File Coverage

script/sdif

Criterion	Covered	Total	%
statement	441	663	66.5
branch	145	294	49.3
condition	81	186	43.5
subroutine	38	66	57.5
pod			n/a
total	705	1209	58.3

#!/usr/bin/env perl

##
## sdif: sdiff clone
##
## Copyright (c) 1992- Kazumasa Utashiro
##
## Original version on Jul 24 1991
##

=pod

=head1 NAME

sdif - side-by-side diff viewer for ANSI terminal

=head1 VERSION

Version 4.46

=head1 SYNOPSIS

    sdif file_1 file_2

    diff ... | sdif

  OPTIONS:

    -i, --ignore-case
    -b, --ignore-space-change
    -w, --ignore-all-space
    -B, --ignore-blank-lines

    --[no]number, -n    print line number
    --digit=#           set the line number digits (default 4)
    --truncate, -t      truncate long line
    --boundary=#        line folding boundary (default word)
    --context, -c, -C#  context diff
    --unified, -u, -U#  unified diff

    --width=#, -W#      width of output (default 80)
    --margin=#          margin column number (default 0)
    --runin=#           run-in column number (default --margin)
    --runout=#          run-out column number (default --margin)
    --mark=position     mark position (right, left, center, side) or no
    --column=order      column order (default ONM)
    --view, -v          viewer mode
    --parallel[=#], -V  treat unknown text as common part (default 2)
    --ambiguous=s       ambiguous character width (detect, wide, narrow)
    --[no-]command      print diff control command (default on)
    --[no-]filename     print diff filename (default on)
    --[no-]prefix       process git --graph output (default on)
    --prefix-pattern    prefix pattern

    --color=when        'always' (default), 'never' or 'auto'
    --nocolor           --color=never
    --colormap, --cm    specify color map
    --colortable[=#]    show color table (optional #: 6, 12, 24)
    --[no-]256          on/off ANSI 256 color mode (default on)
    --[no-]cc           color command line  (default true)
    --[no-]fc                 file name     (default true)
    --[no-]lc                 line number   (default true)
    --[no-]mc                 diff mark     (default true)
    --[no-]tc                 normal text   (default true)
    --[no-]uc                 unknown text  (default true)

    --man               display manual page
    --version           show version
    --diff=s            set diff command
    --diffopts=s        set diff command options

    --[no-]lenience     suppress unexpected input warning (default on)
    --limit key=val     set limit (line, length)
    --visible xx=1      set visible chars
    --tabhead=char      set tabhead char
    --tabspace=char     set tabspace char
    --tabstyle=style    set tabstyle (dot, symbol, shade, bar, dash...)
    --tabstop=#         set tabstop width (default 8)

    --[no-]cdif         use ``cdif'' as word context diff backend
    --unit=s            pass through to cdif (word, letter, char, mecab)
    --cdifopts=s        set cdif command options

=cut

use v5.14;
use warnings;
use utf8;
use Encode;
use open IO => ':utf8';
use Carp;
use charnames ':full';
use List::Util qw(min max reduce sum pairmap first);
use Pod::Usage;
use Text::ParseWords qw(shellwords);
use Data::Dumper; {
    $Data::Dumper::Terse = 1;
}

use App::sdif;
my $version = $App::sdif::VERSION;

use App::sdif::Util;
use IO::Divert;

my $default_cdif = 'cdif';
my @default_cdifopts = qw(--sdif);
my $default_lenience = 1;
my $default_256 = 1;
my $default_prefix = 1;
my $default_prefix_pattern = q/(?:\\| )*(?:  )?/;
my @cdifopts;
my $read_stdin;

our $screen_width;

if (my $env = $ENV{'SDIFOPTS'}) {
    unshift @ARGV, shellwords($env);
}

use open IO => ':utf8', ':std';
map { $_ = decode 'utf8', $_ unless utf8::is_utf8($_) } @ARGV;

my $app;

use Getopt::EX::Hashed; {

    Getopt::EX::Hashed->configure( DEFAULT => [ is => 'rw' ] );

