRef` is similar in usage to a `std::function` but has the
// following differences:
//
// * It doesn't own the underlying object.
// * It doesn't have a null or empty state.
// * It never performs deep copies or allocations.
// * It's much faster and cheaper to construct.
// * It's trivially copyable and destructable.
//
// Generally, `absl::FunctionRef` should not be used as a return value, data
// member, or to initialize a `std::function`. Such usages will often lead to
// problematic lifetime issues. Once you convert something to an
// `absl::FunctionRef` you cannot make a deep copy later.
//
// This class is suitable for use wherever a "const std::function<>&"
// would be used without making a copy. ForEach functions and other versions of
// the visitor pattern are a good example of when this class should be used.
//
// This class is trivial to copy and should be passed by value.
#ifndef ABSL_FUNCTIONAL_FUNCTION_REF_H_
#define ABSL_FUNCTIONAL_FUNCTION_REF_H_
#include <cassert>
#include <functional>
#include <type_traits>
#include "absl/functional/internal/function_ref.h"
#include "absl/meta/type_traits.h"
namespace absl {
// FunctionRef
//
// Dummy class declaration to allow the partial specialization based on function
// types below.
template <typename T>
class FunctionRef;
// FunctionRef
//
// An `absl::FunctionRef` is a lightweight wrapper to any invokable object with
// a compatible signature. Generally, an `absl::FunctionRef` should only be used
// as an argument type and should be preferred as an argument over a const
// reference to a `std::function`.
//
// Example:
//
// // The following function takes a function callback by const reference
// bool Visitor(const std::function<void(my_proto&,
// absl::string_view)>& callback);
//
// // Assuming that the function is not stored or otherwise copied, it can be
// // replaced by an `absl::FunctionRef`:
// bool Visitor(absl::FunctionRef<void(my_proto&, absl::string_view)>
// callback);
//
// Note: the assignment operator within an `absl::FunctionRef` is intentionally
// deleted to prevent misuse; because the `absl::FunctionRef` does not own the
// underlying type, assignment likely indicates misuse.
template <typename R, typename... Args>
class FunctionRef<R(Args...)> {
private:
// Used to disable constructors for objects that are not compatible with the
// signature of this FunctionRef.
template <typename F,
typename FR = absl::base_internal::InvokeT<F, Args&&...>>
using EnableIfCompatible =
typename std::enable_if<std::is_void<R>::value ||
std::is_convertible<FR, R>::value>::type;
public:
// Constructs a FunctionRef from any invokable type.
template <typename F, typename = EnableIfCompatible<const F&>>
FunctionRef(const F& f) // NOLINT(runtime/explicit)
: invoker_(&absl::functional_internal::InvokeObject<F, R, Args...>) {
absl::functional_internal::AssertNonNull(f);
ptr_.obj = &f;
}
// Overload for function pointers. This eliminates a level of indirection that
// would happen if the above overload was used (it lets us store the pointer
// instead of a pointer to a pointer).
//
// This overload is also used for references to functions, since references to
// functions can decay to function pointers implicitly.
template <
typename F, typename = EnableIfCompatible<F*>,
absl::functional_internal::EnableIf<absl::is_function<F>::value> = 0>
FunctionRef(F* f) // NOLINT(runtime/explicit)
: invoker_(&absl::functional_internal::InvokeFunction<F*, R, Args...>) {
assert(f != nullptr);
ptr_.fun = reinterpret_cast<decltype(ptr_.fun)>(f);
}
// To help prevent subtle lifetime bugs, FunctionRef is not assignable.
// Typically, it should only be used as an argument type.
FunctionRef& operator=(const FunctionRef& rhs) = delete;
// Call the underlying object.
R operator()(Args... args) const {
return invoker_(ptr_, std::forward<Args>(args)...);
}
private:
absl::functional_internal::VoidPtr ptr_;
absl::functional_internal::Invoker<R, Args...> invoker_;
};
} // namespace absl
#endif // ABSL_FUNCTIONAL_FUNCTION_REF_H_

