| /* |
| * |
| * Copyright 2017 gRPC 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 |
| * |
| * http://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 GRPC_CORE_LIB_SUPPORT_VECTOR_H |
| #define GRPC_CORE_LIB_SUPPORT_VECTOR_H |
| |
| #include <cassert> |
| |
| #include "src/core/lib/support/memory.h" |
| |
| namespace grpc_core { |
| |
| // NOTE: We eventually want to use absl::InlinedVector here. However, |
| // there are currently build problems that prevent us from using absl. |
| // In the interim, we define a custom implementation as a place-holder, |
| // with the intent to eventually replace this with the absl |
| // implementation. |
| // |
| // This place-holder implementation does not implement the full set of |
| // functionality from the absl version; it has just the methods that we |
| // currently happen to need in gRPC. If additional functionality is |
| // needed before this gets replaced with the absl version, it can be |
| // added, with the following proviso: |
| // |
| // ANY METHOD ADDED HERE MUST COMPLY WITH THE INTERFACE IN THE absl |
| // IMPLEMENTATION! |
| // |
| // TODO(ctiller, nnoble, roth): Replace this with absl::InlinedVector |
| // once we integrate absl into the gRPC build system in a usable way. |
| template <typename T, size_t N> |
| class InlinedVector { |
| public: |
| InlinedVector() {} |
| ~InlinedVector() { |
| for (size_t i = 0; i < size_ && i < N; ++i) { |
| T& value = *reinterpret_cast<T*>(inline_ + i); |
| value.~T(); |
| } |
| if (size_ > N) { // Avoid subtracting two signed values. |
| for (size_t i = 0; i < size_ - N; ++i) { |
| dynamic_[i].~T(); |
| } |
| } |
| gpr_free(dynamic_); |
| } |
| |
| // For now, we do not support copying. |
| InlinedVector(const InlinedVector&) = delete; |
| InlinedVector& operator=(const InlinedVector&) = delete; |
| |
| T& operator[](size_t offset) { |
| assert(offset < size_); |
| if (offset < N) { |
| return *reinterpret_cast<T*>(inline_ + offset); |
| } else { |
| return dynamic_[offset - N]; |
| } |
| } |
| |
| template <typename... Args> |
| void emplace_back(Args&&... args) { |
| if (size_ < N) { |
| new (&inline_[size_]) T(std::forward<Args>(args)...); |
| } else { |
| if (size_ - N == dynamic_capacity_) { |
| size_t new_capacity = |
| dynamic_capacity_ == 0 ? 2 : dynamic_capacity_ * 2; |
| T* new_dynamic = static_cast<T*>(gpr_malloc(sizeof(T) * new_capacity)); |
| for (size_t i = 0; i < dynamic_capacity_; ++i) { |
| new (&new_dynamic[i]) T(std::move(dynamic_[i])); |
| dynamic_[i].~T(); |
| } |
| gpr_free(dynamic_); |
| dynamic_ = new_dynamic; |
| dynamic_capacity_ = new_capacity; |
| } |
| new (&dynamic_[size_ - N]) T(std::forward<Args>(args)...); |
| } |
| ++size_; |
| } |
| |
| void push_back(const T& value) { emplace_back(value); } |
| |
| void push_back(T&& value) { emplace_back(std::move(value)); } |
| |
| size_t size() const { return size_; } |
| |
| private: |
| typename std::aligned_storage<sizeof(T)>::type inline_[N]; |
| T* dynamic_ = nullptr; |
| size_t size_ = 0; |
| size_t dynamic_capacity_ = 0; |
| }; |
| |
| } // namespace grpc_core |
| |
| #endif |