# File digest/sha2/lib/sha2.rb, line 23
    def initialize(bitlen = 256)
      case bitlen
      when 256
        @sha2 = Digest::SHA256.new
      when 384
        @sha2 = Digest::SHA384.new
      when 512
        @sha2 = Digest::SHA512.new
      else
        raise ArgumentError, "unsupported bit length: %s" % bitlen.inspect
      end
      @bitlen = bitlen
    end

# File digest/sha2/lib/sha2.rb, line 55
    def block_length
      @sha2.block_length
    end

# File digest/sha2/lib/sha2.rb, line 59
    def digest_length
      @sha2.digest_length
    end

# File digest/sha2/lib/sha2.rb, line 64
    def initialize_copy(other)
      @sha2 = other.instance_eval { @sha2.clone }
    end

# File digest/sha2/lib/sha2.rb, line 69
    def inspect
      "#<%s:%d %s>" % [self.class.name, @bitlen, hexdigest]
    end

# File digest/sha2/lib/sha2.rb, line 38
    def reset
      @sha2.reset
      self
    end

# File digest/sha2/lib/sha2.rb, line 44
    def update(str)
      @sha2.update(str)
      self
    end