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Marshal格式

2002-04-04 草稿....

nil
true
false

分别是'0', 'T', 'F'

p Marshal.Dump(nil).unpack("x2 a*")
# => ["0"]

此时，即使设置了实例变量也无法Dump。

class NilClass
  attr_accessor :foo
end
nil.foo = 1
p nil.foo                           # => 1
p Marshal.Dump(nil).unpack("x2 a*") # => ["0"]
Fixnum

在'i'之后是表示Fixnum的数据结构。

以数值n为例，在表示数值部分的形式中(不仅限于Fixnum，在其它地方也是如此)，保存着

形式 1:

n == 0:       0
0 < n < 123:  n + 5
-124 < n < 0: n - 5

这样的数值(1 byte)。之所以加减5，是为了有别于下面的形式。

例:

p Marshal.Dump(-1).unpack("x2 a*") # => "i\372"
p Marshal.Dump(0).unpack("x2 a*")  # => "i\000"
p Marshal.Dump(1).unpack("x2 a*")  # => "i\006"
p Marshal.Dump(2).unpack("x2 a*")  # => "i\a"   ("i\007")

若数值N超出形式1的范围时，则有下面的形式。

形式 2:

| len | n1 | n2 | n3 | n4 |
 <-1-> <-     len       ->
 byte        bytes

len的值是-4 ～ -1, 1 ～ 4。这表示符号和后续的数据存在于n1 ～ n|len|。

# 举个更好的例子...
def foo(len, n1, n2 = 0, n3 = 0, n4 = 0)

    case len
    when -3;           n4 = 255
    when -2;      n3 = n4 = 255
    when -1; n2 = n3 = n4 = 255
    end

    n = (0xffffff00 | n1) &
        (0xffff00ff | n2 * 0x100) &
        (0xff00ffff | n3 * 0x10000) &
        (0x00ffffff | n4 * 0x1000000)
    # p "%x" % n
    n = -((n ^ 0xffff_ffff) + 1) if len < 0
    n
end

p Marshal.Dump(-125).unpack("x2 acC*") # => ["i", -1, 131]
p foo(-1, 131)
p Marshal.Dump(-255).unpack("x2 acC*") # => ["i", -1, 1]
p foo(-1, 1)
p Marshal.Dump(-256).unpack("x2 acC*") # => ["i", -1, 0]
p foo(-1, 0)
p Marshal.Dump(-257).unpack("x2 acC*") # => ["i", -2, 255, 254]
p foo(-2, 255, 254)
p Marshal.Dump(124).unpack("x2 acC*") # => ["i", 1, 124]
p foo(1, 124)
p Marshal.Dump(256).unpack("x2 acC*") # => ["i", 2, 0, 1]
p foo(2, 0, 1)

即使设定了实例变量，也无法Dump。

class Fixnum
  attr_accessor :foo
end
99.foo = 1
p 99.foo                           # => 1
p 999.foo                          # => nil
p Marshal.Dump(99).unpack("x2 ac") # => ["i", 104]
instance of the user class

'C': String, Regexp, Array, Hash 的子类的实例变量

| 'C' | 类名(Symbol)的 Dump | 父类的实例的 Dump |

例 1:

class Foo < String # (or Regexp, Array, Hash)
end
p Marshal.Dump(Foo.new("foo")).unpack("x2 a a c a3 aca*")
# => ["C", ":", 8, "Foo", "\"", 8, "foo"]
                          ^^^ (or '/', '[', '{')

例 2: 有实例变量(请参考instance variable)

class Foo < String # (or Regexp, Array, Hash)
  def initialize(obj)
    @foo = obj
    super(obj)
  end
end
p Marshal.Dump(Foo.new("foo")).unpack("x2 a a a c a3 aca3 caca4 aca*")
# => ["I", "C", ":", 8, "Foo", "\"", 8, "foo", 6, ":", 9, "@foo", "\"", 8, "foo"]

