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✏️ Editing: ReadKey.pm

# -*- buffer-read-only: t -*-
#
# This file is auto-generated. ***ANY*** changes here will be lost
#
package Term::ReadKey;

use strict;
use warnings;

=head1 NAME

Term::ReadKey - A perl module for simple terminal control

=head1 SYNOPSIS

use Term::ReadKey;
    ReadMode 4; # Turn off controls keys
    while (not defined ($key = ReadKey(-1))) {
        # No key yet
    }
    print "Get key $key\n";
    ReadMode 0; # Reset tty mode before exiting

=head1 DESCRIPTION

Term::ReadKey is a compiled perl module dedicated to providing simple
control over terminal driver modes (cbreak, raw, cooked, etc.,) support for
non-blocking reads, if the architecture allows, and some generalized handy
functions for working with terminals. One of the main goals is to have the
functions as portable as possible, so you can just plug in "use
Term::ReadKey" on any architecture and have a good likelihood of it working.

Version 2.30.01:
Added handling of arrows, page up/down, home/end, insert/delete keys 
under Win32. These keys emit xterm-compatible sequences.
Works with Term::ReadLine::Perl.

=over 4

=item ReadMode MODE [, Filehandle]

Takes an integer argument or a string synonym (case insensitive), which
can currently be one of the following values:

INT   SYNONYM    DESCRIPTION

0    'restore'   Restore original settings.

1    'normal'    Change to what is commonly the default mode,
                     echo on, buffered, signals enabled, Xon/Xoff
                     possibly enabled, and 8-bit mode possibly disabled.

2    'noecho'    Same as 1, just with echo off. Nice for
                     reading passwords.

3    'cbreak'    Echo off, unbuffered, signals enabled, Xon/Xoff
                     possibly enabled, and 8-bit mode possibly enabled.

4    'raw'       Echo off, unbuffered, signals disabled, Xon/Xoff
                     disabled, and 8-bit mode possibly disabled.

5    'ultra-raw' Echo off, unbuffered, signals disabled, Xon/Xoff 
                     disabled, 8-bit mode enabled if parity permits,
                     and CR to CR/LF translation turned off.

These functions are automatically applied to the STDIN handle if no
other handle is supplied. Modes 0 and 5 have some special properties
worth mentioning: not only will mode 0 restore original settings, but it
cause the next ReadMode call to save a new set of default settings. Mode
5 is similar to mode 4, except no CR/LF translation is performed, and if
possible, parity will be disabled (only if not being used by the terminal,
however. It is no different from mode 4 under Windows.)

If you just need to read a key at a time, then modes 3 or 4 are probably
sufficient. Mode 4 is a tad more flexible, but needs a bit more work to
control. If you use ReadMode 3, then you should install a SIGINT or END
handler to reset the terminal (via ReadMode 0) if the user aborts the
program via C<^C>. (For any mode, an END handler consisting of "ReadMode 0"
is actually a good idea.)

If you are executing another program that may be changing the terminal mode,
you will either want to say

ReadMode 1;             # same as ReadMode 'normal'
    system('someprogram');
    ReadMode 1;

which resets the settings after the program has run, or:

$somemode=1;
    ReadMode 0;             # same as ReadMode 'restore'
    system('someprogram');
    ReadMode 1;

which records any changes the program may have made, before resetting the
mode.

=item ReadKey MODE [, Filehandle]

Takes an integer argument, which can currently be one of the following 
values:

0    Perform a normal read using getc
    -1   Perform a non-blocked read
    >0	 Perform a timed read

If the filehandle is not supplied, it will default to STDIN. If there is
nothing waiting in the buffer during a non-blocked read, then undef will be
returned.  In most situations, you will probably want to use C<ReadKey -1>.

I<NOTE> that if the OS does not provide any known mechanism for non-blocking
reads, then a C<ReadKey -1> can die with a fatal error. This will hopefully
not be common.

If MODE is greater then zero, then ReadKey will use it as a timeout value in
seconds (fractional seconds are allowed), and won't return C<undef> until
that time expires.

I<NOTE>, again, that some OS's may not support this timeout behaviour.

If MODE is less then zero, then this is treated as a timeout
of zero, and thus will return immediately if no character is waiting. A MODE
of zero, however, will act like a normal getc.

I<NOTE>, there are currently some limitations with this call under Windows.
It may be possible that non-blocking reads will fail when reading repeating
keys from more then one console.

=item ReadLine MODE [, Filehandle]

Takes an integer argument, which can currently be one of the following 
values:

0    Perform a normal read using scalar(<FileHandle>)
    -1   Perform a non-blocked read
    >0	 Perform a timed read

If there is nothing waiting in the buffer during a non-blocked read, then
undef will be returned.

I<NOTE>, that if the OS does not provide any known mechanism for
non-blocking reads, then a C<ReadLine 1> can die with a fatal
error. This will hopefully not be common.

