use strict;
use warnings;
use Compress::Bzip2;

my $error_file = "errors.txt";
open ERRORS, ">$error_file";
my @files = glob("$path");
my $correct_number_of_lines = 244812;

while (@files) {
	
	# Code adapted from http://hell.jedicoder.net/?p=82
	my @children = ();
	my %bz_handles = ();
	for(1..8) {
		
		my $file = shift @files;
		my $pid = fork();
		
		if ($pid) {
			# Parent
			push @children, $pid;

		} elsif ($pid == 0) {
			# Child
			
			# Using bzcat function adapted from Compress::Bzip2
			# documentation
			my $number_of_lines = 0;
			my $line = "";
			# I tried $bz = bzopen($file, "rb") first but it 
			# didn't work so I figured a hash might be better to 
			# generate a new variable each time?
			$bz_handles{$pid} = bzopen($file, "rb") 
				or print ERRORS "Cannot open $file" . "\n";
			while ($bz_handles{$pid}->bzreadline($line) > 0) {
				$number_of_lines++;
			}
			if ($bz_handles{$pid}->bzerror != BZ_STREAM_END) {
				print ERRORS "Error reading from $file" . "\n";
			}
			$bz_handles{$pid}->bzclose() ;
			if ($number_of_lines != $correct_number_of_lines) {
				print ERRORS $file . "\t" . $number_of_lines . "\n";; 
			}
			exit(0);
			
		} else {
			die "couldn't fork: $!\n";
		}
	}
	foreach my $child (@children) {
		waitpid($child, 0);
	}
}