| /* |
| * |
| * 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_GPRPP_INLINED_VECTOR_H |
| #define GRPC_CORE_LIB_GPRPP_INLINED_VECTOR_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <cassert> |
| #include <cstring> |
| |
| #include "src/core/lib/gprpp/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(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() { init_data(); } |
| ~InlinedVector() { destroy_elements(); } |
| |
| // copy constructor |
| InlinedVector(const InlinedVector& v) { |
| init_data(); |
| copy_from(v); |
| } |
| |
| InlinedVector& operator=(const InlinedVector& v) { |
| if (this != &v) { |
| clear(); |
| copy_from(v); |
| } |
| return *this; |
| } |
| |
| // move constructor |
| InlinedVector(InlinedVector&& v) { |
| init_data(); |
| move_from(v); |
| } |
| |
| InlinedVector& operator=(InlinedVector&& v) { |
| if (this != &v) { |
| clear(); |
| move_from(v); |
| } |
| return *this; |
| } |
| |
| T* data() { |
| return dynamic_ != nullptr ? dynamic_ : reinterpret_cast<T*>(inline_); |
| } |
| |
| const T* data() const { |
| return dynamic_ != nullptr ? dynamic_ : reinterpret_cast<const T*>(inline_); |
| } |
| |
| T& operator[](size_t offset) { |
| assert(offset < size_); |
| return data()[offset]; |
| } |
| |
| const T& operator[](size_t offset) const { |
| assert(offset < size_); |
| return data()[offset]; |
| } |
| |
| void reserve(size_t capacity) { |
| if (capacity > capacity_) { |
| T* new_dynamic = static_cast<T*>(gpr_malloc(sizeof(T) * capacity)); |
| move_elements(data(), new_dynamic, size_); |
| gpr_free(dynamic_); |
| dynamic_ = new_dynamic; |
| capacity_ = capacity; |
| } |
| } |
| |
| template <typename... Args> |
| void emplace_back(Args&&... args) { |
| if (size_ == capacity_) { |
| reserve(capacity_ * 2); |
| } |
| new (&(data()[size_])) 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)); } |
| |
| void pop_back() { |
| assert(!empty()); |
| size_t s = size(); |
| T& value = data()[s - 1]; |
| value.~T(); |
| size_--; |
| } |
| |
| size_t size() const { return size_; } |
| bool empty() const { return size_ == 0; } |
| |
| size_t capacity() const { return capacity_; } |
| |
| void clear() { |
| destroy_elements(); |
| init_data(); |
| } |
| |
| private: |
| void copy_from(const InlinedVector& v) { |
| // if v is allocated, make sure we have enough capacity. |
| if (v.dynamic_ != nullptr) { |
| reserve(v.capacity_); |
| } |
| // copy over elements |
| for (size_t i = 0; i < v.size_; ++i) { |
| new (&(data()[i])) T(v[i]); |
| } |
| // copy over metadata |
| size_ = v.size_; |
| capacity_ = v.capacity_; |
| } |
| |
| void move_from(InlinedVector& v) { |
| // if v is allocated, then we steal its dynamic array; otherwise, we |
| // move the elements individually. |
| if (v.dynamic_ != nullptr) { |
| dynamic_ = v.dynamic_; |
| } else { |
| move_elements(v.data(), data(), v.size_); |
| } |
| // copy over metadata |
| size_ = v.size_; |
| capacity_ = v.capacity_; |
| // null out the original |
| v.init_data(); |
| } |
| |
| static void move_elements(T* src, T* dst, size_t num_elements) { |
| for (size_t i = 0; i < num_elements; ++i) { |
| new (&dst[i]) T(std::move(src[i])); |
| src[i].~T(); |
| } |
| } |
| |
| void init_data() { |
| dynamic_ = nullptr; |
| size_ = 0; |
| capacity_ = N; |
| } |
| |
| void destroy_elements() { |
| for (size_t i = 0; i < size_; ++i) { |
| T& value = data()[i]; |
| value.~T(); |
| } |
| gpr_free(dynamic_); |
| } |
| |
| typename std::aligned_storage<sizeof(T)>::type inline_[N]; |
| T* dynamic_; |
| size_t size_; |
| size_t capacity_; |
| }; |
| |
| } // namespace grpc_core |
| |
| #endif /* GRPC_CORE_LIB_GPRPP_INLINED_VECTOR_H */ |