diff --git a/PyCmo/PyCmo.py b/PyCmo/PyCmo.py
index d43f291..0bb6ec9 100644
--- a/PyCmo/PyCmo.py
+++ b/PyCmo/PyCmo.py
@@ -1,6 +1,7 @@
-import VTReader
-import VTStruct
+import VTReader, VTStruct, VTConstants
+
+ckFile = VTStruct.CKFile()
+VTReader.CKFileReader.Load(ckFile, "D:\\libcmo21\\PyCmo\\Language.nmo", VTConstants.CK_LOAD_FLAGS(VTConstants.CK_LOAD_FLAGS.CK_LOAD_DEFAULT))
+print(ckFile)
+print(str(ckFile.m_FileObjects))
 
-with open("D:\\libcmo21\\PyCmo\\Gameplay.nmo", 'rb') as fs:
-    composition = VTReader.ReadCKComposition(fs)
-    print(composition.Header)
\ No newline at end of file
diff --git a/PyCmo/VTConstants.py b/PyCmo/VTConstants.py
index c69a075..9b63ce2 100644
--- a/PyCmo/VTConstants.py
+++ b/PyCmo/VTConstants.py
@@ -1,50 +1,70 @@
 import enum
 
+class CKEnumItem(object):
+    def __init__(self, name: str, value: int):
+        self.name: str = name
+        self.value: int = value
+
 class CKEnum(object):
     def __init__(self, val: int):
         self.m_Value: int = val
 
+        self.__ItemsList = (
+            CKEnumItem(attr, getattr(self, attr)) 
+            for attr in dir(self) if not attr.startswith("__") and not callable(getattr(self, attr))
+        )
+
+    def Set(self, data: int):
+        self.m_Value = data
+
+    def __iter__(self):
+        return self.__ItemsList
 
     def __repr__(self):
         for i in self:
-            if i.value == val:
-                return i.name
+            if i.value == self.m_Value:
+                return '<' + i.name + '>'
 
-        return "[None]"
+        return "<[None] {:d}>".format(self.m_Value)
 
     def __str__(self):
         return self.__repr__()
 
 class CKFlagEnum(CKEnum):
-    def Contain(self: CKFlagEnum, probe: int):
-        return bool(self.m_Value & probe)
-
-    def Add(self: CKFlagEnum, data: int):
+    def Add(self, data: int):
         self.m_Value = self.m_Value | data
 
+    def __contains__(self, probe):
+        if isinstance(probe, int):
+            return bool(self.m_Value & probe)
+        if isinstance(probe, CKFlagEnum):
+            return bool(self.m_Value & probe.m_Value)
+
+        return False
+
     def __repr__(self):
         pending = []
 
         for i in self:
             # if it have exactly same entry, return directly
-            if i.value == val:
+            if i.value == self.m_Value:
                 return i.name
 
             # check exist
-            if bool(val & i.value):
+            if bool(self.m_Value & i.value):
                 pending.append(i.name)
 
         result = ', '.join(pending)
-        return result if len(result) != 9 else "[None]"
+        return ('<' + result + '>') if len(result) != 9 else "<[None] {:d}>".format(self.m_Value)
 
-class CK_FILE_WRITEMODE(CKFlagEnum, enum.IntEnum):
+class CK_FILE_WRITEMODE(CKFlagEnum):
     CKFILE_UNCOMPRESSED	       =0	# Save data uncompressed
     CKFILE_CHUNKCOMPRESSED_OLD =1	# Obsolete
     CKFILE_EXTERNALTEXTURES_OLD=2	# Obsolete : use CKContext::SetGlobalImagesSaveOptions instead.
     CKFILE_FORVIEWER           =4	# Don't save Interface Data within the file, the level won't be editable anymore in the interface
     CKFILE_WHOLECOMPRESSED     =8	# Compress the whole file
 
-class CK_LOAD_FLAGS(CKFlagEnum, enum.IntEnum):
+class CK_LOAD_FLAGS(CKFlagEnum):
     CK_LOAD_ANIMATION					=1<<0	# Load animations
     CK_LOAD_GEOMETRY					=1<<1	# Load geometry.
     CK_LOAD_DEFAULT						=CK_LOAD_GEOMETRY|CK_LOAD_ANIMATION	# Load animations & geometry
@@ -56,8 +76,85 @@ class CK_LOAD_FLAGS(CKFlagEnum, enum.IntEnum):
     CK_LOAD_CHECKDEPENDENCIES			=1<<7 # Check if every plugins needed are availables
     CK_LOAD_ONLYBEHAVIORS				=1<<8 # 
 
