File Coverage

blib/lib/Text/WideChar/Util.pm

Criterion	Covered	Total	%
statement	161	205	78.5
branch	68	102	66.6
condition	21	28	75.0
subroutine	14	20	70.0
pod	9	9	100.0
total	273	364	75.0

package Text::WideChar::Util;

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2021-04-14'; # DATE
our $DIST = 'Text-WideChar-Util'; # DIST
our $VERSION = '0.172'; # VERSION

use 5.010001;
use locale;
use strict;
use utf8;
use warnings;

use Unicode::GCString;

require Exporter;
our @ISA       = qw(Exporter);
our @EXPORT_OK = qw(
                       mbpad
                       pad
                       mbswidth
                       mbswidth_height
                       length_height
                       mbtrunc
                       trunc
                       mbwrap
                       wrap
               );

sub mbswidth {
    Unicode::GCString->new($_[0])->columns;
}

sub mbswidth_height {
    my $text = shift;
    my $num_lines = 0;
    my $len = 0;
    for my $e (split /(\r?\n)/, $text) {
        if ($e =~ /\n/) {
            $num_lines++;
            next;
        }
        $num_lines = 1 if $num_lines == 0;
        my $l = mbswidth($e);
        $len = $l if $len < $l;
    }
    [$len, $num_lines];
}

sub length_height {
    my $text = shift;
    my $num_lines = 0;
    my $len = 0;
    for my $e (split /(\r?\n)/, $text) {
        if ($e =~ /\n/) {
            $num_lines++;
            next;
        }
        $num_lines = 1 if $num_lines == 0;
        my $l = length($e);
        $len = $l if $len < $l;
    }
    [$len, $num_lines];
}

sub _get_indent_width {
    my ($is_mb, $indent, $tab_width) = @_;
    my $w = 0;
    for (split //, $indent) {
        if ($_ eq "\t") {
            # go to the next tab
            $w = $tab_width * (int($w/$tab_width) + 1);
        } else {
            $w += $is_mb ? mbswidth($_) : 1;
        }
    }
    $w;
}

# 3002 = IDEOGRAPHIC FULL STOP
# ff0c = FULLWIDTH COMMA

our $re_cjk = qr/(?:
                     \p{Block=CJK_Compatibility}
                 |   \p{Block=CJK_Compatibility_Forms}
                 |   \p{Block=CJK_Compatibility_Ideographs}
                 |   \p{Block=CJK_Compatibility_Ideographs_Supplement}
                 |   \p{Block=CJK_Radicals_Supplement}
                 |   \p{Block=CJK_Strokes}
                 |   \p{Block=CJK_Symbols_And_Punctuation}
                 |   \p{Block=CJK_Unified_Ideographs}
                 |   \p{Block=CJK_Unified_Ideographs_Extension_A}
                 |   \p{Block=CJK_Unified_Ideographs_Extension_B}
                 |   \p{Hiragana}\p{Katakana}\p{Hangul}\x{30fc}
                #|   \p{Block=CJK_Unified_Ideographs_Extension_C}
                     [\x{3002}\x{ff0c}]
                 )/x;
our $re_cjk_class = qr/[
                           \p{Block=CJK_Compatibility}
                           \p{Block=CJK_Compatibility_Forms}
                           \p{Block=CJK_Compatibility_Ideographs}
                           \p{Block=CJK_Compatibility_Ideographs_Supplement}
                           \p{Block=CJK_Radicals_Supplement}
                           \p{Block=CJK_Strokes}
                           \p{Block=CJK_Symbols_And_Punctuation}
                           \p{Block=CJK_Unified_Ideographs}
                           \p{Block=CJK_Unified_Ideographs_Extension_A}
                           \p{Block=CJK_Unified_Ideographs_Extension_B}
                           \p{Hiragana}\p{Katakana}\p{Hangul}\x{30fc}
                           \x{3002}
                           \x{ff0c}
                      ]/x;
our $re_cjk_negclass = qr/[^
                              \p{Block=CJK_Compatibility}
                              \p{Block=CJK_Compatibility_Forms}
                              \p{Block=CJK_Compatibility_Ideographs}
                              \p{Block=CJK_Compatibility_Ideographs_Supplement}
                              \p{Block=CJK_Radicals_Supplement}
                              \p{Block=CJK_Strokes}
                              \p{Block=CJK_Symbols_And_Punctuation}
                              \p{Block=CJK_Unified_Ideographs}
                              \p{Block=CJK_Unified_Ideographs_Extension_A}
                              \p{Block=CJK_Unified_Ideographs_Extension_B}
                              \p{Hiragana}\p{Katakana}\p{Hangul}\x{30fc}
                              \x{3002}
                              \x{ff0c}
                      ]/x;

sub _wrap {
    my ($is_mb, $text, $width, $opts) = @_;
    $width //= 80;
    $opts  //= {};

