1 <?php
2 
3 namespace dokuwiki\Utf8;
4 
5 /**
6  * Convert between UTF-8 and a list of Unicode Code Points
7  */
8 class Unicode
9 {
10     /**
11      * Takes an UTF-8 string and returns an array of ints representing the
12      * Unicode characters. Astral planes are supported ie. the ints in the
13      * output can be > 0xFFFF. Occurrances of the BOM are ignored. Surrogates
14      * are not allowed.
15      *
16      * If $strict is set to true the function returns false if the input
17      * string isn't a valid UTF-8 octet sequence and raises a PHP error at
18      * level E_USER_WARNING
19      *
20      * Note: this function has been modified slightly in this library to
21      * trigger errors on encountering bad bytes
22      *
23      * @author <hsivonen@iki.fi>
24      * @author Harry Fuecks <hfuecks@gmail.com>
25      * @see    unicode_to_utf8
26      * @link   http://hsivonen.iki.fi/php-utf8/
27      * @link   http://sourceforge.net/projects/phputf8/
28      * @todo break into less complex chunks
29      * @todo use exceptions instead of user errors
30      *
31      * @param  string $str UTF-8 encoded string
32      * @param  boolean $strict Check for invalid sequences?
33      * @return mixed array of unicode code points or false if UTF-8 invalid
34      */
35     public static function fromUtf8($str, $strict = false)
36     {
37         $mState = 0;     // cached expected number of octets after the current octet
38         // until the beginning of the next UTF8 character sequence
39         $mUcs4 = 0;     // cached Unicode character
40         $mBytes = 1;     // cached expected number of octets in the current sequence
41 
42         $out = [];
43 
44         $len = strlen($str);
45 
46         for ($i = 0; $i < $len; $i++) {
47             $in = ord($str[$i]);
48 
49             if ($mState === 0) {
50                 // When mState is zero we expect either a US-ASCII character or a
51                 // multi-octet sequence.
52                 if (0 === (0x80 & $in)) {
53                     // US-ASCII, pass straight through.
54                     $out[] = $in;
55                     $mBytes = 1;
56                 } elseif (0xC0 === (0xE0 & $in)) {
57                     // First octet of 2 octet sequence
58                     $mUcs4 = $in;
59                     $mUcs4 = ($mUcs4 & 0x1F) << 6;
60                     $mState = 1;
61                     $mBytes = 2;
62                 } elseif (0xE0 === (0xF0 & $in)) {
63                     // First octet of 3 octet sequence
64                     $mUcs4 = $in;
65                     $mUcs4 = ($mUcs4 & 0x0F) << 12;
66                     $mState = 2;
67                     $mBytes = 3;
68                 } elseif (0xF0 === (0xF8 & $in)) {
69                     // First octet of 4 octet sequence
70                     $mUcs4 = $in;
71                     $mUcs4 = ($mUcs4 & 0x07) << 18;
72                     $mState = 3;
73                     $mBytes = 4;
74                 } elseif (0xF8 === (0xFC & $in)) {
75                     /* First octet of 5 octet sequence.
76                      *
77                      * This is illegal because the encoded codepoint must be either
78                      * (a) not the shortest form or
79                      * (b) outside the Unicode range of 0-0x10FFFF.
80                      * Rather than trying to resynchronize, we will carry on until the end
81                      * of the sequence and let the later error handling code catch it.
82                      */
83                     $mUcs4 = $in;
84                     $mUcs4 = ($mUcs4 & 0x03) << 24;
85                     $mState = 4;
86                     $mBytes = 5;
87                 } elseif (0xFC === (0xFE & $in)) {
88                     // First octet of 6 octet sequence, see comments for 5 octet sequence.
89                     $mUcs4 = $in;
90                     $mUcs4 = ($mUcs4 & 1) << 30;
91                     $mState = 5;
92                     $mBytes = 6;
93                 } elseif ($strict) {
94                     /* Current octet is neither in the US-ASCII range nor a legal first
95                      * octet of a multi-octet sequence.
96                      */
97                     trigger_error(
98                         'utf8_to_unicode: Illegal sequence identifier ' .
99                         'in UTF-8 at byte ' . $i,
100                         E_USER_WARNING
101                     );
102                     return false;
103                 }
104             } elseif (0x80 === (0xC0 & $in)) {
105                 // When mState is non-zero, we expect a continuation of the multi-octet
106                 // sequence
107                 // Legal continuation.
108                 $shift = ($mState - 1) * 6;
109                 $tmp = $in;
110                 $tmp = ($tmp & 0x0000003F) << $shift;
111                 $mUcs4 |= $tmp;
112                 /**
113                  * End of the multi-octet sequence. mUcs4 now contains the final
114                  * Unicode codepoint to be output
115                  */
116                 if (0 === --$mState) {
117                     /*
118                      * Check for illegal sequences and codepoints.