    has help           => ' h   ' ;
    has version        => '     ' ;
    has man            => '     ' ;
    has debug          => 'd +  ' ;
    has number         => 'n !  ' ;
    has digit          => '  =i ' , default => 4 ;
    has column         => '  =s ' ;
    has truncate       => 't !  ' ;
    has boundary       => '  =s ' , default => 'word' ;
    has onword         => '  !  ' ;
    has mark           => '  =s ' , default => 'center' ;
    has prefix         => '  !  ' , default => $default_prefix ;
    has prefix_pattern => '  =s ' , default => $default_prefix_pattern ;
    has width          => 'W =i ' ;
    has margin         => '  =i ' , default => 0 ;
    has runin          => '  =i ' ;
    has runout         => '  =i ' ;
    has view           => 'v !  ' ;
    has parallel       => 'V :2 ' , default => 0 ;
    has ambiguous      => '  =s ' , default => 'narrow' ;
    has filename       => '  !  ' , default => 1 ;
    has command        => '  !  ' , default => 1 ;
    has diff           => '  =s ' , default => 'diff' ;
    has diffopts       => '  =s@' , default => [] ;
    has color          => '  =s ' , default => 'always' ;
    has colormap       => 'cm=s@' , default => [] ;
    has colordump      => '     ' ;
    has 256            => '  !  ' , default => $default_256 ;
    has commandcolor   => 'cc!  ' , default => 1 ;
    has filecolor      => 'fc!  ' , default => 1 ;
    has linecolor      => 'lc!  ' , default => 1 ;
    has markcolor      => 'mc!  ' , default => 1 ;
    has textcolor      => 'tc!  ' , default => 1 ;
    has unknowncolor   => 'uc!  ' , default => 1 ;
    has cdif           => '  :s ' , default => '' ;
    has cdifopts       => '  =s ' ;
    has colortable     => '  :s ' , any => qr/^(|6|12|24)$/ ;
    has lenience       => '  !  ' , default => $default_lenience ;
    has limit          => '  =s%' , default => { length => 10000 } ;
    has visible        => '  =i%' , default => {} ;
    has tabstop        => '  =i ' , default => 8 ;
    has tabhead        => '  =s ' ;
    has tabstyle       => 'ts=s ' ;
    has tabspace       => '  =s ' ;
    has unit           => 'by:s ' ;

    has ignore_case         => 'i    ' ;
    has ignore_space_change => 'b    ' ;
    has ignore_all_space    => 'w    ' ;
    has ignore_blank_lines  => 'B    ' ;
    has context             => 'C  =i' ;
    has unified             => 'U  =i' ;
    has c                   => '     ' ;
    has u                   => '     ' ;

    has '+onword'
	=> sub { $_->boundary = $_[1] ? 'word' : '' } ;

    has '+cdifopts'
	=> sub { push @cdifopts, shellwords $_[1] } ;

    has '+ignore_case'
	=> sub { push @{$app->diffopts}, '-i'; push @cdifopts, '-i' } ;
    has '+ignore_space_change'
	=> sub { push @{$app->diffopts}, '-b'; push @cdifopts, '-w' } ;
    has '+ignore_all_space'
	=> sub { push @{$app->diffopts}, '-w'; push @cdifopts, '-w' } ;
    has '+ignore_blank_lines'
	=> sub { push @{$app->diffopts}, '-B' } ;

    has '+c'       => sub { push @{$app->diffopts}, '-c' } ;
    has '+u'       => sub { push @{$app->diffopts}, '-u' } ;
    has '+context' => sub { push @{$app->diffopts}, '-C' . $_[1] } ;
    has '+unified' => sub { push @{$app->diffopts}, '-U' . $_[1] } ;

    has nocolor => 'no-color' , action => sub { $app->color = 'never' } ;
    has nocdif  => 'no-cdif'  , action => sub { $app->cdif = undef } ;

    has mecab   => '!' , action => sub { $app->unit = $_[1] ? 'mecab' : undef } ;

    has '+ambiguous' => sub {
	if ($_[1] =~ /^(?:wide|full)/) {
	    $Text::VisualWidth::PP::EastAsian = 1;
	    Text::ANSI::Fold->configure(ambiguous => 'wide');
	}
    } ;

    has '+help'    => sub { usage() } ;
    has '+version' => sub { print "$version\n"; exit 0 } ;
    has '+man'     => sub { pod2usage {-verbose => 2} } ;

} no Getopt::EX::Hashed;

$app = Getopt::EX::Hashed->new() or die;

my @SAVEDARGV = @ARGV;
use Getopt::EX::Long qw(:DEFAULT Configure ExConfigure);
ExConfigure BASECLASS => [ "App::sdif", "Getopt::EX" ];
Configure "bundling";
$app->getopt or usage({status => 1});

warn "\@ARGV = (@SAVEDARGV)\n" if $app->debug;