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// Copyright 2019 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.
#include "absl/functional/function_ref.h"
#include <memory>
#include "benchmark/benchmark.h"
#include "absl/base/attributes.h"
namespace absl {
namespace {
int dummy = 0;
void FreeFunction() { benchmark::DoNotOptimize(dummy); }
struct TrivialFunctor {
void operator()() const { benchmark::DoNotOptimize(dummy); }
};
struct LargeFunctor {
void operator()() const { benchmark::DoNotOptimize(this); }
std::string a, b, c;
};
template <typename Function, typename... Args>
void ABSL_ATTRIBUTE_NOINLINE CallFunction(Function f, Args&&... args) {
f(std::forward<Args>(args)...);
}
template <typename Function, typename Callable, typename... Args>
void ConstructAndCallFunctionBenchmark(benchmark::State& state,
const Callable& c, Args&&... args) {
for (auto _ : state) {
CallFunction<Function>(c, std::forward<Args>(args)...);
}
}
void BM_TrivialStdFunction(benchmark::State& state) {
ConstructAndCallFunctionBenchmark<std::function<void()>>(state,
TrivialFunctor{});
}
BENCHMARK(BM_TrivialStdFunction);
void BM_TrivialFunctionRef(benchmark::State& state) {
ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state,
TrivialFunctor{});
}
BENCHMARK(BM_TrivialFunctionRef);
void BM_LargeStdFunction(benchmark::State& state) {
ConstructAndCallFunctionBenchmark<std::function<void()>>(state,
LargeFunctor{});
}
BENCHMARK(BM_LargeStdFunction);
void BM_LargeFunctionRef(benchmark::State& state) {
ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state, LargeFunctor{});
}
BENCHMARK(BM_LargeFunctionRef);
void BM_FunPtrStdFunction(benchmark::State& state) {
ConstructAndCallFunctionBenchmark<std::function<void()>>(state, FreeFunction);
}
BENCHMARK(BM_FunPtrStdFunction);
void BM_FunPtrFunctionRef(benchmark::State& state) {
ConstructAndCallFunctionBenchmark<FunctionRef<void()>>(state, FreeFunction);
}
BENCHMARK(BM_FunPtrFunctionRef);
// Doesn't include construction or copy overhead in the loop.
template <typename Function, typename Callable, typename... Args>
void CallFunctionBenchmark(benchmark::State& state, const Callable& c,
Args... args) {
Function f = c;
for (auto _ : state) {
benchmark::DoNotOptimize(&f);
f(args...);
}
}
struct FunctorWithTrivialArgs {
void operator()(int a, int b, int c) const {
benchmark::DoNotOptimize(a);
benchmark::DoNotOptimize(b);
benchmark::DoNotOptimize(c);
}
};
void BM_TrivialArgsStdFunction(benchmark::State& state) {
CallFunctionBenchmark<std::function<void(int, int, int)>>(
state, FunctorWithTrivialArgs{}, 1, 2, 3);
}
BENCHMARK(BM_TrivialArgsStdFunction);
void BM_TrivialArgsFunctionRef(benchmark::State& state) {
CallFunctionBenchmark<FunctionRef<void(int, int, int)>>(
state, FunctorWithTrivialArgs{}, 1, 2, 3);
}
BENCHMARK(BM_TrivialArgsFunctionRef);
struct FunctorWithNonTrivialArgs {
void operator()(std::string a, std::string b, std::string c) const {
benchmark::DoNotOptimize(&a);
benchmark::DoNotOptimize(&b);
benchmark::DoNotOptimize(&c);
}
};
void BM_NonTrivialArgsStdFunction(benchmark::State& state) {
std::string a, b, c;
CallFunctionBenchmark<
std::function<void(std::string, std::string, std::string)>>(
state, FunctorWithNonTrivialArgs{}, a, b, c);
}
BENCHMARK(BM_NonTrivialArgsStdFunction);
void BM_NonTrivialArgsFunctionRef(benchmark::State& state) {
std::string a, b, c;
CallFunctionBenchmark<
FunctionRef<void(std::string, std::string, std::string)>>(
state, FunctorWithNonTrivialArgs{}, a, b, c);
}
BENCHMARK(BM_NonTrivialArgsFunctionRef);
} // namespace
} // namespace absl

