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 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 util;
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37 |
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38 | # ascii2unicode takes an (extended) ascii string (ISO-8859-1)
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39 | # and returns a unicode array.
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40 | sub ascii2unicode {
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41 | my ($in) = @_;
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42 | my $out = [];
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43 |
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44 | my $i = 0;
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45 | my $len = length($in);
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46 | while ($i < $len) {
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47 | push (@$out, ord(substr ($in, $i, 1)));
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48 | $i++;
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49 | }
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50 |
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51 | return $out;
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52 | }
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53 |
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54 | # ascii2utf8 takes a reference to an (extended) ascii string and returns a
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55 | # UTF-8 encoded string. This is just a faster version of
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56 | # "&unicode2utf8(&ascii2unicode($str));"
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57 | sub ascii2utf8 {
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58 | my ($in) = @_;
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59 | my $out = "";
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60 |
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61 | if (!defined($in)|| !defined($$in)) {
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62 | return $out;
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63 | }
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64 |
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65 | my ($c);
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66 | my $i = 0;
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67 | my $len = length($$in);
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68 | while ($i < $len) {
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69 | $c = ord (substr ($$in, $i, 1));
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70 | if ($c < 0x80) {
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71 | # ascii character
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72 | $out .= chr ($c);
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73 |
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74 | } else {
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75 | # extended ascii character
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76 | $out .= chr (0xc0 + (($c >> 6) & 0x1f));
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77 | $out .= chr (0x80 + ($c & 0x3f));
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78 | }
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79 | $i++;
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80 | }
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81 |
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82 | return $out;
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83 | }
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84 |
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85 | # unicode2utf8 takes a unicode array as input and encodes it
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86 | # using utf-8
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87 | sub unicode2utf8 {
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88 | my ($in) = @_;
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89 | my $out = "";
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90 |
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91 | foreach $num (@$in) {
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92 | next unless defined $num;
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93 | if ($num < 0x80) {
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94 | $out .= chr ($num);
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95 |
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96 | } elsif ($num < 0x800) {
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97 | $out .= chr (0xc0 + (($num >> 6) & 0x1f));
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98 | $out .= chr (0x80 + ($num & 0x3f));
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99 |
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100 | } elsif ($num < 0xFFFF) {
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101 | $out .= chr (0xe0 + (($num >> 12) & 0xf));
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102 | $out .= chr (0x80 + (($num >> 6) & 0x3f));
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103 | $out .= chr (0x80 + ($num & 0x3f));
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104 |
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105 | } else {
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106 | # error, don't encode anything
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107 | die;
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108 | }
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109 | }
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110 | return $out;
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111 | }
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112 |
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113 | # utf82unicode takes a utf-8 string and produces a unicode
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114 | # array
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115 | sub utf82unicode {
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116 | my ($in) = @_;
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117 | my $out = [];
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118 |
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119 | my $i = 0;
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120 | my ($c1, $c2, $c3);
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121 | $len = length($in);
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122 | while ($i < $len) {
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123 | if (($c1 = ord(substr ($in, $i, 1))) < 0x80) {
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124 | # normal ascii character
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125 | push (@$out, $c1);
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126 |
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127 | } elsif ($c1 < 0xc0) {
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128 | # error, was expecting the first byte of an
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129 | # encoded character. Do nothing.
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130 |
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131 | } elsif ($c1 < 0xe0 && $i+1 < $len) {
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132 | # an encoded character with two bytes
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133 | $c2 = ord (substr ($in, $i+1, 1));
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134 | if ($c2 >= 0x80 && $c2 < 0xc0) {
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135 | # everything looks ok
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136 | push (@$out, ((($c1 & 0x1f) << 6) +
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137 | ($c2 & 0x3f)));
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138 | $i++; # gobbled an extra byte
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139 | }
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140 |
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141 | } elsif ($c1 < 0xf0 && $i+2 < $len) {
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142 | # an encoded character with three bytes
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143 | $c2 = ord (substr ($in, $i+1, 1));
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144 | $c3 = ord (substr ($in, $i+2, 1));
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145 | if ($c2 >= 0x80 && $c2 < 0xc0 &&
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146 | $c3 >= 0x80 && $c3 < 0xc0) {
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147 | # everything looks ok
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148 | push (@$out, ((($c1 & 0xf) << 12) +
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149 | (($c2 & 0x3f) << 6) +
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150 | ($c3 & 0x3f)));
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151 |
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152 | $i += 2; # gobbled an extra two bytes
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153 | }
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154 |
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155 | } else {
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156 | # error, only decode Unicode characters not full UCS.
