C The method to implement serialization includes manual implementation and use of third-party libraries. Manual implementation is suitable for simple structures. You need to read and write byte streams in the order of fields, pay attention to string boundaries and cross-platform issues; common steps: 1. Write object fields into byte streams in sequence 2. Read in the same order when deserializing 3. You need to record the length or ending characters when processing strings 4. Consider the differences in byte order and alignment. Use third-party libraries to suit complex needs. Common solutions: 1. Boost.Serialization supports multiple formats but depends on Boost 2. protobuf is efficient across languages, suitable for communication and persistence 3. FlatBuffers directly access data without parsing 4. MessagePack is lightweight and cross-platform; taking protobuf as an example process as defining.proto files, generating code, and calling class methods to complete serialization/deserialization. Notes include version compatibility, data security, performance optimization and readability selection.

C itself does not have a built-in serialization mechanism like Java or Python, but through some common methods, we can implement persistent storage or network transmission of object state. The key is to understand the purpose of serialization and choose the appropriate implementation method.

What is serialization?

Serialization refers to converting the state of an object into a form that can be stored or transferred (such as binary, JSON, XML, etc.). In C, this process is usually implemented manually, or done with the help of a third-party library.

How to manually implement basic serialization?

If you only need to deal with simple data structures, writing serialization and deserialization functions manually is a viable option.

• Basic idea : Write each field of the object into a byte stream in sequence (such as std::ofstream ) and read it in the same order when deserialized.
• Note the field order : the field order must be consistent during serialization and deserialization, otherwise the data will be incorrect.
• Be careful when processing strings : strings need to record length or end with \0 , otherwise the boundary cannot be judged during reading.
• Consider cross-platform issues : for example, different systems may have different endian orders (big endian/little endian), and the structure alignment may also be different.

For example, a simple structure:

 struct Person {
    int age;
    std::string name;

    void serialize(std::ostream& os) const {
        os.write(reinterpret_cast<const char*>(&age), sizeof(age));
        uint32_t len = name.size();
        os.write(reinterpret_cast<const char*>(&len), sizeof(len));
        os.write(name.data(), len);
    }

    void deserialize(std::istream& is) {
        is.read(reinterpret_cast<char*>(&age), sizeof(age));
        uint32_t len;
        is.read(reinterpret_cast<char*>(&len), sizeof(len));
        name.resize(len);
        is.read(&name[0], len);
    }
};

Use third-party libraries to simplify operations

For more complex requirements, such as nested structures, cross-language compatibility, network communication, etc., it is recommended to use existing serialization libraries.

Common C serialization libraries include:

• Boost.Serialization : Powerful, supports multiple formats, but relying on the Boost library, the compilation may be heavier.
• Google Protocol Buffers (protobuf) : Good cross-language support, high efficiency, suitable for network communication and persistence.
• FlatBuffers : Access serialized data without parsing, suitable for performance-sensitive scenarios.
• MessagePack : JSON-like binary format, lightweight and cross-platform.

A simple process to use protobuf:

1. Define the .proto file description structure
2. Use protoc to compile and generate C code
3. Serialization/deserialization using generated classes

For example:

 message Person {
  int32 age = 1;
  string name = 2;
}

Then:

 Person person;
person.set_age(25);
person.set_name("Tom");

std::string buffer;
person.SerializeToString(&buffer); // Serialize Person p2;
p2.ParseFromString(buffer); // Deserialization

Issues to be aware of

When using serialization, some details are easily overlooked but are important:

• Version compatibility : If the structure changes (such as adding and deleting fields), make sure that the old data can be correctly parsed by the new code.
• Security : Don't blindly trust deserialized data, especially when it comes from the network, to prevent malicious input.
• Performance : For large amounts of data or high frequency operations, select efficient serialization formats and libraries.
• Readability : If you need debugging or manual viewing, you can choose JSON, XML and other formats.

Basically that's it. Manual implementation is not complicated but it is easy to ignore details. Using libraries is easier to use but also requires understanding the basic principles.

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