-CK_CLASSID = int
-class CKCID(enum.IntEnum):
+class CK_FO_OPTIONS(CKEnum):
+    CK_FO_DEFAULT = 0
+    CK_FO_RENAMEOBJECT = 1
+    CK_FO_REPLACEOBJECT = 2
+    CK_FO_DONTLOADOBJECT = 3
+
+CK_ID = int
+
+ClassHierarchy = {
+    1: ("CKCID_OBJECT", ),
+    2: ("CKCID_OBJECT", "CKCID_PARAMETERIN", ),
+    4: ("CKCID_OBJECT", "CKCID_PARAMETEROPERATION", ),
+    5: ("CKCID_OBJECT", "CKCID_STATE", ),
+    6: ("CKCID_OBJECT", "CKCID_BEHAVIORLINK", ),
+    8: ("CKCID_OBJECT", "CKCID_BEHAVIOR", ),
+    9: ("CKCID_OBJECT", "CKCID_BEHAVIORIO", ),
+    12: ("CKCID_OBJECT", "CKCID_RENDERCONTEXT", ),
+    13: ("CKCID_OBJECT", "CKCID_KINEMATICCHAIN", ),
+    11: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", ),
+    15: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_OBJECTANIMATION", ),
+    16: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_ANIMATION", ),
+    18: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_ANIMATION", "CKCID_KEYEDANIMATION", ),
+    19: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", ),
+    52: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_DATAARRAY", ),
+    10: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SCENE", ),
+    21: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_LEVEL", ),
+    22: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_PLACE", ),
+    23: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_GROUP", ),
+    24: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SOUND", ),
+    25: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SOUND", "CKCID_WAVESOUND", ),
+    26: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SOUND", "CKCID_MIDISOUND", ),
+    30: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_MATERIAL", ),
+    31: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_TEXTURE", ),
+    32: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_MESH", ),
+    53: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_MESH", "CKCID_PATCHMESH", ),
+    47: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", ),
+    27: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", "CKCID_2DENTITY", ),
+    28: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", "CKCID_2DENTITY", "CKCID_SPRITE", ),
+    29: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", "CKCID_2DENTITY", "CKCID_SPRITETEXT", ),
+    33: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", ),
+    50: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_GRID", ),
+    36: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CURVEPOINT", ),
+    37: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_SPRITE3D", ),
+    43: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CURVE", ),
+    34: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CAMERA", ),
+    35: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CAMERA", "CKCID_TARGETCAMERA", ),
+    38: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_LIGHT", ),
+    39: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_LIGHT", "CKCID_TARGETLIGHT", ),
+    40: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CHARACTER", ),
+    41: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_3DOBJECT", ),
+    42: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_3DOBJECT", "CKCID_BODYPART", ),
+    46: ("CKCID_OBJECT", "CKCID_PARAMETER", ),
+    45: ("CKCID_OBJECT", "CKCID_PARAMETER", "CKCID_PARAMETERLOCAL", ),
+    55: ("CKCID_OBJECT", "CKCID_PARAMETER", "CKCID_PARAMETERLOCAL", "CKCID_PARAMETERVARIABLE", ),
+    3: ("CKCID_OBJECT", "CKCID_PARAMETER", "CKCID_PARAMETEROUT", ),
+    48: ("CKCID_OBJECT", "CKCID_INTERFACEOBJECTMANAGER", ),
+    49: ("CKCID_OBJECT", "CKCID_CRITICALSECTION", ),
+    51: ("CKCID_OBJECT", "CKCID_LAYER", ),
+    54: ("CKCID_OBJECT", "CKCID_PROGRESSIVEMESH", ),
+    20: ("CKCID_OBJECT", "CKCID_SYNCHRO", ),
+    80: ("CKCID_OBJECTARRAY", ),
+    81: ("CKCID_SCENEOBJECTDESC", ),
+    82: ("CKCID_ATTRIBUTEMANAGER", ),
+    83: ("CKCID_MESSAGEMANAGER", ),
+    84: ("CKCID_COLLISIONMANAGER", ),
+    85: ("CKCID_OBJECTMANAGER", ),
+    86: ("CKCID_FLOORMANAGER", ),
+    87: ("CKCID_RENDERMANAGER", ),
+    88: ("CKCID_BEHAVIORMANAGER", ),
+    89: ("CKCID_INPUTMANAGER", ),
+    90: ("CKCID_PARAMETERMANAGER", ),
+    91: ("CKCID_GRIDMANAGER", ),
+    92: ("CKCID_SOUNDMANAGER", ),
+    93: ("CKCID_TIMEMANAGER", ),
+    -1: ("CKCID_CUIKBEHDATA", ),
+    56: ("CKCID_MAXCLASSID", ),
+    128: ("CKCID_MAXMAXCLASSID", ),
+}
+class CK_CLASSID(CKEnum):
     CKCID_OBJECT = 1
     CKCID_PARAMETERIN = 2
     CKCID_PARAMETEROPERATION = 4
@@ -129,91 +226,74 @@ class CKCID(enum.IntEnum):
     CKCID_MAXCLASSID = 56
     CKCID_MAXMAXCLASSID = 128
 
