Implement REP CSI

[Andreas Stöckel]

vterm does not implement the REP CSI defined in ECMA-48 section 8.3.103. This CSI is heavily used by ncurses if "TERM=xterm" to draw forms. The REP CSI repeats the last character n times until the end of the line.

Examples:

echo -e "a\e[bb"
aab

echo -e "a\e[0bb"
aab

echo -e "a\e[2bb"
aaab

echo -e "a\e[9000bb"
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa [...]
b

See the attached image for the "demo_form" ncurses example application without REP.

(Note: I've already fixed this bug, but need the bug number to name the test case correctly.)

[Andreas Stöckel (andreas-stoeckel)]

I've implemented the REP CSI in the following patch:

[PATCH] Implement REP CSI (ECMA-48 §8.3.103)
https://github.com/astoeckel/libvterm/commit/7e1aad25b4d26d54fb8d135f6c2fee4634a20d3c.patch

I'm not sure if I've handled line-wrapping with two-column characters correctly, but other than that it should be ok, I think.

See attached image for the ncurses test application demo_form with the patch applied.

[Paul "LeoNerd" Evans (leonerd)]

LGTM. Nice coverage of test cases too including some full-width Unicode.

I'll merge this as is, but then I'll rename the test case file. For actually-added features it's best to name those something relating to the feature itself so they're easier to find. The "LP" series of bug numbered-files is largely for obscure cornercases or unusual situations that come up in actual bug reports.

Looking at the test numbers currently I may have to do a bit of renumbering first though.

[Paul "LeoNerd" Evans (leonerd)]

Renumbered as of -r725

[Paul "LeoNerd" Evans (leonerd)]

And now doc added in -r726

Also I've marked it on

  https://docs.google.com/spreadsheets/d/19W-lXWS9jYwqCK-LwgYo31GucPPxYVld_hVEcfpNpXg/edit#gid=1132946242