#!./perl

BEGIN {
    chdir 't' if -d 't';
    @INC = '../lib';
    unless (find PerlIO::Layer 'perlio') {
	print "1..0 # Skip: not perlio\n";
	exit 0;
    }
}

$| = 1;
print "1..20\n";

my $fh;
my $var = "ok 2\n";
open($fh,"+<",\$var) or print "not ";
print "ok 1\n";
print <$fh>;
print "not " unless eof($fh);
print "ok 3\n";
seek($fh,0,0) or print "not ";
print "not " if eof($fh);
print "ok 4\n";
print "ok 5\n";
print $fh "ok 7\n" or print "not ";
print "ok 6\n";
print $var;
$var = "foo\nbar\n";
seek($fh,0,0) or print "not ";
print "not " if eof($fh);
print "ok 8\n";
print "not " unless <$fh> eq "foo\n";
print "ok 9\n";
my $rv = close $fh;
if (!$rv) {
    print "# Close on scalar failed: $!\n";
    print "not ";
}
print "ok 10\n";

# Test that semantics are similar to normal file-based I/O
# Check that ">" clobbers the scalar
$var = "Something";
open $fh, ">", \$var;
print "# Got [$var], expect []\n";
print "not " unless $var eq "";
print "ok 11\n";
#  Check that file offset set to beginning of scalar
my $off = tell($fh);
print "# Got $off, expect 0\n";
print "not " unless $off == 0;
print "ok 12\n";
# Check that writes go where they should and update the offset
$var = "Something";
print $fh "Brea";
$off = tell($fh);
print "# Got $off, expect 4\n";
print "not " unless $off == 4;
print "ok 13\n";
print "# Got [$var], expect [Breathing]\n";
print "not " unless $var eq "Breathing";
print "ok 14\n";
close $fh;

# Check that ">>" appends to the scalar
$var = "Something ";
open $fh, ">>", \$var;
$off = tell($fh);
print "# Got $off, expect 10\n";
print "not " unless $off == 10;
print "ok 15\n";
print "# Got [$var], expect [Something ]\n";
print "not " unless $var eq "Something ";
print "ok 16\n";
#  Check that further writes go to the very end of the scalar
$var .= "else ";
print "# Got [$var], expect [Something else ]\n";
print "not " unless $var eq "Something else ";
print "ok 17\n";
$off = tell($fh);
print "# Got $off, expect 10\n";
print "not " unless $off == 10;
print "ok 18\n";
print $fh "is here";
print "# Got [$var], expect [Something else is here]\n";
print "not " unless $var eq "Something else is here";
print "ok 19\n";
close $fh;

# Check that updates to the scalar from elsewhere do not
# cause problems
$var = "line one\nline two\line three\n";
open $fh, "<", \$var;
while (<$fh>) {
    $var = "foo";
}
close $fh;
print "# Got [$var], expect [foo]\n";
print "not " unless $var eq "foo";
print "ok 20\n";