I<NOTE> that a non-blocking test is only performed for the first character
in the line, not the entire line.  This call will probably B<not> do what
you assume, especially with C<ReadMode> MODE values higher then 1. For
example, pressing Space and then Backspace would appear to leave you
where you started, but any timeouts would now be suspended.

B<This call is currently not available under Windows>.

=item GetTerminalSize [Filehandle]

Returns either an empty array if this operation is unsupported, or a four
element array containing: the width of the terminal in characters, the
height of the terminal in character, the width in pixels, and the height in
pixels. (The pixel size will only be valid in some environments.)

I<NOTE>, under Windows, this function must be called with an B<output>
filehandle, such as C<STDOUT>, or a handle opened to C<CONOUT$>.

=item SetTerminalSize WIDTH,HEIGHT,XPIX,YPIX [, Filehandle]

Return -1 on failure, 0 otherwise.

I<NOTE> that this terminal size is only for B<informative> value, and
changing the size via this mechanism will B<not> change the size of
the screen. For example, XTerm uses a call like this when
it resizes the screen. If any of the new measurements vary from the old, the
OS will probably send a SIGWINCH signal to anything reading that tty or pty.

B<This call does not work under Windows>.

=item GetSpeed [, Filehandle]

Returns either an empty array if the operation is unsupported, or a two
value array containing the terminal in and out speeds, in B<decimal>. E.g,
an in speed of 9600 baud and an out speed of 4800 baud would be returned as
(9600,4800). Note that currently the in and out speeds will always be
identical in some OS's.

B<No speeds are reported under Windows>.

=item GetControlChars [, Filehandle]

Returns an array containing key/value pairs suitable for a hash. The pairs
consist of a key, the name of the control character/signal, and the value
of that character, as a single character.

B<This call does nothing under Windows>.

Each key will be an entry from the following list:

DISCARD
	DSUSPEND
	EOF
	EOL
	EOL2
	ERASE
	ERASEWORD
	INTERRUPT
	KILL
	MIN
	QUIT
	QUOTENEXT
	REPRINT
	START
	STATUS
	STOP
	SUSPEND
	SWITCH
	TIME

Thus, the following will always return the current interrupt character,
regardless of platform.

%keys = GetControlChars;
	$int = $keys{INTERRUPT};

=item SetControlChars [, Filehandle]

Takes an array containing key/value pairs, as a hash will produce. The pairs
should consist of a key that is the name of a legal control
character/signal, and the value should be either a single character, or a
number in the range 0-255. SetControlChars will die with a runtime error if
an invalid character name is passed or there is an error changing the
settings. The list of valid names is easily available via

%cchars = GetControlChars();
	@cnames = keys %cchars;

B<This call does nothing under Windows>.

=back

=head1 AUTHOR

Kenneth Albanowski <kjahds@kjahds.com>

Currently maintained by Jonathan Stowe <jns@gellyfish.co.uk>

=head1 SUPPORT

The code is maintained at

https://github.com/jonathanstowe/TermReadKey

Please feel free to fork and suggest patches.

=head1 LICENSE

Prior to the 2.31 release the license statement was:

Unlimited distribution and/or modification is allowed as long as this
               copyright notice remains intact.

And was only stated in the README file.

Because I believe the original author's intent was to be more open than the
other commonly used licenses I would like to leave that in place. However if
you or your lawyers require something with some more words you can optionally
choose to license this under the standard Perl license:

This module is free software; you can redistribute it and/or modify it
      under the terms of the Artistic License. For details, see the full
      text of the license in the file "Artistic" that should have been provided
      with the version of perl you are using.

This program is distributed in the hope that it will be useful, but
      without any warranty; without even the implied warranty of merchantability
      or fitness for a particular purpose.

=cut

use vars qw($VERSION);

$VERSION = '2.37';

require Exporter;
require DynaLoader;

use vars qw(@ISA @EXPORT_OK @EXPORT);

@ISA = qw(Exporter DynaLoader);

# Items to export into callers namespace by default
# (move infrequently used names to @EXPORT_OK below)

@EXPORT = qw(
  ReadKey
  ReadMode
  ReadLine
  GetTerminalSize
  SetTerminalSize
  GetSpeed
  GetControlChars
  SetControlChars
);

@EXPORT_OK = qw();

bootstrap Term::ReadKey;

# Should we use LINES and COLUMNS to try and get the terminal size?
# Change this to zero if you have systems where these are commonly
# set to erroneous values. (But if either are near zero, they won't be
# used anyhow.)

use vars qw($UseEnv $CurrentMode %modes);

$UseEnv = 1;

$CurrentMode = 0;

%modes = (                            # lowercase is canonical
    original    => 0,
    restore     => 0,
    normal      => 1,
    noecho      => 2,
    cbreak      => 3,
    raw         => 4,
    'ultra-raw' => 5
);