$App::sdif::Util::NO_WARNINGS = $app->lenience;

use Text::VisualWidth::PP qw(vwidth);
use Text::ANSI::Fold qw(ansi_fold :constants); {
    Text::ANSI::Fold->configure(padding => 1,
				expand  => 1,
				tabstop => $app->tabstop);
}

$app->visible->{ht} //= 1 if $app->tabstyle;
if ($app->visible->{ht}) {
    Text::ANSI::Fold->configure(
	tabstyle => $app->tabstyle,
	map  { $_->[0] => unicode($_->[1]) }
	grep { $_->[1] }
	[ tabhead  => $app->tabhead  ],
	[ tabspace => $app->tabspace ],
	);
}

sub unicode {
    my $char = shift or return undef;
    if ($char =~ /^\X$/) {
	$char;
    } else {
	eval qq["\\N{$char}"] or die "$!";
    }
}

if ($app->margin > 0) {
    if ($app->runin and $app->margin < $app->runin) {
	die "margin must be >= runin\n";
    }
    Text::ANSI::Fold->configure(
	linebreak => LINEBREAK_ALL,
	margin    => $app->margin,
	runin     => $app->runin // $app->margin,
	runout    => $app->runout // $app->margin,
	);
}

my %colormap = do {
    my $col = $app->{256} ? 0 : 1;
    pairmap { $a => (ref $b eq 'ARRAY') ? $b->[$col] : $b } (
	UNKNOWN  =>    ""         ,
	OCOMMAND =>  [ "555/010"  , "GS"  ],
	NCOMMAND =>  [ "555/010"  , "GS"  ],
	MCOMMAND =>  [ "555/010"  , "GS"  ],
	OFILE    =>  [ "551/010D" , "GDS" ],
	NFILE    =>  [ "551/010D" , "GDS" ],
	MFILE    =>  [ "551/010D" , "GDS" ],
	OMARK    =>  [ "010/444"  , "G/W" ],
	NMARK    =>  [ "010/444"  , "G/W" ],
	MMARK    =>  [ "010/444"  , "G/W" ],
	UMARK    =>    ""         ,
	OLINE    =>  [ "220"      , "Y"   ],
	NLINE    =>  [ "220"      , "Y"   ],
	MLINE    =>  [ "220"      , "Y"   ],
	ULINE    =>    ""         ,
	OTEXT    =>  [ "K/454"    , "G"   ],
	NTEXT    =>  [ "K/454"    , "G"   ],
	MTEXT    =>  [ "K/454"    , "G"   ],
	UTEXT    =>    ""         ,
	NOTICE   =>    "R"        ,
    );
};

use Getopt::EX::Colormap;
$Getopt::EX::Colormap::NO_RESET_EL = 1;
use constant SGR_RESET => "\e[m";
my $color_handler = Getopt::EX::Colormap
    ->new(HASH => \%colormap)
    ->load_params(@{$app->colormap});

$colormap{OUMARK} ||= $colormap{UMARK} || $colormap{OMARK};
$colormap{NUMARK} ||= $colormap{UMARK} || $colormap{NMARK};
$colormap{OULINE} ||= $colormap{ULINE} || $colormap{OLINE};
$colormap{NULINE} ||= $colormap{ULINE} || $colormap{NLINE};

for (
    [ $app->unknowncolor => q/UNKNOWN/ ],
    [ $app->commandcolor => q/COMMAND/ ],
    [ $app->filecolor    => q/FILE/ ],
    [ $app->linecolor    => q/LINE/ ],
    [ $app->markcolor    => q/MARK/ ],
    [ $app->textcolor    => q/TEXT/ ],
) {
    my($color, $label) = @$_;
    $color and next;
    for (grep /$label/, keys %colormap) {
	$colormap{$_} = '';
    }
}

if ($app->colordump) {
    print $color_handler->colormap(
	name => '--changeme', option => '--colormap');
    exit;
}

my $painter = do {
    if (($app->color eq 'always')
	or (($app->color eq 'auto') and (-t STDOUT))) {
	sub { $color_handler->color(@_) };
    } else {
	sub { $_[1] } ;
    }
};

