str_concat.rb

# frozen_string_literal: true
require_relative '../harness/loader'

NUM_ITERS = 10 * 1024
TEST_STR = 'sssssséé'.freeze
EXPECTED_OUTPUT = TEST_STR * NUM_ITERS
OUTPUT = {}

# Structuring this with a single method means we will not
# get a single-encoding call site. That doesn't matter now,
# but may matter with more-optimised generated code.
def concat_single_test(n, encoding, str_to_add)
  # We used to supply capacity when building a string, but so far
  # it makes only a very small difference - around 5.08 vs 5.09 sec
  # for 10k iterations. Maybe add it back when/if we've optimised
  # significantly more?
  s = String.new(encoding: encoding)
  i = 0
  while i < n
    s << str_to_add
    i += 1
  end

  s
end

if ENV["RUBY_BENCH_RACTOR_HARNESS"]
  def concat_test
    # So far, binary versus UTF-8 encoding makes effectively no
    # difference in speed here. Observed diff is around 69.5 vs 68.9
    # iters/sec.
    concat_single_test(NUM_ITERS, Encoding::UTF_8, TEST_STR)
    concat_single_test(NUM_ITERS, Encoding::BINARY, TEST_STR)
  end
else
  def concat_test
    # So far, binary versus UTF-8 encoding makes effectively no
    # difference in speed here. Observed diff is around 69.5 vs 68.9
    # iters/sec.
    OUTPUT[:one] = concat_single_test(NUM_ITERS, Encoding::UTF_8, TEST_STR)
    OUTPUT[:two] = concat_single_test(NUM_ITERS, Encoding::BINARY, TEST_STR)
  end
end

run_benchmark(100) do
  100.times { concat_test }
end

unless ENV["RUBY_BENCH_RACTOR_HARNESS"]
  if OUTPUT[:one] != EXPECTED_OUTPUT
    raise "Incorrect output for UTF-8 encoding!"
  end

  if OUTPUT[:two] != EXPECTED_OUTPUT
    raise "Incorrect output for binary encoding!"
  end
end