How to detect modifications in an ABAP Object?

Hi all,
I was wondering if there's a simple way of detecting modifications in an ABAP Object.
Imagine an ABAP entity object which holds several attributes and you need to know if this object has been modified. Instead of having to check attribute by attribute to compare it's previous value with the new one I came with the idea of calculating a HASH code for the object before the execution of the application which can change the object attributes and comparing it with the HASH calculated for the same object after the execution.
That way, checking only two hashes simplifies a lot the code. So.... is there any way of calculating a HASH for any object instance? if not... any other approach?
Thanks in advance.

Sorry Hüseyin Dereli, but I'm not talking about source version control, but how to detect attribute modifications of an ABAP Object Instance.
for example, suppose you have a program which reads data from DataBase and stores temporally that data into an ABAP Object like this:
ABAP Object AAAA{
   private attr1
   private attr2
and passes this ABAP Object into a screen for user interaction, or even a FunctionModule or Method or anything else...
data: myObject type ref to AAAA.
myObject-attr1 = 1
myObject-attr2 = 2.
CallFunction AnyFunction Changing data = myObject
After the execution of AnyFunction I would like to know if myObject has been changed but I'm trying not to check attribute by attribute because if myObject has a lot of attributes (not in this example but in the real source code)
It would be great if we could do something like this:
data: myObject type ref to AAAA,
          oldHash type hash,
           newHash type hash.
myObject-attr1 = 1
myObject-attr2 = 2.
oldHash = myObject->get_hash()
CallFunction AnyFunction Changing data = myObject
newHash = myObject->get_hash()
if oldHash NE newHash.
* MyObject has been modified
endif.

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