1 | ###########################################################################
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2 | #
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3 | # unicode.pm --
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4 | # A component of the Greenstone digital library software
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5 | # from the New Zealand Digital Library Project at the
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6 | # University of Waikato, New Zealand.
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7 | #
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8 | # Copyright (C) 1999-2004 New Zealand Digital Library Project
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9 | #
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10 | # This program is free software; you can redistribute it and/or modify
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11 | # it under the terms of the GNU General Public License as published by
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12 | # the Free Software Foundation; either version 2 of the License, or
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13 | # (at your option) any later version.
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14 | #
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15 | # This program is distributed in the hope that it will be useful,
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16 | # but WITHOUT ANY WARRANTY; without even the implied warranty of
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17 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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18 | # GNU General Public License for more details.
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19 | #
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20 | # You should have received a copy of the GNU General Public License
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21 | # along with this program; if not, write to the Free Software
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22 | # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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23 | #
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24 | ###########################################################################
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25 |
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26 | # useful functions for dealing with Unicode
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27 |
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28 | # Unicode strings are stored as arrays of scalars as perl
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29 | # lacks characters are 8-bit (currently)
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30 |
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31 | package unicode;
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32 |
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33 | eval {require bytes};
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34 |
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35 | use encodings;
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36 | use strict;
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37 | use util;
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38 | use MIME::Base64; # for base64 encoding
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39 |
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40 | no strict 'refs';
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41 |
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42 | # ascii2unicode takes an (extended) ascii string (ISO-8859-1)
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43 | # and returns a unicode array.
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44 | sub ascii2unicode {
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45 | my ($in) = @_;
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46 | my $out = [];
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47 |
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48 | my $i = 0;
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49 | my $len = length($in);
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50 | while ($i < $len) {
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51 | push (@$out, ord(substr ($in, $i, 1)));
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52 | $i++;
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53 | }
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54 |
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55 | return $out;
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56 | }
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57 |
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58 | # ascii2utf8 takes a reference to an (extended) ascii string and returns a
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59 | # UTF-8 encoded string. This is just a faster version of
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60 | # "&unicode2utf8(&ascii2unicode($str));"
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61 | # "Extended ascii" really means "iso_8859_1"
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62 | sub ascii2utf8 {
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63 | my ($in) = @_;
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64 | my $out = "";
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65 |
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66 | if (!defined($in)|| !defined($$in)) {
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67 | return $out;
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68 | }
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69 |
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70 | my ($c);
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71 | my $i = 0;
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72 | my $len = length($$in);
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73 | while ($i < $len) {
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74 | $c = ord (substr ($$in, $i, 1));
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75 | if ($c < 0x80) {
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76 | # ascii character
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77 | $out .= chr ($c);
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78 |
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79 | } else {
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80 | # extended ascii character
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81 | $out .= chr (0xc0 + (($c >> 6) & 0x1f));
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82 | $out .= chr (0x80 + ($c & 0x3f));
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83 | }
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84 | $i++;
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85 | }
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86 |
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87 | return $out;
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88 | }
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89 |
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90 | # unicode2utf8 takes a unicode array as input and encodes it
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91 | # using utf-8
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92 | sub unicode2utf8 {
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93 | my ($in) = @_;
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94 | my $out = "";
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95 |
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96 | foreach my $num (@$in) {
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97 | next unless defined $num;
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98 | if ($num < 0x80) {
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99 | $out .= chr ($num);
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100 |
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101 | } elsif ($num < 0x800) {
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102 | $out .= chr (0xc0 + (($num >> 6) & 0x1f));
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103 | $out .= chr (0x80 + ($num & 0x3f));
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104 |
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105 | } elsif ($num < 0xFFFF) {
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106 | $out .= chr (0xe0 + (($num >> 12) & 0xf));
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107 | $out .= chr (0x80 + (($num >> 6) & 0x3f));
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108 | $out .= chr (0x80 + ($num & 0x3f));
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109 |
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110 | } else {
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111 | # error, don't encode anything
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112 | die;
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113 | }
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114 | }
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115 | return $out;
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116 | }
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117 |
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118 | # utf82unicode takes a utf-8 string and produces a unicode
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119 | # array
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120 | sub utf82unicode {
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121 | my ($in) = @_;
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122 | my $out = [];
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123 |
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124 | my $i = 0;
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125 | my ($c1, $c2, $c3);
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126 | my $len = length($in);
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127 | while ($i < $len) {
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128 | if (($c1 = ord(substr ($in, $i, 1))) < 0x80) {
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129 | # normal ascii character
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130 | push (@$out, $c1);
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131 |
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132 | } elsif ($c1 < 0xc0) {
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133 | # error, was expecting the first byte of an
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134 | # encoded character. Do nothing.
