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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_CONTAINER_INTERNAL_INLINED_VECTOR_INTERNAL_H_
#define ABSL_CONTAINER_INTERNAL_INLINED_VECTOR_INTERNAL_H_
#include <cstddef>
#include <iterator>
#include <memory>
#include <utility>
#include "absl/container/internal/compressed_tuple.h"
#include "absl/meta/type_traits.h"
namespace absl {
namespace inlined_vector_internal {
template <typename InlinedVector>
class Storage;
template <template <typename, size_t, typename> class InlinedVector, typename T,
size_t N, typename A>
class Storage<InlinedVector<T, N, A>> {
public:
class Allocation; // TODO(johnsoncj): Remove after migration
using allocator_type = A;
using value_type = typename allocator_type::value_type;
using pointer = typename allocator_type::pointer;
using const_pointer = typename allocator_type::const_pointer;
using reference = typename allocator_type::reference;
using const_reference = typename allocator_type::const_reference;
using rvalue_reference = typename allocator_type::value_type&&;
using size_type = typename allocator_type::size_type;
using difference_type = typename allocator_type::difference_type;
using iterator = pointer;
using const_iterator = const_pointer;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
explicit Storage(const allocator_type& alloc)
: metadata_(alloc, /* empty and inlined */ 0) {}
size_type GetSize() const { return GetSizeAndIsAllocated() >> 1; }
bool GetIsAllocated() const { return GetSizeAndIsAllocated() & 1; }
Allocation& GetAllocation() {
return reinterpret_cast<Allocation&>(rep_.allocation_storage.allocation);
}
const Allocation& GetAllocation() const {
return reinterpret_cast<const Allocation&>(
rep_.allocation_storage.allocation);
}
pointer GetInlinedData() {
return reinterpret_cast<pointer>(
std::addressof(rep_.inlined_storage.inlined[0]));
}
const_pointer GetInlinedData() const {
return reinterpret_cast<const_pointer>(
std::addressof(rep_.inlined_storage.inlined[0]));
}
pointer GetAllocatedData() { return GetAllocation().buffer(); }
const_pointer GetAllocatedData() const { return GetAllocation().buffer(); }
size_type GetAllocatedCapacity() const { return GetAllocation().capacity(); }
allocator_type& GetAllocator() { return metadata_.template get<0>(); }
const allocator_type& GetAllocator() const {
return metadata_.template get<0>();
}
void SetAllocatedSize(size_type size) {
GetSizeAndIsAllocated() = (size << 1) | static_cast<size_type>(1);
}
void SetInlinedSize(size_type size) { GetSizeAndIsAllocated() = size << 1; }
void AddSize(size_type count) { GetSizeAndIsAllocated() += count << 1; }
void InitAllocation(const Allocation& allocation) {
new (static_cast<void*>(std::addressof(rep_.allocation_storage.allocation)))
Allocation(allocation);
}
void SwapSizeAndIsAllocated(Storage& other) {
using std::swap;
swap(GetSizeAndIsAllocated(), other.GetSizeAndIsAllocated());
}
// TODO(johnsoncj): Make the below types private after migration
class Allocation {
size_type capacity_;
pointer buffer_;
public:
Allocation(allocator_type& a, size_type capacity)
: capacity_(capacity), buffer_(Create(a, capacity)) {}
void Dealloc(allocator_type& a) {
std::allocator_traits<allocator_type>::deallocate(a, buffer_, capacity_);
}
size_type capacity() const { return capacity_; }
const_pointer buffer() const { return buffer_; }
pointer buffer() { return buffer_; }
static pointer Create(allocator_type& a, size_type n) {
return std::allocator_traits<allocator_type>::allocate(a, n);
}
};
private:
size_type& GetSizeAndIsAllocated() { return metadata_.template get<1>(); }
const size_type& GetSizeAndIsAllocated() const {
return metadata_.template get<1>();
}
// Stores either the inlined or allocated representation
union Rep {
using ValueTypeBuffer =
absl::aligned_storage_t<sizeof(value_type), alignof(value_type)>;
using AllocationBuffer =
absl::aligned_storage_t<sizeof(Allocation), alignof(Allocation)>;
// Structs wrap the buffers to perform indirection that solves a bizarre
// compilation error on Visual Studio (all known versions).
struct InlinedRep {
ValueTypeBuffer inlined[N];
};
struct AllocatedRep {
AllocationBuffer allocation;
};
InlinedRep inlined_storage;
AllocatedRep allocation_storage;
};
container_internal::CompressedTuple<allocator_type, size_type> metadata_;
Rep rep_;
};
} // namespace inlined_vector_internal
} // namespace absl
#endif // ABSL_CONTAINER_INTERNAL_INLINED_VECTOR_INTERNAL_H_