Improve email trimming based on existing content

If incomming email is recieved then take last char of it and go over comments and desciption (and/or email logs) to find comment that ends with it and if there is match check the last - 1 and so on. It should end if there is totally same content or when end of comparing queue (comments, description, logs) is reached. So if there is any match then select that on that has more character same and remove such same content from new one after that put to the end of it somethin like: (Continue #if(x > 0) at char x of#else on#end comment Z ...)

I have suggested that due to such regexp splitter is not possible to set that way that required content is not cut off.