diff --git a/ext/cbor/buffer_class.c b/ext/cbor/buffer_class.c
index 14300dd..626e646 100644
--- a/ext/cbor/buffer_class.c
+++ b/ext/cbor/buffer_class.c
@@ -38,9 +38,10 @@ static ID s_write;
 static ID s_append;
 static ID s_close;
 
+static msgpack_buffer_t* Buffer_get(VALUE self);
+
 #define BUFFER(from, name) \
-    msgpack_buffer_t *name = NULL; \
-    Data_Get_Struct(from, msgpack_buffer_t, name); \
+    msgpack_buffer_t *name = Buffer_get(from); \
     if(name == NULL) { \
         rb_raise(rb_eArgError, "NULL found for " # name " when shouldn't be."); \
     }
@@ -51,22 +52,64 @@ static ID s_close;
         rb_raise(rb_eTypeError, "instance of String needed"); \
     }
 
+static void Buffer_mark(void* data)
+{
+    msgpack_buffer_t* b = data;
+    msgpack_buffer_mark(b);
+}
+
 static void Buffer_free(void* data)
 {
     if(data == NULL) {
         return;
     }
-    msgpack_buffer_t* b = (msgpack_buffer_t*) data;
+    msgpack_buffer_t* b = data;
     msgpack_buffer_destroy(b);
-    xfree(b);
+    xfree(data);
+}
+
+#ifdef TypedData_Make_Struct
+static size_t Buffer_memsize(const void* data)
+{
+    return data == NULL ? 0 : sizeof(msgpack_buffer_t);
+}
+
+static const rb_data_type_t buffer_data_type = {
+    "CBOR::Buffer",
+    {Buffer_mark, Buffer_free, Buffer_memsize,},
+    NULL, NULL, 0
+};
+
+static const rb_data_type_t wrapped_buffer_data_type = {
+    "CBOR::WrappedBuffer",
+    {Buffer_mark, NULL, Buffer_memsize,},
+    &buffer_data_type, NULL, 0
+};
+#endif
+
+static msgpack_buffer_t* Buffer_get(VALUE self)
+{
+    msgpack_buffer_t* b = NULL;
+#ifdef TypedData_Make_Struct
+    TypedData_Get_Struct(self, msgpack_buffer_t, &buffer_data_type, b);
+#else
+    Data_Get_Struct(self, msgpack_buffer_t, b);
+#endif
+    return b;
 }
 
 static VALUE Buffer_alloc(VALUE klass)
 {
-    msgpack_buffer_t* b = ALLOC_N(msgpack_buffer_t, 1);
+    msgpack_buffer_t* b;
+    VALUE self;
+#ifdef TypedData_Make_Struct
+    self = TypedData_Make_Struct(klass, msgpack_buffer_t, &buffer_data_type, b);
+#else
+    self = Data_Make_Struct(klass, msgpack_buffer_t, Buffer_mark, Buffer_free, b);
+#endif
     msgpack_buffer_init(b);
 
-    return Data_Wrap_Struct(klass, msgpack_buffer_mark, Buffer_free, b);
+    return self;
 }
 
 static ID get_partial_read_method(VALUE io)
@@ -118,7 +161,11 @@ void MessagePack_Buffer_initialize(msgpack_buffer_t* b, VALUE io, VALUE options)
 VALUE MessagePack_Buffer_wrap(msgpack_buffer_t* b, VALUE owner)
 {
     b->owner = owner;
-    return Data_Wrap_Struct(cMessagePack_Buffer, msgpack_buffer_mark, NULL, b);
+#ifdef TypedData_Make_Struct
+    return TypedData_Wrap_Struct(cMessagePack_Buffer, &wrapped_buffer_data_type, b);
+#else
+    return Data_Wrap_Struct(cMessagePack_Buffer, Buffer_mark, NULL, b);
+#endif
 }
 