119                      */
120                     // From Unicode 3.1, non-shortest form is illegal
121                     if (
122                         ((2 === $mBytes) && ($mUcs4 < 0x0080)) ||
123                         ((3 === $mBytes) && ($mUcs4 < 0x0800)) ||
124                         ((4 === $mBytes) && ($mUcs4 < 0x10000)) ||
125                         (4 < $mBytes) ||
126                         // From Unicode 3.2, surrogate characters are illegal
127                         (($mUcs4 & 0xFFFFF800) === 0xD800) ||
128                         // Codepoints outside the Unicode range are illegal
129                         ($mUcs4 > 0x10FFFF)
130                     ) {
131                         if ($strict) {
132                             trigger_error(
133                                 'utf8_to_unicode: Illegal sequence or codepoint ' .
134                                 'in UTF-8 at byte ' . $i,
135                                 E_USER_WARNING
136                             );
137 
138                             return false;
139                         }
140                     }
141 
142                     if (0xFEFF !== $mUcs4) {
143                         // BOM is legal but we don't want to output it
144                         $out[] = $mUcs4;
145                     }
146 
147                     //initialize UTF8 cache
148                     $mState = 0;
149                     $mUcs4 = 0;
150                     $mBytes = 1;
151                 }
152             } elseif ($strict) {
153                 /**
154                  *((0xC0 & (*in) != 0x80) && (mState != 0))
155                  * Incomplete multi-octet sequence.
156                  */
157                 trigger_error(
158                     'utf8_to_unicode: Incomplete multi-octet ' .
159                     '   sequence in UTF-8 at byte ' . $i,
160                     E_USER_WARNING
161                 );
162 
163                 return false;
164             }
165         }
166         return $out;
167     }
168 
169     /**
170      * Takes an array of ints representing the Unicode characters and returns
171      * a UTF-8 string. Astral planes are supported ie. the ints in the
172      * input can be > 0xFFFF. Occurrances of the BOM are ignored. Surrogates
173      * are not allowed.
174      *
175      * If $strict is set to true the function returns false if the input
176      * array contains ints that represent surrogates or are outside the
177      * Unicode range and raises a PHP error at level E_USER_WARNING
178      *
179      * Note: this function has been modified slightly in this library to use
180      * output buffering to concatenate the UTF-8 string (faster) as well as
181      * reference the array by it's keys
182      *
183      * @param  array $arr of unicode code points representing a string
184      * @param  boolean $strict Check for invalid sequences?
185      * @return string|false UTF-8 string or false if array contains invalid code points
186      *
187      * @author <hsivonen@iki.fi>
188      * @author Harry Fuecks <hfuecks@gmail.com>
189      * @see    utf8_to_unicode
190      * @link   http://hsivonen.iki.fi/php-utf8/
191      * @link   http://sourceforge.net/projects/phputf8/
192      * @todo use exceptions instead of user errors
193      */
194     public static function toUtf8($arr, $strict = false)
195     {
196         if (!is_array($arr)) return '';
197         ob_start();
198 
199         foreach (array_keys($arr) as $k) {
200             if (($arr[$k] >= 0) && ($arr[$k] <= 0x007f)) {
201                 # ASCII range (including control chars)
202                 echo chr($arr[$k]);
203             } elseif ($arr[$k] <= 0x07ff) {
204                 # 2 byte sequence
205                 echo chr(0xc0 | ($arr[$k] >> 6));
206                 echo chr(0x80 | ($arr[$k] & 0x003f));
207             } elseif ($arr[$k] == 0xFEFF) {
208                 # Byte order mark (skip)
209                 // nop -- zap the BOM
210             } elseif ($arr[$k] >= 0xD800 && $arr[$k] <= 0xDFFF) {
211                 # Test for illegal surrogates
212                 // found a surrogate
213                 if ($strict) {
214                     trigger_error(
215                         'unicode_to_utf8: Illegal surrogate ' .
216                         'at index: ' . $k . ', value: ' . $arr[$k],
217                         E_USER_WARNING
218                     );
219                     return false;
220                 }
221             } elseif ($arr[$k] <= 0xffff) {
222                 # 3 byte sequence
223                 echo chr(0xe0 | ($arr[$k] >> 12));
224                 echo chr(0x80 | (($arr[$k] >> 6) & 0x003f));
225                 echo chr(0x80 | ($arr[$k] & 0x003f));
226             } elseif ($arr[$k] <= 0x10ffff) {
227                 # 4 byte sequence
228                 echo chr(0xf0 | ($arr[$k] >> 18));
229                 echo chr(0x80 | (($arr[$k] >> 12) & 0x3f));
230                 echo chr(0x80 | (($arr[$k] >> 6) & 0x3f));
231                 echo chr(0x80 | ($arr[$k] & 0x3f));
232             } elseif ($strict) {
233                 trigger_error(
234                     'unicode_to_utf8: Codepoint out of Unicode range ' .
235                     'at index: ' . $k . ', value: ' . $arr[$k],
236                     E_USER_WARNING
237                 );
238 
239                 // out of range
240                 return false;
241             }
242         }
243 
244         return ob_get_clean();
245     }
246 }
247