-    __ClassHierarchy = {
-        1: ("CKCID_OBJECT", ),
-        2: ("CKCID_OBJECT", "CKCID_PARAMETERIN", ),
-        4: ("CKCID_OBJECT", "CKCID_PARAMETEROPERATION", ),
-        5: ("CKCID_OBJECT", "CKCID_STATE", ),
-        6: ("CKCID_OBJECT", "CKCID_BEHAVIORLINK", ),
-        8: ("CKCID_OBJECT", "CKCID_BEHAVIOR", ),
-        9: ("CKCID_OBJECT", "CKCID_BEHAVIORIO", ),
-        12: ("CKCID_OBJECT", "CKCID_RENDERCONTEXT", ),
-        13: ("CKCID_OBJECT", "CKCID_KINEMATICCHAIN", ),
-        11: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", ),
-        15: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_OBJECTANIMATION", ),
-        16: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_ANIMATION", ),
-        18: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_ANIMATION", "CKCID_KEYEDANIMATION", ),
-        19: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", ),
-        52: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_DATAARRAY", ),
-        10: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SCENE", ),
-        21: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_LEVEL", ),
-        22: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_PLACE", ),
-        23: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_GROUP", ),
-        24: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SOUND", ),
-        25: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SOUND", "CKCID_WAVESOUND", ),
-        26: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_SOUND", "CKCID_MIDISOUND", ),
-        30: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_MATERIAL", ),
-        31: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_TEXTURE", ),
-        32: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_MESH", ),
-        53: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_MESH", "CKCID_PATCHMESH", ),
-        47: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", ),
-        27: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", "CKCID_2DENTITY", ),
-        28: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", "CKCID_2DENTITY", "CKCID_SPRITE", ),
-        29: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_RENDEROBJECT", "CKCID_2DENTITY", "CKCID_SPRITETEXT", ),
-        33: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", ),
-        50: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_GRID", ),
-        36: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CURVEPOINT", ),
-        37: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_SPRITE3D", ),
-        43: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CURVE", ),
-        34: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CAMERA", ),
-        35: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CAMERA", "CKCID_TARGETCAMERA", ),
-        38: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_LIGHT", ),
-        39: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_LIGHT", "CKCID_TARGETLIGHT", ),
-        40: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_CHARACTER", ),
-        41: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_3DOBJECT", ),
-        42: ("CKCID_OBJECT", "CKCID_SCENEOBJECT", "CKCID_BEOBJECT", "CKCID_3DENTITY", "CKCID_3DOBJECT", "CKCID_BODYPART", ),
-        46: ("CKCID_OBJECT", "CKCID_PARAMETER", ),
-        45: ("CKCID_OBJECT", "CKCID_PARAMETER", "CKCID_PARAMETERLOCAL", ),
-        55: ("CKCID_OBJECT", "CKCID_PARAMETER", "CKCID_PARAMETERLOCAL", "CKCID_PARAMETERVARIABLE", ),
-        3: ("CKCID_OBJECT", "CKCID_PARAMETER", "CKCID_PARAMETEROUT", ),
-        48: ("CKCID_OBJECT", "CKCID_INTERFACEOBJECTMANAGER", ),
-        49: ("CKCID_OBJECT", "CKCID_CRITICALSECTION", ),
-        51: ("CKCID_OBJECT", "CKCID_LAYER", ),
-        54: ("CKCID_OBJECT", "CKCID_PROGRESSIVEMESH", ),
-        20: ("CKCID_OBJECT", "CKCID_SYNCHRO", ),
-        80: ("CKCID_OBJECTARRAY", ),
-        81: ("CKCID_SCENEOBJECTDESC", ),
-        82: ("CKCID_ATTRIBUTEMANAGER", ),
-        83: ("CKCID_MESSAGEMANAGER", ),
-        84: ("CKCID_COLLISIONMANAGER", ),
-        85: ("CKCID_OBJECTMANAGER", ),
-        86: ("CKCID_FLOORMANAGER", ),
-        87: ("CKCID_RENDERMANAGER", ),
-        88: ("CKCID_BEHAVIORMANAGER", ),
-        89: ("CKCID_INPUTMANAGER", ),
-        90: ("CKCID_PARAMETERMANAGER", ),
-        91: ("CKCID_GRIDMANAGER", ),
-        92: ("CKCID_SOUNDMANAGER", ),
-        93: ("CKCID_TIMEMANAGER", ),
-        -1: ("CKCID_CUIKBEHDATA", ),
-        56: ("CKCID_MAXCLASSID", ),
-        128: ("CKCID_MAXMAXCLASSID", ),
-    }
-
-    def __init__(self, code: CK_CLASSID):
-        self.code: CK_CLASSID = code
     def __repr__(self):
-        hierarchy = self.__ClassHierarchy.get(self.code, None)
+        hierarchy = ClassHierarchy.get(self.m_Value, None)
         if hierarchy is None:
-            return "[Undefined]"
+            return "[Undefined] {:d}".format(self.m_Value)
         return "{} ({})".format(
             hierarchy[-1],
             ' -> '.join(hierarchy)
         )
+    def __str__(self):
+        hierarchy = ClassHierarchy.get(self.m_Value, None)
+        if hierarchy is None:
+            return "[Undefined] {:d}".format(self.m_Value)
+        return hierarchy[-1]
 
