Adds new StringViewDictionary with specialized methods to retrieve values by the hash of the StringView
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Deukhoofd 2022-05-16 16:36:52 +02:00
parent b9ea517f6e
commit e0c16b772c
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@ -0,0 +1,141 @@
#ifndef ARBUTILS_STRINGVIEWDICTIONARY_HPP
#define ARBUTILS_STRINGVIEWDICTIONARY_HPP
#include <algorithm>
#include <functional>
#include <optional>
#include <unordered_map>
#include "../Ensure.hpp"
#include "../StringView.hpp"
namespace ArbUt {
/// @brief Wrapper around unordered_map, allowing safer access and adding several helper methods.
template <class ValueT> class StringViewDictionary {
private:
struct StringViewHash
{
using hash_type = std::hash<StringView>;
using is_transparent = void;
size_t operator()(const char* str) const { return hash_type{}(str); }
size_t operator()(StringView const& str) const { return hash_type{}(str); }
size_t operator()(u32 hash) const { return hash; }
};
std::unordered_map<StringView, ValueT, StringViewHash, std::equal_to<>> _map;
using iterator = typename std::unordered_map<StringView, ValueT>::iterator;
using const_iterator = typename std::unordered_map<StringView, ValueT>::const_iterator;
public:
/// @brief The type used for the indexer of the dictionary.
typedef StringView keyType;
/// @brief The type used for the value in the dictionary.
typedef ValueT valueType;
StringViewDictionary() : _map() {}
/// @brief Initialises a dictionary with a certain capacity.
explicit StringViewDictionary(size_t capacity) : _map(capacity) {}
/// @brief Initialises a dictionary from an initializer_list.
StringViewDictionary(const std::initializer_list<std::pair<const StringView, ValueT>>& l) : _map(l) {}
/// @brief Copy operator
StringViewDictionary(const StringViewDictionary& other) noexcept : _map(other._map) {}
/// @brief Assignment operator
StringViewDictionary& operator=(const StringViewDictionary& other) noexcept {
if (this == &other) {
return *this;
}
_map = other._map;
return *this;
}
/// @brief Removes all items from the dictionary.
inline void Clear() noexcept { _map.clear(); }
/// @brief Inserts a new item in the dictionary. This will throw if the dictionary already contains the key.
inline void Insert(const StringView& key, const ValueT& value) {
[[maybe_unused]] const auto& v = _map.insert({key, value});
#ifndef NO_ASSERT
if (!v.second)
throw ArbUt::Exception("Key already exists");
#endif
}
/// @brief Sets a key in the dictionary to a specific value.
inline void Set(const StringView& key, const ValueT& value) { _map[key] = value; }
/// @brief Gets a value from the dictionary.
[[nodiscard]] inline ValueT& Get(const StringView& key) {
#ifndef NO_ASSERT
return _map.at(key);
#else
return _map[key];
#endif
}
/// @brief Gets a value from the dictionary.
[[nodiscard]] inline const ValueT& Get(const StringView& key) const { return _map.at(key); }
/// @brief Gets a value from the dictionary using the direct hash of the key.
[[nodiscard]] inline ValueT& GetFromHash(u32 hash) {
#ifndef NO_ASSERT
return _map.find(hash)->second;
#else
return _map[key];
#endif
}
/// @brief Gets a value from the dictionary using the direct hash of the key.
[[nodiscard]] inline const ValueT& GetFromHash(u32 hash) const { return _map.find(hash)->second; }
/// @brief Try to get an item from the dictionary using a key. Returns false if no item is found, and out will
/// not be touched in that case.
inline std::optional<std::reference_wrapper<const ValueT>> TryGet(const StringView& key) const noexcept {
const auto& find = _map.find(key);
if (find == _map.end()) {
return {};
}
return std::ref(find->second);
}
/// @brief Try to get an item from the dictionary using the hash of a key. Returns false if no item is found, and out will
/// not be touched in that case.
inline std::optional<std::reference_wrapper<const ValueT>> TryGet(u32 hash) const noexcept {
const auto& find = _map.find(hash);
if (find == _map.end()) {
return {};
}
return std::ref(find->second);
}
/// @brief Removes an item with a certain key from the dictionary
inline void Remove(const StringView& key) { _map.erase(key); }
/// @brief Returns the number of items in the dictionary.
[[nodiscard]] inline size_t Count() const noexcept { return _map.size(); }
/// @brief Checks whether the dictionary contains a specific key.
inline bool Has(const StringView& key) const noexcept { return _map.find(key) != _map.end(); }
/// @brief Indexing operator to get a value from the dictionary using a key.
inline ValueT& operator[](const StringView& key) { return Get(key); }
/// @brief Indexing operator to get a value from the dictionary using a key.
inline const ValueT& operator[](const StringView& key) const { return Get(key); }
/// @brief returns an iterator to the beginning of the specified bucket
iterator begin() noexcept { return _map.begin(); }
/// @brief returns an iterator to the beginning of the specified bucket
const_iterator begin() const noexcept { return _map.begin(); }
/// @brief returns an iterator to the end of the specified bucket
iterator end() noexcept { return _map.end(); }
/// @brief returns an iterator to the end of the specified bucket
const_iterator end() const { return _map.end(); }
/// @brief returns the backing unordered_map.
const std::unordered_map<StringView, ValueT>& GetStdMap() const noexcept { return _map; }
/// @brief returns the backing unordered_map.
std::unordered_map<StringView, ValueT>& GetStdMap() noexcept { return _map; }
};
}
#endif // ARBUTILS_STRINGVIEWDICTIONARY_HPP

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@ -1,6 +1,7 @@
#ifdef TESTS_BUILD #ifdef TESTS_BUILD
#include <doctest.h> #include <doctest.h>
#include "../src/Collections/Dictionary.hpp" #include "../src/Collections/Dictionary.hpp"
#include "../src/Collections/StringViewDictionary.hpp"
using namespace ArbUt; using namespace ArbUt;
TEST_CASE("Create Dictionary, insert values") { TEST_CASE("Create Dictionary, insert values") {
@ -107,4 +108,14 @@ TEST_CASE("Create Dictionary with different types, insert values, iterate over k
CHECK(i == 3); CHECK(i == 3);
} }
TEST_CASE("Create StringViewDictionary, insert values, get values by hash") {
auto dic = StringViewDictionary<i32>(5);
dic.Insert("foo"_cnc, 5);
dic.Insert("bar"_cnc, 100);
dic.Insert("zet"_cnc, 2000);
CHECK(dic.GetFromHash("bar"_cnc) == 100);
}
#endif #endif