protobuf问题总结

来源：互联网发布：时间小人 js插件编辑：程序博客网时间：2024/05/18 06:19

今天遇到奇葩问题解析string始终不对

这里搜集一下网上的说法:

The C++ implementation of protocol buffers returns the byte and string types as std::string. This structure contains a length function telling you how long the corresponding data is (as well as the data itself.) Thus there is no special significance of embeded \0 characters.

The setting functions accept a string too, or there are versions that accept a buffer and length. If you want to set a field you can just do this:

pb.set_foo( std::string( data, data_length ) );

pb.set_foo( data, data_length )

A follow-up to my own previous comment - I figured out how to do enums and optional types. The latter is done via nullable types, I never saw that documented here.
If anyone knows how to encode default values, I would love to hear about it.
Meanwhile, here's a demo proto definition and its corresponding proto.net implemenation. Hope that helpful to someone:
// -----------------------------------------------------------------------------// DemoMessage.proto// -----------------------------------------------------------------------------message DemoMessage {  message WildThing  {    enum Coolness {      COOLNESS_NOT_SO_MUCH = 0;      COOLNESS_EXTREMELY_SO = 1;    }    optional Coolness coolness = 1 [default = COOLNESS_NOT_SO_MUCH];    optional float toxicity_PPM = 2 [default = 0.12];  }  optional InnerThing wildThing = 1;  optional uint64 posixTime_Msec = 2;  optional float volume_dBm = 3 [default = -112.0];}// -----------------------------------------------------------------------------// Proto.DemoMessage.cs// -----------------------------------------------------------------------------using System;using System.IO;using ProtoBuf;// -----------------------------------------------------------------------------namespace Whatever{    // -------------------------------------------------------------------------    [ProtoContract]    public sealed class Proto_DemoMessage    {        [ProtoContract]        public sealed class WildThingMessage        {            public enum CoolnessSetting { NotSoMuch = 0, ExtremelySo = 1 }            [ProtoMember(1, IsRequired = false)]            public CoolnessSetting? Coolness { get; set; }            [ProtoMember(2, IsRequired = false)]            public float? Toxicity_PPM { get; set; }        }        [ProtoMember(1, IsRequired = false)]        public WildThingMessage WildThing { get; set; }        [ProtoMember(2, IsRequired = false)]        public UInt64? PosixTime_Msec { get; set; }        [ProtoMember(3, IsRequired = false)]        public float? Volume_dBm { get; set; }        // ---------------------------------------------------------------------        // ---------------------------------------------------------------------        public byte[] Serialize()        {            byte[] b = null;            using (var ms = new MemoryStream())            {                Serializer.Serialize<Proto_DemoMessage>(ms, this);                b = new byte[ms.Position];                var fullB = ms.GetBuffer();                Array.Copy(fullB, b, b.Length);            }            return b;        }        // ---------------------------------------------------------------------        public static Proto_DemoMessage Deserialize(byte[] serializationBytes)        {            Proto_DemoMessage m = null;            using (var ms = new MemoryStream(serializationBytes))            {                m = Serializer.Deserialize<Proto_DemoMessage>(ms);            }            return m;        }    }}
Hello, standart BinnaryWriter? is faster then ProtoBuf?, why ? Here is my code:
private static void Main(string[] args)        {            Test test = new Test();            test.Name = "TestName";            //=====BinaryFormatter            var st = new Stopwatch();            st.Start();            var formatter = new BinaryFormatter();            for (int i = 0; i < 100; i++)            {                using (var stream = new MemoryStream())                {                    stream.Position = 0;                    formatter.Serialize(stream, test);                    stream.Position = 0;                    var result = (Test)formatter.Deserialize(stream);                    string name = result.Name;                    stream.Close();                }            }            st.Stop();            Console.WriteLine("BinaryFormatter = " + st.ElapsedMilliseconds);            //======ProtoBuf            st.Reset();            st.Start();            for (int i = 0; i < 100; i++)            {                using (var stream = new MemoryStream())                {                    stream.Position = 0;                    Serializer.Serialize(stream, test);                    stream.Position = 0;                    var result = Serializer.Deserialize<Test>(stream);                    string name = result.Name;                    stream.Close();                }            }            st.Stop();            Console.WriteLine("ProtoBuff = " + st.ElapsedMilliseconds);        }        [ProtoContract]        [Serializable]        internal class Test        {            [ProtoMember(1)]            public string Name { get; set; }        }
The result is: BinaryFormatter? = 6 msec ProtoBuf? = 352 msec

https://github.com/hultqvist/protobuf

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