strange (crystal lang https://github.com/manastech/crystal)

1.cr

def foo(n)
  String.new_with_capacity(n * 4 + 10) do |buf|
    bufc = 0
    bar(n) do |byte|
      buf[bufc] = byte
      bufc += 1
    end
    bufc
  end
end

def bar(n)
  n.times do
    yield 33_u8
    yield 34_u8
    yield 35_u8
    yield 36_u8
  end

  case rand(3)
  when 1
    yield 37_u8
    yield 38_u8
  when 2
    yield 39_u8
    yield 33_u8
    yield 33_u8
  end
end

t = Time.now
s = 0_u64
1000.times{ |i| res = foo(100000); s += res[i] }
p s
p Time.now - t

2.cr

def foo(n)
  String.new_with_capacity(n * 4 + 10) do |buf|
    bufc = 0
    bar(n) do |byte|
      buf[bufc] = byte
      bufc += 1
    end
    bufc
  end
end

def bar(n)
  n.times do
    yield 33_u8
    yield 34_u8
    yield 35_u8
    yield 36_u8
  end

  case rand(3)
  when 1
    yield 37_u8
    yield 38_u8
  when 2
    yield 39_u8
    yield 33_u8
    #yield 33_u8
  end
end

t = Time.now
s = 0_u64
1000.times{ |i| res = foo(100000); s += res[i] }
p s
p Time.now - t

./bin/crystal 1.cr --release && ./1
34500
1.4392
./bin/crystal 2.cr --release && ./2
34500
0.309147