##
## setup cdif command and option
##
if (defined $app->cdif and $app->cdif eq '') {
    $app->cdif = $default_cdif;
}

for (
    [ "unit"     , "=" , $app->unit     , undef             ] ,
    [ "256"      , "!" , $app->{256}    , $default_256      ] ,
    [ "prefix"   , "!" , $app->prefix   , $default_prefix   ] ,
    [ "lenience" , "!" , $app->lenience , $default_lenience ] ,
    )
{
    my($name, $type, $var, $default) = @$_;
    if ($type eq "!") {
	next if not defined $var;
	next if $var == $default;
	unshift @cdifopts, sprintf("--%s%s", $var ? '' : 'no-', $name);
    } elsif ($type eq "=") {
	next if not defined $var;
	unshift @cdifopts, sprintf("--%s=%s", $name, $var);
    } else {
	die;
    }
}

unshift @cdifopts, @default_cdifopts;

my($OLD, $NEW, $DIFF);
if (@ARGV == 2) {
    ($OLD, $NEW) = @ARGV;
    $DIFF = "$app->{diff} @{$app->{diffopts}} $OLD $NEW |";
} elsif (@ARGV < 2) {
    $DIFF = shift || '-';
    $read_stdin++;
} else {
    usage({status => 1}, "Unexpected arguments.\n\n");
}
my $readfile =
    ($OLD and $NEW) && !$read_stdin && !(grep { /^-[cuCU]/ } @{$app->diffopts});

use constant {
    RIGHT => 'right',
    LEFT  => 'left',
    NO    => 'no',
};
my %markpos = (
    center => [ RIGHT , LEFT  , LEFT  ],
    side   => [ LEFT  , RIGHT , LEFT  ],
    right  => [ RIGHT , RIGHT , RIGHT ],
    left   => [ LEFT  , LEFT  , LEFT  ],
    no     => [ NO    , NO    , NO    ],
    none   => [ NO    , NO    , NO    ],
    );
unless ($markpos{$app->mark}) {
    my @keys = sort keys %markpos;
    usage "Use one from (@keys) for option --mark\n\n";
}
my @markpos = @{$markpos{$app->mark}};
my($omarkpos, $nmarkpos, $mmarkpos) = @markpos;

my $num_format = sprintf '%%%dd', $app->digit;

$screen_width = $app->width || &terminal_width;

sub column_width {
    my $column = shift;
    state %column_width;
    $column_width{$screen_width * 1000 + $column} //= do {
	use integer;
	my $w = $screen_width;
	$w -= $column if $app->mark;
	max 1, $w / $column;
    };
}

##
## --colortable
##
if (defined(my $n = $app->colortable)) {
    no strict 'refs';
    &{"Getopt::EX::Colormap::colortable$n"}($screen_width);
    exit;
}

##
## Column order
##
my @column = !$app->column ? () : do {
    map { $_ - 1 }
    map { { O=>1, N=>2, M=>3 }->{$_} // $_ }
    $app->column =~ /[0-9ONM]/g;
};

##
## Git --graph prefix pattern
##
my $prefix_re = do {
    if ($app->prefix) {
	qr/$app->{prefix_pattern}/;
    } else {
	"";
    }
};

if ($app->debug) {
    printf STDERR "\$OLD = %s\n", $OLD // "undef";
    printf STDERR "\$NEW = %s\n", $NEW // "undef";
    printf STDERR "\$DIFF = %s\n", $DIFF // "undef";
}

if ($app->cdif) {
    my $pid = open DIFF, '-|';
    if (not defined $pid) {
	die "$!" if not defined $pid;
    }
    ## child
    elsif ($pid == 0) {
	if ($DIFF ne '-') {
	    open(STDIN, $DIFF) || die "cannot open diff: $!\n";
	}
	do { exec shellwords($app->cdif), @cdifopts } ;
	warn "exec failed: $!";
	print while <>;
	exit;
    }
    ## parent
    else {
	## nothing to do
    }
} else {
    open(DIFF, $DIFF) || die "cannot open diff: $!\n";
}

if ($readfile) {

    binmode DIFF, ':raw';
    my $DIFFOUT = do { local $/;  };
    close DIFF;
    open  DIFF, '<', \$DIFFOUT or die;

    open OLD, $OLD or die "$OLD: $!\n";
    open NEW, $NEW or die "$NEW: $!\n";

