Length-delimited encoding

So far, we’ve seen how to encode values that have static sizes. For example, when dealing with the encoding of an int32, Protobuf deals with 4 bytes and turns them into a variable number of bytes. The same is true with other number types. In this section, we are going to learn how to encode a value that has a dynamic size. In other words, a size that can only be determined at runtime.

The types with such a dynamic size are strings and bytes. However, some other parts of Protobuf are encoded with length-delimited encoding: embedded messages and packed repeated fields. We are going to talk about the latter in the next section, but we are going to see strings and embedded messages here.

Let’s look at an example of encoding strings in Protobuf. Once again, we are going to create a message (length_delimited/encoding.proto):

syntax = "proto3";
message Encoding {
  string s = 1;
}

We’re also going to describe the...