varint.rb

require 'benchmark'
require 'protobuf'
require 'varint/varint'

ITERATIONS = 1_000_000

class Test
  extend ::Varint
  
  def self.pure_alt(io)
    int_val = 0
    shift = 0
    loop do
      byte = io.getbyte
      int_val |= (byte & 0b0111_1111) << shift
      shift += 7
      return int_val if (byte & 0b1000_0000) == 0
    end
  end
end

Benchmark.bm do |x|
  x.report(:pure_protobuf) do
    ITERATIONS.times do
      Protobuf::Decoder.read_varint(StringIO.new("9_999_999_999_999_999_999"))
    end
  end
  
  x.report(:pure_alt) do
    ITERATIONS.times do
      Test.pure_alt(StringIO.new("9_999_999_999_999_999_999"))
    end
  end

  x.report(:c) do
    ITERATIONS.times do
      Test.decode(StringIO.new("9_999_999_999_999_999_999"))
    end
  end
end
`