    # For reading /dev/fd/*
    seek OLD, 0, 0 or die unless -p OLD;
    seek NEW, 0, 0 or die unless -p NEW;
}

my @boundary = (boundary => $app->boundary);
my $color_re = qr{ \e \[ [\d;]* [mK] }x;

our $oline = 1;
our $nline = 1;
our $mline = 1;

while () {
    #
    # normal diff
    #
    if (/^([\d,]+)([adc])([\d,]+)$/) {
	my(@old, @new);
	my($left, $ctrl, $right) = ($1, $2, $3);
	my($l1, $l2) = range($left);
	my($r1, $r2) = range($right);
	if ($readfile) {
	    my $identical_line = $l1 - $oline + 1 - ($ctrl ne 'a');
	    print_identical($identical_line);
	}
	if ($app->debug || $read_stdin) {
	    print_command_n($_, $_);
	}
	if ($ctrl eq 'd' || $ctrl eq 'c') {
	    ($oline) = $left =~ /^(\d+)/;
	    my $n = $l2 - $l1 + 1;
	    @old = read_line(*DIFF, $n);
	    $readfile and read_line(*OLD, $n);
	}
	read_line(*DIFF, 1) if $ctrl eq 'c';
	if ($ctrl eq 'a' || $ctrl eq 'c') {
	    ($nline) = $right =~ /^(\d+)/;
	    my $n = $r2 - $r1 + 1;
	    @new = read_line(*DIFF, $n);
	    $readfile and read_line(*NEW, $n);
	}
	map {
	    s/^([<>])\s?/{'<' => '-', '>' => '+'}->{$1}/e
	} @old, @new;
	flush_buffer([], \@old, \@new);
    }
    #
    # context diff
    #
    elsif (/^\*\*\* /) {
	my $next = ;
	print_command_n({ type => 'FILE' }, $_, $next);
    }
    elsif ($_ eq "***************\n") {
	my(@old, @new);
	my $ohead = $_ = ;
	my($left, $right);
	unless (($left) = /^\*\*\* ([\d,]+) \*\*\*\*$/) {
	    print;
	    next;
	}
	my $oline = range($left);
	my $dline = 0;
	my $cline = 0;
	my $nhead = $_ = ;
	unless (($right) = /^--- ([\d,]+) ----$/) {
	    @old = read_line(*DIFF, $oline - 1, $nhead);
	    $nhead = $_ = ;
	    unless (($right) = /^--- ([\d,]+) ----$/) {
		print $ohead, @old, $_;
		next;
	    }
	    for (@old) {
		/^-/ and ++$dline;
		/^!/ and ++$cline;
	    }
	}
	my $nline = range($right);
	if (@old == 0 or $cline != 0 or ($oline - $dline != $nline)) {
	    @new = read_line(*DIFF, $nline);
	}
	print_command_n($ohead, $nhead);
	($oline) = $left =~ /^(\d+)/;
	($nline) = $right =~ /^(\d+)/;

	my @buf = merge_diffc(\@old, \@new);
	flush_buffer(@buf);
    }
    #
    # unified diff
    #
    elsif (/^($prefix_re)(--- (?s:.*))/) {
	my($prefix, $left) = ($1, $2);
	my $right = ;
	local $screen_width = $screen_width;
	if ($prefix) {
	    $right =~ s/^\Q$prefix//;
	    print $prefix;
	    $screen_width -= length $prefix;
	}
	print_command_n({ type => 'FILE' }, $left, $right);
    }
    elsif (m{^
	   (?$prefix_re)
	   (?
	     \@\@ [ ]
	     \-(?\d+) (?:,(?\d+))? [ ]
	     \+(?\d+) (?:,(?\d+))? [ ]
	     \@\@
	     (?s:.*)
	   )
	   }x) {
	($oline, $nline) = @+{qw(oline nline)};
	my($o, $n) = ($+{o}//1, $+{n}//1);
	my($prefix, $command) = @+{qw(prefix command)};

	local $screen_width = $screen_width;
	my($divert, %read_opt);
	if ($prefix) {
	    $screen_width -= length $prefix;
	    $read_opt{prefix} = $prefix;
	    $divert = IO::Divert->new(FINAL => sub { s/^/$prefix/mg });
	}

	print_command_n({ type => 'COMMAND' }, $command, $command);
	my @buf = read_unified_2 \%read_opt, *DIFF, $o, $n;

	flush_buffer(@buf);
    }
    #
    # diff --combined (only support 3 files)
    #
    elsif (/^diff --(?:cc|combined)/) {
	my @lines = ($_);
	push @lines, read_until { /^\+\+\+/ } *DIFF;
	if (not defined $lines[-1]) {
	    pop @lines;
	    print @lines;
	    next;
	}
	print @lines;
    }
    elsif (/^\@{3} -(\d+)(?:,(\d+))? -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? \@{3}/)  {
	print_command_n({ type => 'COMMAND' }, $_, $_, $_);