除此以外，将变为'o'。这是因为内部结构有所差异所致(请参考Object)

例:

class Foo
end
p Marshal.Dump(Foo.new).unpack("x2 a a c a*")
# => ["o", ":", 8, "Foo\000"]

'u'

若定义了_Dump、_load的话，就是'u'。因为无法Dump实例变量，所以必须使用_Dump/_load进行处理。

| 'u' | 类名(Symbol)的 Dump | _Dump 的结果的长度(Fixnum形式) |
| _Dump 的返回值 |

例:

class Foo
  def self._load
  end
  def _Dump(obj)
    "hogehoge"
  end
end
p Marshal.Dump(Foo.new).unpack("x2 a aca3 c a*")
# => ["u", ":", 8, "Foo", 13, "hogehoge"]

'U' ruby 1.8 特性

若定义了marshal_Dump、marshal_load的话，就是'U'。因为无法Dump实例变量，所以必须使用marshal_Dump/marshal_load来处理。

| 'U' | 类名(Symbol)的 Dump | marshal_Dump 方法的返回值的 Dump |

例:

class Foo
  def marshal_Dump
    "hogehoge"
  end
  def marshal_load(obj)
  end
end
p Marshal.Dump(Foo.new).unpack("x2 a aca3 a c a*")

# => ["U", ":", 8, "Foo", "\"", 13, "hogehoge"]
Object

'o'

| 'o' | 类名(Symbol)的 Dump | 实例变量的数量(Fixnum形式) |
| 实例变量名(Symbol) 的Dump(1) | 值(1) |
          :
          :
| 实例变量名(Symbol) 的Dump(n) | 值(n) |

例 1:

p Marshal.Dump(Object.new).unpack("x2 a a c a*")
# => ["o", ":", 11, "Object\000"]

例 2: 有实例变量

class Foo
  def initialize
    @foo = "foo"
    @bar = "bar"
  end
end
p Marshal.Dump(Foo.new).unpack("x2 a a c a3 c aca4 aca3 aca4 aca3")
# => ["o", ":", 8, "Foo", 7,
      ":", 9, "@bar", "\"", 8, "bar",
      ":", 9, "@foo", "\"", 8, "foo"]
Float

'f'

| 'f' | 数串的长度(Fixnum形式) | "%.16g" 的字符串 |

例:

p Marshal.Dump(Math::PI).unpack("x2 a c a*")
# => ["f", 22, "3.141592653589793"]

p Marshal.Dump(0.0/0).unpack("x2 a c a*")  # => ["f", 8, "nan"]
p Marshal.Dump(1.0/0).unpack("x2 a c a*")  # => ["f", 8, "inf"]
p Marshal.Dump(-1.0/0).unpack("x2 a c a*") # => ["f", 9, "-inf"]
p Marshal.Dump(-0.0).unpack("x2 a c a*")   # => ["f", 9, "-0"]
Bignum

'l'

| 'l' | '+'/'-' | short的个数(Fixnum形式) | ... |

例:

p Marshal.Dump(2**32).unpack("x2 a a c a*")
# => ["l", "+", 8, "\000\000\000\000\001\000"]

# => ["l", "+", 8, "\000\000\001\000"]  <- BUG: ruby version 1.6.3
String

'"'

| '"' | 长度(Fixnum形式) | 字符串 |

例:

p Marshal.Dump("hogehoge").unpack("x2 a c a*")
# => ["\"", 13, "hogehoge"]
Regexp

'/'

| '/' | 长度(Fixnum形式) | source字符串 | 选项 |

选项是 options的结果+汉字代码的flag值。

例:

p Marshal.Dump(/(hoge)*/).unpack("x2 a c a7 c")
# => ["/", 12, "(hoge)*", 0]

p Marshal.Dump(/hogehoge/m).unpack("x2 a c a8 c")
# => ["/", 13, "hogehoge", 4]

p Marshal.Dump(/hogehoge/e).unpack("x2 a c a8 c")