# reduce Carp memory footprint, only load when needed
sub croak { require Carp; goto &Carp::croak; }
sub carp  { require Carp; goto &Carp::carp; }

sub ReadMode
{
    my $mode = $modes{ lc $_[0] };  # lowercase is canonical
    my $fh = normalizehandle( ( @_ > 1 ? $_[1] : \*STDIN ) );

if ( defined($mode) )    { $CurrentMode = $mode }
    elsif ( $_[0] =~ /^\d/ ) { $CurrentMode = $_[0] }
    else                     { croak("Unknown terminal mode `$_[0]'"); }

SetReadMode($CurrentMode, $fh);
}

sub normalizehandle
{
    my ($file) = @_; # allows fake signature optimization

no strict;
    #	print "Handle = $file\n";
    if ( ref($file) ) { return $file; }    # Reference is fine

#	if ($file =~ /^\*/) { return $file; } # Type glob is good
    if ( ref( \$file ) eq 'GLOB' ) { return $file; }    # Glob is good

#	print "Caller = ",(caller(1))[0],"\n";
    return \*{ ( ( caller(1) )[0] ) . "::$file" };
}

sub GetTerminalSize
{
    my $file = normalizehandle( ( @_ > 0 ? $_[0] : \*STDOUT ) );

my (@results, @fail);

if ( &termsizeoptions() & 1 )                       # VIO
    {
        @results = GetTermSizeVIO($file);
        push( @fail, "VIOGetMode call" );
    }
    elsif ( &termsizeoptions() & 2 )                    # GWINSZ
    {
        @results = GetTermSizeGWINSZ($file);
        push( @fail, "TIOCGWINSZ ioctl" );
    }
    elsif ( &termsizeoptions() & 4 )                    # GSIZE
    {
        @results = GetTermSizeGSIZE($file);
        push( @fail, "TIOCGSIZE ioctl" );
    }
    elsif ( &termsizeoptions() & 8 )                    # WIN32
    {
        @results = GetTermSizeWin32($file);
        push( @fail, "Win32 GetConsoleScreenBufferInfo call" );
    }
    else
    {
        @results = ();
    }

if ( @results < 4 and $UseEnv )
    {
        my ($C) = defined( $ENV{COLUMNS} ) ? $ENV{COLUMNS} : 0;
        my ($L) = defined( $ENV{LINES} )   ? $ENV{LINES}   : 0;
        if ( ( $C >= 2 ) and ( $L >= 2 ) )
        {
            @results = ( $C + 0, $L + 0, 0, 0 );
        }
        push( @fail, "COLUMNS and LINES environment variables" );
    }

if ( @results < 4 && $^O ne 'MSWin32')
    {
        my ($prog) = "resize";

# Workaround for Solaris path silliness
        if ( -f "/usr/openwin/bin/resize" ) {
            $prog = "/usr/openwin/bin/resize";
        }

my ($resize) = scalar(`$prog 2>/dev/null`);
        if (defined $resize
            and (  $resize =~ /COLUMNS\s*=\s*(\d+)/
                or $resize =~ /setenv\s+COLUMNS\s+'?(\d+)/ )
           )
        {
            $results[0] = $1;
            if (   $resize =~ /LINES\s*=\s*(\d+)/
                or $resize =~ /setenv\s+LINES\s+'?(\d+)/ )
            {
                $results[1] = $1;
                @results[ 2, 3 ] = ( 0, 0 );
            }
            else
            {
                @results = ();
            }
        }
        else
        {
            @results = ();
        }
        push( @fail, "resize program" );
    }

if ( @results < 4 && $^O ne 'MSWin32' )
    {
        my ($prog) = "stty size";

my ($stty) = scalar(`$prog 2>/dev/null`);
        if (defined $stty
            and (  $stty =~ /(\d+) (\d+)/ )
           )
        {
            $results[0] = $2;
            $results[1] = $1;
            @results[ 2, 3 ] = ( 0, 0 );
        }
        else
        {
            @results = ();
        }
        push( @fail, "stty program" );
    }

if ( @results != 4 )
    {
        carp("Unable to get Terminal Size."
             . join( "", map( " The $_ didn't work.", @fail ) ));
	return undef;
    }

@results;
}

# blockoptions: 
#nodelay
#select
sub ReadKey {
    my $File = normalizehandle((@_>1?$_[1]:\*STDIN));
    if (defined $_[0] && $_[0] > 0) {
        if ($_[0]) { return undef if &selectfile($File,$_[0]) == 0 }
    }
    if (defined $_[0] && $_[0] < 0) { &setnodelay($File,1); }
    my $value = getc $File;
    if (defined $_[0] && $_[0] < 0) { &setnodelay($File,0); }
    $value;
}
sub ReadLine {
    my $File = normalizehandle((@_>1?$_[1]:\*STDIN));
    if (defined $_[0] && $_[0] > 0) {
        if ($_[0]) { return undef if &selectfile($File,$_[0]) == 0 }
    }
    if (defined $_[0] && $_[0] < 0) { &setnodelay($File,1) };
    my $value = scalar(<$File>);
    if (defined $_[0] && $_[0] < 0) { &setnodelay($File,0) };
    $value;
}
1;
# ex: set ro:

MR SKB