| 1 | ###########################################################################
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| 2 | #
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| 3 | # multiread.pm --
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| 4 | #
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| 5 | # Copyright (C) 1999 DigiLib Systems Limited, NZ
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| 6 | # Copyright (C) 2005 New Zealand Digital Library project
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| 7 | #
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| 8 | # This program is free software; you can redistribute it and/or modify
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| 9 | # it under the terms of the GNU General Public License as published by
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| 10 | # the Free Software Foundation; either version 2 of the License, or
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| 11 | # (at your option) any later version.
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| 12 | #
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| 13 | # This program is distributed in the hope that it will be useful,
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| 14 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 15 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 16 | # GNU General Public License for more details.
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| 17 | #
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| 18 | # You should have received a copy of the GNU General Public License
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| 19 | # along with this program; if not, write to the Free Software
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| 20 | # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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| 21 | #
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| 22 | ###########################################################################
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| 23 |
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| 24 | # the multiread object will read in a number of encodings,
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| 25 | # the results are always returned in the utf-8 format
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| 26 |
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| 27 | # encodings currently supported are
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| 28 | #
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| 29 | # utf8 - either utf8 or unicode (automatically detected)
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| 30 | # unicode - 2-byte UCS (does endian detection)
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| 31 | #
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| 32 | # plus all encodings in the "encodings" package
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| 33 |
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| 34 | package multiread;
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| 35 |
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| 36 | eval {require bytes};
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| 37 |
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| 38 | use strict;
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| 39 | use unicode;
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| 40 |
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| 41 | sub new {
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| 42 | my ($class) = @_;
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| 43 |
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| 44 | my $self = {'handle' => "",
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| 45 | 'first' => 1,
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| 46 | 'encoding' => "utf8",
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| 47 | 'bigendian' => 1};
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| 48 |
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| 49 | return bless $self, $class;
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| 50 | }
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| 51 |
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| 52 | # set_handle expects the file to be already open but
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| 53 | # not read yet
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| 54 | sub set_handle {
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| 55 | my $self = shift;
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| 56 | $self->{'handle'} = shift;
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| 57 | binmode( $self->{'handle'} );
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| 58 | $self->{'first'} = 1;
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| 59 | $self->{'encoding'} = "utf8";
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| 60 | $self->{'bigendian'} = 1;
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| 61 | }
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| 62 |
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| 63 | # set_encoding should be called after set_handle
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| 64 | sub set_encoding {
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| 65 | my $self = shift;
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| 66 | $self->{'encoding'} = shift;
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| 67 | }
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| 68 |
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| 69 | sub get_encoding {
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| 70 | my $self = shift (@_);
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| 71 | return $self->{'encoding'};
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| 72 | }
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| 73 |
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| 74 | # undef will be returned if the eof has been reached
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| 75 | # the result will always be returned in utf-8
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| 76 |
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| 77 | sub read_unicode_char {
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| 78 | my $self = shift (@_);
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| 79 |
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| 80 | # make sure we have a file handle
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| 81 | return undef if ($self->{'handle'} eq "");
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| 82 | my $handle = $self->{'handle'};
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| 83 |
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| 84 | if ($self->{'encoding'} eq "utf8") {
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| 85 | # utf-8 text, how many characters we get depends
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| 86 | # on what we find
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| 87 | my $c1 = "";
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| 88 | my $c2 = "";
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| 89 | my $c3 = "";
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| 90 |
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| 91 | while (!eof ($handle)) {
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| 92 | $c1 = ord (getc ($handle));
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| 93 |
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| 94 | if ($c1 <= 0x7f) {
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| 95 | # one byte character
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| 96 | return chr ($c1);
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| 97 |
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| 98 | } elsif ($c1 >= 0xc0 && $c1 <= 0xdf) {
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| 99 | # two byte character
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| 100 | $c2 = getc ($handle) if (!eof ($handle));
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| 101 | return chr ($c1) . $c2;
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| 102 |
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| 103 | } elsif ($c1 >= 0xe0 && $c1 <= 0xef) {
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| 104 | # three byte character
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| 105 | $c2 = getc ($handle) if (!eof ($handle));
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| 106 | $c3 = getc ($handle) if (!eof ($handle));
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| 107 | return chr ($c1) . $c2 . $c3;
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| 108 | }
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| 109 |
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| 110 | # if we get here there was an error in the file, we should
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| 111 | # be able to recover from it however, maybe the file is in
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| 112 | # another encoding
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| 113 | }
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| 114 |
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| 115 | return undef if (eof ($handle));
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| 116 | }
