#! /usr/bin/perl

use CDB_File;
use strict;

sub unnetstrings {
	my($netstrings) = @_;
	my @result;
	while ($netstrings =~ s/^([0-9]+)://) {
		push @result, substr($netstrings, 0, $1, '');
		$netstrings =~ s/^,//;
	}
	return @result;
}

my $chunk = 8192;

sub extract {
	my($file, $t, $b) = @_;
	my $head = $$b{"H$file"};
	my ($code, $type) = $head =~ m/^([0-9]+)(.)/;
	if ($type eq "/") {
		mkdir $file, 0777;
	} elsif ($type eq "_") {
		my ($total, $now, $got, $x);
		open OUT, ">$file" or die "open for output: $!\n";
		exists $$b{"D$code"} or die "corrupt bun file\n";
		my $fh = $t->handle;
		sysseek $fh, $t->datapos, 0;
		$total = $t->datalen;
		while ($total) {
			$now = ($total > $chunk) ? $chunk : $total;
			$got = sysread $fh, $x, $now;
			if (not $got) { die "read error\n"; }
			$total -= $got;
			print OUT $x;
		}
		close OUT;
	} else {
		print STDERR "warning: skipping unknown file type\n";
	}
}

die "usage\n" if @ARGV != 1;

my (%b, $t);
$t = tie %b, 'CDB_File', $ARGV[0] or die "tie: $!\n";
map { extract $_, $t, \%b } unnetstrings $b{""};