    # our algorithm: split into paragraphs, then process each paragraph. at the
    # start of paragraph, determine indents (either from %opts, or deduced from
    # text, like in Emacs) then push first-line indent. proceed to push words,
    # while adding subsequent-line indent at the start of each line.

    my $tw = $opts->{tab_width} // 8;
    die "Please specify a positive tab width" unless $tw > 0;
    my $optfli  = $opts->{flindent};
    my $optfliw = defined $optfli ? _get_indent_width($is_mb, $optfli, $tw) : undef;
    my $optsli  = $opts->{slindent};
    my $optsliw = defined $optsli ? _get_indent_width($is_mb, $optsli, $tw) : undef;
    my $optkts  = $opts->{keep_trailing_space} // 0;
    my @res;

    my @para = split /(\n(?:[ \t]*\n)+)/, $text;
    #say "D:para=[",join(", ", @para),"]";

    my ($maxww, $minww);

  PARA:
    while (my ($ptext, $pbreak) = splice @para, 0, 2) {
        my $x = 0;
        my $y = 0;
        my $line_has_word = 0;

        # determine indents
        my ($fli, $sli, $fliw, $sliw);
        if (defined $optfli) {
            $fli  = $optfli;
            $fliw = $optfliw;
        } else {
            # XXX emacs can also treat ' #' as indent, e.g. when wrapping
            # multi-line perl comment.
            ($fli) = $ptext =~ /\A([ \t]*)\S/;
            if (defined $fli) {
                $fliw = _get_indent_width($is_mb, $fli, $tw);
            } else {
                $fli  = "";
                $fliw = 0;
            }
        }
        if (defined $optsli) {
            $sli  = $optsli;
            $sliw = $optsliw;
        } else {
            ($sli) = $ptext =~ /\A[^\n]*\S[\n]([ \t+]*)\S/;
            if (defined $sli) {
                $sliw = _get_indent_width($is_mb, $sli, $tw);
            } else {
                $sli  = "";
                $sliw = 0;
            }
        }
        die "Subsequent indent must be less than width" if $sliw >= $width;

        push @res, $fli;
        $x += $fliw;

        my @words0; # (WORD1, WORD1_IS_CJK?, WS_AFTER?, WORD2, WORD2_IS_CJK?, WS_AFTER?, ...)
        # we differentiate/split between CJK "word" (cluster of CJK letters,
        # really) and non-CJK word, e.g. "我很爱你my可爱的and beautiful,
        # beautiful wife" is split to ["我很爱你", "my", "可爱的", "and",
        # "beautiful,", "beautiful", "wife"]. we do this because CJK word can be
        # line-broken on a per-letter basis, as they don't separate words with
        # whitespaces.
        while ($ptext =~ /(?: ($re_cjk+)|(\S+) ) (\s*)/gox) {
            my $ws_after = $3 ? 1:0;
            if ($1) {
                push @words0, $1, 1, $ws_after;
            } else {
                my $ptext2 = $2;
                while ($ptext2 =~ /($re_cjk_class+)|
                                   ($re_cjk_negclass+)/gox) {
                    if ($1) {
                        push @words0, $1, 1, 0;
                    } else {
                        push @words0, $2, 0, 0;
                    }
                }
                $words0[-1] = $ws_after;
            }
        }

        # process each word
        my $prev_ws_after;
        while (@words0) {
            my ($word0, $is_cjk, $ws_after) = splice @words0, 0, 3;
            my @words;
            my @wordsw;
            while (1) {
                my $wordw = $is_mb ? mbswidth($word0) : length($word0);

                # long cjk word is not truncated here because it will be
                # line-broken later when wrapping.
                if ($wordw <= $width-$sliw || $is_cjk) {
                    push @words , $word0;
                    push @wordsw, $wordw;
                    last;
                }
                # truncate long word
                if ($is_mb) {
                    my $res = mbtrunc($word0, $width-$sliw, 1);
                    push @words , $res->[0];
                    push @wordsw, $res->[1];
                    $word0 = substr($word0, length($res->[0]));
                    #say "D:truncated long word (mb): $text -> $res->[0] & $res->[1], word0=$word0";
                } else {
                    my $w2 = substr($word0, 0, $width-$sliw);
                    push @words , $w2;
                    push @wordsw, $width-$sliw;
                    $word0 = substr($word0, $width-$sliw);
                    #say "D:truncated long word: $w2, ".($width-$sliw).", word0=$word0";
                }
            }

            for my $word (@words) {
                my $wordw = shift @wordsw;
                #say "D:x=$x word=$word is_cjk=$is_cjk ws_after=$ws_after wordw=$wordw line_has_word=$line_has_word width=$width";

