Why does the ringbuffer index move backward?

[shi-yan]

I'm trying to understand the codebase as I also want to implement a terminal emulator.

But I have a question, it seems that the ringbuffer moves its internal index backward.

For example, if we save 1, 2, 3. Internally they are saved as 3,2,1, I'm curious why this is the case?

does this design have benefits in terms of avoiding data copying and allocation? Thanks!

[shi-yan]

after putting logs, I now understand the logic. What confused me was the naming of the variable zero in storage. it doesn't point to the logic index zero (the topmost visible row), instead, it points to the bottommost row.