[537] | 1 | ###########################################################################
|
---|
| 2 | #
|
---|
| 3 | # unicode.pm --
|
---|
| 4 | # A component of the Greenstone digital library software
|
---|
| 5 | # from the New Zealand Digital Library Project at the
|
---|
| 6 | # University of Waikato, New Zealand.
|
---|
| 7 | #
|
---|
| 8 | # Copyright (C) 1999 New Zealand Digital Library Project
|
---|
| 9 | #
|
---|
| 10 | # This program is free software; you can redistribute it and/or modify
|
---|
| 11 | # it under the terms of the GNU General Public License as published by
|
---|
| 12 | # the Free Software Foundation; either version 2 of the License, or
|
---|
| 13 | # (at your option) any later version.
|
---|
| 14 | #
|
---|
| 15 | # This program is distributed in the hope that it will be useful,
|
---|
| 16 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
|
---|
| 17 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
---|
| 18 | # GNU General Public License for more details.
|
---|
| 19 | #
|
---|
| 20 | # You should have received a copy of the GNU General Public License
|
---|
| 21 | # along with this program; if not, write to the Free Software
|
---|
| 22 | # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
---|
| 23 | #
|
---|
| 24 | ###########################################################################
|
---|
| 25 |
|
---|
[71] | 26 | # useful functions for dealing with Unicode
|
---|
| 27 |
|
---|
| 28 | # Unicode strings are stored as arrays of scalars as perl
|
---|
| 29 | # lacks characters are 8-bit (currently)
|
---|
| 30 |
|
---|
| 31 | package unicode;
|
---|
| 32 |
|
---|
| 33 |
|
---|
[73] | 34 |
|
---|
| 35 | # ascii2unicode takes a (extended) ascii string and
|
---|
| 36 | # returns a unicode array.
|
---|
| 37 | sub ascii2unicode {
|
---|
| 38 | my ($in) = @_;
|
---|
| 39 | my $out = [];
|
---|
| 40 |
|
---|
| 41 | my $i = 0;
|
---|
| 42 | my $len = length($in);
|
---|
| 43 | while ($i < $len) {
|
---|
| 44 | push (@$out, ord(substr ($in, $i, 1)));
|
---|
| 45 | $i++;
|
---|
| 46 | }
|
---|
| 47 |
|
---|
| 48 | return $out;
|
---|
| 49 | }
|
---|
| 50 |
|
---|
| 51 |
|
---|
| 52 | # ascii2utf8 takes a (extended) ascii string and
|
---|
| 53 | # returns a UTF-8 encoded string. This is just
|
---|
| 54 | # a faster version of "&unicode2utf8(&ascii2unicode($str));"
|
---|
| 55 | sub ascii2utf8 {
|
---|
| 56 | my ($in) = @_;
|
---|
| 57 | my $out = "";
|
---|
| 58 |
|
---|
| 59 | my ($c);
|
---|
| 60 | my $i = 0;
|
---|
| 61 | my $len = length($in);
|
---|
| 62 | while ($i < $len) {
|
---|
| 63 | $c = ord (substr ($in, $i, 1));
|
---|
| 64 | if ($c < 0x80) {
|
---|
| 65 | # ascii character
|
---|
| 66 | $out .= chr ($c);
|
---|
| 67 |
|
---|
| 68 | } else {
|
---|
| 69 | # extended ascii character
|
---|
| 70 | $out .= chr (0xc0 + (($c >> 6) & 0x1f));
|
---|
| 71 | $out .= chr (0x80 + ($c & 0x3f));
|
---|
| 72 | }
|
---|
| 73 | $i++;
|
---|
| 74 | }
|
---|
| 75 |
|
---|
| 76 | return $out;
|
---|
| 77 | }
|
---|
| 78 |
|
---|
| 79 |
|
---|
[71] | 80 | # unicode2utf8 takes a unicode array as input and encodes it
|
---|
| 81 | # using utf-8
|
---|
| 82 | sub unicode2utf8 {
|
---|
| 83 | my ($in) = @_;
|
---|
| 84 | my $out = "";
|
---|
| 85 |
|
---|
| 86 | foreach $num (@$in) {
|
---|
| 87 | if ($num < 0x80) {
|
---|
| 88 | $out .= chr ($num);
|
---|
| 89 |
|
---|
| 90 | } elsif ($num < 0x800) {
|
---|
| 91 | $out .= chr (0xc0 + (($num >> 6) & 0x1f));
|
---|
| 92 | $out .= chr (0x80 + ($num & 0x3f));
|
---|
| 93 |
|
---|
| 94 | } elsif ($num < 0xFFFF) {
|
---|
| 95 | $out .= chr (0xe0 + (($num >> 12) & 0xf));
|
---|
| 96 | $out .= chr (0x80 + (($num >> 6) & 0x3f));
|
---|
| 97 | $out .= chr (0x80 + ($num & 0x3f));
|
---|
| 98 |
|
---|
| 99 | } else {
|
---|
| 100 | # error, don't encode anything
|
---|
| 101 | die;
|
---|
| 102 | }
|
---|
| 103 | }
|
---|
| 104 |
|
---|
| 105 | return $out;
|
---|
| 106 | }
|
---|
| 107 |
|
---|
| 108 |
|
---|
| 109 | # utf82unicode takes a utf-8 string and produces a unicode
|
---|
| 110 | # array
|
---|
| 111 | sub utf82unicode {
|
---|
| 112 | my ($in) = @_;
|
---|
| 113 | my $out = [];
|
---|
| 114 |
|
---|
| 115 | my $i = 0;
|
---|
| 116 | my ($c1, $c2, $c3);
|
---|
| 117 | $len = length($in);
|
---|
| 118 | while ($i < $len) {
|
---|
| 119 | if (($c1 = ord(substr ($in, $i, 1))) < 0x80) {
|
---|
| 120 | # normal ascii character
|
---|
| 121 | push (@$out, $c1);
|
---|
| 122 |
|
---|
| 123 | } elsif ($c1 < 0xc0) {
|
---|
| 124 | # error, was expecting the first byte of an
|
---|
| 125 | # encoded character. Do nothing.
