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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: casts.h
-// -----------------------------------------------------------------------------
-//
-// This header file defines casting templates to fit use cases not covered by
-// the standard casts provided in the C++ standard. As with all cast operations,
-// use these with caution and only if alternatives do not exist.
-
-#ifndef ABSL_BASE_CASTS_H_
-#define ABSL_BASE_CASTS_H_
-
-#include <cstring>
-#include <memory>
-#include <type_traits>
-#include <utility>
-
-#include "absl/base/internal/identity.h"
-#include "absl/base/macros.h"
-#include "absl/meta/type_traits.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-
-namespace internal_casts {
-
-template <class Dest, class Source>
-struct is_bitcastable
-    : std::integral_constant<
-          bool,
-          sizeof(Dest) == sizeof(Source) &&
-              type_traits_internal::is_trivially_copyable<Source>::value &&
-              type_traits_internal::is_trivially_copyable<Dest>::value &&
-              std::is_default_constructible<Dest>::value> {};
-
-}  // namespace internal_casts
-
-// implicit_cast()
-//
-// Performs an implicit conversion between types following the language
-// rules for implicit conversion; if an implicit conversion is otherwise
-// allowed by the language in the given context, this function performs such an
-// implicit conversion.
-//
-// Example:
-//
-//   // If the context allows implicit conversion:
-//   From from;
-//   To to = from;
-//
-//   // Such code can be replaced by:
-//   implicit_cast<To>(from);
-//
-// An `implicit_cast()` may also be used to annotate numeric type conversions
-// that, although safe, may produce compiler warnings (such as `long` to `int`).
-// Additionally, an `implicit_cast()` is also useful within return statements to
-// indicate a specific implicit conversion is being undertaken.
-//
-// Example:
-//
-//   return implicit_cast<double>(size_in_bytes) / capacity_;
-//
-// Annotating code with `implicit_cast()` allows you to explicitly select
-// particular overloads and template instantiations, while providing a safer
-// cast than `reinterpret_cast()` or `static_cast()`.
-//
-// Additionally, an `implicit_cast()` can be used to allow upcasting within a
-// type hierarchy where incorrect use of `static_cast()` could accidentally
-// allow downcasting.
-//
-// Finally, an `implicit_cast()` can be used to perform implicit conversions
-// from unrelated types that otherwise couldn't be implicitly cast directly;
-// C++ will normally only implicitly cast "one step" in such conversions.
-//
-// That is, if C is a type which can be implicitly converted to B, with B being
-// a type that can be implicitly converted to A, an `implicit_cast()` can be
-// used to convert C to B (which the compiler can then implicitly convert to A
-// using language rules).
-//
-// Example:
-//
-//   // Assume an object C is convertible to B, which is implicitly convertible
-//   // to A
-//   A a = implicit_cast<B>(C);
-//
-// Such implicit cast chaining may be useful within template logic.
-template <typename To>
-constexpr To implicit_cast(typename absl::internal::identity_t<To> to) {
-  return to;
-}
-
-// bit_cast()
-//
-// Performs a bitwise cast on a type without changing the underlying bit
-// representation of that type's value. The two types must be of the same size
-// and both types must be trivially copyable. As with most casts, use with
-// caution. A `bit_cast()` might be needed when you need to temporarily treat a
-// type as some other type, such as in the following cases:
-//
-//    * Serialization (casting temporarily to `char *` for those purposes is
-//      always allowed by the C++ standard)
-//    * Managing the individual bits of a type within mathematical operations
-//      that are not normally accessible through that type
-//    * Casting non-pointer types to pointer types (casting the other way is
-//      allowed by `reinterpret_cast()` but round-trips cannot occur the other
-//      way).
-//
-// Example:
-//
-//   float f = 3.14159265358979;
-//   int i = bit_cast<int32_t>(f);
-//   // i = 0x40490fdb
-//
-// Casting non-pointer types to pointer types and then dereferencing them
-// traditionally produces undefined behavior.
-//
-// Example:
-//
-//   // WRONG
-//   float f = 3.14159265358979;            // WRONG
-//   int i = * reinterpret_cast<int*>(&f);  // WRONG
-//
-// The address-casting method produces undefined behavior according to the ISO
-// C++ specification section [basic.lval]. Roughly, this section says: if an
-// object in memory has one type, and a program accesses it with a different
-// type, the result is undefined behavior for most values of "different type".
-//
-// Such casting results in type punning: holding an object in memory of one type
-// and reading its bits back using a different type. A `bit_cast()` avoids this
-// issue by implementing its casts using `memcpy()`, which avoids introducing
-// this undefined behavior.
-//
-// NOTE: The requirements here are more strict than the bit_cast of standard
-// proposal p0476 due to the need for workarounds and lack of intrinsics.
-// Specifically, this implementation also requires `Dest` to be
-// default-constructible.
-template <
-    typename Dest, typename Source,
-    typename std::enable_if<internal_casts::is_bitcastable<Dest, Source>::value,
-                            int>::type = 0>
-inline Dest bit_cast(const Source& source) {
-  Dest dest;
-  memcpy(static_cast<void*>(std::addressof(dest)),
-         static_cast<const void*>(std::addressof(source)), sizeof(dest));
-  return dest;
-}
-
-// NOTE: This overload is only picked if the requirements of bit_cast are
-// not met. It is therefore UB, but is provided temporarily as previous
-// versions of this function template were unchecked. Do not use this in
-// new code.
-template <
-    typename Dest, typename Source,
-    typename std::enable_if<
-        !internal_casts::is_bitcastable<Dest, Source>::value,
-        int>::type = 0>
-ABSL_DEPRECATED(
-    "absl::bit_cast type requirements were violated. Update the types "
-    "being used such that they are the same size and are both "
-    "TriviallyCopyable.")
-inline Dest bit_cast(const Source& source) {
-  static_assert(sizeof(Dest) == sizeof(Source),
-                "Source and destination types should have equal sizes.");
-
-  Dest dest;
-  memcpy(&dest, &source, sizeof(dest));
-  return dest;
-}
-
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_BASE_CASTS_H_