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| 117 |
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| 118 | if ($self->{'encoding'} eq "unicode") {
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| 119 | # unicode text, get the next two characters
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| 120 | return undef if (eof ($handle));
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| 121 | my $c1 = ord (getc ($handle));
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| 122 | return undef if (eof ($handle));
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| 123 | my $c2 = ord (getc ($handle));
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| 124 |
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| 125 | return &unicode::unicode2utf8 ([(($self->{'bigendian'}) ? ($c1*256+$c2) : ($c2*256+$c1))]);
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| 126 | }
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| 127 |
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| 128 | return undef;
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| 129 | }
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| 130 |
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| 131 |
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| 132 | # undef will be returned if the eof has been reached
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| 133 | # the result will always be returned in utf-8
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| 134 | sub read_line {
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| 135 | my $self = shift (@_);
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| 136 |
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| 137 | # make sure we have a file handle
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| 138 | return undef if ($self->{'handle'} eq "");
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| 139 |
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| 140 | my $handle = $self->{'handle'};
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| 141 |
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| 142 | if ($self->{'encoding'} eq "utf8") {
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| 143 | # utf-8 line
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| 144 | return <$handle>;
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| 145 | }
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| 146 |
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| 147 | if ($self->{'encoding'} eq "unicode") {
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| 148 | # unicode line
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| 149 | my $c = "";
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| 150 | my ($c1, $c2) = ("", "");
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| 151 | my $out = "";
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| 152 | while (read ($handle, $c, 2) == 2) {
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| 153 | $c1 = ord (substr ($c, 0, 1));
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| 154 | $c2 = ord (substr ($c, 1, 1));
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| 155 | $c = &unicode::unicode2utf8([(($self->{'bigendian'}) ? ($c1*256+$c2) : ($c2*256+$c1))]);
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| 156 | $out .= $c;
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| 157 | last if ($c eq "\n");
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| 158 | }
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| 159 |
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| 160 | return $out if (length ($out) > 0);
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| 161 | return undef;
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| 162 | }
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| 163 |
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| 164 | if ($self->{'encoding'} eq "iso_8859_1") {
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| 165 | # we'll use ascii2utf8() for this as it's faster than going
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| 166 | # through convert2unicode()
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| 167 | my $line = "";
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| 168 | if (defined ($line = <$handle>)) {
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| 169 | return &unicode::ascii2utf8 (\$line);
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| 170 | }
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| 171 | }
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| 172 |
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| 173 | # everything else uses unicode::convert2unicode
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| 174 | my $line = "";
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| 175 | if (defined ($line = <$handle>)) {
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| 176 | return &unicode::unicode2utf8 (&unicode::convert2unicode ($self->{'encoding'}, \$line));
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| 177 | }
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| 178 |
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| 179 | return undef;
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| 180 | }
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| 181 |
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| 182 |
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| 183 |
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| 184 | # this will look for a Byte Order Marker at the start of the file, and
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| 185 | # set the encoding appropriately if there is one, returning any
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| 186 | # non-marker text on the first line (or returns undef).
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| 187 | sub find_unicode_bom {
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| 188 | my $self=shift;
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| 189 |
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| 190 | my $non_bom_text=""; # to return if we read in 'real' text
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| 191 |
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| 192 | if ($self->{'first'} == 0) { return }
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| 193 |
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| 194 | # make sure we have a file handle
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| 195 | return if ($self->{'handle'} eq "");
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| 196 | my $handle = $self->{'handle'};
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| 197 |
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| 198 | $self->{'first'} = 0;
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| 199 |
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| 200 | my $b1 = ord(getc ($handle));
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| 201 | my $b2;
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| 202 | my $b3;
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| 203 |
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| 204 | if ($b1 == 0xfe || $b1 == 0xff) {
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| 205 | $b2 = ord (getc ($handle)) if (!eof ($handle));
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| 206 | if ($b1 == 0xff && $b2 == 0xfe) {
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| 207 | $self->{'encoding'} = "unicode";
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| 208 | $self->{'bigendian'} = 0;
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| 209 | return;
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| 210 | } elsif ($b1 == 0xfe && $b2 == 0xff) {
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| 211 | $self->{'encoding'} = "unicode";
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| 212 | $self->{'bigendian'} = 1;
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| 213 | return;
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| 214 | } elsif ($b1 == 0xef && $b2 == 0xbb) {
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| 215 | $b3 = ord(getc($handle));
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| 216 | if ($b3 == 0xbf) {
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| 217 | $self->{'encoding'} = "utf8";
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| 218 | $self->{'bigendian'} = 1;
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| 219 | return;
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| 220 | }
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| 221 | }
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| 222 | } else { # $b1 != fe or ff
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| 223 | $handle->ungetc($b1); return;
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| 224 | }
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| 225 | # if here, we have removed some chars and they aren't a BOM
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| 226 | if ($self->{'encoding'} eq "unicode") { # return the 2byte char
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| 227 | if (defined ($b3)) { # we looked at this... return it
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| 228 | $handle->ungetc($b3);
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| 229 | }
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| 230 | return &unicode::unicode2utf8([$self->{'bigendian'}?