 static VALUE Buffer_initialize(int argc, VALUE* argv, VALUE self)
@@ -512,4 +559,3 @@ void MessagePack_Buffer_module_init(VALUE mMessagePack)
     rb_define_alias(cMessagePack_Buffer, "to_s", "to_str");
     rb_define_method(cMessagePack_Buffer, "to_a", Buffer_to_a, 0);
 }
-
diff --git a/ext/cbor/core_ext.c b/ext/cbor/core_ext.c
index ed268d6..f8973cc 100644
--- a/ext/cbor/core_ext.c
+++ b/ext/cbor/core_ext.c
@@ -49,8 +49,7 @@ static inline VALUE delegete_to_pack(int argc, VALUE* argv, VALUE self)
         return delegete_to_pack(argc, argv, self); \
     } \
     VALUE packer = argv[0]; \
-    msgpack_packer_t *pk; \
-    Data_Get_Struct(packer, msgpack_packer_t, pk);
+    msgpack_packer_t *pk = MessagePack_Packer_get(packer);
 
 static VALUE NilClass_to_msgpack(int argc, VALUE* argv, VALUE self)
 {
@@ -198,4 +197,3 @@ void MessagePack_core_ext_module_init()
     rb_define_method(rb_cCBOR_Simple,   "to_cbor", Simple_to_msgpack, -1);
     rb_define_method(rb_cCBOR_Tagged,   "to_cbor", Tagged_to_msgpack, -1);
 }
-
diff --git a/ext/cbor/packer_class.c b/ext/cbor/packer_class.c
index 2a99ab9..05d00f4 100644
--- a/ext/cbor/packer_class.c
+++ b/ext/cbor/packer_class.c
@@ -39,15 +39,23 @@ static ID s_write;
 //static VALUE s_packer_value;
 //static msgpack_packer_t* s_packer;
 
+static msgpack_packer_t* Packer_get(VALUE self);
+
 #define PACKER(from, name) \
-    msgpack_packer_t* name; \
-    Data_Get_Struct(from, msgpack_packer_t, name); \
+    msgpack_packer_t* name = Packer_get(from); \
     if(name == NULL) { \
         rb_raise(rb_eArgError, "NULL found for " # name " when shouldn't be."); \
     }
 
-static void Packer_free(msgpack_packer_t* pk)
+static void Packer_mark(void* data)
 {
+    msgpack_packer_t* pk = data;
+    msgpack_packer_mark(pk);
+}
+
+static void Packer_free(void* data)
+{
+    msgpack_packer_t* pk = data;
     if(pk == NULL) {
         return;
     }
@@ -55,13 +63,47 @@ static void Packer_free(msgpack_packer_t* pk)
     xfree(pk);
 }
 
+#ifdef TypedData_Make_Struct
+static size_t Packer_memsize(const void* data)
+{
+    return data == NULL ? 0 : sizeof(msgpack_packer_t);
+}
+
+static const rb_data_type_t packer_data_type = {
+    "CBOR::Packer",
+    {Packer_mark, Packer_free, Packer_memsize,},
+    NULL, NULL, 0
+};
+#endif
+
+static msgpack_packer_t* Packer_get(VALUE self)
+{
+    msgpack_packer_t* pk = NULL;
+#ifdef TypedData_Make_Struct
+    TypedData_Get_Struct(self, msgpack_packer_t, &packer_data_type, pk);
+#else
+    Data_Get_Struct(self, msgpack_packer_t, pk);
+#endif
+    return pk;
+}
+
+msgpack_packer_t* MessagePack_Packer_get(VALUE self)
+{
+    PACKER(self, pk);
+    return pk;
+}
+
 static VALUE Packer_alloc(VALUE klass)
 {
-    msgpack_packer_t* pk = ALLOC_N(msgpack_packer_t, 1);
+    msgpack_packer_t* pk;
+    VALUE self;
+#ifdef TypedData_Make_Struct
+    self = TypedData_Make_Struct(klass, msgpack_packer_t, &packer_data_type, pk);
+#else
+    self = Data_Make_Struct(klass, msgpack_packer_t, Packer_mark, Packer_free, pk);
+#endif
     msgpack_packer_init(pk);
 
-    VALUE self = Data_Wrap_Struct(klass, msgpack_packer_mark, Packer_free, pk);
-
     msgpack_packer_set_to_msgpack_method(pk, s_to_msgpack, self);
     pk->buffer_ref = MessagePack_Buffer_wrap(PACKER_BUFFER_(pk), self);
 