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157 | # Do nothing.
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158 | }
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159 |
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160 | $i++;
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161 | }
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162 |
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163 | return $out;
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164 | }
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165 |
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166 | # unicode2ucs2 takes a unicode array and produces a UCS-2
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167 | # unicode string (every two bytes forms a unicode character)
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168 | sub unicode2ucs2 {
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169 | my ($in) = @_;
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170 | my $out = "";
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171 |
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172 | foreach $num (@$in) {
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173 | $out .= chr (($num & 0xff00) >> 8);
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174 | $out .= chr ($num & 0xff);
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175 | }
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176 |
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177 | return $out;
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178 | }
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179 |
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180 | # ucs22unicode takes a UCS-2 string and produces a unicode array
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181 | sub ucs22unicode {
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182 | my ($in) = @_;
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183 | my $out = [];
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184 |
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185 | my $i = 0;
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186 | my $len = length ($in);
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187 | while ($i+1 < $len) {
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188 | push (@$out, ord (substr($in, $i, 1)) << 8 +
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189 | ord (substr($in, $i+1, 1)));
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190 |
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191 | $i ++;
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192 | }
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193 |
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194 | return $out;
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195 | }
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196 |
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197 | # takes a reference to a string and returns a reference to a unicode array
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198 | sub convert2unicode {
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199 | my ($encoding, $textref) = @_;
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200 |
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201 | if (!defined $encodings::encodings->{$encoding}) {
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202 | print STDERR "unicode::convert2unicode: ERROR: Unsupported encoding ($encoding)\n";
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203 | return [];
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204 | }
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205 |
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206 | my $encodename = "$encoding-unicode";
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207 | my $enc_info = $encodings::encodings->{$encoding};
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208 | my $mapfile = &util::filename_cat($ENV{'GSDLHOME'}, "mappings",
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209 | "to_uc", $enc_info->{'mapfile'});
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210 | if (!&loadmapencoding ($encodename, $mapfile)) {
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211 | print STDERR "unicode: ERROR - could not load encoding $encodename\n";
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212 | return [];
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213 | }
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214 |
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215 | if (defined $enc_info->{'converter'}) {
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216 | my $converter = $enc_info->{'converter'};
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217 | return &$converter ($encodename, $textref);
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218 | }
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219 |
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220 | if ($translations{$encodename}->{'count'} == 1) {
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221 | return &singlebyte2unicode ($encodename, $textref);
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222 | } else {
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223 | return &doublebyte2unicode ($encodename, $textref);
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224 | }
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225 | }
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226 |
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227 | # singlebyte2unicode converts simple 8 bit encodings where characters below
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228 | # 0x80 are normal ascii characters and the rest are decoded using the
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229 | # appropriate mapping files.
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230 | #
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231 | # Examples of encodings that may be converted using singlebyte2unicode are
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232 | # the iso-8859 and windows-125* series.
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233 | sub singlebyte2unicode {
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234 | my ($encodename, $textref) = @_;
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235 |
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236 | my @outtext = ();
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237 | my $len = length($$textref);
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238 | my ($c);
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239 | my $i = 0;
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240 |
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241 | while ($i < $len) {
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242 | if (($c = ord(substr($$textref, $i, 1))) < 0x80) {
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243 | # normal ascii character
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244 | push (@outtext, $c);
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245 | } else {
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246 | $c = &transchar ($encodename, $c);
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247 | # put a black square if cannot translate
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248 | $c = 0x25A1 if $c == 0;
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249 | push (@outtext, $c);
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250 | }
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251 | $i ++;
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252 | }
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253 | return \@outtext;
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254 | }
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255 |
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256 | # doublebyte2unicode converts simple two byte encodings where characters
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257 | # below code point 0x80 are single-byte characters and the rest are
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258 | # double-byte characters.