                $maxww = $wordw if !defined($maxww) || $maxww < $wordw;
                $minww = $wordw if !defined($minww) || $minww > $wordw;

                my $x_after_word = $x + ($line_has_word ? 1:0) + $wordw;
                if ($x_after_word <= $width) {
                    # the addition of word hasn't exceeded column width
                    if ($line_has_word) {
                        if ($prev_ws_after) {
                            push @res, " ";
                            $x++;
                        }
                    }
                    push @res, $word;
                    $x += $wordw;
                } else {
                    while (1) {
                        if ($is_cjk) {
                            # CJK word can be broken
                            my $res;
                            if ($prev_ws_after) {
                                $res = mbtrunc($word, $width - $x - 1, 1);
                                push @res, " ", $res->[0];
                            } else {
                                $res = mbtrunc($word, $width - $x, 1);
                                push @res, $res->[0];
                            }
                            my $word2 = substr($word, length($res->[0]));
                            #say "D:truncated CJK word: $word -> $res->[0] & $res->[1], remaining=$word2";
                            $prev_ws_after = 0;
                            $word = $word2;
                            $wordw = mbswidth($word);
                        }

                        # move the word to the next line
                        push @res, " " if $prev_ws_after && $optkts;
                        push @res, "\n", $sli;
                        $y++;

                        if ($sliw + $wordw <= $width) {
                            push @res, $word;
                            $x = $sliw + $wordw;
                            last;
                        } else {
                            # still too long, truncate again
                            $x = $sliw;
                        }
                    }
                }
                $line_has_word++;
            }
            $prev_ws_after = $ws_after;
        }

        if (defined $pbreak) {
            push @res, $pbreak;
        } else {
            push @res, "\n" if $ptext =~ /\n[ \t]*\z/;
        }
    }

    if ($opts->{return_stats}) {
        return [join("", @res), {
            max_word_width => $maxww,
            min_word_width => $minww,
        }];
    } else {
        return join("", @res);
    }
}

sub mbwrap {
    _wrap(1, @_);
}

sub wrap {
    _wrap(0, @_);
}

sub _pad {
    my ($is_mb, $text, $width, $which, $padchar, $is_trunc) = @_;
    if ($which) {
        $which = substr($which, 0, 1);
    } else {
        $which = "r";
    }
    $padchar //= " ";

    my $w = $is_mb ? mbswidth($text) : length($text);
    if ($is_trunc && $w > $width) {
        my $res = mbtrunc($text, $width, 1);
        $text = $res->[0] . ($padchar x ($width-$res->[1]));
    } else {
        if ($which eq 'l') {
            $text = ($padchar x ($width-$w)) . $text;
        } elsif ($which eq 'c') {
            my $n = int(($width-$w)/2);
            $text = ($padchar x $n) . $text . ($padchar x ($width-$w-$n));
        } else {
            $text .= ($padchar x ($width-$w));
        }
    }
    $text;
}

sub mbpad {
    _pad(1, @_);
}

sub pad {
    _pad(0, @_);
}

sub _trunc {
    my ($is_mb, $text, $width, $return_width) = @_;

    # return_width (undocumented): if set to 1, will return [truncated_text,
    # visual width, length(chars) up to truncation point]

    my $w = $is_mb ? mbswidth($text) : length($text);
    die "Invalid argument, width must not be negative" unless $width >= 0;
    if ($w <= $width) {
        return $return_width ? [$text, $w, length($text)] : $text;
    }

    my $c = 0;

    # perform binary cutting
    my @res;
    my $wres = 0; # total width of text in @res
    my $l = int($w/2); $l = 1 if $l == 0;
    my $end = 0;
    while (1) {
        my $left  = substr($text, 0, $l);
        my $right = $l > length($text) ? "" : substr($text, $l);
        my $wl = $is_mb ? mbswidth($left) : length($left);
        #say "D:left=$left, right=$right, wl=$wl";
        if ($wres + $wl > $width) {
            $text = $left;
        } else {
            push @res, $left;
            $wres += $wl;
            $c += length($left);
            $text = $right;
        }
        $l = int(($l+1)/2);
        #say "D:l=$l";
        last if $l==1 && $end>1;
        $end++ if $l==1;
    }
    if ($return_width) {
        return [join("", @res), $wres, $c];
    } else {
        return join("", @res);
    }
}

sub mbtrunc {
    _trunc(1, @_);
}

sub trunc {
    _trunc(0, @_);
}

1;
# ABSTRACT: Routines for text containing wide characters

__END__