# => ["/", 13, "hogehoge", 32]
Array

'['

| '[' | 元素数(Fixnum形式) | 元素的 Dump | ... |

例:

p Marshal.Dump(["hogehoge", /hogehoge/]).unpack("x2 a c aca8 aca*")
# => ["[", 7, "\"", 13, "hogehoge", "/", 13, "hogehoge\000"]
Hash

'{'

| '{' | 元素数(Fixnum形式) | 键的 Dump | 值的 Dump | ... |

例:

p Marshal.Dump({"hogehoge", /hogehoge/}).unpack("x2 a c aca8 aca*")
# => ["{", 6, "\"", 13, "hogehoge", "/", 13, "hogehoge\000"]
Hash with default value ( not Proc )

'}'

| '}' | 元素数(Fixnum形式) | 键的 Dump | 值的 Dump | ... | 默认值 |

例:

h = Hash.new(true)
h["foo"] = "bar"
p Marshal.Dump(h).unpack("x2 a c aca3 aca*")
# => ["}", 6, "\"", 8, "foo", "\"", 8, "barT"]

若某Hash的默认对象是Proc的话，则无法Dump该Hash

h = Hash.new { }
Marshal.Dump(h)
=> -:2:in `Dump': cannot Dump hash with default proc (TypeError)
Struct

'S': 结构体类的实例的Dump

| 'S' | 类名(Symbol) 的 Dump | 成员数量(Fixnum形式) |
| 成员名(Symbol) 的 Dump | 值 | ... |

例:

Struct.new("XXX", :foo, :bar)
p Marshal.Dump(Struct::XXX.new).unpack("x2 a ac a11 c aca3a aca3a")
# => ["S", ":", 16, "Struct::XXX", 7,
      ":", 8, "foo", "0",
      ":", 8, "bar", "0"]
Class/Module (old format)

'M'

| 'M' | 长度(Fixnum形式) | 模块/类名 |

例: 因为已经无法dump这种形式，所以使用load进行说明。

class Mod
end
p Marshal.load([4,7, 'M', 3+5, 'Mod'].pack("ccaca*"))
# => Mod
Class/Module

'c', 'm'

| 'c'/'m' | 类名的长度(Fixnum 形式) | 类名 |

例:

class Foo
end
p Marshal.Dump(Foo).unpack("x2 a c a*") # => ["c", 8, "Foo"]

例 2: 无法dump类/模块的实例变量

module Bar
  @bar = 1
end
p Bar.instance_eval { @bar }
Marshal.Dump(Bar, open("/tmp/foo", "w"))
# => 1

module Bar
end
p bar = Marshal.load(open("/tmp/foo"))
p bar.instance_eval { @bar }
# => nil

例 3: 无法dump类变量

module Baz
  @@baz = 1
  def self.baz
    @@baz
  end
end
p Baz.baz
Marshal.Dump(Baz, open("/tmp/foo", "w"))
# => 1

module Baz
  def self.baz
    @@baz
  end
end
p baz = Marshal.load(open("/tmp/foo"))
baz.baz
# => Baz
     -:3:in `baz': uninitialized class variable @@baz in Baz (NameError)
             from -:7
Symbol

':'

| ':' | 符号名的长度(Fixnum形式) | 符号名 |

例:

p Marshal.Dump(:foo).unpack("x2 a c a*")
# => [":", 8, "foo"]
Symbol (link)

';'

| ';' | 表明Symbol实际状态的号码(Fixnum形式) |

在相应符号名已被dump/load时使用。该号码是内部管理的号码。(在dump/load时，会生成哈希表以便对Symbol进行管理。它表示记录位置)

例:

p Marshal.Dump([:foo, :foo]).unpack("x2 ac aca3 aC*")
# => ["[", 7, ":", 8, "foo", ";", 0]

p Marshal.Dump([:foo, :foo, :bar, :bar]).
    unpack("x2 ac aca3 aC aca3 aC*")
# => ["[", 9, ":", 8, "foo", ";", 0, ":", 8, "bar", ";", 6]
instance variable