 
-CKERROR = int
-class CKERR():
+ErrorDescription = {
+    0: "Operation successful",
+    -1: "One of the parameter passed to the function was invalid",
+    -2: "One of the parameter passed to the function was invalid",
+    -3: "The parameter size was invalid",
+    -4: "The operation type didn't exist",
+    -5: "The function used to execute the operation is not yet implemented",
+    -6: "There was not enough memory to perform the action",
+    -7: "The function  is not yet implemented",
+    -11: "There was an attempt to remove something not present",
+    -13: "There is no level currently created",
+    -14: "There is no level currently created",
+    -16: "The notification message was not used",
+    -17: "Attempt to add an item that was already present",
+    -18: "the render context is not valid",
+    -19: "the render context is not activated for rendering",
+    -20: "there was no plugins to load this kind of file",
+    -21: "there was no plugins to save this kind of file",
+    -22: "attempt to load an invalid file",
+    -23: "attempt to load with an invalid plugin",
+    -24: "attempt use an object that wasnt initialized",
+    -25: "attempt use a message type that wasn't registred",
+    -29: "No dll file found in the parse directory",
+    -30: "this dll has already been registred",
+    -31: "this dll does not contain information to create the prototype",
+    -34: "Invalid Object (attempt to Get an object from an invalid ID)",
+    -35: "Invalid window was provided as console window",
+    -36: "Invalid kinematic chain ( end and start effector may not be part of the same hierarchy )",
+    -37: "Keyboard not attached or not working properly",
+    -38: "Mouse not attached or not working properly",
+    -39: "Joystick not attached or not working properly",
+    -40: "Try to link imcompatible Parameters",
+    -44: "There is no render engine dll",
+    -45: "There is no current level (use CKSetCurrentLevel )",
+    -46: "Sound Management has been disabled",
+    -47: "DirectInput Management has been disabled",
+    -48: "Guid is already in use or invalid",
+    -49: "There was no more free space on disk when trying to save a file",
+    -50: "Impossible to write to file (write-protection ?)",
+    -51: "The behavior cannnot be added to this entity",
+    -52: "The behavior cannnot be added to this entity",
+    -53: "A manager was registered more than once",
+    -54: "CKprocess or TimeManager process while CK is paused will fail",
+    -55: "Some plugins were missing whileloading a file",
+    -56: "Virtools version too old to load this file",
+    -57: "CRC Error while loading file",
+    -58: "A Render context is already in Fullscreen Mode",
+    -59: "Operation was cancelled by user",
+    -121: "there were no animation key at the given index",
+    -122: "attemp to acces an animation key with an invalid index",
+    -123: "the animation is invalid (no entity associated or zero length)",
+}
+class CKERROR(CKEnum):
     CKERR_OK =  0
     CKERR_INVALIDPARAMETER = -1
     CKERR_INVALIDPARAMETERTYPE = -2
@@ -265,61 +345,6 @@ class CKERR():
     CKERR_INVALIDINDEX = -122
     CKERR_INVALIDANIMATION = -123
 