	($oline, $nline, $mline) = ($1, $3, $5);
	state $read_unified_3 = read_unified_sub(3);
	my @buf = $read_unified_3->(*DIFF, $2 // 1, $4 // 1, $6 // 1);
	flush_buffer_3(@buf);
    }
    #
    # conflict marker
    #
    elsif (/^<<<<<<<\h*+(.*)/) {
      CONFLICT:
	{
	    my %name = (o => $_);
	    my($c1, $c2, $c3, $c4);
	    $c1 = $_;

	    my @old = read_until { /^=======$/ } *DIFF;
	    $c2 = pop @old // do {
		flush_unknown($c1, @old);
		last;
	    };

	    my @new = read_until { /^>>>>>>>\h*+(.*)/ } *DIFF;
	    $c4 = pop @new // do {
		flush_unknown($c1, @old, $c2, @new);
		last;
	    };
	    $name{n} = $c4;

	    my @mrg;
	    my $mrg = first { $old[$_] =~ /^\Q|||||||\E\h*+(.*)/ } keys @old;
	    if (defined $mrg or $app->parallel > 2) {
		if (defined $mrg) {
		    $name{m} = $old[$mrg];
		    ($c3, @mrg) = splice @old, $mrg;
		} else {
		    $name{m} = $name{o};
		    $name{o} = $name{n};
		    @mrg = @old;
		    @old = @new;
		}
		s/^/--/ for @old, @mrg;
		s/^/++/ for @new;
		print_command_n({ type => 'FILE' }, @name{qw(o m n)});
		flush_buffer_3([], \@old, \@mrg, \@new);
	    } else {
		s/^/-/ for @old;
		s/^/+/ for @new;
		print_command_n({ type => 'FILE' }, @name{qw(o n)});
		flush_buffer([], \@old, \@new);
	    }
	}
    }
    #
    # #ifdef            custom container
    #
    #   #ifdef JA         ::::::: ja
    #   japanese text     japanese text
    #   #endif            :::::::
    #   #ifdef EN         ::::::: en
    #   english text      english text
    #   #endif            :::::::
    #
    elsif (/^(\#ifdef|:{7,})\h++(.*)/) {
      COLON:
	{
	    my($c1, $c2, $c3, $c4) = ($_);
	    my $start = $1;
	    my $end = $start eq '#ifdef' ? qr/^#endif$/ : qr/^$start$/;
	    my($m1, $m2) = ($2);

	    my @old = read_until { /$end/ } *DIFF;
	    $c2 = pop @old // do {
		flush_unknown($c1, @old);
		last;
	    };
	    $c3 = ;
	    if ($c3 !~ /^${start}\h++(.*)/) {
		flush_unknown($c1, @old, $c2, $c3);
		last;
	    }
	    $m2 = $1;
	    my @new = read_until { /$end/ } *DIFF;
	    $c4 = pop @new // do {
		flush_unknown($c1, @old, $c2, $c3, @new);
		last;
	    };

	    @old = (" $c1", map(s/^/-/r, @old), " $c2");
	    @new = (" $c3", map(s/^/+/r, @new), " $c4");
	    flush_buffer([], \@old, \@new);
	}
    }
    else {
	flush_unknown($_);
    }
}
continue {
    STDOUT->flush;
}

close DIFF;
my $exit = $DIFF =~ /\|$/ ? $? >> 8 : 0;

if ($readfile) {
    if ($exit < 2) {
	print_identical(-1);
    }
    close OLD;
    close NEW;
}

exit($exit > 1);

######################################################################

##
## Convert diff -c output to -u compatible format.
##
sub merge_diffc {
    my @o = @{+shift};
    my @n = @{+shift};
    for (@o, @n) {
	s/(?<= ^[ \-\+\!] ) [\t ]//x or die "Format error (-c).\n";
    }

    my @buf;
    while (@o or @n) {

	push @buf, \( my( @common, @old, @new ) );

	while (@o and $o[0] =~ /^ /) {
	    push @common, shift @o;
	    shift @n if @n;
	}
	while (@n and $n[0] =~ /^ /) {
	    push @common, shift @n;
	}

	push @old, shift @o while @o and $o[0] =~ /^\-/;
	next if @old;

	push @new, shift @n while @n and $n[0] =~ /^\+/;
	next if @new;

	push @old, shift @o while @o and $o[0] =~ s/^!/-/;
	push @new, shift @n while @n and $n[0] =~ s/^!/+/;
    }