|
---|
| 126 |
|
---|
| 127 | } elsif ($c1 < 0xe0 && $i+1 < $len) {
|
---|
| 128 | # an encoded character with two bytes
|
---|
| 129 | $c2 = ord (substr ($in, $i+1, 1));
|
---|
| 130 | if ($c2 >= 0x80 && $c2 < 0xc0) {
|
---|
| 131 | # everything looks ok
|
---|
| 132 | push (@$out, ((($c1 & 0x1f) << 6) +
|
---|
| 133 | ($c2 & 0x3f)));
|
---|
| 134 | $i++; # gobbled an extra byte
|
---|
| 135 | }
|
---|
| 136 |
|
---|
| 137 | } elsif ($c1 < 0xf0 && $i+2 < $len) {
|
---|
| 138 | # an encoded character with three bytes
|
---|
| 139 | $c2 = ord (substr ($in, $i+1, 1));
|
---|
| 140 | $c3 = ord (substr ($in, $i+2, 1));
|
---|
| 141 | if ($c2 >= 0x80 && $c2 < 0xc0 &&
|
---|
| 142 | $c3 >= 0x80 && $c3 < 0xc0) {
|
---|
| 143 | # everything looks ok
|
---|
| 144 | push (@$out, ((($c1 & 0xf) << 12) +
|
---|
| 145 | (($c2 & 0x3f) << 6) +
|
---|
| 146 | ($c3 & 0x3f)));
|
---|
| 147 |
|
---|
| 148 | $i += 2; # gobbled an extra two bytes
|
---|
| 149 | }
|
---|
| 150 |
|
---|
| 151 | } else {
|
---|
| 152 | # error, only decode Unicode characters not full UCS.
|
---|
| 153 | # Do nothing.
|
---|
| 154 | }
|
---|
| 155 |
|
---|
| 156 | $i++;
|
---|
| 157 | }
|
---|
| 158 |
|
---|
| 159 | return $out;
|
---|
| 160 | }
|
---|
| 161 |
|
---|
| 162 |
|
---|
| 163 | # unicode2ucs2 takes a unicode array and produces a UCS-2
|
---|
| 164 | # unicode string (every two bytes forms a unicode character)
|
---|
| 165 | sub unicode2ucs2 {
|
---|
| 166 | my ($in) = @_;
|
---|
| 167 | my $out = "";
|
---|
| 168 |
|
---|
| 169 | foreach $num (@$in) {
|
---|
| 170 | $out .= chr (($num & 0xff00) >> 8);
|
---|
| 171 | $out .= chr ($num & 0xff);
|
---|
| 172 | }
|
---|
| 173 |
|
---|
| 174 | return $out;
|
---|
| 175 | }
|
---|
| 176 |
|
---|
| 177 |
|
---|
| 178 | # ucs22unicode takes a UCS-2 string and produces a unicode array
|
---|
| 179 | sub ucs22unicode {
|
---|
| 180 | my ($in) = @_;
|
---|
| 181 | my $out = [];
|
---|
| 182 |
|
---|
| 183 | my $i = 0;
|
---|
| 184 | my $len = length ($in);
|
---|
| 185 | while ($i+1 < $len) {
|
---|
| 186 | push (@$out, ord (substr($in, $i, 1)) << 8 +
|
---|
| 187 | ord (substr($in, $i+1, 1)));
|
---|
| 188 |
|
---|
| 189 | $i ++;
|
---|
| 190 | }
|
---|
| 191 |
|
---|
| 192 | return $out;
|
---|
| 193 | }
|
---|
| 194 |
|
---|
| 195 |
|
---|
| 196 | 1;
|
---|
| 197 |
|
---|