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135 |
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136 | } elsif ($c1 < 0xe0 && $i+1 < $len) {
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137 | # an encoded character with two bytes
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138 | $c2 = ord (substr ($in, $i+1, 1));
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139 | if ($c2 >= 0x80 && $c2 < 0xc0) {
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140 | # everything looks ok
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141 | push (@$out, ((($c1 & 0x1f) << 6) +
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142 | ($c2 & 0x3f)));
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143 | $i++; # gobbled an extra byte
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144 | }
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145 |
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146 | } elsif ($c1 < 0xf0 && $i+2 < $len) {
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147 | # an encoded character with three bytes
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148 | $c2 = ord (substr ($in, $i+1, 1));
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149 | $c3 = ord (substr ($in, $i+2, 1));
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150 | if ($c2 >= 0x80 && $c2 < 0xc0 &&
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151 | $c3 >= 0x80 && $c3 < 0xc0) {
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152 | # everything looks ok
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153 | push (@$out, ((($c1 & 0xf) << 12) +
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154 | (($c2 & 0x3f) << 6) +
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155 | ($c3 & 0x3f)));
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156 |
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157 | $i += 2; # gobbled an extra two bytes
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158 | }
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159 |
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160 | } else {
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161 | # error, only decode Unicode characters not full UCS.
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162 | # Do nothing.
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163 | }
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164 |
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165 | $i++;
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166 | }
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167 |
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168 | return $out;
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169 | }
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170 |
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171 | # unicode2ucs2 takes a unicode array and produces a UCS-2
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172 | # unicode string (every two bytes forms a unicode character)
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173 | sub unicode2ucs2 {
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174 | my ($in) = @_;
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175 | my $out = "";
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176 |
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177 | foreach my $num (@$in) {
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178 | $out .= chr (($num & 0xff00) >> 8);
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179 | $out .= chr ($num & 0xff);
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180 | }
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181 |
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182 | return $out;
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183 | }
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184 |
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185 | # ucs22unicode takes a UCS-2 string and produces a unicode array
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186 | sub ucs22unicode {
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187 | my ($in) = @_;
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188 | my $out = [];
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189 |
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190 | my $i = 0;
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191 | my $len = length ($in);
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192 | while ($i+1 < $len) {
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193 | push (@$out, ord (substr($in, $i, 1)) << 8 +
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194 | ord (substr($in, $i+1, 1)));
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195 |
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196 | $i ++;
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197 | }
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198 |
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199 | return $out;
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200 | }
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201 |
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202 | # takes a reference to a string and returns a reference to a unicode array
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203 | sub convert2unicode {
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204 | my ($encoding, $textref) = @_;
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205 |
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206 | if (!defined $encodings::encodings->{$encoding}) {
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207 | print STDERR "unicode::convert2unicode: ERROR: Unsupported encoding ($encoding)\n";
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208 | return [];
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209 | }
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210 |
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211 | my $encodename = "$encoding-unicode";
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212 | my $enc_info = $encodings::encodings->{$encoding};
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213 | my $mapfile = &util::filename_cat($ENV{'GSDLHOME'}, "mappings",
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214 | "to_uc", $enc_info->{'mapfile'});
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215 | if (!&loadmapencoding ($encodename, $mapfile)) {
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216 | print STDERR "unicode: ERROR - could not load encoding $encodename: $! $mapfile\n";
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217 | return [];
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218 | }
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219 |
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220 | if (defined $enc_info->{'converter'}) {
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221 | my $converter = $enc_info->{'converter'};
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222 | return &$converter ($encodename, $textref);
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223 | }
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224 |
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225 | if ($unicode::translations{$encodename}->{'count'} == 1) {
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226 | return &singlebyte2unicode ($encodename, $textref);
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227 | } else {
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228 | return &doublebyte2unicode ($encodename, $textref);
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229 | }
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230 | }
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231 |
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232 | # singlebyte2unicode converts simple 8 bit encodings where characters below
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233 | # 0x80 are normal ascii characters and the rest are decoded using the
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234 | # appropriate mapping files.
