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#!/usr/bin/perl -w
#
# Prints out a series of arguments suitable for passing to sleep,
# as poll intervals. Helper for t-poll-loop in tests/lib.
#
# Separate script becauwe (a) shell is very bad at FP arithmetic and
# (b) printing the arithmetic in shell debug output wouldn't be nice either.
use strict;
use IO::Handle;
open DEBUG, ">/dev/null" or die $!;
while (@ARGV) {
last unless $ARGV[0] =~ m/^-/;
$_ = shift @ARGV;
if ($_ eq '--') {
last;
} elsif (m/^--debug$/) {
open DEBUG, ">&2" or die $!;
} else {
die "$0: unknown option $_\n";
}
}
die "$0: need (only) timeout argument" unless @ARGV==1;
our ($overall_timeout) = @ARGV;
my @output;
my $left = 1;
# Parameters (fixed)
#
# These parameters lead to 11 attempts,
# with a first interval of 0.0236 T (0.707s with T=30)
# and a final one of 0.25 T (7.5s with T=30)
# On timeout, we sleep too long by 0.00475 T (0.143s with T=30)
# This all seems reasonable.
my $sleep = 0.25;
my $ratio = 1.3;
printf DEBUG "# %10s %10s %12s\n", 'total', 'interval', 'actual';
for (;;) {
my $actual_sleep = $sleep * $overall_timeout;
printf DEBUG "# %10.7f %10.7f %12.7f\n", $left, $sleep, $actual_sleep;
push @output, $actual_sleep;
$left -= $sleep;
$sleep /= $ratio;
last if $left < 0;
};
printf DEBUG "# %10.7f %-9d %12.7f\n", $left, 0, $left * $overall_timeout;
@output = reverse @output;
print "0 @output\n" or die $!;
flush STDOUT or die $!;
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