First pass at adding key files

site/slowtwitch.com/cgi-bin/articles/admin/GT/JSON/PP56.pm

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+package GT::JSON::PP56;
+
+use 5.006;
+use strict;
+
+my @properties;
+
+$GT::JSON::PP56::VERSION = '1.07';
+
+BEGIN {
+
+    sub utf8::is_utf8 {
+        my $len =  length $_[0]; # char length
+        {
+            use bytes; #  byte length;
+            return $len != length $_[0]; # if !=, UTF8-flagged on.
+        }
+    }
+
+
+    sub utf8::upgrade {
+        ; # noop;
+    }
+
+
+    sub utf8::downgrade ($;$) {
+        return 1 unless ( utf8::is_utf8( $_[0] ) );
+
+        if ( _is_valid_utf8( $_[0] ) ) {
+            my $downgrade;
+            for my $c ( unpack( "U*", $_[0] ) ) {
+                if ( $c < 256 ) {
+                    $downgrade .= pack("C", $c);
+                }
+                else {
+                    $downgrade .= pack("U", $c);
+                }
+            }
+            $_[0] = $downgrade;
+            return 1;
+        }
+        else {
+            Carp::croak("Wide character in subroutine entry") unless ( $_[1] );
+            0;
+        }
+    }
+
+
+    sub utf8::encode ($) { # UTF8 flag off
+        if ( utf8::is_utf8( $_[0] ) ) {
+            $_[0] = pack( "C*", unpack( "C*", $_[0] ) );
+        }
+        else {
+            $_[0] = pack( "U*", unpack( "C*", $_[0] ) );
+            $_[0] = pack( "C*", unpack( "C*", $_[0] ) );
+        }
+    }
+
+
+    sub utf8::decode ($) { # UTF8 flag on
+        if ( _is_valid_utf8( $_[0] ) ) {
+            utf8::downgrade( $_[0] );
+            $_[0] = pack( "U*", unpack( "U*", $_[0] ) );
+        }
+    }
+
+
+    *GT::JSON::PP::JSON_PP_encode_ascii      = \&_encode_ascii;
+    *GT::JSON::PP::JSON_PP_encode_latin1     = \&_encode_latin1;
+    *GT::JSON::PP::JSON_PP_decode_surrogates = \&GT::JSON::PP::_decode_surrogates;
+    *GT::JSON::PP::JSON_PP_decode_unicode    = \&GT::JSON::PP::_decode_unicode;
+
+    unless ( defined &B::SVp_NOK ) { # missing in B module.
+        eval q{ sub B::SVp_NOK () { 0x02000000; } };
+    }
+
+}
+
+
+
+sub _encode_ascii {
+    join('',
+        map {
+            $_ <= 127 ?
+                chr($_) :
+            $_ <= 65535 ?
+                sprintf('\u%04x', $_) : sprintf('\u%x\u%x', GT::JSON::PP::_encode_surrogates($_));
+        } _unpack_emu($_[0])
+    );
+}
+
+
+sub _encode_latin1 {
+    join('',
+        map {
+            $_ <= 255 ?
+                chr($_) :
+            $_ <= 65535 ?
+                sprintf('\u%04x', $_) : sprintf('\u%x\u%x', GT::JSON::PP::_encode_surrogates($_));
+        } _unpack_emu($_[0])
+    );
+}
+
+
+sub _unpack_emu { # for Perl 5.6 unpack warnings
+    return   !utf8::is_utf8($_[0]) ? unpack('C*', $_[0]) 
+           : _is_valid_utf8($_[0]) ? unpack('U*', $_[0])
+           : unpack('C*', $_[0]);
+}
+
+
+sub _is_valid_utf8 {
+    my $str = $_[0];
+    my $is_utf8;
+
+    while ($str =~ /(?:
+          (
+             [\x00-\x7F]
+            |[\xC2-\xDF][\x80-\xBF]
+            |[\xE0][\xA0-\xBF][\x80-\xBF]
+            |[\xE1-\xEC][\x80-\xBF][\x80-\xBF]
+            |[\xED][\x80-\x9F][\x80-\xBF]
+            |[\xEE-\xEF][\x80-\xBF][\x80-\xBF]
+            |[\xF0][\x90-\xBF][\x80-\xBF][\x80-\xBF]
+            |[\xF1-\xF3][\x80-\xBF][\x80-\xBF][\x80-\xBF]
+            |[\xF4][\x80-\x8F][\x80-\xBF][\x80-\xBF]
+          )
+        | (.)
+    )/xg)
+    {
+        if (defined $1) {
+            $is_utf8 = 1 if (!defined $is_utf8);
+        }
+        else {
+            $is_utf8 = 0 if (!defined $is_utf8);
+            if ($is_utf8) { # eventually, not utf8
+                return;
+            }
+        }
+    }
+
+    return $is_utf8;
+}
+
+
+sub GT::JSON::PP::incr_parse {
+    local $Carp::CarpLevel = 1;
+    ( $_[0]->{_incr_parser} ||= GT::JSON::PP::IncrParser->new )->incr_parse( @_ );
+}
+
+
+sub GT::JSON::PP::incr_text : lvalue {
+    $_[0]->{_incr_parser} ||= GT::JSON::PP::IncrParser->new;
+
+    if ( $_[0]->{_incr_parser}->{incr_parsing} ) {
+        Carp::croak("incr_text can not be called when the incremental parser already started parsing");
+    }
+    $_[0]->{_incr_parser}->{incr_text};
+}
+
+
+sub GT::JSON::PP::incr_skip {
+    ( $_[0]->{_incr_parser} ||= GT::JSON::PP::IncrParser->new )->incr_skip;
+}
+
+
+sub GT::JSON::PP::incr_reset {
+    ( $_[0]->{_incr_parser} ||= GT::JSON::PP::IncrParser->new )->incr_reset;
+}
+
+
+1;
+__END__
+
+=pod
+
+=head1 NAME
+
+GT::JSON::PP56 - Helper module in using GT::JSON::PP in Perl 5.6
+
+=head1 DESCRIPTION
+
+GT::JSON::PP calls internally.
+
+=head1 AUTHOR
+
+Makamaka Hannyaharamitu, E<lt>makamaka[at]cpan.orgE<gt>
+
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright 2007-2008 by Makamaka Hannyaharamitu
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself. 
+
+=cut
+