'I': Object, Class, Module 的实例以外的对象

| 'I' | 对象的 Dump | 实例变量的数量(Fixnum形式) |
| 实例变量名(Symbol) 的Dump(1) | 值(1) |
          :
          :
| 实例变量名(Symbol) 的Dump(n) | 值(n) |

因为Object的实例中包含实例变量，所以会采用其他的形式进行Dump(请参考Object)。该形式只针对Array 或 String 的实例。

例:

obj = String.new
obj.instance_eval { @foo = "bar" }
p Marshal.Dump(obj).unpack("x2 a ac c a c a4 aca*")
# => ["I", "\"", 0, 6, ":", 9, "@foo", "\"", 8, "bar"]

类或模块(Class/Module的实例)不会dump实例变量的信息。(请参考Class/Module)

link

'@'

| '@' | 表明对象实际状态的号码(Fixnum形式 |

在相应对象已被dump/load时使用。该号码是内部管理的号码。(在dump/load时，会生成哈希表以便对对象进行管理。它表示记录位置)

例:

obj = Object.new
p Marshal.Dump([obj, obj]).unpack("x2 ac aaca6c aca*")
# => ["[", 7, "o", ":", 11, "Object", 0, "@", 6, ""]

ary = []
ary.push ary
p Marshal.Dump(ary).unpack("x2 acac")

# => ["[", 6, "@", 0]

Marshal 的BUG

在ruby version 1.6中发现了下列BUG。括号()中列出的是正确的运作方式(1.7的运作方式)。

<= 1.6.7
  • 类的clone中的实例是可以Dump的，但却不能加载(因为是无名类的对象，所以无法Dump)
  • 当某对象通过include/extend无名Module而定义了特殊方法后，仍可以Dump/加载该对象(若某对象include了无名模块的话，则不能Dump该对象)
1.6.6, 1.6.7
  • 拥有实例变量的Array和String是可以Dump的，但却不能加载(既能Dump，又能加载)
<= 1.6.5
  • 类的clone中的实例是可以Dump的，但却不能正常加载。否则就会生成奇怪的对象(?)
  • 特殊类被dump成为普通类了(特殊类是无法Dump的)
  • 无名类是可以Dump的，但却不能加载(无名类是无法Dump的)
<= 1.6.4
  • 模块可以Dump却不能加载(可以加载)
  • 无名模块可以Dump却不能加载(无名模块是不能Dump的)
<= 1.6.3
  • dump Float时，其保存精度偏低
<= 1.6.2
  • dump时，无法保存正则表达式中/m, /x 选项的状态
1.6.2, 1.6.3
  • 在1.6.2, 1.6.3中，Bignum可以Dump却不能加载。按理说其他版本也会有这个BUG，但因为没有测试脚本，所以无法证实。
<= 1.6.1
  • dump时无法保存Range中的特定标识，该标识表明该范围中是否包含终点

下面就是测试脚本(请参考[RAA:RubyUnit])

# test for Marshal for ruby version 1.6
require 'rubyunit'

$version_dependent_behavior = true
# for test_userClass, test_userModule
module UserModule
  def foo
  end
end
class UserClass
  def foo
  end
end

class TestMarshal < RUNIT::TestCase

  def assert_no_Dumpable(obj)
    ex = assert_exception(TypeError) {
      begin
        # Marshal.Dump will cause TypeError or ArgumentError
        Marshal.Dump obj
      rescue ArgumentError
        case $!.message
        when /can't Dump anonymous/,
             /cannot Dump hash with default proc/
          raise TypeError
        else
          raise "unknown error"
        end
      end
    }
  end
  def assert_Dumpable_but_not_equal(obj)
    obj2 = Marshal.load(Marshal.Dump(obj))
    assert(obj != obj2)
    assert_equals(obj.type, obj2.type)
  end
  def assert_Dumpable_and_equal(obj)
    obj2 = Marshal.load(Marshal.Dump(obj))
    assert_equals(obj, obj2)
    assert_equals(obj.type, obj2.type)