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// Copyright 2019 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.
#include "absl/functional/function_ref.h"
#include <memory>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/container/internal/test_instance_tracker.h"
#include "absl/memory/memory.h"
namespace absl {
namespace {
void RunFun(FunctionRef<void()> f) { f(); }
TEST(FunctionRefTest, Lambda) {
bool ran = false;
RunFun([&] { ran = true; });
EXPECT_TRUE(ran);
}
int Function() { return 1337; }
TEST(FunctionRefTest, Function1) {
FunctionRef<int()> ref(&Function);
EXPECT_EQ(1337, ref());
}
TEST(FunctionRefTest, Function2) {
FunctionRef<int()> ref(Function);
EXPECT_EQ(1337, ref());
}
int NoExceptFunction() noexcept { return 1337; }
// TODO(jdennett): Add a test for noexcept member functions.
TEST(FunctionRefTest, NoExceptFunction) {
FunctionRef<int()> ref(NoExceptFunction);
EXPECT_EQ(1337, ref());
}
TEST(FunctionRefTest, ForwardsArgs) {
auto l = [](std::unique_ptr<int> i) { return *i; };
FunctionRef<int(std::unique_ptr<int>)> ref(l);
EXPECT_EQ(42, ref(absl::make_unique<int>(42)));
}
TEST(FunctionRef, ReturnMoveOnly) {
auto l = [] { return absl::make_unique<int>(29); };
FunctionRef<std::unique_ptr<int>()> ref(l);
EXPECT_EQ(29, *ref());
}
TEST(FunctionRef, ManyArgs) {
auto l = [](int a, int b, int c) { return a + b + c; };
FunctionRef<int(int, int, int)> ref(l);
EXPECT_EQ(6, ref(1, 2, 3));
}
TEST(FunctionRef, VoidResultFromNonVoidFunctor) {
bool ran = false;
auto l = [&]() -> int {
ran = true;
return 2;
};
FunctionRef<void()> ref(l);
ref();
EXPECT_TRUE(ran);
}
TEST(FunctionRef, CastFromDerived) {
struct Base {};
struct Derived : public Base {};
Derived d;
auto l1 = [&](Base* b) { EXPECT_EQ(&d, b); };
FunctionRef<void(Derived*)> ref1(l1);
ref1(&d);
auto l2 = [&]() -> Derived* { return &d; };
FunctionRef<Base*()> ref2(l2);
EXPECT_EQ(&d, ref2());
}
TEST(FunctionRef, VoidResultFromNonVoidFuncton) {
FunctionRef<void()> ref(Function);
ref();
}
TEST(FunctionRef, MemberPtr) {
struct S {
int i;
};
S s{1100111};
auto mem_ptr = &S::i;
FunctionRef<int(const S& s)> ref(mem_ptr);
EXPECT_EQ(1100111, ref(s));
}
TEST(FunctionRef, MemberFun) {
struct S {
int i;
int get_i() const { return i; }
};
S s{22};
auto mem_fun_ptr = &S::get_i;
FunctionRef<int(const S& s)> ref(mem_fun_ptr);
EXPECT_EQ(22, ref(s));
}
TEST(FunctionRef, MemberFunRefqualified) {
struct S {
int i;
int get_i() && { return i; }
};
auto mem_fun_ptr = &S::get_i;
S s{22};
FunctionRef<int(S && s)> ref(mem_fun_ptr);
EXPECT_EQ(22, ref(std::move(s)));
}
#if !defined(_WIN32) && defined(GTEST_HAS_DEATH_TEST)
TEST(FunctionRef, MemberFunRefqualifiedNull) {
struct S {
int i;
int get_i() && { return i; }
};
auto mem_fun_ptr = &S::get_i;
mem_fun_ptr = nullptr;
EXPECT_DEBUG_DEATH({ FunctionRef<int(S && s)> ref(mem_fun_ptr); }, "");
}
TEST(FunctionRef, NullMemberPtrAssertFails) {
struct S {
int i;
};
using MemberPtr = int S::*;
MemberPtr mem_ptr = nullptr;
EXPECT_DEBUG_DEATH({ FunctionRef<int(const S& s)> ref(mem_ptr); }, "");
}
#endif // GTEST_HAS_DEATH_TEST
TEST(FunctionRef, CopiesAndMovesPerPassByValue) {
absl::test_internal::InstanceTracker tracker;
absl::test_internal::CopyableMovableInstance instance(0);
auto l = [](absl::test_internal::CopyableMovableInstance) {};
FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
ref(instance);
EXPECT_EQ(tracker.copies(), 1);
EXPECT_EQ(tracker.moves(), 1);
}
TEST(FunctionRef, CopiesAndMovesPerPassByRef) {
absl::test_internal::InstanceTracker tracker;
absl::test_internal::CopyableMovableInstance instance(0);
auto l = [](const absl::test_internal::CopyableMovableInstance&) {};
FunctionRef<void(const absl::test_internal::CopyableMovableInstance&)> ref(l);
ref(instance);
EXPECT_EQ(tracker.copies(), 0);
EXPECT_EQ(tracker.moves(), 0);
}
TEST(FunctionRef, CopiesAndMovesPerPassByValueCallByMove) {
absl::test_internal::InstanceTracker tracker;
absl::test_internal::CopyableMovableInstance instance(0);
auto l = [](absl::test_internal::CopyableMovableInstance) {};
FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
ref(std::move(instance));
EXPECT_EQ(tracker.copies(), 0);
EXPECT_EQ(tracker.moves(), 2);
}
TEST(FunctionRef, CopiesAndMovesPerPassByValueToRef) {
absl::test_internal::InstanceTracker tracker;
absl::test_internal::CopyableMovableInstance instance(0);
auto l = [](const absl::test_internal::CopyableMovableInstance&) {};
FunctionRef<void(absl::test_internal::CopyableMovableInstance)> ref(l);
ref(std::move(instance));
EXPECT_EQ(tracker.copies(), 0);
EXPECT_EQ(tracker.moves(), 1);
}
TEST(FunctionRef, PassByValueTypes) {
using absl::functional_internal::Invoker;
using absl::functional_internal::VoidPtr;
using absl::test_internal::CopyableMovableInstance;
struct Trivial {
void* p[2];
};
struct LargeTrivial {
void* p[3];
};
static_assert(std::is_same<Invoker<void, int>, void (*)(VoidPtr, int)>::value,
"Scalar types should be passed by value");
static_assert(
std::is_same<Invoker<void, Trivial>, void (*)(VoidPtr, Trivial)>::value,
"Small trivial types should be passed by value");
static_assert(std::is_same<Invoker<void, LargeTrivial>,
void (*)(VoidPtr, LargeTrivial &&)>::value,
"Large trivial types should be passed by rvalue reference");
static_assert(
std::is_same<Invoker<void, CopyableMovableInstance>,
void (*)(VoidPtr, CopyableMovableInstance &&)>::value,
"Types with copy/move ctor should be passed by rvalue reference");
// References are passed as references.
static_assert(
std::is_same<Invoker<void, int&>, void (*)(VoidPtr, int&)>::value,
"Reference types should be preserved");
static_assert(
std::is_same<Invoker<void, CopyableMovableInstance&>,
void (*)(VoidPtr, CopyableMovableInstance&)>::value,
"Reference types should be preserved");
static_assert(
std::is_same<Invoker<void, CopyableMovableInstance&&>,
void (*)(VoidPtr, CopyableMovableInstance &&)>::value,
"Reference types should be preserved");
// Make sure the address of an object received by reference is the same as the
// addess of the object passed by the caller.
{
LargeTrivial obj;
auto test = [&obj](LargeTrivial& input) { ASSERT_EQ(&input, &obj); };
absl::FunctionRef<void(LargeTrivial&)> ref(test);
ref(obj);
}
{
Trivial obj;
auto test = [&obj](Trivial& input) { ASSERT_EQ(&input, &obj); };
absl::FunctionRef<void(Trivial&)> ref(test);
ref(obj);
}
}
} // namespace
} // namespace absl

