[protobuf] Repeated Fields Encoding
Hello, Considering the following proto file: message FileDescriptor { required string Filename = 1; optional int64 Size = 2 [default = 0]; } message FileList { repeated FileDescriptor Files = 1; } If you create something like this: (and I'm duplicating the data because it made it easier to spot in a hex editor) files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); and then serialize it using the Protobuf.Serializer I expected it to generate something like Tag for the FileList - Id 1, WireType 2 = 0x0A Length of the payload (all the bytes for all the files that follow) But instead I found everything is simply repeated. 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 I'm wondering, is this an implementation detail (and allowed by the protobol buffer specifications) or a requirement of the google protocol buffer specifications ? It does seem to add quite a bit of overhead, imagine the FileList has other properties, they would be repeated for every instance of FileDescriptor ? Or am I missing something ? -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] Repeated Fields Encoding
I think this also came to me directly and I answered earlier, but this is the expected layout of repeated data, where each item in a list is mapped separately in the data stream. Marc On 1 Feb 2011, at 11:01, Timothy Parez timothypa...@gmail.com wrote: Hello, Considering the following proto file: message FileDescriptor { required string Filename = 1; optional int64 Size = 2 [default = 0]; } message FileList { repeated FileDescriptor Files = 1; } If you create something like this: (and I'm duplicating the data because it made it easier to spot in a hex editor) files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); and then serialize it using the Protobuf.Serializer I expected it to generate something like Tag for the FileList - Id 1, WireType 2 = 0x0A Length of the payload (all the bytes for all the files that follow) But instead I found everything is simply repeated. 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 I'm wondering, is this an implementation detail (and allowed by the protobol buffer specifications) or a requirement of the google protocol buffer specifications ? It does seem to add quite a bit of overhead, imagine the FileList has other properties, they would be repeated for every instance of FileDescriptor ? Or am I missing something ? -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en. -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.
Re: [protobuf] Repeated Fields Encoding
The encoding is documented in detail here: http://code.google.com/apis/protocolbuffers/docs/encoding.html http://code.google.com/apis/protocolbuffers/docs/encoding.htmlThe short answer is, yes, repeated fields are literally encoded as repeated individual values, unless you use packed encoding. On Tue, Feb 1, 2011 at 3:01 AM, Timothy Parez timothypa...@gmail.comwrote: Hello, Considering the following proto file: message FileDescriptor { required string Filename = 1; optional int64 Size = 2 [default = 0]; } message FileList { repeated FileDescriptor Files = 1; } If you create something like this: (and I'm duplicating the data because it made it easier to spot in a hex editor) files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); files.Files.Add(new FileDescriptor() { Filename = AAA, Size = 100 }); and then serialize it using the Protobuf.Serializer I expected it to generate something like Tag for the FileList - Id 1, WireType 2 = 0x0A Length of the payload (all the bytes for all the files that follow) But instead I found everything is simply repeated. 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 0A 0B 0A 07 41 41 41 41 41 41 41 10 64 I'm wondering, is this an implementation detail (and allowed by the protobol buffer specifications) or a requirement of the google protocol buffer specifications ? It does seem to add quite a bit of overhead, imagine the FileList has other properties, they would be repeated for every instance of FileDescriptor ? Or am I missing something ? -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.comprotobuf%2bunsubscr...@googlegroups.com . For more options, visit this group at http://groups.google.com/group/protobuf?hl=en. -- You received this message because you are subscribed to the Google Groups Protocol Buffers group. To post to this group, send email to protobuf@googlegroups.com. To unsubscribe from this group, send email to protobuf+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/protobuf?hl=en.