    # check values of instance variable
    ivars = obj.instance_variables
    ivars2 = obj2.instance_variables
    assert_equals(ivars, ivars2)
    while ivars.size != 0
      assert_equals(obj.instance_eval(ivars.shift),
                    obj2.instance_eval(ivars2.shift))
    end
  end

  def test_Object
    assert_Dumpable_but_not_equal Object.new
  end

  # object with singleton method
  def test_Object_with_singleton_method
    obj = Object.new
    # On ruby version 1.6.0 - 1.6.2, cause parse error (nested method)
    class <<obj
      def foo
      end
    end

    # object has singleton method can't be Dumped
    assert_no_Dumpable obj
  end

  # object with singleton method (with named module)
  def test_Object_with_singleton_method2
    obj = Object.new
    # On ruby version 1.6.0 - 1.6.2, cause parse error (nested method)
    class <<obj
      include UserModule
    end

    # On ruby version 1.6.0 - 1.6.7, no consider the singleton
    # method with Mix-in.
    # On ruby version 1.7, Dumpable object which is extended by
    # named module.
    assert_Dumpable_but_not_equal obj
  end

  # object with singleton method (with anonymous module)
  def test_Object_with_singleton_method3
    obj = Object.new
    # On ruby version 1.6.0 - 1.6.2, cause parse error (nested method)
    class <<obj
      include Module.new
    end

    if $version_dependent_behavior and RUBY_VERSION <= "1.6.7"
      # On ruby version 1.6.0 - 1.6.7, no consider the singleton method with Mix-in.
      assert_Dumpable_but_not_equal obj
    else
      # object has singleton method (with anonymous module) can't be Dumped
      assert_no_Dumpable obj
    end
  end

  # singleton class
  def test_singletonClass
    obj = Object.new
    # On ruby version 1.6.0 - 1.6.2, cause parse error (nested method)
    singleton_class = class <<obj
                        def foo
                        end
                        self
                      end

    # singleton class can't be Dumped
    # On ruby version 1.6.0 - 1.6.5, singleton class be able to Dumped
    # as normal class.
    if $version_dependent_behavior and RUBY_VERSION <= "1.6.5"
      assert_equals(Object, Marshal.load(Marshal.Dump(singleton_class)))
    else
      assert_no_Dumpable singleton_class
    end
  end

  def test_Array
    assert_Dumpable_and_equal [1,"foo", :foo]
  end

  def test_Array_with_instance_variable
    ary = [1,"foo", :foo]
    ary.instance_eval{ @var = 1 }

    if $version_dependent_behavior and %w(1.6.6 1.6.7).member?(RUBY_VERSION)
      # On ruby version 1.6.6 - 1.6.7, Array(or String ...) has instance
      # variable is able to be Dumped, but can't load it.
      Dump = Marshal.Dump(ary)
      ex = assert_exception(ArgumentError) {
        Marshal.load(Dump)
      }
    else
      assert_Dumpable_and_equal ary
    end
  end

  def test_Binding
    assert_no_Dumpable binding
  end

  def test_Continuation
    assert_no_Dumpable callcc {|c| c}
  end

  def test_Data
    # assert_fail("")
  end

  def test_Exception
    assert_Dumpable_but_not_equal Exception.new("hoge")
  end

  def test_Dir
    assert_no_Dumpable Dir.open("/")
  end

  def test_FalseClass
    assert_Dumpable_and_equal false
  end

  def test_File__Stat
    assert_no_Dumpable File.stat("/")
  end

  def test_Hash
    assert_Dumpable_and_equal(1=>"1",2=>"2")

