75 lines
2.6 KiB
C
75 lines
2.6 KiB
C
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/*
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* Copyright (C) 2021 The Android Open Source Project
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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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* http://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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*/
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#pragma once
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#include <memory>
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#include <string>
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namespace unwindstack {
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// Ref-counted read-only string. Used to avoid string allocations/copies.
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// It is intended to be transparent std::string replacement in most cases.
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class SharedString {
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public:
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SharedString() : data_() {}
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SharedString(std::string&& s) : data_(std::make_shared<const std::string>(std::move(s))) {}
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SharedString(const std::string& s) : SharedString(std::string(s)) {}
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SharedString(const char* s) : SharedString(std::string(s)) {}
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void clear() { data_.reset(); }
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bool is_null() const { return data_.get() == nullptr; }
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bool empty() const { return is_null() ? true : data_->empty(); }
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const char* c_str() const { return is_null() ? "" : data_->c_str(); }
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operator const std::string&() const {
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[[clang::no_destroy]] static const std::string empty;
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return data_ ? *data_.get() : empty;
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}
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operator std::string_view() const { return static_cast<const std::string&>(*this); }
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private:
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std::shared_ptr<const std::string> data_;
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};
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static inline bool operator==(const SharedString& a, SharedString& b) {
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return static_cast<std::string_view>(a) == static_cast<std::string_view>(b);
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}
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static inline bool operator==(const SharedString& a, std::string_view b) {
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return static_cast<std::string_view>(a) == b;
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}
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static inline bool operator==(std::string_view a, const SharedString& b) {
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return a == static_cast<std::string_view>(b);
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}
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static inline bool operator!=(const SharedString& a, SharedString& b) {
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return !(a == b);
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}
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static inline bool operator!=(const SharedString& a, std::string_view b) {
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return !(a == b);
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}
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static inline bool operator!=(std::string_view a, const SharedString& b) {
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return !(a == b);
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}
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static inline std::string operator+(const SharedString& a, const char* b) {
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return static_cast<const std::string&>(a) + b;
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}
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static inline std::string operator+(const char* a, const SharedString& b) {
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return a + static_cast<const std::string&>(b);
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}
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} // namespace unwindstack
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