-    __ErrorDescription = {
-        0: "Operation successful",
-        -1: "One of the parameter passed to the function was invalid",
-        -2: "One of the parameter passed to the function was invalid",
-        -3: "The parameter size was invalid",
-        -4: "The operation type didn't exist",
-        -5: "The function used to execute the operation is not yet implemented",
-        -6: "There was not enough memory to perform the action",
-        -7: "The function  is not yet implemented",
-        -11: "There was an attempt to remove something not present",
-        -13: "There is no level currently created",
-        -14: "There is no level currently created",
-        -16: "The notification message was not used",
-        -17: "Attempt to add an item that was already present",
-        -18: "the render context is not valid",
-        -19: "the render context is not activated for rendering",
-        -20: "there was no plugins to load this kind of file",
-        -21: "there was no plugins to save this kind of file",
-        -22: "attempt to load an invalid file",
-        -23: "attempt to load with an invalid plugin",
-        -24: "attempt use an object that wasnt initialized",
-        -25: "attempt use a message type that wasn't registred",
-        -29: "No dll file found in the parse directory",
-        -30: "this dll has already been registred",
-        -31: "this dll does not contain information to create the prototype",
-        -34: "Invalid Object (attempt to Get an object from an invalid ID)",
-        -35: "Invalid window was provided as console window",
-        -36: "Invalid kinematic chain ( end and start effector may not be part of the same hierarchy )",
-        -37: "Keyboard not attached or not working properly",
-        -38: "Mouse not attached or not working properly",
-        -39: "Joystick not attached or not working properly",
-        -40: "Try to link imcompatible Parameters",
-        -44: "There is no render engine dll",
-        -45: "There is no current level (use CKSetCurrentLevel )",
-        -46: "Sound Management has been disabled",
-        -47: "DirectInput Management has been disabled",
-        -48: "Guid is already in use or invalid",
-        -49: "There was no more free space on disk when trying to save a file",
-        -50: "Impossible to write to file (write-protection ?)",
-        -51: "The behavior cannnot be added to this entity",
-        -52: "The behavior cannnot be added to this entity",
-        -53: "A manager was registered more than once",
-        -54: "CKprocess or TimeManager process while CK is paused will fail",
-        -55: "Some plugins were missing whileloading a file",
-        -56: "Virtools version too old to load this file",
-        -57: "CRC Error while loading file",
-        -58: "A Render context is already in Fullscreen Mode",
-        -59: "Operation was cancelled by user",
-        -121: "there were no animation key at the given index",
-        -122: "attemp to acces an animation key with an invalid index",
-        -123: "the animation is invalid (no entity associated or zero length)",
-    }
-
-    def __init__(self, code: CKERROR):
-        self.code: CKERROR = code
     def __repr__(self):
-        return self.__ErrorDescription.get(self.code, "[Undefined]")
+        return ErrorDescription.get(self.m_Value, "[Undefined] {:d}".format(self.m_Value))
 
diff --git a/PyCmo/VTReader.py b/PyCmo/VTReader.py
index 5e7e6d6..4a6694e 100644
--- a/PyCmo/VTReader.py
+++ b/PyCmo/VTReader.py
@@ -3,50 +3,52 @@ import PyCmoMisc
 import struct, io, datetime, zlib
 import typing
 
-g_HeaderPacker = struct.Struct('<' + 'i' * 8)
+g_Header1Packer = struct.Struct('<iiIiiiii')
+g_Header2Packer = struct.Struct('<iiiiiiii')
+g_FileObjectPacker = struct.Struct('<iiii')
 
 class CKFileReader():
 
     @staticmethod
     def ReadFileHeaders(self: VTStruct.CKFile) -> VTConstants.CKERROR:
         if self.m_Parser is None:
-            return VTConstants.CKERR.CKERR_INVALIDPARAMETER
-        header = VTStruct.CKFileHeader()
+            return VTConstants.CKERROR(VTConstants.CKERROR.CKERR_INVALIDPARAMETER)
+        parser = self.m_Parser
 
-        # check magic words
-        magic_words = self.m_Parser.GetReader()[0:4]
+        # ========== magic words ==========
+        magic_words = parser.GetReader()[0:4]
         if magic_words != b'Nemo':
-            return VTConstants.CKERR.CKERR_INVALIDFILE
+            return VTConstants.CKERROR(VTConstants.CKERROR.CKERR_INVALIDFILE)
         
-        # read header1
-        if self.m_Parser.GetSize() < 0x20:
-            return VTConstants.CKERR.CKERR_INVALIDFILE
-        header1 = g_HeaderPacker.unpack(self.m_Parser.GetReader().read(8 * 4))
+        # ========== read header1 ==========
+        if parser.GetSize() < 0x20:
+            return VTConstants.CKERROR(VTConstants.CKERROR.CKERR_INVALIDFILE)
+        header1 = list(g_Header1Packer.unpack(parser.GetReader().read(8 * 4)))
 
         # check header1
         if header1[5]:  # i don't know what is this fields stands for
-            header1 = tuple(0 for _ in range(8))
+            header1 = list(0 for _ in range(8))
 
         # virtools is too old to open this file. file is too new.
         if header1[4] > 9:  # file version
-            return VTConstants.CKERR.CKERR_OBSOLETEVIRTOOLS
+            return VTConstants.CKERROR(VTConstants.CKERROR.CKERR_OBSOLETEVIRTOOLS)
 
