How do I serialize and deserialize contents with std::unordered_map for large datasets?

In C++, to serialize and deserialize an std::unordered_map, we can use various techniques, including JSON or binary serialization. For large datasets, it is crucial to ensure that the serialization process is efficient to minimize memory usage and processing time.

Serialization

Serialization involves transforming the std::unordered_map into a storable format. For an unordered map, we typically convert each key-value pair into a string format. Here’s an example using JSON format for serialization:


    #include <unordered_map>
    #include <string>
    #include <fstream>
    #include <nlohmann/json.hpp> // for JSON handling
    using json = nlohmann::json;

    std::string serialize(const std::unordered_map<std::string, int> &data) {
        json j = data; // convert to JSON
        return j.dump(); // return JSON as string
    }

Deserialization

Deserialization is the reverse process where we convert the stored format back into an std::unordered_map. Here's how we can do it:


    std::unordered_map<std::string, int> deserialize(const std::string &str) {
        json j = json::parse(str); // parse JSON string
        return j.get<std::unordered_map<std::string, int>>(); // convert to unordered_map
    }

Example Usage


    int main() {
        std::unordered_map<std::string, int> myMap = {{"apple", 1}, {"banana", 2}, {"cherry", 3}};
        
        // Serialize
        std::string serializedData = serialize(myMap);
        
        // Save to file
        std::ofstream outFile("data.json");
        outFile << serializedData;
        outFile.close();
        
        // Load from file
        std::ifstream inFile("data.json");
        std::string deserializedData((std::istreambuf_iterator<char>(inFile)), std::istreambuf_iterator<char>());

        // Deserialize
        auto newMap = deserialize(deserializedData);
    }

serialization deserialization unordered_map C++ JSON large datasets

How do I serialize and deserialize contents with std::unordered_map for large datasets?

Serialization

Deserialization

Example Usage

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How do I serialize and deserialize contents with std::unordered_map for large datasets?

Serialization

Deserialization

Example Usage

Related Questions

Popular Topics

Recent Languages