    @buf;
}

sub flush_unknown {
    if ($app->parallel > 2) {
	flush_buffer_3( [ map s/^/  /r, @_ ] );
    }
    elsif ($app->parallel > 1) {
	flush_buffer( [ map s/^/ /r, @_ ] );
    }
    else {
	print $painter->('UNKNOWN', $_) for @_;
    }
}

sub flush_buffer {

    push @_, [] while @_ % 3;

    if ($app->view) {
	@_ = do {
	    map { @$_ }
	    reduce {
		[ [] ,
		  [ map { @$_ } $a->[1], $b->[0], $b->[1] ] ,
		  [ map { @$_ } $a->[2], $b->[0], $b->[2] ] ] }
	    map { $_ ? [ ( splice @_, 0, 3 ) ] : [ [], [], [] ] }
	    0 .. @_ / 3 ;
	};
    }

    while (my($s, $o, $n) = splice @_, 0, 3) {
	for (@$s) {
	    s/^(.)// or die;
	    print_column_23($1, $_, $1, $_);
	    $oline++;
	    $nline++;
	}

	my $max = $app->limit->{line};
	my $one_side = !@$o || !@$n;
	my $count = 0;
	while (@$o or @$n) {
	    my $old = shift @$o;
	    my $new = shift @$n;
	    my $omark = $old ? $old =~ s/^(.)// && $1 : ' ';
	    my $nmark = $new ? $new =~ s/^(.)// && $1 : ' ';

	    print_column_23($omark, $old, $nmark, $new);

	    $oline++ if defined $old;
	    $nline++ if defined $new;

	    # truncate one-sided (add/delete) section exceeding max lines
	    if ($max and $one_side and ++$count >= $max and @$o + @$n > 0) {
		my $rest = @$o + @$n;
		my $msg = $painter->(
		    'NOTICE',
		    sprintf "... %d lines omitted ...\n", $rest,
		);
		# show message on the side that has content
		# suppress line number by localizing $oline/$nline
		{
		    local($oline, $nline) = (undef, undef);
		    if (@$n) {
			print_column_23(' ', undef, ' ', $msg);
		    } else {
			print_column_23(' ', $msg, ' ', undef);
		    }
		}
		# advance line counter past omitted lines
		$oline += $rest if !@$n;
		$nline += $rest if !@$o;
		last;
	    }
	}
    }
}

sub flush_buffer_3 {

    push @_, [] while @_ % 4;

    if ($app->view) {
	@_ = do {
	    map { @$_ }
	    reduce {
		[ [] ,
		  [ map { @$_ } $a->[1], $b->[0], $b->[1] ] ,
		  [ map { @$_ } $a->[2], $b->[0], $b->[2] ] ,
		  [ map { @$_ } $a->[3], $b->[0], $b->[3] ] ] }
	    map { $_ ? [ splice @_, 0, 4 ] : [ [], [], [], [] ] }
	    0 .. @_ / 4;
	};
    }

    while (@_) {
	my @d = splice @_, 0, 4;

	for my $common (@{shift @d}) {
	    $common =~ s/^  //;
	    print_column_23(' ', $common, ' ', $common, ' ', $common);
	    $oline++;
	    $nline++;
	    $mline++;
	}

	while (first { @$_ > 0 } @d) {
	    my $old = shift @{$d[0]};
	    my $new = shift @{$d[1]};
	    my $mrg = shift @{$d[2]};
	    my $om = $old ? $old =~ s/^(?|(\-).| (\+)|( ) )// && $1 : ' ';
	    my $nm = $new ? $new =~ s/^(?|.(\-)|(\+) |( ) )// && $1 : ' ';
	    my $mm = $mrg ? $mrg =~ s/^(?|(\+).|.(\+)|( ) )// && $1 : ' ';

	    print_column_23($om, $old, $nm, $new, $mm, $mrg);

	    $oline++ if defined $old;
	    $nline++ if defined $new;
	    $mline++ if defined $mrg;
	}
    }
}

sub print_identical {
    my $n = shift;
    while ($n--) {
	my $old = ;
	my $new = ;
	defined $old or defined $new or last;
	print_column_23(' ', $old, ' ', $new);
	$oline++;
	$nline++;
	$mline++;
    }
}

sub linenum {
    my $n = shift;
    defined $n ? (sprintf $num_format, $n) : (' ' x $app->digit);
}

sub print_column_23 {
    my $column = @_ / 2;
    my $width = column_width $column;
    my($omark, $old, $nmark, $new, $mmark, $mrg) = @_;
    my $print_number = $app->number;

    my($onum, $nnum, $mnum) = ('', '', '');
    my $nspace = $print_number ? ' ' : '';
    if (defined $old) {
	$old =~ s/\R\z//;
	$onum = linenum($oline) if $print_number;
    }
    if (defined $new) {
	$new =~ s/\R\z//;
	$nnum = linenum($nline) if $print_number;
    }
    if (defined $mrg) {
	$mrg =~ s/\R\z//;
	$mnum = linenum($mline) if $print_number;
    }

