package IO::Handle;

use 5.006_001;
use strict;
our($VERSION, @EXPORT_OK, @ISA);
use Carp;
use Symbol;
use SelectSaver;
use IO ();	# Load the XS module

require Exporter;
@ISA = qw(Exporter);

$VERSION = "1.31";
$VERSION = eval $VERSION;

@EXPORT_OK = qw(
    autoflush
    output_field_separator
    output_record_separator
    input_record_separator
    input_line_number
    format_page_number
    format_lines_per_page
    format_lines_left
    format_name
    format_top_name
    format_line_break_characters
    format_formfeed
    format_write

    print
    printf
    say
    getline
    getlines

    printflush
    flush

    SEEK_SET
    SEEK_CUR
    SEEK_END
    _IOFBF
    _IOLBF
    _IONBF
);

################################################
## Constructors, destructors.
##

sub new {
    my $class = ref($_[0]) || $_[0] || "IO::Handle";
    if (@_ != 1) {
	# Since perl will automatically require IO::File if needed, but
	# also initialises IO::File's @ISA as part of the core we must
	# ensure IO::File is loaded if IO::Handle is. This avoids effect-
	# ively "half-loading" IO::File.
	if ($] > 5.013 && $class eq 'IO::File' && !$INC{"IO/File.pm"}) {
	    require IO::File;
	    shift;
	    return IO::File::->new(@_);
	}
	croak "usage: $class->new()";
    }
    my $io = gensym;
    bless $io, $class;
}

sub new_from_fd {
    my $class = ref($_[0]) || $_[0] || "IO::Handle";
    @_ == 3 or croak "usage: $class->new_from_fd(FD, MODE)";
    my $io = gensym;
    shift;
    IO::Handle::fdopen($io, @_)
	or return undef;
    bless $io, $class;
}

#
# There is no need for DESTROY to do anything, because when the
# last reference to an IO object is gone, Perl automatically
# closes its associated files (if any).  However, to avoid any
# attempts to autoload DESTROY, we here define it to do nothing.
#
sub DESTROY {}

################################################
## Open and close.
##

sub _open_mode_string {
    my ($mode) = @_;
    $mode =~ /^\+?(<|>>?)$/
      or $mode =~ s/^r(\+?)$/$1</
      or $mode =~ s/^w(\+?)$/$1>/
      or $mode =~ s/^a(\+?)$/$1>>/
      or croak "IO::Handle: bad open mode: $mode";
    $mode;
}

sub fdopen {
    @_ == 3 or croak 'usage: $io->fdopen(FD, MODE)';
    my ($io, $fd, $mode) = @_;
    local(*GLOB);

    if (ref($fd) && "".$fd =~ /GLOB\(/o) {
	# It's a glob reference; Alias it as we cannot get name of anon GLOBs
	my $n = qualify(*GLOB);
	*GLOB = *{*$fd};
	$fd =  $n;
    } elsif ($fd =~ m#^\d+$#) {
	# It's an FD number; prefix with "=".
	$fd = "=$fd";
    }

    open($io, _open_mode_string($mode) . '&' . $fd)
	? $io : undef;
}

sub close {
    @_ == 1 or croak 'usage: $io->close()';
    my($io) = @_;

    close($io);
}

################################################
## Normal I/O functions.
##

# flock
# select

sub opened {
    @_ == 1 or croak 'usage: $io->opened()';
    defined fileno($_[0]);
}

sub fileno {
    @_ == 1 or croak 'usage: $io->fileno()';
    fileno($_[0]);
}

sub getc {
    @_ == 1 or croak 'usage: $io->getc()';
    getc($_[0]);
}

sub eof {
    @_ == 1 or croak 'usage: $io->eof()';
    eof($_[0]);
}

sub print {
    @_ or croak 'usage: $io->print(ARGS)';
    my $this = shift;
    print $this @_;
}

sub printf {
    @_ >= 2 or croak 'usage: $io->printf(FMT,[ARGS])';
    my $this = shift;
    printf $this @_;
}

sub say {
    @_ or croak 'usage: $io->say(ARGS)';
    my $this = shift;
    local $\ = "\n";
    print $this @_;
}

sub getline {
    @_ == 1 or croak 'usage: $io->getline()';
    my $this = shift;
    return scalar <$this>;
} 