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235 | #
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236 | # Examples of encodings that may be converted using singlebyte2unicode are
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237 | # the iso-8859 and windows-125* series.
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238 | sub singlebyte2unicode {
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239 | my ($encodename, $textref) = @_;
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240 |
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241 | my @outtext = ();
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242 | my $len = length($$textref);
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243 | my ($c);
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244 | my $i = 0;
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245 |
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246 | while ($i < $len) {
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247 | if (($c = ord(substr($$textref, $i, 1))) < 0x80) {
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248 | # normal ascii character
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249 | push (@outtext, $c);
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250 | } else {
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251 | $c = &transchar ($encodename, $c);
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252 | # put a black square if cannot translate
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253 | $c = 0x25A1 if $c == 0;
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254 | push (@outtext, $c);
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255 | }
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256 | $i ++;
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257 | }
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258 | return \@outtext;
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259 | }
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260 |
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261 | # doublebyte2unicode converts simple two byte encodings where characters
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262 | # below code point 0x80 are single-byte characters and the rest are
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263 | # double-byte characters.
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264 | #
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265 | # Examples of encodings that may be converted using doublebyte2unicode are
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266 | # CJK encodings like GB encoded Chinese and UHC Korean.
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267 | #
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268 | # Note that no error checking is performed to make sure that the input text
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269 | # is valid for the given encoding.
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270 | #
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271 | # Also, encodings that may contain characters of more than two bytes are
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272 | # not supported (any EUC encoded text may in theory contain 3-byte
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273 | # characters but in practice only one and two byte characters are used).
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274 | sub doublebyte2unicode {
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275 | my ($encodename, $textref) = @_;
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276 |
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277 | my @outtext = ();
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278 | my $len = length($$textref);
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279 | my ($c1, $c2);
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280 | my $i = 0;
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281 |
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282 | while ($i < $len) {
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283 | if (($c1 = ord(substr($$textref, $i, 1))) >= 0x80) {
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284 | if ($i+1 < $len) {
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285 | # double-byte character
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286 | $c2 = ord(substr($$textref, $i+1, 1));
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287 | my $c = &transchar ($encodename, ($c1 << 8) | $c2);
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288 | # put a black square if cannot translate
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289 | $c = 0x25A1 if $c == 0;
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290 | push (@outtext, $c);
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291 | $i += 2;
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292 |
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293 | } else {
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294 | # error
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295 | print STDERR "unicode: ERROR missing second half of double-byte character\n";
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296 | $i++;
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297 | }
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298 |
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299 | } else {
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300 | # single-byte character
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301 | push (@outtext, $c1);
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302 | $i++;
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303 | }
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304 | }
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305 | return \@outtext;
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306 | }
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307 |
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308 | # Shift-JIS to unicode
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309 | # We can't use doublebyte2unicode for Shift-JIS because it uses some
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310 | # single-byte characters above code point 0x80 (i.e. half-width katakana
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311 | # characters in the range 0xA1-0xDF)
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312 | sub shiftjis2unicode {
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313 | my ($encodename, $textref) = @_;
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314 |
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315 | my @outtext = ();
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316 | my $len = length($$textref);
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317 | my ($c1, $c2);
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318 | my $i = 0;
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319 |
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320 | while ($i < $len) {
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321 | $c1 = ord(substr($$textref, $i, 1));
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322 |
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323 | if (($c1 >= 0xA1 && $c1 <= 0xDF) || $c1 == 0x5c || $c1 == 0x7E) {
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324 | # Single-byte half-width katakana character or
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325 | # JIS Roman yen or overline characters
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326 | my $c = &transchar ($encodename, $c1);
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327 | # - put a black square if cannot translate
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328 | $c = 0x25A1 if $c == 0;
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329 | push (@outtext, $c);
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330 | $i++;
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331 |
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332 | } elsif ($c1 < 0x80) {
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333 | # ASCII
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334 | push (@outtext, $c1);
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335 | $i ++;
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336 |
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337 | } elsif ($c1 < 0xEF) {
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338 | if ($i+1 < $len) {
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339 | $c2 = ord(substr($$textref, $i+1, 1));
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340 | if (($c2 >= 0x40 && $c2 <= 0x7E) || ($c2 >= 0x80 && $c2 <= 0xFC)) {
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341 | # Double-byte shift-jis character
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342 | my $c = &transchar ($encodename, ($c1 << 8) | $c2);