-        # read header2
+        # ========== read header2 ==========
         # file ver < 5 do not have second header
         if header1[4] < 5:
-            header2 = tuple(0 for _ in range(8))
+            header2 = list(0 for _ in range(8))
         else:
-            if self.m_Parser.GetSize() < 0x40:
-                return VTConstants.CKERR.CKERR_INVALIDFILE
+            if parser.GetSize() < 0x40:
+                return VTConstants.CKERROR(VTConstants.CKERROR.CKERR_INVALIDFILE)
 
-            header2 = g_HeaderPacker.unpack(self.m_Parser.GetReader().read(8 * 4))
+            header2 = g_Header2Packer.unpack(parser.GetReader().read(8 * 4))
 
         # forcely reset too big product ver
         if header2[5] >= 12:    # product version
             header2[5] = 0
             header2[6] = 0x1010000   # product build
 
-        # assign value
+        # ========== assign value ==========
         self.m_FileInfo.ProductVersion = header2[5]
         self.m_FileInfo.ProductBuild = header2[6]
         self.m_FileInfo.FileWriteMode.m_Value = header1[6]
@@ -62,31 +64,78 @@ class CKFileReader():
         self.m_FileInfo.DataUnPackSize = header2[1]
         self.m_FileInfo.Crc = header1[2]
 
+        # ========== crc and body unpacker ==========
+        # file version greater than 8 have crc feature and compression feature
+        if self.m_FileInfo.FileVersion >= 8:
+            # reset crc field of header
+            header1[2] = 0
 
-        # process date independently
-        # date is in BCD code
-        day = PyCmoMisc.BcdCodeToDecCode((raw_date >> 24) & 0xff)
-        month = PyCmoMisc.BcdCodeToDecCode((raw_date >> 16) & 0xff - 1)
-        month = (month % 12) + 1
-        year = PyCmoMisc.BcdCodeToDecCode(raw_date & 0xffff)
-        header.Timestamp = datetime.date(year, month, day)
+            # compute crc
+            gotten_crc = zlib.adler32(g_Header1Packer.pack(*header1), 0)
 
-        if header.FileVersion >= 8:
-            # check crc
-            gotten_crc = zlib.adler32(b'Nemo Fi\0', 0)
-            gotten_crc = zlib.adler32(struct.pack("<6I", 0, raw_date, header.FileVersion, header.FileVersion2, header.SaveFlags, header.PrewHdrPackSize), gotten_crc)   # reset crc as zero
-            gotten_crc = zlib.adler32(struct.pack("<8I", header.DataPackSize, header.DataUnpackSize, header.ManagerCount, header.ObjectCount, header.MaxIDSaved, header.ProductVersion, header.ProductBuild, header.PrewHdrUnpackSize), gotten_crc)
-            gotten_crc = zlib.adler32(fs.read(header.PrewHdrPackSize), gotten_crc)
-            gotten_crc = zlib.adler32(fs.read(header.DataPackSize), gotten_crc)
-            if gotten_crc != header.Crc:
-                raise Exception("Crc Error")
+            reader = parser.GetReader()
+            pos_cache = reader.tell()
+            reader.seek(8 * 4, io.SEEK_SET)
+            gotten_crc = zlib.adler32(reader.read(
+                8 * 4 + self.m_FileInfo.Hdr1PackSize + self.m_FileInfo.DataPackSize
+            ), gotten_crc)
+            reader.seek(pos_cache, io.SEEK_SET)
+
+            # compare crc
+            if gotten_crc != self.m_FileInfo.Crc:
+                return VTConstants.CKERROR(VTConstants.CKERROR.CKERR_FILECRCERROR)
+
+
+            # compare size to decide wheher use compress feature
+            if self.m_FileInfo.Hdr1UnPackSize != self.m_FileInfo.Hdr1PackSize:
+                # create a new parser for following analyze
+                parser = VTUtils.SmallZlibFileReader(parser, self.m_FileInfo.Hdr1PackSize, self.m_FileInfo.Hdr1UnPackSize)
+
+        # ========== object list read ==========
+        # file ver >= 7 have this features
+        if self.m_FileInfo.FileVersion >= 7:
+            self.m_SaveIDMax = self.m_FileInfo.MaxIDSaved
+            # resize
+            self.m_FileObjects = list(VTStruct.CKFileObject() for _ in range(self.m_FileInfo.ObjectCount))
+
+            # read data
+            reader = parser.GetReader()
+            for fileobj in self.m_FileObjects:
+                # set useless fields
+                fileobj.ObjPtr = None
+                fileobj.Name = None
+                fileobj.Data = None
+
+                # read basic fields
+                (fileobj.Object, cid, fileobj.FileIndex, namelen) = g_FileObjectPacker.unpack(
+                    reader.read(g_FileObjectPacker.size)
+                )
+                fileobj.ObjectCid.Set(cid)
+
+                # read name
+                if namelen > 0:
+                    fileobj.Name = reader.read(namelen).decode('utf-8', errors = 'ignore')
+                    
+        # ========== dep list read ==========
+        # only file ver >= 8, this sector is existed
+        if self.m_FileInfo.FileVersion >= 8:
+            pass
 
