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Is it possible to shift the contents of a file while writing to it using FileWriter?
I need to write data constants to the head of the file and if I do that it overwrites the file.
What technique should I use to do this or should I make make copies of the file (with the new data on top) on every file write?
If you want to overwrite certain bytes of the file and not others, you can use seek and write to do so. If you want to change the content of every byte in the file (by, for example, adding a single byte to the beginning of the file) then you need to write a new file and potentially rename it after you’ve done writing it.
Think of the answer to the question “what will be the contents of the byte at offset x after I’m done?”. If, for a large percent of the possible values of x the answer is “not what it used to be” then you need a new file.