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// Copyright 2019 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_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_
#define ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_
#include <cassert>
#include <functional>
#include <type_traits>
#include "absl/base/internal/invoke.h"
#include "absl/meta/type_traits.h"
namespace absl {
namespace functional_internal {
// Like a void* that can handle function pointers as well. The standard does not
// allow function pointers to round-trip through void*, but void(*)() is fine.
//
// Note: It's important that this class remains trivial and is the same size as
// a pointer, since this allows the compiler to perform tail-call optimizations
// when the underlying function is a callable object with a matching signature.
union VoidPtr {
const void* obj;
void (*fun)();
};
// Chooses the best type for passing T as an argument.
// Attempt to be close to SystemV AMD64 ABI. Objects with trivial copy ctor are
// passed by value.
template <typename T>
constexpr bool PassByValue() {
return !std::is_lvalue_reference<T>::value &&
absl::is_trivially_copy_constructible<T>::value &&
absl::is_trivially_copy_assignable<
typename std::remove_cv<T>::type>::value &&
std::is_trivially_destructible<T>::value &&
sizeof(T) <= 2 * sizeof(void*);
}
template <typename T>
struct ForwardT : std::conditional<PassByValue<T>(), T, T&&> {};
// An Invoker takes a pointer to the type-erased invokable object, followed by
// the arguments that the invokable object expects.
//
// Note: The order of arguments here is an optimization, since member functions
// have an implicit "this" pointer as their first argument, putting VoidPtr
// first allows the compiler to perform tail-call optimization in many cases.
template <typename R, typename... Args>
using Invoker = R (*)(VoidPtr, typename ForwardT<Args>::type...);
//
// InvokeObject and InvokeFunction provide static "Invoke" functions that can be
// used as Invokers for objects or functions respectively.
//
// static_cast<R> handles the case the return type is void.
template <typename Obj, typename R, typename... Args>
R InvokeObject(VoidPtr ptr, typename ForwardT<Args>::type... args) {
auto o = static_cast<const Obj*>(ptr.obj);
return static_cast<R>(
absl::base_internal::Invoke(*o, std::forward<Args>(args)...));
}
template <typename Fun, typename R, typename... Args>
R InvokeFunction(VoidPtr ptr, typename ForwardT<Args>::type... args) {
auto f = reinterpret_cast<Fun>(ptr.fun);
return static_cast<R>(
absl::base_internal::Invoke(f, std::forward<Args>(args)...));
}
template <typename Sig>
void AssertNonNull(const std::function<Sig>& f) {
assert(f != nullptr);
(void)f;
}
template <typename F>
void AssertNonNull(const F&) {}
template <typename F, typename C>
void AssertNonNull(F C::*f) {
assert(f != nullptr);
(void)f;
}
template <bool C>
using EnableIf = typename ::std::enable_if<C, int>::type;
} // namespace functional_internal
} // namespace absl
#endif // ABSL_FUNCTIONAL_INTERNAL_FUNCTION_REF_H_