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259 | #
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260 | # Examples of encodings that may be converted using doublebyte2unicode are
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261 | # CJK encodings like GB encoded Chinese and UHC Korean.
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262 | #
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263 | # Note that no error checking is performed to make sure that the input text
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264 | # is valid for the given encoding.
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265 | #
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266 | # Also, encodings that may contain characters of more than two bytes are
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267 | # not supported (any EUC encoded text may in theory contain 3-byte
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268 | # characters but in practice only one and two byte characters are used).
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269 | sub doublebyte2unicode {
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270 | my ($encodename, $textref) = @_;
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271 |
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272 | my @outtext = ();
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273 | my $len = length($$textref);
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274 | my ($c1, $c2);
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275 | my $i = 0;
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276 |
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277 | while ($i < $len) {
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278 | if (($c1 = ord(substr($$textref, $i, 1))) >= 0x80) {
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279 | if ($i+1 < $len) {
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280 | # double-byte character
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281 | $c2 = ord(substr($$textref, $i+1, 1));
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282 | my $c = &transchar ($encodename, ($c1 << 8) | $c2);
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283 | # put a black square if cannot translate
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284 | $c = 0x25A1 if $c == 0;
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285 | push (@outtext, $c);
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286 | $i += 2;
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287 |
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288 | } else {
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289 | # error
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290 | print STDERR "unicode: ERROR missing second half of double-byte character\n";
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291 | $i++;
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292 | }
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293 |
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294 | } else {
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295 | # single-byte character
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296 | push (@outtext, $c1);
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297 | $i++;
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298 | }
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299 | }
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300 | return \@outtext;
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301 | }
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302 |
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303 | # Shift-JIS to unicode
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304 | # We can't use doublebyte2unicode for Shift-JIS because it uses some
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305 | # single-byte characters above code point 0x80 (i.e. half-width katakana
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306 | # characters in the range 0xA1-0xDF)
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307 | sub shiftjis2unicode {
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308 | my ($encodename, $textref) = @_;
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309 |
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310 | my @outtext = ();
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311 | my $len = length($$textref);
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312 | my ($c1, $c2);
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313 | my $i = 0;
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314 |
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315 | while ($i < $len) {
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316 | $c1 = ord(substr($$textref, $i, 1));
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317 |
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318 | if (($c1 >= 0xA1 && $c1 <= 0xDF) || $c1 == 0x5c || $c1 == 0x7E) {
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319 | # Single-byte half-width katakana character or
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320 | # JIS Roman yen or overline characters
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321 | my $c = &transchar ($encodename, $c1);
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322 | # - put a black square if cannot translate
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323 | $c = 0x25A1 if $c == 0;
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324 | push (@outtext, $c);
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325 | $i++;
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326 |
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327 | } elsif ($c1 < 0x80) {
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328 | # ASCII
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329 | push (@outtext, $c1);
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330 | $i ++;
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331 |
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332 | } elsif ($c1 < 0xEF) {
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333 | if ($i+1 < $len) {
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334 | $c2 = ord(substr($$textref, $i+1, 1));
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335 | if (($c2 >= 0x40 && $c2 <= 0x7E) || ($c2 >= 0x80 && $c2 <= 0xFC)) {
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336 | # Double-byte shift-jis character
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337 | my $c = &transchar ($encodename, ($c1 << 8) | $c2);
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338 | # put a black square if cannot translate
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339 | $c = 0x25A1 if $c == 0;
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340 | push (@outtext, $c);
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341 | } else {
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342 | # error
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343 | print STDERR "unicode: ERROR Invalid Shift-JIS character\n";
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344 | }
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345 | $i += 2;
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346 | } else {
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347 | # error
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348 | print STDERR "unicode: ERROR missing second half of Shift-JIS character\n";
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349 | $i ++;
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350 | }
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351 | } else {
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352 | # error
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353 | print STDERR "unicode: ERROR Invalid Shift-JIS character\n";
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354 | $i ++;
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355 | }
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356 | }
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357 | return \@outtext;
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358 | }
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359 |
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360 | sub transchar {
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361 | my ($encoding, $from) = @_;
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362 | my $high = ($from / 256) % 256;
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363 | my $low = $from % 256;
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364 |
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365 | return 0 unless defined $translations{$encoding};
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366 |
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367 | my $block = $translations{$encoding}->{'map'};
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368 |
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369 | if (ref ($block->[$high]) ne "ARRAY") {
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370 | return 0;
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371 | }
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372 | return $block->[$high]->[$low];
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373 | }
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374 |
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375 | # %translations is of the form:
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376 | #
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377 | # encodings{encodingname-encodingname}->{'map'}->blocktranslation
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378 | # blocktranslation->[[0-255],[256-511], ..., [65280-65535]]
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379 | #
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380 | # Any of the top translation blocks can point to an undefined
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381 | # value. This data structure aims to allow fast translation and
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382 | # efficient storage.
