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- //
- // Copyright 2017 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: macros.h
- // -----------------------------------------------------------------------------
- //
- // This header file defines the set of language macros used within Abseil code.
- // For the set of macros used to determine supported compilers and platforms,
- // see absl/base/config.h instead.
- //
- // This code is compiled directly on many platforms, including client
- // platforms like Windows, Mac, and embedded systems. Before making
- // any changes here, make sure that you're not breaking any platforms.
- #ifndef ABSL_BASE_MACROS_H_
- #define ABSL_BASE_MACROS_H_
- #include <cassert>
- #include <cstddef>
- #include "absl/base/attributes.h"
- #include "absl/base/config.h"
- #include "absl/base/optimization.h"
- #include "absl/base/port.h"
- // ABSL_ARRAYSIZE()
- //
- // Returns the number of elements in an array as a compile-time constant, which
- // can be used in defining new arrays. If you use this macro on a pointer by
- // mistake, you will get a compile-time error.
- #define ABSL_ARRAYSIZE(array) \
- (sizeof(::absl::macros_internal::ArraySizeHelper(array)))
- namespace absl {
- ABSL_NAMESPACE_BEGIN
- namespace macros_internal {
- // Note: this internal template function declaration is used by ABSL_ARRAYSIZE.
- // The function doesn't need a definition, as we only use its type.
- template <typename T, size_t N>
- auto ArraySizeHelper(const T (&array)[N]) -> char (&)[N];
- } // namespace macros_internal
- ABSL_NAMESPACE_END
- } // namespace absl
- // ABSL_BAD_CALL_IF()
- //
- // Used on a function overload to trap bad calls: any call that matches the
- // overload will cause a compile-time error. This macro uses a clang-specific
- // "enable_if" attribute, as described at
- // https://clang.llvm.org/docs/AttributeReference.html#enable-if
- //
- // Overloads which use this macro should be bracketed by
- // `#ifdef ABSL_BAD_CALL_IF`.
- //
- // Example:
- //
- // int isdigit(int c);
- // #ifdef ABSL_BAD_CALL_IF
- // int isdigit(int c)
- // ABSL_BAD_CALL_IF(c <= -1 || c > 255,
- // "'c' must have the value of an unsigned char or EOF");
- // #endif // ABSL_BAD_CALL_IF
- #if ABSL_HAVE_ATTRIBUTE(enable_if)
- #define ABSL_BAD_CALL_IF(expr, msg) \
- __attribute__((enable_if(expr, "Bad call trap"), unavailable(msg)))
- #endif
- // ABSL_ASSERT()
- //
- // In C++11, `assert` can't be used portably within constexpr functions.
- // ABSL_ASSERT functions as a runtime assert but works in C++11 constexpr
- // functions. Example:
- //
- // constexpr double Divide(double a, double b) {
- // return ABSL_ASSERT(b != 0), a / b;
- // }
- //
- // This macro is inspired by
- // https://akrzemi1.wordpress.com/2017/05/18/asserts-in-constexpr-functions/
- #if defined(NDEBUG)
- #define ABSL_ASSERT(expr) \
- (false ? static_cast<void>(expr) : static_cast<void>(0))
- #else
- #define ABSL_ASSERT(expr) \
- (ABSL_PREDICT_TRUE((expr)) ? static_cast<void>(0) \
- : [] { assert(false && #expr); }()) // NOLINT
- #endif
- // `ABSL_INTERNAL_HARDENING_ABORT()` controls how `ABSL_HARDENING_ASSERT()`
- // aborts the program in release mode (when NDEBUG is defined). The
- // implementation should abort the program as quickly as possible and ideally it
- // should not be possible to ignore the abort request.
- #if (ABSL_HAVE_BUILTIN(__builtin_trap) && \
- ABSL_HAVE_BUILTIN(__builtin_unreachable)) || \
- (defined(__GNUC__) && !defined(__clang__))
- #define ABSL_INTERNAL_HARDENING_ABORT() \
- do { \
- __builtin_trap(); \
- __builtin_unreachable(); \
- } while (false)
- #else
- #define ABSL_INTERNAL_HARDENING_ABORT() abort()
- #endif
- // ABSL_HARDENING_ASSERT()
- //
- // `ABSL_HARDENING_ASSERT()` is like `ABSL_ASSERT()`, but used to implement
- // runtime assertions that should be enabled in hardened builds even when
- // `NDEBUG` is defined.
- //
- // When `NDEBUG` is not defined, `ABSL_HARDENING_ASSERT()` is identical to
- // `ABSL_ASSERT()`.
- //
- // See `ABSL_OPTION_HARDENED` in `absl/base/options.h` for more information on
- // hardened mode.
- #if ABSL_OPTION_HARDENED == 1 && defined(NDEBUG)
- #define ABSL_HARDENING_ASSERT(expr) \
- (ABSL_PREDICT_TRUE((expr)) ? static_cast<void>(0) \
- : [] { ABSL_INTERNAL_HARDENING_ABORT(); }())
- #else
- #define ABSL_HARDENING_ASSERT(expr) ABSL_ASSERT(expr)
- #endif
- #ifdef ABSL_HAVE_EXCEPTIONS
- #define ABSL_INTERNAL_TRY try
- #define ABSL_INTERNAL_CATCH_ANY catch (...)
- #define ABSL_INTERNAL_RETHROW do { throw; } while (false)
- #else // ABSL_HAVE_EXCEPTIONS
- #define ABSL_INTERNAL_TRY if (true)
- #define ABSL_INTERNAL_CATCH_ANY else if (false)
- #define ABSL_INTERNAL_RETHROW do {} while (false)
- #endif // ABSL_HAVE_EXCEPTIONS
- #endif // ABSL_BASE_MACROS_H_
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