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343 | # put a black square if cannot translate
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344 | $c = 0x25A1 if $c == 0;
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345 | push (@outtext, $c);
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346 | } else {
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347 | # error
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348 | print STDERR "unicode: ERROR Invalid Shift-JIS character\n";
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349 | }
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350 | $i += 2;
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351 | } else {
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352 | # error
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353 | print STDERR "unicode: ERROR missing second half of Shift-JIS character\n";
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354 | $i ++;
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355 | }
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356 | } else {
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357 | # error
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358 | print STDERR "unicode: ERROR Invalid Shift-JIS character\n";
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359 | $i ++;
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360 | }
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361 | }
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362 | return \@outtext;
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363 | }
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364 |
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365 | sub transchar {
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366 | my ($encoding, $from) = @_;
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367 | my $high = ($from / 256) % 256;
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368 | my $low = $from % 256;
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369 |
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370 | return 0 unless defined $unicode::translations{$encoding};
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371 |
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372 | my $block = $unicode::translations{$encoding}->{'map'};
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373 |
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374 | if (ref ($block->[$high]) ne "ARRAY") {
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375 | return 0;
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376 | }
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377 | return $block->[$high]->[$low];
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378 | }
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379 |
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380 | # %translations is of the form:
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381 | #
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382 | # encodings{encodingname-encodingname}->{'map'}->blocktranslation
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383 | # blocktranslation->[[0-255],[256-511], ..., [65280-65535]]
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384 | #
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385 | # Any of the top translation blocks can point to an undefined
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386 | # value. This data structure aims to allow fast translation and
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387 | # efficient storage.
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388 | %unicode::translations = ();
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389 |
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390 | # @array256 is used for initialisation, there must be
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391 | # a better way...
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392 | # What about this?: @array256 = (0) x 256;
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393 | @unicode::array256 = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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394 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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395 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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396 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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397 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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398 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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399 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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400 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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401 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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402 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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403 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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404 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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405 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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406 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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407 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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408 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0);
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409 |
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410 | # returns 1 if successful, 0 if unsuccessful
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411 | sub loadmapencoding {
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412 | my ($encoding, $mapfile) = @_;
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413 |
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414 | # check to see if the encoding has already been loaded
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415 | return 1 if (defined $unicode::translations{$encoding});
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416 |
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417 | if (! -r $mapfile || -d $mapfile) {
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418 | return 0;
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419 | }
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420 | return 0 unless open (MAPFILE, $mapfile);
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421 | binmode (MAPFILE);
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422 |
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423 | $unicode::translations{$encoding} = {'map' => [@unicode::array256], 'count' => 0};
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424 | my $block = $unicode::translations{$encoding};
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425 |
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426 | my ($in,$i,$j);
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427 | while (1) {
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428 | my $ret=read(MAPFILE, $in, 1);
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429 | if (!defined($ret)) { # error
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430 | print STDERR "unicode.pm: error reading mapfile: $!\n";
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431 | last;
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432 | }
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433 | if ($ret != 1) { last }
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434 | $i = unpack ("C", $in);
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435 | $block->{'map'}->[$i] = [@unicode::array256];
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436 | for ($j=0; $j<256 && read(MAPFILE, $in, 2)==2; $j++) {
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437 | my ($n1, $n2) = unpack ("CC", $in);
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438 | $block->{'map'}->[$i]->[$j] = ($n1*256) + $n2;
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439 | }
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440 | $block->{'count'} ++;
|
---|
441 | }
|
---|
442 |
|
---|
443 | close (MAPFILE);
|
---|
444 | }
|
---|
445 |
|
---|
446 | # unicode2singlebyte converts unicode to simple 8 bit encodings where
|
---|
447 | # characters below 0x80 are normal ascii characters and the rest are encoded
|
---|
448 | # using the appropriate mapping files.
|
---|
449 | #
|
---|
450 | # Examples of encodings that may be converted using unicode2singlebyte are
|
---|
451 | # the iso-8859 and windows-125* series, KOI8-R (Russian), and the Kazakh encoding.