-        return header
 
-    
     @staticmethod
-    def ReadCKComposition(fs: io.BufferedReader):
-        composition = VTStruct.CKComposition()
+    def Load(self: VTStruct.CKFile, filename: str, load_flags: VTConstants.CK_LOAD_FLAGS) -> VTConstants.CKERROR:
+        # todo: clear first
 
-        composition.Header = ReadCKFileHeader(fs)
-        return composition
+        # setup basic fields
+        self.m_FileName = filename
+        self.m_Flags = load_flags
+        
+        # setup parser
+        self.m_Parser = VTUtils.RawFileReader(filename)
+
+        # read header first
+        err = CKFileReader.ReadFileHeaders(self)
+
+        # todo: finish other read
+
+        return err
diff --git a/PyCmo/VTStruct.py b/PyCmo/VTStruct.py
index ea22c65..1dd740d 100644
--- a/PyCmo/VTStruct.py
+++ b/PyCmo/VTStruct.py
@@ -2,12 +2,24 @@ import VTConstants, VTUtils
 import PyCmoMisc
 import datetime
 
+class CKGUID():
+    def __init__(self):
+        self.D1: int = 0
+        self.D2: int = 0
+    def __init__(self, d1: int, d2: int):
+        self.D1: int = d1
+        self.D2: int = d2
+    def __repr__(self):
+        return f"<CKGUID: 0x{self.D1:08X}, 0x{self.D2:08X}"
+    def __str__(self):
+        return self.__repr__()
+
 class CKFileInfo:
-    def __init__(self: CKFileInfo):
+    def __init__(self):
         self.ProductVersion: int = 0
         self.ProductBuild: int = 0
 
-        self.FileWriteMode: VTConstants.CK_FILE_WRITEMODE = 0
+        self.FileWriteMode: VTConstants.CK_FILE_WRITEMODE = VTConstants.CK_FILE_WRITEMODE(0)
         
         self.FileVersion: int = 0
         self.CKVersion: int = 0
@@ -22,9 +34,9 @@ class CKFileInfo:
         self.Hdr1PackSize: int = 0
         self.Hdr1UnPackSize: int = 0
         self.DataPackSize: int = 0
-        self.DataUnpackSize: int = 0
+        self.DataUnPackSize: int = 0
 
-    def GetProductBuildTuple(self: CKFileInfo) -> tuple[int]:
+    def GetProductBuildTuple(self) -> tuple[int]:
         return (
             (self.ProductBuild >> 24) & 0xff, 
             (self.ProductBuild >> 16) & 0xff, 
@@ -32,29 +44,73 @@ class CKFileInfo:
             self.ProductBuild & 0xff
         )
 
-    def __repr__(self: CKFileInfo) -> str:
-        return f"""Version (File / CK): {self.FileVersion:08X} / {self.CKVersion:08X}
-Product (Version / Build): {self.ProductVersion:d} / {'.0'.join(self.GetProductBuildTuple())}
-Save Flags: {self.SaveFlags}
-File Size: {PyCmoMisc.OutputSizeHumanReadable(self.FileSize)}
-Crc: 0x{self.Crc:08X}
+    def __repr__(self) -> str:
+        return f"""<CKFile: 
+    Version (File / CK): {self.FileVersion:d} / 0x{self.CKVersion:08X}
+    Product (Version / Build): {self.ProductVersion:d} / {'.0'.join(map(lambda x: str(x), self.GetProductBuildTuple()))}
+    Save Flags: {self.FileWriteMode}
+    File Size: {PyCmoMisc.OutputSizeHumanReadable(self.FileSize)}
+    Crc: 0x{self.Crc:08X}
 
-Preview Header (Pack / Unpack): {PyCmoMisc.OutputSizeHumanReadable(self.PrewHdrPackSize)} / {PyCmoMisc.OutputSizeHumanReadable(self.PrewHdrUnpackSize)}
-Data (Pack / Unpack): {PyCmoMisc.OutputSizeHumanReadable(self.DataPackSize)} / {PyCmoMisc.OutputSizeHumanReadable(self.DataUnpackSize)}
+    Hdr1 (Pack / Unpack): {PyCmoMisc.OutputSizeHumanReadable(self.Hdr1PackSize)} / {PyCmoMisc.OutputSizeHumanReadable(self.Hdr1UnPackSize)}
+    Data (Pack / Unpack): {PyCmoMisc.OutputSizeHumanReadable(self.DataPackSize)} / {PyCmoMisc.OutputSizeHumanReadable(self.DataUnPackSize)}
 