*gets = \&getline;  # deprecated

sub getlines {
    @_ == 1 or croak 'usage: $io->getlines()';
    wantarray or
	croak 'Can\'t call $io->getlines in a scalar context, use $io->getline';
    my $this = shift;
    return <$this>;
}

sub truncate {
    @_ == 2 or croak 'usage: $io->truncate(LEN)';
    truncate($_[0], $_[1]);
}

sub read {
    @_ == 3 || @_ == 4 or croak 'usage: $io->read(BUF, LEN [, OFFSET])';
    read($_[0], $_[1], $_[2], $_[3] || 0);
}

sub sysread {
    @_ == 3 || @_ == 4 or croak 'usage: $io->sysread(BUF, LEN [, OFFSET])';
    sysread($_[0], $_[1], $_[2], $_[3] || 0);
}

sub write {
    @_ >= 2 && @_ <= 4 or croak 'usage: $io->write(BUF [, LEN [, OFFSET]])';
    local($\) = "";
    $_[2] = length($_[1]) unless defined $_[2];
    print { $_[0] } substr($_[1], $_[3] || 0, $_[2]);
}

sub syswrite {
    @_ >= 2 && @_ <= 4 or croak 'usage: $io->syswrite(BUF [, LEN [, OFFSET]])';
    if (defined($_[2])) {
	syswrite($_[0], $_[1], $_[2], $_[3] || 0);
    } else {
	syswrite($_[0], $_[1]);
    }
}

sub stat {
    @_ == 1 or croak 'usage: $io->stat()';
    stat($_[0]);
}

################################################
## State modification functions.
##

sub autoflush {
    my $old = new SelectSaver qualify($_[0], caller);
    my $prev = $|;
    $| = @_ > 1 ? $_[1] : 1;
    $prev;
}

sub output_field_separator {
    carp "output_field_separator is not supported on a per-handle basis"
	if ref($_[0]);
    my $prev = $,;
    $, = $_[1] if @_ > 1;
    $prev;
}

sub output_record_separator {
    carp "output_record_separator is not supported on a per-handle basis"
	if ref($_[0]);
    my $prev = $\;
    $\ = $_[1] if @_ > 1;
    $prev;
}

sub input_record_separator {
    carp "input_record_separator is not supported on a per-handle basis"
	if ref($_[0]);
    my $prev = $/;
    $/ = $_[1] if @_ > 1;
    $prev;
}

sub input_line_number {
    local $.;
    () = tell qualify($_[0], caller) if ref($_[0]);
    my $prev = $.;
    $. = $_[1] if @_ > 1;
    $prev;
}

sub format_page_number {
    my $old;
    $old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
    my $prev = $%;
    $% = $_[1] if @_ > 1;
    $prev;
}

sub format_lines_per_page {
    my $old;
    $old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
    my $prev = $=;
    $= = $_[1] if @_ > 1;
    $prev;
}

sub format_lines_left {
    my $old;
    $old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
    my $prev = $-;
    $- = $_[1] if @_ > 1;
    $prev;
}

sub format_name {
    my $old;
    $old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
    my $prev = $~;
    $~ = qualify($_[1], caller) if @_ > 1;
    $prev;
}

sub format_top_name {
    my $old;
    $old = new SelectSaver qualify($_[0], caller) if ref($_[0]);
    my $prev = $^;
    $^ = qualify($_[1], caller) if @_ > 1;
    $prev;
}

sub format_line_break_characters {
    carp "format_line_break_characters is not supported on a per-handle basis"
	if ref($_[0]);
    my $prev = $:;
    $: = $_[1] if @_ > 1;
    $prev;
}

sub format_formfeed {
    carp "format_formfeed is not supported on a per-handle basis"
	if ref($_[0]);
    my $prev = $^L;
    $^L = $_[1] if @_ > 1;
    $prev;
}

sub formline {
    my $io = shift;
    my $picture = shift;
    local($^A) = $^A;
    local($\) = "";
    formline($picture, @_);
    print $io $^A;
}

sub format_write {
    @_ < 3 || croak 'usage: $io->write( [FORMAT_NAME] )';
    if (@_ == 2) {
	my ($io, $fmt) = @_;
	my $oldfmt = $io->format_name(qualify($fmt,caller));
	CORE::write($io);
	$io->format_name($oldfmt);
    } else {
	CORE::write($_[0]);
    }
}

sub fcntl {
    @_ == 3 || croak 'usage: $io->fcntl( OP, VALUE );';
    my ($io, $op) = @_;
    return fcntl($io, $op, $_[2]);
}

sub ioctl {
    @_ == 3 || croak 'usage: $io->ioctl( OP, VALUE );';
    my ($io, $op) = @_;
    return ioctl($io, $op, $_[2]);
}

# this sub is for compatibility with older releases of IO that used
# a sub called constant to determine if a constant existed -- GMB
#
# The SEEK_* and _IO?BF constants were the only constants at that time
# any new code should just chech defined(&CONSTANT_NAME)

sub constant {
    no strict 'refs';
    my $name = shift;
    (($name =~ /^(SEEK_(SET|CUR|END)|_IO[FLN]BF)$/) && defined &{$name})
	? &{$name}() : undef;
}

# so that flush.pl can be deprecated

sub printflush {
    my $io = shift;
    my $old;
    $old = new SelectSaver qualify($io, caller) if ref($io);
    local $| = 1;
    if(ref($io)) {
        print $io @_;
    }
    else {
	print @_;
    }
}

1;
