Bittorrent的编码模块的ruby代码

最近看了看bt的源码，随手写了些ruby的代码：

def encode(x)
  case x.class.to_s
  when "Float"
    encode_num(x)
  when "Fixnum"
    encode_num(x)
  when "Bignum"
    encode_num(x)
  when "String"
    encode_string(x)
  when "Array"
    encode_list(x)
  when "Hash"
    encode_hash(x)
  else
    "unknown"    
  end
end
def encode_num(x)
  "i#{x.to_s}e"
end
def encode_string(x)
  "#{x.size}:#{x}"
end
def encode_list(x)
  str="l"
  x.each do |temp|
    str+=encode(temp)
  end
  str+="e"
end
def encode_hash(x)
  str="d"
  x.each do |key,val|
    str+=encode(key)
    str+=encode(val)    
  end
  str+="e"
end
puts encode("abcd")             # returns "4:abcd"
puts encode(1000)               # returns "i1000e"
puts encode([1,2,3])            # returns "li1ei2ei3ee"
puts encode({"key" => "value"}) # returns "d3:key5:valuee"

def decode(io)
  c = io.getc
  case c.chr
  when 'i'
    i = ''
    while c = io.getc
      if c.chr == 'e'
        if i.match(/^(0|-?[1-9][0-9]*)$/)
          return i.to_i
        end
      else
        i += c.chr
      end
    end
  when '0'..'9'
    n = c.chr
    while b = io.getc
      case b.chr
      when '0'..'9'
        n += b.chr
      when ':'
        strlen = n.to_i
        str = io.read(strlen)
        if str.length == strlen
          return str
        end
      end
    end
  when 'l'
    list = []
    while item = decode(io)
      list.push(item)
    end
    return list
  when 'd'
    dict = {}
    while key = decode(io)
      val = decode(io)
      dict[key] = val
    end
    return dict
  when 'e'
    return false
  end
end
puts decode(StringIO.new("4:abcd"))
puts decode(StringIO.new("i1000e"))
puts decode(StringIO.new("li1ei2ei3ee"))
puts decode(StringIO.new("d3:key5:valuee"))