5
absl/strings/BUILD.bazel
View file

@ -413,8 +413,9 @@ cc_test(
deps = [
":pow10_helper",
":strings",
"//absl/base:core_headers",
"//absl/base:raw_logging_internal",
"//absl/random",
"//absl/random:distributions",
"@com_google_googletest//:gtest_main",
],
)
@ -428,6 +429,8 @@ cc_test(
deps = [
":strings",
"//absl/base:raw_logging_internal",
"//absl/random",
"//absl/random:distributions",
"@com_github_google_benchmark//:benchmark_main",
],
)

2
absl/strings/CMakeLists.txt
View file

@ -277,6 +277,8 @@ absl_cc_test(
absl::core_headers
absl::pow10_helper
absl::raw_logging_internal
absl::random_random
absl::random_distributions
gmock_main
)

33
absl/strings/escaping.cc
View file

@ -35,27 +35,6 @@
namespace absl {
namespace {
// Digit conversion.
constexpr char kHexChar[] = "0123456789abcdef";
constexpr char kHexTable[513] =
"000102030405060708090a0b0c0d0e0f"
"101112131415161718191a1b1c1d1e1f"
"202122232425262728292a2b2c2d2e2f"
"303132333435363738393a3b3c3d3e3f"
"404142434445464748494a4b4c4d4e4f"
"505152535455565758595a5b5c5d5e5f"
"606162636465666768696a6b6c6d6e6f"
"707172737475767778797a7b7c7d7e7f"
"808182838485868788898a8b8c8d8e8f"
"909192939495969798999a9b9c9d9e9f"
"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf"
"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff";
// These are used for the leave_nulls_escaped argument to CUnescapeInternal().
constexpr bool kUnescapeNulls = false;
@ -348,14 +327,14 @@ std::string CEscapeInternal(absl::string_view src, bool use_hex,
(last_hex_escape && absl::ascii_isxdigit(c)))) {
if (use_hex) {
dest.append("\\" "x");
dest.push_back(kHexChar[c / 16]);
dest.push_back(kHexChar[c % 16]);
dest.push_back(numbers_internal::kHexChar[c / 16]);
dest.push_back(numbers_internal::kHexChar[c % 16]);
is_hex_escape = true;
} else {
dest.append("\\");
dest.push_back(kHexChar[c / 64]);
dest.push_back(kHexChar[(c % 64) / 8]);
dest.push_back(kHexChar[c % 8]);
dest.push_back(numbers_internal::kHexChar[c / 64]);
dest.push_back(numbers_internal::kHexChar[(c % 64) / 8]);
dest.push_back(numbers_internal::kHexChar[c % 8]);
}
} else {
dest.push_back(c);
@ -1019,7 +998,7 @@ template <typename T>
void BytesToHexStringInternal(const unsigned char* src, T dest, ptrdiff_t num) {
auto dest_ptr = &dest[0];
for (auto src_ptr = src; src_ptr != (src + num); ++src_ptr, dest_ptr += 2) {
const char* hex_p = &kHexTable[*src_ptr * 2];
const char* hex_p = &numbers_internal::kHexTable[*src_ptr * 2];
std::copy(hex_p, hex_p + 2, dest_ptr);
}
}

