• 先关注一下GPB怎么序列化和反序列化
  • Parsing and Serialization(C++)
    • 举例
• encoding介绍

官方手册: https://developers.google.com/protocol-buffers

1. 先关注一下GPB怎么序列化和反序列化

1.1. Parsing and Serialization(C++)

Finally, each protocol buffer class has methods for writing and reading messages of your chosen type using the protocol buffer binary format. These include:

• bool SerializeToString(string* output) const;: serializes the message and stores the bytes in the given string. Note that the bytes are binary, not text; we only use the string class as a convenient container.
• bool ParseFromString(const string& data);: parses a message from the given string.
• bool ParseFromArray(const void * data, int size): Parse a protocol buffer contained in an array of bytes.
• bool SerializeToOstream(ostream* output) const;: writes the message to the given C++ ostream.
• bool ParseFromIstream(istream* input);: parses a message from the given C++ istream.

These are just a couple of the options provided for parsing and serialization. Again, see the Message API reference for a complete list.

1.1.1. 举例

比如定义了一个proto是AddressBook, protoc生成了对应的类.

# 声明这个类的对象
tutorial::AddressBook address_book;

# 从os.in读一个对象出来
fstream input(argv[1], ios::in | ios::binary);
address_book.ParseFromIstream(&input)

# 写到os.out
fstream output(argv[1], ios::out | ios::trunc | ios::binary);
address_book.SerializeToOstream(&output)

2. encoding介绍

是binary模式的编码, int是变长的, 叫varints

简明列表:https://developers.google.com/protocol-buffers/docs/encoding