    # 1.7 feature.
    if $version_dependent_behavior and RUBY_VERSION >= '1.7.0'
      # On ruby version 1.7, hash with default Proc cannot be Dumped.
      # see [ruby-dev:15417]
      assert_no_Dumpable(Hash.new { })
    end
  end

  def test_IO
    assert_no_Dumpable IO.new(0)
  end

  def test_File
    assert_no_Dumpable File.open("/")
  end

  def test_MatchData
    assert_no_Dumpable(/foo/ =~ "foo" && $~)
  end

  def test_Method
    assert_no_Dumpable Object.method(:method)
  end

  def test_UnboundMethod
    assert_no_Dumpable Object.instance_method(:id)
  end

  def test_Module
    # On ruby version 1.6.0 - 1.6.4, loaded module is not a module.
    if $version_dependent_behavior and RUBY_VERSION <= '1.6.4'
      Dump = Marshal.Dump Enumerable
      ex = assert_exception(TypeError) {
        Marshal.load Dump
      }
      assert_matches(ex.message, /is not a module/)
    else
      assert_Dumpable_and_equal Enumerable
    end
  end

  def test_userModule
    # On ruby version 1.6.0 - 1.6.4, loaded module is not a module.
    if $version_dependent_behavior and RUBY_VERSION <= '1.6.4'
      # same as test_Module
    else
      # Note: this module must be defineed for Marshal.load.
      assert_Dumpable_and_equal(UserModule)
    end
  end

  def test_anonymousModule
    # On ruby version 1.6.0 - 1.6.4, anonymous class is able to be Dumped,
    # but loaded object is not identical.
    if $version_dependent_behavior and RUBY_VERSION <= '1.6.4'
      Dump = Marshal.Dump(Module.new)
      ex = assert_exception(ArgumentError) {
        Marshal.load Dump
      }
      assert_matches(ex.message, /can\'t retrieve anonymous class/)
    else
      assert_no_Dumpable Module.new
    end
  end

  def test_Class
    assert_Dumpable_and_equal Class
  end

  def test_userClass
    # Note: this class must be defineed for Marshal.load.
    assert_Dumpable_and_equal(UserClass)
  end
  def test_anonymousClass
    # On ruby version 1.6.0 - 1.6.5, anonymous class able to be Dumped,
    # but can't load it.
    if $version_dependent_behavior and RUBY_VERSION <= '1.6.5'
      Dump = Marshal.Dump(Class.new)
      ex = assert_exception(ArgumentError) {
        Marshal.load(Dump)
      }
      assert_matches(ex.message, /can\'t retrieve anonymous class/)
    else
      assert_no_Dumpable Class.new
    end
  end

  def test_clonedClass
    # On ruby version 1.6.0 - 1.6.7, instance of cloned class is able to
    # Dumped, but loaded object is not identical.
    # see [ruby-dev:14961]
    if $version_dependent_behavior
      if RUBY_VERSION <= '1.6.5'
        obj = String.clone.new("foo")
        Dump = Marshal.Dump(obj)
        obj2 = Marshal.load Dump
        assert(obj == obj2)
        assert(obj.type != obj2.type)
        assert(obj.type.inspect == obj2.type.inspect)
      elsif RUBY_VERSION <= '1.6.7'
        Dump = Marshal.Dump(String.clone.new("foo"))
        assert_exception(ArgumentError) {
          Marshal.load Dump
        }
      else
        assert_no_Dumpable String.clone.new("foo")
      end
    else
      # anonymous class can't be Dumped
      assert_no_Dumpable String.clone.new("foo")
    end
  end

  def test_Numeric
    # assert_fail("")
  end

  def test_Integer
    # assert_fail("")
  end

  def test_Fixnum
    assert_Dumpable_and_equal 100
  end

  def test_Bignum
    # derived from Rubicon
    assert_Dumpable_and_equal 123456789012345678901234567890
    assert_Dumpable_and_equal -123**99
    if $version_dependent_behavior and %w(1.6.2 1.6.3).member?(RUBY_VERSION)
      Dump = Marshal.Dump 2**32
      ex = assert_exception(ArgumentError) {
        Marshal.load(Dump)
      }
      assert_matches(ex.message, /marshal data too short/)
    else
      assert_Dumpable_and_equal 2**32
    end
  end

