115 lines
3.6 KiB
C++
115 lines
3.6 KiB
C++
// Copyright 2018 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef ABSL_CONTAINER_INTERNAL_COUNTING_ALLOCATOR_H_
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#define ABSL_CONTAINER_INTERNAL_COUNTING_ALLOCATOR_H_
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#include <cstdint>
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#include <memory>
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#include "absl/base/config.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace container_internal {
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// This is a stateful allocator, but the state lives outside of the
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// allocator (in whatever test is using the allocator). This is odd
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// but helps in tests where the allocator is propagated into nested
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// containers - that chain of allocators uses the same state and is
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// thus easier to query for aggregate allocation information.
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template <typename T>
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class CountingAllocator {
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public:
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using Allocator = std::allocator<T>;
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using AllocatorTraits = std::allocator_traits<Allocator>;
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using value_type = typename AllocatorTraits::value_type;
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using pointer = typename AllocatorTraits::pointer;
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using const_pointer = typename AllocatorTraits::const_pointer;
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using size_type = typename AllocatorTraits::size_type;
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using difference_type = typename AllocatorTraits::difference_type;
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CountingAllocator() = default;
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explicit CountingAllocator(int64_t* bytes_used) : bytes_used_(bytes_used) {}
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CountingAllocator(int64_t* bytes_used, int64_t* instance_count)
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: bytes_used_(bytes_used), instance_count_(instance_count) {}
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template <typename U>
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CountingAllocator(const CountingAllocator<U>& x)
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: bytes_used_(x.bytes_used_), instance_count_(x.instance_count_) {}
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pointer allocate(
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size_type n,
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typename AllocatorTraits::const_void_pointer hint = nullptr) {
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Allocator allocator;
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pointer ptr = AllocatorTraits::allocate(allocator, n, hint);
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if (bytes_used_ != nullptr) {
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*bytes_used_ += n * sizeof(T);
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}
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return ptr;
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}
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void deallocate(pointer p, size_type n) {
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Allocator allocator;
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AllocatorTraits::deallocate(allocator, p, n);
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if (bytes_used_ != nullptr) {
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*bytes_used_ -= n * sizeof(T);
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}
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}
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template <typename U, typename... Args>
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void construct(U* p, Args&&... args) {
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Allocator allocator;
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AllocatorTraits::construct(allocator, p, std::forward<Args>(args)...);
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if (instance_count_ != nullptr) {
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*instance_count_ += 1;
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}
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}
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template <typename U>
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void destroy(U* p) {
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Allocator allocator;
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AllocatorTraits::destroy(allocator, p);
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if (instance_count_ != nullptr) {
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*instance_count_ -= 1;
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}
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}
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template <typename U>
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class rebind {
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public:
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using other = CountingAllocator<U>;
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};
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friend bool operator==(const CountingAllocator& a,
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const CountingAllocator& b) {
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return a.bytes_used_ == b.bytes_used_ &&
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a.instance_count_ == b.instance_count_;
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}
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friend bool operator!=(const CountingAllocator& a,
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const CountingAllocator& b) {
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return !(a == b);
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}
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int64_t* bytes_used_ = nullptr;
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int64_t* instance_count_ = nullptr;
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};
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} // namespace container_internal
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ABSL_NAMESPACE_END
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} // namespace absl
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#endif // ABSL_CONTAINER_INTERNAL_COUNTING_ALLOCATOR_H_
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