27 Nov
2020
27 Nov
'20
5:23 a.m.
Did I miss a reason for the alternative? Because if you add a caching
layer this approach has been working for me for decades. I rewrote
dired in perl just because perl was everywhere and I could. I've been
dragging the perl one around since at least 1990 and it worked for me
on pretty much any version of Unix. I think MacOS isn't supported but
I'm sure it could be.
To avoid calling tput over and over again, I cached the output for each
terminal and then just evaled the cache which sets a bunch of variables
to the escapes I needed.
It performed just fine on 20mhz SPARCstations so I'm sort of wondering
why the solution for the problem isn't good enough.
# Dig out all the terminal info so we know the escape chars for this terminal.
sub terminal_init
{
local($term) = "$ENV{'HOME'}/.term/$ENV{'TERM'}";
local($i) = 0;
$| = 1;
@pids = ();
$SIG{TERM} = sub { exit(0); };
$SIG{PIPE} = 'IGNORE';
# RedHat 5.0 seems to get this wrong somehow.
#chop($tc_rows = `tput lines`);
#chop($tc_cols = `tput cols`);
open(STTY, "stty -a|");
while (defined($_ = <STTY>)) {
last if /rows = \d/ || /\d rows/ || /rows \d/;
}
close(STTY);
#speed 9600 baud; rows 58; columns 80; line = 0;
#speed 9600 baud; 47 rows; 80 columns;
#rows = 66; columns = 80
$tc_cols = 0;
if (/rows (\d+); columns (\d+);/) {
$tc_rows = $1;
$tc_cols = $2;
} elsif (/(\d+) rows; (\d+) columns;/) {
$tc_rows = $1;
$tc_cols = $2;
} elsif (/rows = (\d+); columns = (\d+)/) {
$tc_rows = $1;
$tc_cols = $2;
}
if ($tc_cols == 0) {
die "Can't get terminal settings.\n";
}
$half_of_screen = int($tc_rows / 2);
# it's cached, go grab it.
if (-f $term) {
open(T, $term);
@t = <T>;
close(T);
eval "@t";
&ttyraw;
return unless $i < $tc_rows;
}
print "Getting terminal info just this once and saving it...";
mkdir("$ENV{'HOME'}/.term", 0755);
open(T, ">$term");
$tc_smcup = `tput smcup`;
$tc_rmcup = `tput rmcup`;
$tc_bold = `tput bold`;
$tc_normal = `tput sgr0`;
$tc_clear = `tput clear`;
$tc_clreos = `tput ed`;
$tc_clreol = `tput el`;
if ($tc_cols < 60) {
die "$0: needs 60 columns";
}
if (length($tc_clreos) == 0) {
die "$0: needs clear to end of screen";
}
if (length($tc_clreol) == 0) {
die "$0: needs clear to end of line";
}
print T "\$tc_smcup = \"$tc_smcup\";\n";
print T "\$tc_rmcup = \"$tc_rmcup\";\n";
print T "\$tc_bold = \"$tc_bold\";\n";
print T "\$tc_normal = \"$tc_normal\";\n";
print T "\$tc_clear = \"$tc_clear\";\n";
print T "\$tc_clreol = \"$tc_clreol\";\n";
print T "\$tc_clreos = \"$tc_clreos\";\n";
for ($i = 0; $i < $tc_rows; ++$i) {
$left[$i] = `tput cup $i 0`;
print T '$left[' . "$i] = \"" . $left[$i] .
"\";\n";
if ($i < $half_of_screen) {
$middle[$i] = `tput cup $i 44`;
print T
'$middle[' . "$i] = \"" . $middle[$i] .
"\";\n";
}
}
print T '$i = ' . "$i;\n";
close(T);
print "done\n";
&ttyraw;
}