#!/usr/bin/perl

# ->resume is not exactly cheap (it saves/restores a LOT
# of global variables), but shouldn't be slow. just to show
# how fast it is, this little proggie compares a normal subroutine
# call with two calls of transfer in a loop.

use Coro;
use Benchmark;

sub a($) { }

$a = bless {}, main::;

sub b {
   my ($self) = shift;
   $self->{b} = shift if @_;
   $self->{b};
}

$b = async {
   # do a little unrolling...
   while() {
      cede; cede; cede; cede; cede;
   }
};

cede;

$main = $Coro::main;

*transfer = \&Coro::State::transfer;

sub doit0 {
   while() {
      # some unrolling here as well..
      transfer($c0, $main); transfer($c0, $main);
      transfer($c0, $main); transfer($c0, $main);
      transfer($c0, $main); transfer($c0, $main);
      transfer($c0, $main); transfer($c0, $main);
   }
}

sub doit1 {
   while() {
      # some unrolling here as well..
      transfer($c1, $main); transfer($c1, $main);
      transfer($c1, $main); transfer($c1, $main);
      transfer($c1, $main); transfer($c1, $main);
      transfer($c1, $main); transfer($c1, $main);
   }
}

$c0 = new Coro::State sub {
   doit0(1,2,3,4,5,6,7,8,9);
};

$c1 = new Coro::State sub {
   doit1(1,2,3,4,5,6,7,8,9);
};

$c0->save (0);
$c1->save (-1);

transfer($main, $c0);
transfer($main, $c1);

timethese 1000000, {
   function  => 'a(5); a(6)',
   method    => '$a->b(5); $a->b(6)',
   cede      => 'cede',
   transfer0 => 'transfer($main, $c0)',
   transfer1 => 'transfer($main, $c1)',
};