    # truncate long lines before processing
    if (my $max = $app->limit->{length}) {
	for ($old, $new, $mrg) {
	    defined and length > $max or next;
	    state $fold = Text::ANSI::Fold->new;
	    my $orig_len = length;
	    ($_, undef) = $fold->fold($_, width => $max);
	    my $truncated = $orig_len - length;
	    $_ .= $painter->('NOTICE',
			      sprintf " ... %d characters omitted ...", $truncated);
	}
    }

    my($OTEXT, $OLINE, $OMARK) =
	$omark =~ /\S/ ? qw(OTEXT OLINE OMARK) : qw(UTEXT OULINE OUMARK);
    my($NTEXT, $NLINE, $NMARK) =
	$nmark =~ /\S/ ? qw(NTEXT NLINE NMARK) : qw(UTEXT NULINE NUMARK);
    my($MTEXT, $MLINE, $MMARK) =
	$mmark =~ /\S/ ? qw(MTEXT MLINE MMARK) : qw(UTEXT NULINE NUMARK)
	if $column >= 3;

    while (1) {
	(my $o, $old) = ansi_fold($old,
				  max(1, $width - length($onum . $nspace)),
				  @boundary);
	(my $n, $new) = ansi_fold($new,
				  max(1, $width - length($nnum . $nspace)),
				  @boundary);
	(my $m, $mrg) = ansi_fold($mrg,
				  max(1, $width - length($mnum . $nspace)),
				  @boundary)
	    if $column >= 3;

	my @f;
	$f[0]{MARK} = $painter->($OMARK, $omark);
	$f[0]{LINE} = $painter->($OLINE, $onum) . $nspace if $print_number;
	$f[0]{TEXT} = $painter->($OTEXT, $o) if $o ne "";
	$f[1]{MARK} = $painter->($NMARK, $nmark);
	$f[1]{LINE} = $painter->($NLINE, $nnum) . $nspace if $print_number;
	$f[1]{TEXT} = $painter->($NTEXT, $n) if $n ne "";
	if ($column >= 3) {
	    $f[2]{MARK} = $painter->($MMARK, $mmark);
	    $f[2]{LINE} = $painter->($MLINE, $mnum) . $nspace if $print_number;
	    $f[2]{TEXT} = $painter->($MTEXT, $m) if $m ne "";
	}
	print_field_n(@f);

	last if $app->truncate;
	last unless $old ne '' or $new ne '' or ($mrg and $mrg ne '');

	if ($print_number) {
	    $onum =~ s/./ /g;
	    $nnum =~ s/./ /g;
	    $mnum =~ s/./ /g if $column >= 3;
	}
	$omark = $old ne '' ? '.' : ' ';
	$nmark = $new ne '' ? '.' : ' ';
	$mmark = $mrg ne '' ? '.' : ' ' if $column >= 3;
    }
}

sub print_command_n {
    my $opt = ref $_[0] ? shift : {};
    my $column = @_;
    my $width = column_width $column;
    my @f;

    $opt->{type} //= 'COMMAND';

    $app->command  or return if $opt->{type} eq 'COMMAND';
    $app->filename or return if $opt->{type} eq 'FILE';

    my @color = map { $_ . $opt->{type} } "O", "N", "M";

    for my $i (keys @_) {
	local $_ = $_[$i];
	chomp if defined;
	($_) = ansi_fold($_, $width);
	my %f;
	my $color = $i < @color ? $color[$i] : $color[-1];
	$f{TEXT} = $painter->($color, $_);
	$f{MARK} = ' ';
	push @f, \%f;
    }

    print_field_n(@f);
}

sub print_field_n {
    if (@column >= @_) {
	@_ = @_[ @column[ keys @_ ] ];
    }
    while (my($i, $f) = each @_) {
	my $markpos = $i < @markpos ? $markpos[$i] : $markpos[-1];
	local $_;
	$_ = $f->{"MARK"} and print if $markpos eq LEFT;
	$_ = $f->{"LINE"} and print;
	$_ = $f->{"TEXT"} and print;
	$_ = $f->{"MARK"} and print if $markpos eq RIGHT;
    }
    print "\n";
}

__END__