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Feature #22431 ยป benchmark.rb

ntkme (Natsuki Natsume), 10/12/2026 10:31 PM

 
# frozen_string_literal: true

require 'bundler/inline'

gemfile do
source 'https://rubygems.org'
gem 'benchmark-ips', require: false
end

require 'benchmark/ips'
require 'stringio'

# Pure ruby equivalent to unsigned leb128
module Varint
module_function

def length(value)
return 1 if value < 128

(value.bit_length + 6) / 7
end

def read(readable)
value = bits = 0
loop do
byte = readable.readbyte
value |= (byte & 0x7f) << bits
bits += 7
break if byte < 0x80
end
value
end

def write(writeable, value)
until value < 0x80
writeable << ((value & 0x7f) | 0x80)
value >>= 7
end
writeable << value
end
end

# N = (0..10)
N = (2_147_483_637..2_147_483_647)

# a stream of varint/leb128
io = StringIO.new.binmode
N.each do |i|
buffer = []
Varint.write(buffer, i)
io.write(buffer.pack('C*'))
end

Benchmark.ips do |x|
x.config(warmup: 1, time: 5)

x.report('write varint (pure ruby)') do
io = StringIO.new
N.each do |i|
buffer = []
Varint.write(buffer, i)
io.write(buffer.pack('C*'))
end
end

x.report('write leb128 (native) ') do
io = StringIO.new
N.each do |i|
io.write([i].pack('R'))
end
end

x.compare!
end

Benchmark.ips do |x|
x.config(warmup: 1, time: 5)

x.report('read varint (pure ruby)') do
io.rewind
N.each do
Varint.read(io)
end
end

x.report('read leb128 (native) ') do
io.rewind
N.each do
buffer = []
loop do
byte = io.readbyte
buffer << byte
break if byte < 0x80
end
buffer.pack('C*').unpack1('R')
end
end

x.compare!
end
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