Ruby script that interprets brainfuck code

bf_interpreter.rb

class BrainfuckInterpreter
  
  BF_CHARS = {
    inc_ptr: ">",
    dec_ptr: "<",
    inc_val: "+",
    dec_val: "-",
    loop_begin: "[",
    loop_end: "]",
    output: ".",
    input: ","
  }

  attr_reader :rounds, :max, :output, :pointer
  attr_accessor :code
  
  def initialize
    @code = ""
    @code_pointer = 0
    @cells = []
    @pointer = 0
    @rounds = 0
    @max = 1
  end
  
  def reset!
    @code_pointer = 0
    @cells = []
    @pointer = 0
    @rounds = 0
    @max = 1
  end

  def interpret! bf_cmds = BF_CHARS, input: $stdin, output: $stdout
    loops = []
    while @code_pointer < @code.length
      c = @code[@code_pointer]
      case c
      when bf_cmds[:dec_ptr]
        @pointer -= 1
      when bf_cmds[:inc_ptr]
        @pointer += 1
      when bf_cmds[:inc_val]
        @cells[@pointer] = @cells[@pointer].to_i + 1
      when bf_cmds[:dec_val]
        @cells[@pointer] -= 1 if @cells[@pointer].to_i > 0
      when bf_cmds[:output]
        output.putc @cells[@pointer].to_i.chr
      when bf_cmds[:input]
        @cells[@pointer] = "#{input.getc.to_s} ".ord
      when bf_cmds[:loop_begin]
        loops << @code_pointer
        @code_pointer = find_closing_bracket(bf_cmds) - 1
      when bf_cmds[:loop_end]
        if @cells[@pointer].to_i == 0
          loops.pop
        else
          @code_pointer = loops[-1]
        end
      else

      end
      @code_pointer += 1
      @rounds += 1
      @max = @pointer if @pointer > max
    end
    
    @max += 1
  end
  
  protected
  
  def find_closing_bracket bf_cmds
    counter = 0
    search = @code_pointer + 1
    
    while search < @code.length
      case @code[search]
      when bf_cmds[:loop_begin]
        counter += 1
      when bf_cmds[:loop_end]
        if counter > 0
          counter -= 1
        else
          break
        end
      end
      search += 1
    end
    
    return search
  end
  
end

=begin
Example:
  int = BrainfuckInterpreter.new
  # simple caeser crypt with key 1
  int.code = "[-]>,[>,]<[+<]>[.>]"
  int.interpret!
=end