Is there any preprocess hook for date api? As I asked in above, Is there any theme preprocess hook for all of the dates that displayed in Themes Files?
I want to perform some mathematical operations on Dates that show on any content type, 
Is there any solution to achieve it in my Themes Files.
Date API introduces several theme functions:


theme_date_combo
theme_date_display_combination
theme_date_display_interval
theme_date_display_range
theme_date_display_single
theme_date_text_parts


All of which can be preprocessed.

If the output you need to override isn't the result of one of those functions, you'll need to look for a different solution (e.g. depending on context you might be able to preprocess a field template).