refactor: reorganize the file structure (#1266)

src/ordered_map.hpp

@@ -0,0 +1,177 @@
+#ifndef __ORDERED_MAP_HPP__
+#define __ORDERED_MAP_HPP__
+
+#include <iostream>
+#include <list>
+#include <string>
+#include <unordered_map>
+
+#include <initializer_list>
+#include <iterator>
+#include <list>
+#include <stdexcept>
+#include <unordered_map>
+#include <utility>
+
+template <typename Key, typename T>
+class OrderedMap {
+public:
+    using key_type        = Key;
+    using mapped_type     = T;
+    using value_type      = std::pair<const Key, T>;
+    using list_type       = std::list<value_type>;
+    using size_type       = typename list_type::size_type;
+    using difference_type = typename list_type::difference_type;
+    using iterator        = typename list_type::iterator;
+    using const_iterator  = typename list_type::const_iterator;
+
+private:
+    list_type data_;
+    std::unordered_map<Key, iterator> index_;
+
+public:
+    // --- constructors ---
+    OrderedMap() = default;
+
+    OrderedMap(std::initializer_list<value_type> init) {
+        for (const auto& kv : init)
+            insert(kv);
+    }
+
+    OrderedMap(const OrderedMap&)                = default;
+    OrderedMap(OrderedMap&&) noexcept            = default;
+    OrderedMap& operator=(const OrderedMap&)     = default;
+    OrderedMap& operator=(OrderedMap&&) noexcept = default;
+
+    // --- element access ---
+    T& at(const Key& key) {
+        auto it = index_.find(key);
+        if (it == index_.end())
+            throw std::out_of_range("OrderedMap::at: key not found");
+        return it->second->second;
+    }
+
+    const T& at(const Key& key) const {
+        auto it = index_.find(key);
+        if (it == index_.end())
+            throw std::out_of_range("OrderedMap::at: key not found");
+        return it->second->second;
+    }
+
+    T& operator[](const Key& key) {
+        auto it = index_.find(key);
+        if (it == index_.end()) {
+            data_.emplace_back(key, T{});
+            auto iter   = std::prev(data_.end());
+            index_[key] = iter;
+            return iter->second;
+        }
+        return it->second->second;
+    }
+
+    // --- iterators ---
+    iterator begin() noexcept { return data_.begin(); }
+    const_iterator begin() const noexcept { return data_.begin(); }
+    const_iterator cbegin() const noexcept { return data_.cbegin(); }
+
+    iterator end() noexcept { return data_.end(); }
+    const_iterator end() const noexcept { return data_.end(); }
+    const_iterator cend() const noexcept { return data_.cend(); }
+
+    // --- capacity ---
+    bool empty() const noexcept { return data_.empty(); }
+    size_type size() const noexcept { return data_.size(); }
+
+    // --- modifiers ---
+    void clear() noexcept {
+        data_.clear();
+        index_.clear();
+    }
+
+    std::pair<iterator, bool> insert(const value_type& value) {
+        auto it = index_.find(value.first);
+        if (it != index_.end()) {
+            return {it->second, false};
+        }
+        data_.push_back(value);
+        auto iter           = std::prev(data_.end());
+        index_[value.first] = iter;
+        return {iter, true};
+    }
+
+    std::pair<iterator, bool> insert(value_type&& value) {
+        auto it = index_.find(value.first);
+        if (it != index_.end()) {
+            return {it->second, false};
+        }
+        data_.push_back(std::move(value));
+        auto iter           = std::prev(data_.end());
+        index_[iter->first] = iter;
+        return {iter, true};
+    }
+
+    void erase(const Key& key) {
+        auto it = index_.find(key);
+        if (it != index_.end()) {
+            data_.erase(it->second);
+            index_.erase(it);
+        }
+    }
+
+    iterator erase(iterator pos) {
+        index_.erase(pos->first);
+        return data_.erase(pos);
+    }
+
+    // --- lookup ---
+    size_type count(const Key& key) const {
+        return index_.count(key);
+    }
+
+    iterator find(const Key& key) {
+        auto it = index_.find(key);
+        if (it == index_.end())
+            return data_.end();
+        return it->second;
+    }
+
+    const_iterator find(const Key& key) const {
+        auto it = index_.find(key);
+        if (it == index_.end())
+            return data_.end();
+        return it->second;
+    }
+
+    bool contains(const Key& key) const {
+        return index_.find(key) != index_.end();
+    }
+
+    // --- comparison ---
+    bool operator==(const OrderedMap& other) const {
+        return data_ == other.data_;
+    }
+
+    bool operator!=(const OrderedMap& other) const {
+        return !(*this == other);
+    }
+
+    template <typename... Args>
+    std::pair<iterator, bool> emplace(Args&&... args) {
+        value_type value(std::forward<Args>(args)...);
+        auto it = index_.find(value.first);
+        if (it != index_.end()) {
+            return {it->second, false};
+        }
+        data_.push_back(std::move(value));
+        auto iter           = std::prev(data_.end());
+        index_[iter->first] = iter;
+        return {iter, true};
+    }
+
+    void swap(OrderedMap& other) noexcept {
+        data_.swap(other.data_);
+        index_.swap(other.index_);
+    }
+};
+
+#endif  // __ORDERED_MAP_HPP__