Dictionary.hpp

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//
//  CeresEngine - A game development framework
//
//  Created by Rogiel Sulzbach.
//  Copyright (c) 2018-2022 Rogiel Sulzbach. All rights reserved.
//
 
#pragma once
 
#include "CeresEngine/Foundation/String.hpp"
#include "CeresEngine/Foundation/Container/InitializerList.hpp"
#include "CeresEngine/Foundation/Container/Map.hpp"
#include "CeresEngine/Foundation/Container/Vector.hpp"
 
#include <algorithm>
 
namespace CeresEngine::ShaderCompiler {
 
    // Bidirectional map template class, where Key = string, Value = T. 'T' must be an asceding enumerable type.
    template<typename T> class Dictionary {
    public:
        Dictionary() = default;
        Dictionary(const Dictionary&) = default;
 
        Dictionary(const InitializerList<Pair<String, T>>& stringToEnumPairs) : mStringToEnum{stringToEnumPairs.begin(), stringToEnumPairs.end()} {
            std::size_t maxIndex = 0;
 
            for(const auto& pair : stringToEnumPairs) {
                maxIndex = std::max(maxIndex, static_cast<std::size_t>(pair.second));
            }
 
            mEnumToString.resize(maxIndex + 1, nullptr);
 
            for(const auto& pair : stringToEnumPairs) {
                const auto idx = static_cast<std::size_t>(pair.second);
                if(mEnumToString[idx] == nullptr) {
                    auto it = mStringToEnum.find(pair.first);
                    if(it != mStringToEnum.end()) {
                        mEnumToString[idx] = &(it->first);
                    }
                }
            }
        }
 
        // Returns a pointer to the enumeration entry which is associated to the specified string, or null on failure.
        [[nodiscard]] const T* stringToEnum(const String& s) const {
            auto it = mStringToEnum.find(s);
            if(it != mStringToEnum.end()) {
                return &(it->second);
            }
            return nullptr;
        }
 
        // Returns the enumeration entry which is associated to the specified string, or the default value on failure.
        [[nodiscard]] T stringToEnumOrDefault(const String& s, const T& defaultValue) const {
            auto it = mStringToEnum.find(s);
            if(it != mStringToEnum.end()) {
                return it->second;
            }
            return defaultValue;
        }
 
        // Returns a pointer to the first string which is associated to the specified enumeration entry, or null on failure.
        [[nodiscard]] const String* enumToString(const T& e) const {
            const auto idx = static_cast<std::size_t>(e);
            if(idx < mEnumToString.size()) {
                return mEnumToString[idx];
            }
            return nullptr;
        }
 
        // Returns the first string which is associated to the specified enumeration entry, or the default string on failure.
        [[nodiscard]] String enumToStringOrDefault(const T& e, const String& defaultString) const {
            const auto idx = static_cast<std::size_t>(e);
            if(idx < mEnumToString.size()) {
                if(const auto s = mEnumToString[idx]) {
                    return *s;
                }
            }
            return defaultString;
        }
 
    private:
        Map<String, T> mStringToEnum;
        Vector<const String*> mEnumToString;
    };
 
} // namespace CeresEngine::ShaderCompiler