|
---|
452 | sub unicode2singlebyte {
|
---|
453 | my ($uniref, $encoding) = @_;
|
---|
454 |
|
---|
455 | my $outtext = "";
|
---|
456 | my $encodename = "unicode-$encoding";
|
---|
457 |
|
---|
458 | if (!exists $encodings::encodings->{$encoding}) {
|
---|
459 | print STDERR "unicode.pm: ERROR - unsupported encoding "
|
---|
460 | . "'$encoding' requested\n";
|
---|
461 | return "";
|
---|
462 | }
|
---|
463 |
|
---|
464 | my $enc_info = $encodings::encodings->{$encoding};
|
---|
465 | my $mapfile = &util::filename_cat($ENV{'GSDLHOME'}, "mappings",
|
---|
466 | "from_uc", $enc_info->{'mapfile'});
|
---|
467 | if (!&loadmapencoding ($encodename, $mapfile)) {
|
---|
468 | print STDERR "unicode: ERROR - could not load encoding $encodename: $! $mapfile\n";
|
---|
469 | return "";
|
---|
470 | }
|
---|
471 |
|
---|
472 | foreach my $c (@$uniref) {
|
---|
473 | if ($c < 0x80) {
|
---|
474 | # normal ascii character
|
---|
475 | $outtext .= chr($c);
|
---|
476 | } else {
|
---|
477 | # extended ascii character
|
---|
478 | $c = &transchar ($encodename, $c);
|
---|
479 |
|
---|
480 | # put a question mark if cannot translate
|
---|
481 | if ($c == 0) {
|
---|
482 | $outtext .= "?";
|
---|
483 | } else {
|
---|
484 | $outtext .= chr($c);
|
---|
485 | }
|
---|
486 | }
|
---|
487 | }
|
---|
488 | return $outtext;
|
---|
489 | }
|
---|
490 |
|
---|
491 |
|
---|
492 | # this makes sure that the referenced input string is utf8 encoded, and
|
---|
493 | # will change/remove bytes that aren't.
|
---|
494 | # returns 0 if the text was already utf8, or 1 if text modified to become utf8
|
---|
495 | sub ensure_utf8 {
|
---|
496 | my $stringref=shift;
|
---|
497 |
|
---|
498 | if (!defined($stringref) || ref($stringref) ne 'SCALAR') {
|
---|
499 | return $stringref;
|
---|
500 | }
|
---|
501 |
|
---|
502 | my $value=$$stringref;
|
---|
503 |
|
---|
504 | my $non_utf8_found = 0;
|
---|
505 | $value =~ m/^/g; # to set \G
|
---|
506 | while ($value =~ m!\G.*?([\x80-\xff]+)!sg) {
|
---|
507 | my $highbytes=$1;
|
---|
508 | my $highbyteslength=length($highbytes);
|
---|
509 | # make sure this block of high bytes is utf-8
|
---|
510 | $highbytes =~ /^/g; # set pos()
|
---|
511 | my $byte_replaced = 0;
|
---|
512 | while ($highbytes =~
|
---|
513 | m!\G (?: [\xc0-\xdf][\x80-\xbf] | # 2 byte utf-8
|
---|
514 | [\xe0-\xef][\x80-\xbf]{2} | # 3 byte
|
---|
515 | [\xf0-\xf7][\x80-\xbf]{3} | # 4 byte
|
---|
516 | [\xf8-\xfb][\x80-\xbf]{4} | # 5 byte
|
---|
517 | [\xfc-\xfd][\x80-\xbf]{5} | # 6 byte
|
---|
518 | )*([\x80-\xff])? !xg
|
---|
519 | ) {
|
---|
520 | # this highbyte is "out-of-place" for valid utf-8
|
---|
521 | my $badbyte=$1;
|
---|
522 | if (!defined $badbyte) {next} # hit end of string
|
---|
523 | my $pos=pos($highbytes);
|
---|
524 | # replace bad byte. assume iso-8859-1 -> utf-8
|
---|
525 | # ascii2utf8 does "extended ascii"... ie iso-8859-1
|
---|
526 | my $replacement=&unicode::ascii2utf8(\$badbyte);
|
---|
527 | substr($highbytes, $pos-1, 1, $replacement);
|
---|
528 | # update the position to continue searching (for \G)
|
---|
529 | pos($highbytes) = $pos+length($replacement)-1;
|
---|
530 | $byte_replaced = 1;
|
---|
531 | }
|
---|
532 | if ($byte_replaced) {
|
---|
533 | # replace this block of high bytes in the $value
|
---|
534 | $non_utf8_found = 1;
|
---|
535 | my $replength=length($highbytes); # we've changed the length
|
---|
536 | my $textpos=pos($value); # pos at end of last match
|
---|
537 | # replace bad bytes with good bytes
|
---|
538 | substr($value, $textpos-$highbyteslength,
|
---|
539 | $highbyteslength, $highbytes);
|
---|
540 | # update the position to continue searching (for \G)
|
---|
541 | pos($value)=$textpos+($replength-$highbyteslength)+1;
|
---|
542 | }
|
---|
543 | }
|
---|
544 |
|
---|
545 | $$stringref = $value;
|
---|
546 | return $non_utf8_found;
|
---|
547 | }
|
---|
548 |
|
---|
549 | # Returns true (1) if the given string is utf8 and false (0) if it isn't.
