protocol buffer

https://developers.google.com/protocol-buffers/docs/overview

Protobuf是一種可以實現內存與外存交換的協議接口。可以理解爲一種通信協議．caffe就是使用了這種協議．

protobuf使用前，先編寫proto文件，這是描述我們需要配置參數的數據結構。例如：
// See README.txt for information and build instructions.

package tutorial;  

option java_package = "com.example.tutorial";  
option java_outer_classname = "AddressBookProtos";  

message Person {  
  required string name = 1;  
  required int32 id = 2;        // Unique ID number for this person.  
  optional string email = 3;  

  enum PhoneType {  
    MOBILE = 0;  
    HOME = 1;  
    WORK = 2;  
  }  

  message PhoneNumber {  
    required string number = 1;  
    optional PhoneType type = 2 [default = HOME];  
  }  

  repeated PhoneNumber phone = 4;  
}  

// Our address book file is just one of these.  
message AddressBook {  
  repeated Person person = 1;  
}  

然後用protobuf工具生成接口代碼：
protoc –cpp_out=. addressbook.proto

運行後生成了兩個文件：addressbook.pb.cc 和addressbook.pb.h
包含了操作參數，序列化，反序列化的接口函數．（add_person(), add_phone(), set_number(), set_email()，SerializeToOstream()，ParseFromIstream()等）