C ++：如何序列化/反序列化对象没有任何库？

问题描述

我试着理解序列化/反序列化在c ++中如何工作，所以我想做没有任何lib。但我真的坚持。我从简单的对象开始，但当我尝试解冻一个向量我明白，我不能得到一个向量，如果我不写它的大小之前。此外，我不知道应该选择哪种格式的文件，因为如果数字将存在于矢量大小之前我没有机会读它正确。但是它只是向量，但我也想做类和地图容器。我的任务是序列化/反序列化一个对象，如下：

I try to understand how serializing/deserializing works in c++, so I want to do that without any libs. But I really stuck with that. I start with simple objects but when I try to deserilize a vector I understand that I can't get a vector without if I don't write it size before. Moreover, I don't know which format of file I should choose because if digits will be existed before size of vector I haven't chance to read it right. However it is only the vector but I also want to do that with classes and map container. My task is serialize/deserialize a objects as this:

PersonInfo
{
    unsigned int    age_;
    string name_;
    enum { undef, man, woman } sex_;
}

Person : PersonInfo
{
    vector<Person>      children_;
    map<string, PersonInfo>     addrBook_;
}

目前我知道如何将简单对象序列化为：

Currently I know how to serialize simple objects in way as this:

vector<PersonInfo> vecPersonInfo;
vecPersonInfo.push_back(*personInfo);
vecPersonInfo.push_back(*oneMorePersonInfo);

ofstream file("file", ios::out | ios::binary);
if (!file) {
    cout<<"can not open file";
} else {
    vector<PersonInfo>::const_iterator iterator = vecPersonInfo.begin();
    for (; iterator != vecPersonInfo.end(); iterator++) {
        file<<*iterator;
    }

你能建议我如何做这个conplex对象或好

Could you please suggest how I can do this for this conplex object or a good tutorial that explain it clearly?

推荐答案

一种模式是实现一个抽象类，定义函数用于序列化，类定义了什么到串行器和什么出来。一个例子是：

One pattern is to implement an abstract class the defines functions for serialization and the class defines what goes into the serializer and what comes out. An example would be:

class Serializable
{
public:
    Serializable(){}
    virtual ~Serializable(){}

    virtual void serialize(std::ostream& stream) = 0;
    virtual void deserialize(std::istream& stream) = 0;
};

然后，您要为要序列化的类/ struct实现Serializable接口：

You then implement Serializable interface for the class/struct that you want to serialize:

struct PersonInfo : public Serializable // Yes! It's possible
{
    unsigned int age_;
    string name_;
    enum { undef, man, woman } sex_;

    virtual void serialize(std::ostream& stream)
    {
        // Serialization code
        stream << age_ << name_ << sex_;
    }

    virtual void deserialize(std::istream& stream)
    {
        // Deserialization code
        stream >> age_ >> name_ >> sex_;
    }
};

休息我相信你知道。这里有一些障碍可以通过，可以在你的休闲：

Rest I believe you know. Here's a few hurdles to pass though and can be done in your leisure:

1. 当你写一个字符串到流中，尝试读取它，你将只得到它的一部分，其余的字符串'腐败'之后读取的值。


2. 如何编程，使其跨平台（little-endian vs big-endian）


3. 您的程序如何自动检测，反序列化时创建哪个类。

Clues：

1. 使用具有编写bool，int，float， / li>
   
2. 使用字符串表示正在序列化的对象类型，并在反序列化时使用factory创建该对象的实例。


3. 使用预定义的宏来确定

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