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383 | %translations = ();
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384 |
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385 | # @array256 is used for initialisation, there must be
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386 | # a better way...
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387 | # What about this?: @array256 = (0) x 256;
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388 | @array256 = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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389 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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390 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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391 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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392 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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393 | 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 |
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405 | # returns 1 if successful, 0 if unsuccessful
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406 | sub loadmapencoding {
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407 | my ($encoding, $mapfile) = @_;
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408 |
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409 | # check to see if the encoding has already been loaded
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410 | return 1 if (defined $translations{$encoding});
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411 |
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412 | return 0 unless open (MAPFILE, $mapfile);
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413 | binmode (MAPFILE);
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414 |
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415 | $translations{$encoding} = {'map' => [@array256], 'count' => 0};
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416 | my $block = $translations{$encoding};
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417 |
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418 | my ($in,$i,$j);
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419 | while (read(MAPFILE, $in, 1) == 1) {
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420 | $i = unpack ("C", $in);
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421 | $block->{'map'}->[$i] = [@array256];
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422 | for ($j=0; $j<256 && read(MAPFILE, $in, 2)==2; $j++) {
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423 | my ($n1, $n2) = unpack ("CC", $in);
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424 | $block->{'map'}->[$i]->[$j] = ($n1*256) + $n2;
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425 | }
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426 | $block->{'count'} ++;
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427 | }
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428 |
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429 | close (MAPFILE);
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430 | }
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431 |
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432 | # unicode2singlebyte converts unicode to simple 8 bit encodings where
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433 | # characters below 0x80 are normal ascii characters and the rest are encoded
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434 | # using the appropriate mapping files.
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435 | #
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436 | # Examples of encodings that may be converted using unicode2singlebyte are
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437 | # the iso-8859 and windows-125* series, KOI8-R (Russian), and the Kazakh encoding.
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438 | sub unicode2singlebyte {
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439 | my ($uniref, $encoding) = @_;
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440 |
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441 | my $outtext = "";
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442 | my $encodename = "unicode-$encoding";
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443 | my $enc_info = $encodings::encodings->{"$encoding"};
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444 | my $mapfile = &util::filename_cat($ENV{'GSDLHOME'}, "mappings",
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445 | "from_uc", $enc_info->{'mapfile'});
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446 | if (!&loadmapencoding ($encodename, $mapfile)) {
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447 | print STDERR "unicode: ERROR - could not load encoding $encodename\n";
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448 | return "";
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449 | }
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450 |
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451 | foreach my $c (@$uniref) {
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452 | if ($c < 0x80) {
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453 | # normal ascii character
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454 | $outtext .= chr($c);
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455 | } else {
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456 | # extended ascii character
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457 | $c = &transchar ($encodename, $c);
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458 |
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459 | # put a question mark if cannot translate
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460 | if ($c == 0) {
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461 | $outtext .= "?";
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462 | } else {
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463 | $outtext .= chr($c);
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464 | }
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465 | }
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466 | }
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467 | return $outtext;
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468 | }
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469 |
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470 | 1;
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