@@ -301,4 +343,3 @@ void MessagePack_Packer_module_init(VALUE mMessagePack)
     rb_define_module_function(mMessagePack, "encode", MessagePack_pack_module_method, -1);
     rb_define_module_function(mMessagePack, "dump", MessagePack_dump_module_method, -1);
 }
-
diff --git a/ext/cbor/packer_class.h b/ext/cbor/packer_class.h
index fdabd67..bdeb00e 100644
--- a/ext/cbor/packer_class.h
+++ b/ext/cbor/packer_class.h
@@ -31,9 +31,10 @@
 
 extern VALUE cMessagePack_Packer;
 
+msgpack_packer_t* MessagePack_Packer_get(VALUE self);
+
 void MessagePack_Packer_module_init(VALUE mMessagePack);
 
 VALUE MessagePack_pack(int argc, VALUE* argv);
 
 #endif
-
diff --git a/ext/cbor/unpacker_class.c b/ext/cbor/unpacker_class.c
index c729e64..b28ec43 100644
--- a/ext/cbor/unpacker_class.c
+++ b/ext/cbor/unpacker_class.c
@@ -39,15 +39,23 @@ static VALUE eMalformedFormatError;
 static VALUE eStackError;
 static VALUE eTypeError;
 
+static msgpack_unpacker_t* Unpacker_get(VALUE self);
+
 #define UNPACKER(from, name) \
-    msgpack_unpacker_t *name = NULL; \
-    Data_Get_Struct(from, msgpack_unpacker_t, name); \
+    msgpack_unpacker_t *name = Unpacker_get(from); \
     if(name == NULL) { \
         rb_raise(rb_eArgError, "NULL found for " # name " when shouldn't be."); \
     }
 
-static void Unpacker_free(msgpack_unpacker_t* uk)
+static void Unpacker_mark(void* data)
+{
+    msgpack_unpacker_t* uk = data;
+    msgpack_unpacker_mark(uk);
+}
+
+static void Unpacker_free(void* data)
 {
+    msgpack_unpacker_t* uk = data;
     if(uk == NULL) {
         return;
     }
@@ -55,13 +63,41 @@ static void Unpacker_free(msgpack_unpacker_t* uk)
     xfree(uk);
 }
 
+#ifdef TypedData_Make_Struct
+static size_t Unpacker_memsize(const void* data)
+{
+    return data == NULL ? 0 : sizeof(msgpack_unpacker_t);
+}
+
+static const rb_data_type_t unpacker_data_type = {
+    "CBOR::Unpacker",
+    {Unpacker_mark, Unpacker_free, Unpacker_memsize,},
+    NULL, NULL, 0
+};
+#endif
+
+static msgpack_unpacker_t* Unpacker_get(VALUE self)
+{
+    msgpack_unpacker_t* uk = NULL;
+#ifdef TypedData_Make_Struct
+    TypedData_Get_Struct(self, msgpack_unpacker_t, &unpacker_data_type, uk);
+#else
+    Data_Get_Struct(self, msgpack_unpacker_t, uk);
+#endif
+    return uk;
+}
+
 static VALUE Unpacker_alloc(VALUE klass)
 {
-    msgpack_unpacker_t* uk = ALLOC_N(msgpack_unpacker_t, 1);
+    msgpack_unpacker_t* uk;
+    VALUE self;
+#ifdef TypedData_Make_Struct
+    self = TypedData_Make_Struct(klass, msgpack_unpacker_t, &unpacker_data_type, uk);
+#else
+    self = Data_Make_Struct(klass, msgpack_unpacker_t, Unpacker_mark, Unpacker_free, uk);
+#endif
     msgpack_unpacker_init(uk);
 
-    VALUE self = Data_Wrap_Struct(klass, msgpack_unpacker_mark, Unpacker_free, uk);
-
     uk->buffer_ref = MessagePack_Buffer_wrap(UNPACKER_BUFFER_(uk), self);
 
     return self;
@@ -426,4 +462,3 @@ void MessagePack_Unpacker_module_init(VALUE mMessagePack)
     rb_define_module_function(mMessagePack, "unpack", MessagePack_unpack_module_method, -1);
     rb_define_module_function(mMessagePack, "decode", MessagePack_unpack_module_method, -1);
 }
-