source: for-distributions/trunk/bin/windows/perl/lib/Encode/MIME/Header/ISO_2022_JP.pm@ 14489

package Encode::MIME::Header::ISO_2022_JP;

use strict;
use base qw(Encode::MIME::Header);

$Encode::Encoding{'MIME-Header-ISO_2022_JP'}
  = bless {encode => 'B', bpl => 76, Name => 'MIME-Header-ISO_2022_JP'}
   => __PACKAGE__;

use constant HEAD   => '=?ISO-2022-JP?B?';
use constant TAIL   => '?=';

use Encode::CJKConstants qw(%RE);

our $VERSION = do { my @r = (q$Revision: 1.1 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r };


# I owe the below codes totally to
#   Jcode by Dan Kogai & http://www.din.or.jp/~ohzaki/perl.htm#JP_Base64

sub encode {
    my $self = shift;
    my $str  = shift;

    utf8::encode($str) if( Encode::is_utf8($str) );
    Encode::from_to($str, 'utf8', 'euc-jp');

    my($trailing_crlf) = ($str =~ /(\n|\r|\x0d\x0a)$/o);

    $str = _mime_unstructured_header($str, $self->{bpl});

    not $trailing_crlf and $str =~ s/(\n|\r|\x0d\x0a)$//o;

    return $str;
}


sub _mime_unstructured_header {
    my ($oldheader, $bpl) = @_;
    my $crlf = $oldheader =~ /\n$/;
    my($header, @words, @wordstmp, $i) = ('');

    $oldheader =~ s/\s+$//;

    @wordstmp = split /\s+/, $oldheader;

    for ($i = 0; $i < $#wordstmp; $i++){
        if( $wordstmp[$i] !~ /^[\x21-\x7E]+$/ and $wordstmp[$i + 1] !~ /^[\x21-\x7E]+$/){
            $wordstmp[$i + 1] = "$wordstmp[$i] $wordstmp[$i + 1]";
        }
        else{
            push(@words, $wordstmp[$i]);
        }
    }

    push(@words, $wordstmp[-1]);

    for my $word (@words){
        if ($word =~ /^[\x21-\x7E]+$/) {
            $header =~ /(?:.*\n)*(.*)/;
            if (length($1) + length($word) > $bpl) {
                $header .= "\n $word";
            }
            else{
                $header .= $word;
            }
        }
        else{
            $header = _add_encoded_word($word, $header, $bpl);
        }

        $header =~ /(?:.*\n)*(.*)/;

        if(length($1) == $bpl){
            $header .= "\n ";
        }
        else {
            $header .= ' ';
        }
    }

    $header =~ s/\n? $//mg;

    $crlf ? "$header\n" : $header;
}


sub _add_encoded_word {
    my($str, $line, $bpl) = @_;
    my $result = '';

    while( length($str) ){
        my $target = $str;
        $str = '';

        if(length($line) + 22 + ($target =~ /^(?:$RE{EUC_0212}|$RE{EUC_C})/o) * 8 > $bpl){
            $line =~ s/[ \t\n\r]*$/\n/;
            $result .= $line;
            $line = ' ';
        }

        while(1){
            my $iso_2022_jp = $target;
            Encode::from_to($iso_2022_jp, 'euc-jp', 'iso-2022-jp');

            my $encoded
             = HEAD . MIME::Base64::encode_base64($iso_2022_jp, '') . TAIL;

            if(length($encoded) + length($line) > $bpl){
                $target =~ s/($RE{EUC_0212}|$RE{EUC_KANA}|$RE{EUC_C}|$RE{ASCII})$//o;
                $str = $1 . $str;
            }
            else{
                $line .= $encoded;
                last;
            }
        }

    }

    $result . $line;
}


1;
__END__