|
---|
550 | # Does not modify the string parameter.
|
---|
551 | sub check_is_utf8 {
|
---|
552 | my $value=shift;
|
---|
553 |
|
---|
554 | if (!defined($value)) {
|
---|
555 | return 0; # not utf8 because it is undefined
|
---|
556 | }
|
---|
557 |
|
---|
558 | $value =~ m/^/g; # to set \G
|
---|
559 | while ($value =~ m!\G.*?([\x80-\xff]+)!sg) {
|
---|
560 | my $highbytes=$1;
|
---|
561 | # make sure this block of high bytes is utf-8
|
---|
562 | $highbytes =~ /^/g; # set pos()
|
---|
563 | while ($highbytes =~
|
---|
564 | m!\G (?: [\xc0-\xdf][\x80-\xbf] | # 2 byte utf-8
|
---|
565 | [\xe0-\xef][\x80-\xbf]{2} | # 3 byte
|
---|
566 | [\xf0-\xf7][\x80-\xbf]{3} | # 4 byte
|
---|
567 | [\xf8-\xfb][\x80-\xbf]{4} | # 5 byte
|
---|
568 | [\xfc-\xfd][\x80-\xbf]{5} | # 6 byte
|
---|
569 | )*([\x80-\xff])? !xg
|
---|
570 | ) {
|
---|
571 | my $badbyte=$1;
|
---|
572 | if (defined $badbyte) { # not end of string
|
---|
573 | return 0; # non-utf8 found
|
---|
574 | }
|
---|
575 | }
|
---|
576 | }
|
---|
577 |
|
---|
578 | return 1;
|
---|
579 | }
|
---|
580 |
|
---|
581 | sub url_encode {
|
---|
582 | my ($text) = @_;
|
---|
583 |
|
---|
584 | if (!&is_url_encoded($text)) {
|
---|
585 | $text =~ s/([^A-Z0-9\ \.\-\_])/sprintf("%%%02X", ord($1))/iseg;
|
---|
586 | # return the url-encoded character entity for underscore back to the entity
|
---|
587 | $text =~ s/%26%23095%3B/&\#095;/g;
|
---|
588 | }
|
---|
589 | return $text;
|
---|
590 | }
|
---|
591 |
|
---|
592 | sub url_decode {
|
---|
593 | my ($text) = @_;
|
---|
594 |
|
---|
595 | $text =~ s/\%([A-F0-9]{2})/pack('C', hex($1))/ige;
|
---|
596 | return $text;
|
---|
597 | }
|
---|
598 |
|
---|
599 | sub is_url_encoded {
|
---|
600 | my ($text) = @_;
|
---|
601 | return ($text =~ m/\%([A-F0-9]{2})/);
|
---|
602 | }
|
---|
603 |
|
---|
604 | # When a filename on the filesystem is already URL-encoded, the
|
---|
605 | # URL to it will have %25s in place of every % sign, so that
|
---|
606 | # URLs in html pages can refer to the URL-encoded filename.
|
---|
607 | # This method changes the URL reference back into the actual
|
---|
608 | # (URL-encoded) filename on the filesystem by replacing %25 with %.
|
---|
609 | sub url_to_filename {
|
---|
610 | my ($text) =@_;
|
---|
611 | $text =~ s/%25/%/g if &is_url_encoded($text);
|
---|
612 | # DM safing would have replaced underscores with character entity _
|
---|
613 | # in SourceFile meta. Undo any such change to get the filename referred to.
|
---|
614 | $text =~ s/&\#095;/_/g;
|
---|
615 | return $text;
|
---|
616 | }
|
---|
617 |
|
---|
618 | # When a filename on the filesystem is already URL-encoded, the
|
---|
619 | # URL to it will have %25s in place of every % sign, so that
|
---|
620 | # URLs in html pages can refer to the URL-encoded filename.
|
---|
621 | # Given a (URL-encoded) filename on the filesystem, this subroutine
|
---|
622 | # returns the URL reference string for it by replacing % with %25.