  def test_Float
    assert_Dumpable_and_equal 1.41421356

    # On ruby version 1.6.4, Dumped format changed from "%.12g" to "%.16g"
    if $version_dependent_behavior and RUBY_VERSION <= '1.6.3'
      assert_Dumpable_but_not_equal Math::PI
    else
      assert_Dumpable_and_equal Math::PI
    end
  end

  def test_Proc
    assert_no_Dumpable proc { }
  end

  def test_Process__Status
    assert_Dumpable_and_equal system("true") && $?
  end

  def test_Range
    # Range#== is changed from 1.6.2
    # On ruby version 1.6.0 - 1.6.1, Range.new(1,2) != Range.new(1,2)
    # assert_Dumpable_and_equal 1..2
    # assert_Dumpable_and_equal 1...2

    obj = Marshal.load(Marshal.Dump 1..2)
    assert_equals(1, obj.begin)
    assert_equals(2, obj.end)
    assert_equals(false, obj.exclude_end?)

    obj = Marshal.load(Marshal.Dump 1...2)
    assert_equals(1, obj.begin)
    assert_equals(2, obj.end)

    # On ruby version 1.6.0 - 1.6.1, the attribute exclude_end? is not saved.
    if $version_dependent_behavior and RUBY_VERSION <= '1.6.1'
      assert_equals(false, obj.exclude_end?)
    else
      assert_equals(true, obj.exclude_end?)
    end
  end

  def test_Regexp
    # this test is no consider the /foo/p
    assert_Dumpable_and_equal /foo/
    assert_Dumpable_and_equal /foo/i
    assert_Dumpable_and_equal /foo/m
    assert_Dumpable_and_equal /foo/x
    assert_Dumpable_and_equal /foo/e
    assert_Dumpable_and_equal /foo/s
    assert_Dumpable_and_equal /foo/u

    # On ruby version 1.6.0 - 1.6.2, Regexp#== is ignore the option.
    for obj in [/foo/, /foo/i, /foo/m, /foo/x, /foo/e, /foo/s, /foo/u]
      obj2 = Marshal.load(Marshal.Dump obj)

      if $version_dependent_behavior and RUBY_VERSION <= '1.6.2' and
          %w(/foo/m /foo/x).member?(obj.inspect)
        # On ruby version 1.6.0 - 1.6.2,
        # //m options is not saved.
        assert_equals('/foo/', obj2.inspect)
      else
        assert_equals(obj.inspect, obj2.inspect)
      end
    end
  end

  def test_String
    assert_Dumpable_and_equal "foo"
  end

  def test_Struct
    assert_Dumpable_and_equal Struct.new("Foo", :foo, :bar)

    Object.const_set('Foo', Struct.new(:foo, :bar))
    assert_Dumpable_and_equal Foo
  end

  def test_aStruct
    assert_Dumpable_and_equal Struct.new("Bar", :foo, :bar).new("foo", "bar")

    # see [ruby-dev:14961]
  end

  def test_Symbol
    assert_Dumpable_and_equal :foo
  end

  def test_Thread
    assert_no_Dumpable Thread.new { sleep }
  end

  def test_ThreadGroup
    assert_no_Dumpable ThreadGroup::Default
  end

  def test_Time
    assert_Dumpable_and_equal Time.now
    assert_Dumpable_and_equal Time.now.gmtime

    # time zone is not saved.
    assert_equals(false, Marshal.load(Marshal.Dump(Time.now)).utc?)
    assert_equals(false, Marshal.load(Marshal.Dump(Time.now.gmtime)).utc?)
  end

  def test_TrueClass
    assert_Dumpable_and_equal true
  end

  def test_NilClass
    assert_Dumpable_and_equal nil
  end
end