29
absl/strings/numbers.cc
View file

@ -19,8 +19,8 @@
#include <algorithm>
#include <cassert>
#include <cfloat> // for DBL_DIG and FLT_DIG
#include <cmath> // for HUGE_VAL
#include <cfloat> // for DBL_DIG and FLT_DIG
#include <cmath> // for HUGE_VAL
#include <cstdint>
#include <cstdio>
#include <cstdlib>
@ -34,6 +34,7 @@
#include "absl/base/internal/raw_logging.h"
#include "absl/strings/ascii.h"
#include "absl/strings/charconv.h"
#include "absl/strings/escaping.h"
#include "absl/strings/internal/memutil.h"
#include "absl/strings/match.h"
#include "absl/strings/str_cat.h"
@ -885,6 +886,28 @@ inline bool safe_uint_internal(absl::string_view text, IntType* value_p,
} // anonymous namespace
namespace numbers_internal {
// Digit conversion.
ABSL_CONST_INIT const char kHexChar[] = "0123456789abcdef";
ABSL_CONST_INIT const char kHexTable[513] =
"000102030405060708090a0b0c0d0e0f"
"101112131415161718191a1b1c1d1e1f"
"202122232425262728292a2b2c2d2e2f"
"303132333435363738393a3b3c3d3e3f"
"404142434445464748494a4b4c4d4e4f"
"505152535455565758595a5b5c5d5e5f"
"606162636465666768696a6b6c6d6e6f"
"707172737475767778797a7b7c7d7e7f"
"808182838485868788898a8b8c8d8e8f"
"909192939495969798999a9b9c9d9e9f"
"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf"
"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff";
bool safe_strto32_base(absl::string_view text, int32_t* value, int base) {
return safe_int_internal<int32_t>(text, value, base);
}
@ -900,6 +923,6 @@ bool safe_strtou32_base(absl::string_view text, uint32_t* value, int base) {
bool safe_strtou64_base(absl::string_view text, uint64_t* value, int base) {
return safe_uint_internal<uint64_t>(text, value, base);
}
} // namespace numbers_internal
} // namespace numbers_internal
} // namespace absl

45
absl/strings/numbers.h
View file

@ -24,6 +24,10 @@
#ifndef ABSL_STRINGS_NUMBERS_H_
#define ABSL_STRINGS_NUMBERS_H_
#ifdef __SSE4_2__
#include <x86intrin.h>
#endif
#include <cstddef>
#include <cstdlib>
#include <cstring>
@ -32,6 +36,8 @@
#include <string>
#include <type_traits>
#include "absl/base/internal/bits.h"
#include "absl/base/internal/endian.h"
#include "absl/base/macros.h"
#include "absl/base/port.h"
#include "absl/numeric/int128.h"
@ -54,7 +60,8 @@ ABSL_MUST_USE_RESULT bool SimpleAtoi(absl::string_view str, int_type* out);
// Converts the given string (optionally followed or preceded by ASCII
// whitespace) into a float, which may be rounded on overflow or underflow.
// See https://en.cppreference.com/w/c/string/byte/strtof for details about the
// allowed formats for `str`. If any errors are encountered, this function
// allowed formats for `str`, except SimpleAtof() is locale-indepdent and will
// always use the "C" locale. If any errors are encountered, this function
// returns `false`, leaving `out` in an unspecified state.
ABSL_MUST_USE_RESULT bool SimpleAtof(absl::string_view str, float* out);
@ -63,7 +70,8 @@ ABSL_MUST_USE_RESULT bool SimpleAtof(absl::string_view str, float* out);
// Converts the given string (optionally followed or preceded by ASCII
// whitespace) into a double, which may be rounded on overflow or underflow.
// See https://en.cppreference.com/w/c/string/byte/strtof for details about the
// allowed formats for `str`. If any errors are encountered, this function
// allowed formats for `str`, except SimpleAtod is locale-independent and will
// always use the "C" locale. If any errors are encountered, this function
// returns `false`, leaving `out` in an unspecified state.
ABSL_MUST_USE_RESULT bool SimpleAtod(absl::string_view str, double* out);
@ -84,6 +92,10 @@ ABSL_MUST_USE_RESULT bool SimpleAtob(absl::string_view str, bool* out);
namespace absl {
namespace numbers_internal {
// Digit conversion.
extern const char kHexChar[17]; // 0123456789abcdef
extern const char kHexTable[513]; // 000102030405060708090a0b0c0d0e0f1011...
// safe_strto?() functions for implementing SimpleAtoi()
bool safe_strto32_base(absl::string_view text, int32_t* value, int base);
bool safe_strto64_base(absl::string_view text, int64_t* value, int base);
@ -170,6 +182,35 @@ ABSL_MUST_USE_RESULT bool safe_strtoi_base(absl::string_view s, int_type* out,
return parsed;
}
// FastHexToBufferZeroPad16()
//
// Outputs `val` into `out` as if by `snprintf(out, 17, "%016x", val)` but
// without the terminating null character. Thus `out` must be of length >= 16.
// Returns the number of non-pad digits of the output (it can never be zero
// since 0 has one digit).
inline size_t FastHexToBufferZeroPad16(uint64_t val, char* out) {
uint64_t be = absl::big_endian::FromHost64(val);
#ifdef __SSE4_2__
const auto kNibbleMask = _mm_set1_epi8(0xf);
const auto kHexDigits = _mm_setr_epi8('0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f');
auto v = _mm_loadu_si64(reinterpret_cast<__m128i*>(&be)); // load lo dword
auto v4 = _mm_srli_epi64(v, 4); // shift 4 right
auto il = _mm_unpacklo_epi8(v4, v); // interleave bytes
auto m = _mm_and_si128(il, kNibbleMask); // mask out nibbles
auto hexchars = _mm_shuffle_epi8(kHexDigits, m); // hex chars
_mm_storeu_si128(reinterpret_cast<__m128i*>(out), hexchars);
#else
for (int i = 0; i < 8; ++i) {
auto byte = (be >> (8 * i)) & 0xFF;
auto* hex = &absl::numbers_internal::kHexTable[byte * 2];
std::memcpy(out + 2 * i, hex, 2);
}
#endif
// | 0x1 so that even 0 has 1 digit.
return 16 - absl::base_internal::CountLeadingZeros64(val | 0x1) / 4;
}
} // namespace numbers_internal
// SimpleAtoi()