-Manager Count: {self.ManagerCount:d}
-Object Count: {self.ObjectCount:d}
-Max ID Saved: {self.MaxIDSaved:d}
-"""
+    Manager Count: {self.ManagerCount:d}
+    Object Count: {self.ObjectCount:d}
+    Max ID Saved: {self.MaxIDSaved:d}
+>"""
+    def __str__(self) -> str:
+        return self.__repr__()
 
+class CKFileObject():
+    def __init__(self):
+        self.Object: VTConstants.CK_ID = 0
+        self.CreatedObject: VTConstants.CK_ID = 0
+        self.ObjectCid: VTConstants.CK_CLASSID = VTConstants.CK_CLASSID(VTConstants.CK_CLASSID.CKCID_OBJECT)
+        self.ObjPtr = None
+        self.Name: str = None
+        self.Data = None
+        self.PostPackSize: int = 0
+        self.PrePackSize: int = 0
+        self.Options: VTConstants.CK_FO_OPTIONS = VTConstants.CK_FO_OPTIONS(VTConstants.CK_FO_OPTIONS.CK_FO_DEFAULT)
+        self.FileIndex: int = 0
+        self.SaveFlags: VTConstants.CK_FILE_WRITEMODE = VTConstants.CK_FILE_WRITEMODE(0)
 
+    def __repr__(self) -> str:
+        return f'<{self.Name if self.Name else "[Anonymous]"}: {self.ObjectCid}>'
+    def __str__(self) -> str:
+        return self.__repr__()
+
+class CKFilePluginDependencies():
+    def __init__(self):
+        self.m_PluginCategory: int = 0
+        self.m_Guids: list[CKGUID] = []
+        self.ValidGuids: list[bool] = []
+        
+    def __repr__(self) -> str:
+        return repr(self.m_Guids)
+    def __str__(self) -> str:
+        return self.__repr__()
 
 class CKFile(object):
     def __init__(self):
-        self.m_FileName: str = ''
+        self.m_SaveIDMax: int = 0
+        self.m_FileObjects: list[CKFileObject] = []
+        self.m_ManagersData = []
+        self.m_PluginDep: list[CKFilePluginDependencies] = []
+        self.m_IndexByClassId: list[list[int]] = []
+        self.m_IncludedFiles: list[str] = []
+
         self.m_FileInfo: CKFileInfo = CKFileInfo()
+
+        self.m_Flags: VTConstants.CK_LOAD_FLAGS = VTConstants.CK_LOAD_FLAGS(VTConstants.CK_LOAD_FLAGS.CK_LOAD_DEFAULT)
+        self.m_FileName: str = ''
         self.m_Parser: VTUtils.UniversalFileReader = None
 
-    def __repr__(self: CKFile) -> str:
-        return self.m_FileInfo
+        self.m_ReadFileDataDone: bool = False
+
+    def __repr__(self) -> str:
+        return repr(self.m_FileInfo)
+    def __str__(self) -> str:
+        return self.__repr__()
 
diff --git a/PyCmo/VTUtils.py b/PyCmo/VTUtils.py
index 40d5f01..ed38ffa 100644
--- a/PyCmo/VTUtils.py
+++ b/PyCmo/VTUtils.py
@@ -6,7 +6,7 @@ class RawFileReader():
     def __init__(self, filename: str):
         self.__size: int = os.path.getsize(filename)
         self.__fs = open(filename, 'rb')
-        self.__mm: mmap.mmap = mmap.mmap(self.__fs.fileno, 0, access = mmap.ACCESS_READ)
+        self.__mm: mmap.mmap = mmap.mmap(self.__fs.fileno(), 0, access = mmap.ACCESS_READ)
     
     def __del__(self):
         self.__mm.close()
@@ -49,7 +49,10 @@ class LargeZlibFileReader():
         return self.__mm
 
 class SmallZlibFileReader():
-    def __init__(self):
+    def __init__(self, raw_reader: RawFileReader, comp_size: int, uncomp_size: int):
+        # set size
+        self.__size: int = uncomp_size
+
         # create io
         self.__ss: io.BytesIO = io.BytesIO()
 
@@ -61,13 +64,16 @@ class SmallZlibFileReader():
         while buf:
             self.__ss.write(parser.decompress(buf))
             buf = reader.read(io.DEFAULT_BUFFER_SIZE)
-        self._ss.write(parser.flush())
+        self.__ss.write(parser.flush())
+
+        # reset cursor
+        self.__ss.seek(0, io.SEEK_SET)
 
     def __del__(self):
         del self.__ss
 
     def GetSize(self) -> int:
-        return len(self.__ss.getvalue())
+        return self.__size
 
     def GetReader(self) -> io.BytesIO:
         return self.__ss