|
---|
623 | # The output string will be the same as the input string if the input
|
---|
624 | # already contains one or more %25s. This is to prevent processing
|
---|
625 | # a url more than once this way.
|
---|
626 | sub filename_to_url {
|
---|
627 | my ($text) = @_;
|
---|
628 |
|
---|
629 | if($text !~ m/%25/) {
|
---|
630 | $text =~ s/%/%25/g;
|
---|
631 | }
|
---|
632 | return $text;
|
---|
633 | }
|
---|
634 |
|
---|
635 | sub base64_encode {
|
---|
636 | my ($text) = @_;
|
---|
637 | if(!&conforms_to_mod_base64($text)) {
|
---|
638 | # return entity for underscore to underscore before encoding
|
---|
639 | $text =~ s/&\#095;/_/g;
|
---|
640 |
|
---|
641 | $text = &MIME::Base64::encode_base64($text);
|
---|
642 | # base64 encoding may introduce + and / signs,
|
---|
643 | # replacing them with - and _ to ensure it's filename-safe
|
---|
644 | $text =~ s/\+/\-/g; # + -> -
|
---|
645 | $text =~ s/\//\_/g; # / -> _
|
---|
646 | }
|
---|
647 | return $text;
|
---|
648 | }
|
---|
649 |
|
---|
650 | # If the input fits the modified base64 pattern, this will try decoding it.
|
---|
651 | # Still, this method does not guarantee the return value is the 'original', only
|
---|
652 | # that the result is where the base64 decoding process has been applied once.
|
---|
653 | # THIS METHOD IS NOT USED at the moment. It's here for convenience and symmetry.
|
---|
654 | sub base64_decode {
|
---|
655 | my ($text) = @_;
|
---|
656 | if(&conforms_to_mod_base64($text)) {
|
---|
657 | # base64 encodes certain chars with + and /, but if we'd encoded it, we'd
|
---|
658 | # have replaced them with - and _ respectively. Undo this before decoding.
|
---|
659 | $text =~ s/\-/\+/g; # - -> +
|
---|
660 | $text =~ s/\_/\//g; # _ -> /
|
---|
661 | $text = &MIME::Base64::decode_base64($text);
|
---|
662 | }
|
---|
663 | return $text;
|
---|
664 | }
|
---|
665 |
|
---|
666 | # Returns true if the given string is compatible with a modified version
|
---|
667 | # of base64 (where the + and / are replaced with - and _), a format which
|
---|
668 | # includes also regular ASCII alphanumeric values. This method does not
|
---|
669 | # guarantee that the given string is actually base64 encoded, since it will
|
---|
670 | # return true for any simple alphanumeric ASCII string as well.
|
---|
671 | sub conforms_to_mod_base64 {
|
---|
672 | my ($text) = @_;
|
---|
673 |
|
---|
674 | # need to treat the entity ref for underscore as underscore
|
---|
675 | $text =~ s/&\#095;/_/g;
|
---|
676 |
|
---|
677 | # base 64 takes alphanumeric and [=+/],
|
---|
678 | # but we use modified base64 where + and / are replaced with - and _
|
---|
679 | return ($text =~ m/^[A-Za-z0-9\=\-\_]+$/); #alphanumeric and [=-_]
|
---|
680 | }
|
---|
681 |
|
---|
682 | sub substr
|
---|
683 | {
|
---|
684 | my ($utf8_string, $offset, $length) = @_;
|
---|
685 |
|
---|
686 | my @unicode_string = @{&utf82unicode($utf8_string)};
|
---|
687 | my $unicode_string_length = scalar(@unicode_string);
|
---|
688 |
|
---|
689 | my $substr_start = $offset;
|
---|
690 | if ($substr_start >= $unicode_string_length) {
|
---|
691 | return "";
|
---|
692 | }
|
---|
693 |
|
---|
694 | my $substr_end = $offset + $length - 1;
|
---|
695 | if ($substr_end >= $unicode_string_length) {
|
---|
696 | $substr_end = $unicode_string_length - 1;
|
---|
697 | }
|
---|
698 |
|
---|
699 | my @unicode_substring = @unicode_string[$substr_start..$substr_end];
|
---|
700 | return &unicode2utf8(\@unicode_substring);
|
---|
701 | }
|
---|
702 |
|
---|
703 |
|
---|
704 | 1;
|
---|