23
absl/strings/numbers_benchmark.cc
View file

@ -20,6 +20,8 @@
#include "benchmark/benchmark.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/random/distributions.h"
#include "absl/random/random.h"
#include "absl/strings/numbers.h"
namespace {
@ -260,4 +262,25 @@ BENCHMARK_TEMPLATE(BM_SimpleAtod, std::string)
->ArgPair(10, 4)
->ArgPair(10, 8);
void BM_FastHexToBufferZeroPad16(benchmark::State& state) {
absl::BitGen rng;
std::vector<uint64_t> nums;
nums.resize(1000);
auto min = std::numeric_limits<uint64_t>::min();
auto max = std::numeric_limits<uint64_t>::max();
for (auto& num : nums) {
num = absl::LogUniform(rng, min, max);
}
char buf[16];
while (state.KeepRunningBatch(nums.size())) {
for (auto num : nums) {
auto digits = absl::numbers_internal::FastHexToBufferZeroPad16(num, buf);
benchmark::DoNotOptimize(digits);
benchmark::DoNotOptimize(buf);
}
}
}
BENCHMARK(BM_FastHexToBufferZeroPad16);
} // namespace

30
absl/strings/numbers_test.cc
View file

@ -17,6 +17,7 @@
#include "absl/strings/numbers.h"
#include <sys/types.h>
#include <cfenv> // NOLINT(build/c++11)
#include <cinttypes>
#include <climits>
@ -36,10 +37,11 @@
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/base/internal/raw_logging.h"
#include "absl/strings/str_cat.h"
#include "absl/random/distributions.h"
#include "absl/random/random.h"
#include "absl/strings/internal/numbers_test_common.h"
#include "absl/strings/internal/pow10_helper.h"
#include "absl/strings/str_cat.h"
namespace {
@ -1187,4 +1189,28 @@ TEST(StrToUint64Base, PrefixOnly) {
}
}
void TestFastHexToBufferZeroPad16(uint64_t v) {
char buf[16];
auto digits = absl::numbers_internal::FastHexToBufferZeroPad16(v, buf);
absl::string_view res(buf, 16);
char buf2[17];
snprintf(buf2, sizeof(buf2), "%016" PRIx64, v);
EXPECT_EQ(res, buf2) << v;
size_t expected_digits = snprintf(buf2, sizeof(buf2), "%" PRIx64, v);
EXPECT_EQ(digits, expected_digits) << v;
}
TEST(FastHexToBufferZeroPad16, Smoke) {
TestFastHexToBufferZeroPad16(std::numeric_limits<uint64_t>::min());
TestFastHexToBufferZeroPad16(std::numeric_limits<uint64_t>::max());
TestFastHexToBufferZeroPad16(std::numeric_limits<int64_t>::min());
TestFastHexToBufferZeroPad16(std::numeric_limits<int64_t>::max());
absl::BitGen rng;
for (int i = 0; i < 100000; ++i) {
TestFastHexToBufferZeroPad16(
absl::LogUniform(rng, std::numeric_limits<uint64_t>::min(),
std::numeric_limits<uint64_t>::max()));
}
}
} // namespace