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| 231 | ($b1*256+$b2) : ($b2*256+$b1)]);
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| 232 | }
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| 233 | # if here, it's utf-8
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| 234 | if ($b2 < 0x80) {
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| 235 | if (defined ($b3)) { # we grabbed this, but don't need it now
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| 236 | $handle->ungetc($b3);
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| 237 | }
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| 238 | return ($b1 . $b2);
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| 239 | }
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| 240 | # if here, we have taken part of a multi-byte char. we need to make
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| 241 | # sure we return the entire character
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| 242 | if (defined($b3) && $b3 < 0x80) { # we have all we need
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| 243 | $handle->ungetc($b3);
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| 244 | return ($b1 . $b2);
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| 245 | }
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| 246 | my $c=$b1.$b2.$b3;
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| 247 | my $b4=$handle->getc();
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| 248 | while ($b4 > 0x7f) { # note - this will return consecutive mb utf8 chars
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| 249 | $c .= $b4;
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| 250 | $b4=$handle->getc();
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| 251 | if (eof($handle)) { last }
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| 252 | }
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| 253 | if (! eof($handle)) {
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| 254 | $handle->ungetc($b4); # this byte is an ascii byte
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| 255 | }
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| 256 | return $c;
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| 257 | }
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| 258 |
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| 259 |
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| 260 |
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| 261 | # will convert entire contents of file to utf8 and append result to $outputref
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| 262 | # this may be a slightly faster way to get the contents of a file than by
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| 263 | # recursively calling read_line()
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| 264 | sub read_file {
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| 265 | my $self = shift (@_);
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| 266 | my ($outputref) = @_;
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| 267 |
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| 268 | # make sure we have a file handle
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| 269 | return if ($self->{'handle'} eq "");
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| 270 |
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| 271 | my $handle = $self->{'handle'};
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| 272 |
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| 273 | # if encoding is set to utf8 or unicode, sniff to see if there is a
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| 274 | # byte order marker
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| 275 | if ($self->{'first'} &&
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| 276 | ($self->{'encoding'} eq "utf8" || $self->{'encoding'} eq 'unicode')) {
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| 277 | # this will change $self's encoding if there is a BOM
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| 278 | my $read_text = $self->find_unicode_bom();
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| 279 | $$outputref .= $read_text if (defined($read_text));
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| 280 | }
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| 281 |
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| 282 | if ($self->{'encoding'} eq "utf8") {
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| 283 | undef $/;
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| 284 | $$outputref .= <$handle>;
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| 285 | $/ = "\n";
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| 286 | return;
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| 287 | }
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| 288 |
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| 289 | if ($self->{'encoding'} eq "unicode") {
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| 290 | my $line = "";
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| 291 | while (defined ($line = $self->read_line())) {
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| 292 | $$outputref .= $line;
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| 293 | }
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| 294 | return;
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| 295 | }
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| 296 |
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| 297 | if ($self->{'encoding'} eq "iso_8859_1" || $self->{'encoding'} eq "ascii") {
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| 298 | # we'll use ascii2utf8() for this as it's faster than going
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| 299 | # through convert2unicode()
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| 300 | undef $/;
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| 301 | my $text = <$handle>;
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| 302 | $/ = "\n";
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| 303 | $$outputref .= &unicode::ascii2utf8 (\$text);
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| 304 | return;
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| 305 | }
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| 306 |
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| 307 | # everything else uses unicode::convert2unicode
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| 308 | undef $/;
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| 309 | my $text = <$handle>;
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| 310 | $/ = "\n";
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| 311 | $$outputref .= &unicode::unicode2utf8 (&unicode::convert2unicode ($self->{'encoding'}, \$text));
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| 312 | }
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| 313 |
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| 314 | 1;
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