tree 2abbe8342df281472a67c1bacfea8ac69c73056c
parent 9d637ca923bb45691809405615095ed8dc2a2431
author Joe Tsai <joetsai@digital-static.net> 1568784773 -0700
committer Joe Tsai <joetsai@digital-static.net> 1568917238 +0000

encoding: optimize for oneofs

Suppose a oneof has N fields, the previous marshaling logic
would traverse every field checking for presence. This is O(N).
Using the protoreflect.Message.WhichOneof method, we can reduce
this to O(1). This optimization is exceptionally useful for oneofs
with a large number of fields.

Change-Id: I5f4aa8b1a899930f5c95e9cf1d68bac4b0b7884d
Reviewed-on: https://go-review.googlesource.com/c/protobuf/+/196121
Reviewed-by: Herbie Ong <herbie@google.com>