Try to reduce the UTF-8 mess.
Get rid of passing around u_char[4]s and define a struct utf8_data which has
character data, size (sequence length) and width. Move UTF-8 character
collection into two functions utf8_open/utf8_append in utf8.c which fill in
this struct and use these functions from input.c and the various functions in
screen-write.c.
Space for rather more data than is necessary for one UTF-8 sequence is in the
utf8_data struct because screen_write_copy is still nasty and needs to reinject
the character (after combining) into screen_write_cell.
UTF-8 combined character fixes.
Thai can have treble combinations (1 x width=1 then 2 x width=0) so bump the
UTF-8 cell data size to 9 and alter the code to allow this.
Also break off the combining code into a separate function, handle any further
combining beyond the buffer size by replacing the character with _s, and when
redrawing the UTF-8 character don't assume the first part has just been
printed, redraw the entire line.
Move the check for whether to force a line wrapper lower down into the tty code
where it has access to the tty width, which is what should have been checked.
Instead of having a complicated check to see if the cursor is in the last
position to avoid an explicit wrap, actually move it there.
Some UTF-8 fixes to come.
When checking whether the region will scroll and the cursor position is thus
unsuitable for using CUD/CUU, check the current cursor position not the target
position.
Add mode keys to move the cursor to the top, middle and bottom of the screen.
H/M/L in vi mode and M-R/M-r in emacs (bottom of screen not bound in emacs).
Do this in a better way - print messages when exiting with nonzero.
Also remove the login shell information from server-info, only the client
should care about it.
When drawing lines that have wrapped naturally, don't force a newline but
permit them to wrap naturally again. This allows terminals that use this to
guess where lines start and end for eg mouse selecting (like xterm) to work
correctly.
This was another long-standing issue raised by several people over the last
while.
Thanks to martynas@ for much testing. This was not trivial to get right so
bringing it in for wider testing and adn to fix any further glitches in-tree.
When backspace is received at the beginning of a line and the previous line was
wrapped, move the cursor back up to the end of the previous line.
Another one of the forgotten persons requested this quite a while ago (I need
to start noting names on todo items...) when it was quite hard to
implement. Now it is easy and I don't see it can do any harm, so hey presto...
Don't run through the column unchanged case if the row was unchanged but there
were no suitable optimisations, instead make it an else to fall through to
absolute addressing.
Use relative cursor movement instead of absolute when possible and when
supported by the terminal to reduce the size of the output data (generally
about 10-20%).
Like linefeed, don't set the scroll region for reverse index unless it will be
needed.
While here, also tidy up a couple of long lines and remove an extraneous blank.
