Problem: Buffer menu does not handle unicode names correctly
(after v9.1.1622)
Solution: Fix the BMHash() function (Yee Cheng Chin)
The Buffers menu uses a BMHash() function to generate a sortable number
to be used for the menu index. It used a naive (and incorrect) way of
encoding multiple ASCII values into a single integer, but assumes each
character to be only in the ASCII 32-96 range. This means if we use
non-ASCII file names (e.g. Unicode values like CJK or emojis) we get
integer underflow and overflow, causing the menu index to wrap around.
Vim's GUI implementations internally use a signed 32-bit integer for the
`gui_mch_add_menu_item()` function and so we need to make sure the menu
index is in the (0, 2^31-1) range.
To do this, if the file name starts with a non-ASCII value, we just use
the first character's value and set the high bit so it sorts after the
other ASCII ones. Otherwise, we just take the first 5 characters, and
use 5 bit for each character to encode a 30-bit number that can be
sorted.
This means Unicode file names won't be sorted beyond the first
character. This is likely going to be fine as there are lots of ways to
query buffers.
related: vim/vim#17403closes: vim/vim#179288f9de4991e
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>
Problem: Patch v9.1.1432 causes performance regressions
Solution: Revert "patch 9.1.1432: GTK GUI: Buffer menu does not handle
unicode correctly" (Yee Cheng Chin).
This reverts commit 08896dd330c6dc8324618fde482db968e6f71088.
The previous change to support Unicode characters properly in the
buffers menu resorted to removing all buffer menus and re-add the
buffers after doing a sort, per each buffer addition. This was quite
slow because if Vim is trying to load in multiple buffers at once (e.g.
when loading a session) this scales in O(n^2) and Vim can freeze for
dozens of seconds when adding a few hundred buffers.
related: vim/vim#17405
related: vim/vim#17928fixes: vim/vim#17897cda0d17f59
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>