5
absl/strings/str_cat.cc
View file

@ -15,12 +15,14 @@
#include "absl/strings/str_cat.h"
#include <assert.h>
#include <algorithm>
#include <cstdint>
#include <cstring>
#include "absl/strings/ascii.h"
#include "absl/strings/internal/resize_uninitialized.h"
#include "absl/strings/numbers.h"
namespace absl {
@ -28,9 +30,8 @@ AlphaNum::AlphaNum(Hex hex) {
char* const end = &digits_[numbers_internal::kFastToBufferSize];
char* writer = end;
uint64_t value = hex.value;
static const char hexdigits[] = "0123456789abcdef";
do {
*--writer = hexdigits[value & 0xF];
*--writer = absl::numbers_internal::kHexChar[value & 0xF];
value >>= 4;
} while (value != 0);

5
absl/strings/substitute.cc
View file

@ -94,7 +94,6 @@ void SubstituteAndAppendArray(std::string* output, absl::string_view format,
assert(target == output->data() + output->size());
}
static const char kHexDigits[] = "0123456789abcdef";
Arg::Arg(const void* value) {
static_assert(sizeof(scratch_) >= sizeof(value) * 2 + 2,
"fix sizeof(scratch_)");
@ -104,7 +103,7 @@ Arg::Arg(const void* value) {
char* ptr = scratch_ + sizeof(scratch_);
uintptr_t num = reinterpret_cast<uintptr_t>(value);
do {
*--ptr = kHexDigits[num & 0xf];
*--ptr = absl::numbers_internal::kHexChar[num & 0xf];
num >>= 4;
} while (num != 0);
*--ptr = 'x';
@ -119,7 +118,7 @@ Arg::Arg(Hex hex) {
char* writer = end;
uint64_t value = hex.value;
do {
*--writer = kHexDigits[value & 0xF];
*--writer = absl::numbers_internal::kHexChar[value & 0xF];
value >>= 4;
} while (value != 0);

63
ci/linux_gcc_alpine_cmake.sh Executable file
View file

@ -0,0 +1,63 @@
#!/bin/bash
#
# Copyright 2019 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.
# TODO(absl-team): This script isn't fully hermetic because
# -DABSL_USE_GOOGLETEST_HEAD=ON means that this script isn't pinned to a fixed
# version of GoogleTest. This means that an upstream change to GoogleTest could
# break this test. Fix this by allowing this script to pin to a known-good
# version of GoogleTest.
set -euox pipefail
if [ -z ${ABSEIL_ROOT:-} ]; then
ABSEIL_ROOT="$(realpath $(dirname ${0})/..)"
fi
if [ -z ${ABSL_CMAKE_CXX_STANDARDS:-} ]; then
ABSL_CMAKE_CXX_STANDARDS="11 14 17"
fi
if [ -z ${ABSL_CMAKE_BUILD_TYPES:-} ]; then
ABSL_CMAKE_BUILD_TYPES="Debug Release"
fi
readonly DOCKER_CONTAINER="gcr.io/google.com/absl-177019/alpine:20191016"
for std in ${ABSL_CMAKE_CXX_STANDARDS}; do
for compilation_mode in ${ABSL_CMAKE_BUILD_TYPES}; do
echo "--------------------------------------------------------------------"
echo "Testing with CMAKE_BUILD_TYPE=${compilation_mode} and -std=c++${std}"
time docker run \
--volume="${ABSEIL_ROOT}:/abseil-cpp:ro" \
--workdir=/abseil-cpp \
--tmpfs=/buildfs:exec \
--cap-add=SYS_PTRACE \
--rm \
-e CFLAGS="-Werror" \
-e CXXFLAGS="-Werror" \
"${DOCKER_CONTAINER}" \
/bin/sh -c "
cd /buildfs && \
cmake /abseil-cpp \
-DABSL_USE_GOOGLETEST_HEAD=ON \
-DABSL_RUN_TESTS=ON \
-DCMAKE_BUILD_TYPE=${compilation_mode} \
-DCMAKE_CXX_STANDARD=${std} && \
make -j$(nproc) && \
ctest -j$(nproc) --output-on-failure"
done
done