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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <chars.h>
include "tty.h"
# TTYGOTO -- Position the cursor to the given absolute screen coordinates.
# We do not require any knowledge of the current screen position; many programs
# will wish to do cursor positioning at a lower level to take advantage of
# knowledge of the current position.
procedure ttygoto (fd, tty, col, line)
int fd # output stream
pointer tty # termcap descriptor
int col # destination column
int line # destination line
pointer sp, cm_in, cm_out
int coords[2], nchars, i
int ttygets(), ttysubi()
errchk salloc, ttygets, ttyputs, ttywrite
begin
call smark (sp)
call salloc (cm_in, SZ_CTRLSTR, TY_CHAR)
call salloc (cm_out, SZ_LINE, TY_CHAR)
# Use the cursor motion control string to position cursor, if the
# terminal has such a capability. Otherwise try to use primitive
# motion commands.
if (ttygets (tty, "cm", Memc[cm_in], SZ_CTRLSTR) > 0) {
# Coordinates are ordered line,col in the termcap entry,
# whereas our args are ordered col,line (e.g., x,y). Store
# in "coords" in the termcap order.
coords[1] = line
coords[2] = col
nchars = ttysubi (Memc[cm_in], Memc[cm_out], SZ_LINE, coords, 2)
# Output cursor motion control string to file.
call ttywrite (fd, tty, Memc[cm_out], nchars, 1)
# If unable to position to the exact coordinates, use primitive
# motion commands to step the rest of the way in. Do not abort
# if unable to do so.
if (coords[2] > 0) {
# Presumably we do not have to step in very often, so we do
# nothing special to buffer the backspace control sequence.
# Most terminals recognize BS in any case.
if (T_BSOK(tty) == YES) {
Memc[cm_out] = BS
Memc[cm_out+1] = EOS
} else if (ttygets (tty, "bc", Memc[cm_out], SZ_CTRLSTR) == 0)
Memc[cm_out] = EOS
for (i=coords[2]; i > 0; i=i-1)
call ttyputs (fd, tty, Memc[cm_out], 1)
}
# Now adjust vertical position if necessary.
if (coords[1] > 0) {
if (ttygets (tty, "up", Memc[cm_out], SZ_CTRLSTR) > 0)
for (i=coords[1]; i > 0; i=i-1)
call ttyputs (fd, tty, Memc[cm_out], 1)
}
} else {
# Terminal has no nifty cursor addressing capability; add code here
# to position cursor by generating a sequence of more primitive
# codes. Not going to bother with this for now.
;
}
call sfree (sp)
end
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