3 * Methods to play with strings.
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24 * A collection of static methods to play with strings.
28 * Test whether a string is valid UTF-8.
30 * The function check for invalid byte sequences, overlong encoding but
31 * not for different normalisations.
33 * @note In MediaWiki 1.21, this function did not provide proper UTF-8 validation.
34 * In particular, the pure PHP code path did not in fact check for overlong forms.
35 * Beware of this when backporting code to that version of MediaWiki.
38 * @param string $value String to check
39 * @return bool Whether the given $value is a valid UTF-8 encoded string
41 static function isUtf8( $value ) {
42 $value = (string)$value;
44 // HHVM 3.4 and older come with an outdated version of libmbfl that
45 // incorrectly allows values above U+10FFFF, so we have to check
46 // for them separately. (This issue also exists in PHP 5.3 and
47 // older, which are no longer supported.)
49 if ( $newPHP === null ) {
50 $newPHP = !mb_check_encoding( "\xf4\x90\x80\x80", 'UTF-8' );
53 return mb_check_encoding( $value, 'UTF-8' ) &&
54 ( $newPHP ||
preg_match( "/\xf4[\x90-\xbf]|[\xf5-\xff]/S", $value ) === 0 );
58 * Perform an operation equivalent to `preg_replace()`
62 * preg_replace( "!$startDelim(.*?)$endDelim!", $replace, $subject );
64 * ..except that it's worst-case O(N) instead of O(N^2). Compared to delimiterReplace(), this
65 * implementation is fast but memory-hungry and inflexible. The memory requirements are such
66 * that I don't recommend using it on anything but guaranteed small chunks of text.
68 * @param string $startDelim
69 * @param string $endDelim
70 * @param string $replace
71 * @param string $subject
74 static function hungryDelimiterReplace( $startDelim, $endDelim, $replace, $subject ) {
75 $segments = explode( $startDelim, $subject );
76 $output = array_shift( $segments );
77 foreach ( $segments as $s ) {
78 $endDelimPos = strpos( $s, $endDelim );
79 if ( $endDelimPos === false ) {
80 $output .= $startDelim . $s;
82 $output .= $replace . substr( $s, $endDelimPos +
strlen( $endDelim ) );
90 * Perform an operation equivalent to `preg_replace_callback()`
94 * preg_replace_callback( "!$startDelim(.*)$endDelim!s$flags", $callback, $subject );
96 * If the start delimiter ends with an initial substring of the end delimiter,
97 * e.g. in the case of C-style comments, the behavior differs from the model
98 * regex. In this implementation, the end must share no characters with the
99 * start, so e.g. `/*\/` is not considered to be both the start and end of a
100 * comment. `/*\/xy/*\/` is considered to be a single comment with contents `/xy/`.
102 * The implementation of delimiterReplaceCallback() is slower than hungryDelimiterReplace()
103 * but uses far less memory. The delimiters are literal strings, not regular expressions.
105 * @param string $startDelim Start delimiter
106 * @param string $endDelim End delimiter
107 * @param callable $callback Function to call on each match
108 * @param string $subject
109 * @param string $flags Regular expression flags
110 * @throws InvalidArgumentException
113 static function delimiterReplaceCallback( $startDelim, $endDelim, $callback,
114 $subject, $flags = ''
120 $encStart = preg_quote( $startDelim, '!' );
121 $encEnd = preg_quote( $endDelim, '!' );
122 $strcmp = strpos( $flags, 'i' ) === false ?
'strcmp' : 'strcasecmp';
123 $endLength = strlen( $endDelim );
126 while ( $inputPos < strlen( $subject ) &&
127 preg_match( "!($encStart)|($encEnd)!S$flags", $subject, $m, PREG_OFFSET_CAPTURE
, $inputPos )
129 $tokenOffset = $m[0][1];
130 if ( $m[1][0] != '' ) {
132 $strcmp( $endDelim, substr( $subject, $tokenOffset, $endLength ) ) == 0
134 # An end match is present at the same location
136 $tokenLength = $endLength;
138 $tokenType = 'start';
139 $tokenLength = strlen( $m[0][0] );
141 } elseif ( $m[2][0] != '' ) {
143 $tokenLength = strlen( $m[0][0] );
145 throw new InvalidArgumentException( 'Invalid delimiter given to ' . __METHOD__
);
148 if ( $tokenType == 'start' ) {
149 # Only move the start position if we haven't already found a start
150 # This means that START START END matches outer pair
151 if ( !$foundStart ) {
153 $inputPos = $tokenOffset +
$tokenLength;
154 # Write out the non-matching section
155 $output .= substr( $subject, $outputPos, $tokenOffset - $outputPos );
156 $outputPos = $tokenOffset;
157 $contentPos = $inputPos;
160 # Move the input position past the *first character* of START,
161 # to protect against missing END when it overlaps with START
162 $inputPos = $tokenOffset +
1;
164 } elseif ( $tokenType == 'end' ) {
167 $output .= call_user_func( $callback, [
168 substr( $subject, $outputPos, $tokenOffset +
$tokenLength - $outputPos ),
169 substr( $subject, $contentPos, $tokenOffset - $contentPos )
173 # Non-matching end, write it out
174 $output .= substr( $subject, $inputPos, $tokenOffset +
$tokenLength - $outputPos );
176 $inputPos = $outputPos = $tokenOffset +
$tokenLength;
178 throw new InvalidArgumentException( 'Invalid delimiter given to ' . __METHOD__
);
181 if ( $outputPos < strlen( $subject ) ) {
182 $output .= substr( $subject, $outputPos );
189 * Perform an operation equivalent to `preg_replace()` with flags.
193 * preg_replace( "!$startDelim(.*)$endDelim!$flags", $replace, $subject );
195 * @param string $startDelim Start delimiter regular expression
196 * @param string $endDelim End delimiter regular expression
197 * @param string $replace Replacement string. May contain $1, which will be
198 * replaced by the text between the delimiters
199 * @param string $subject String to search
200 * @param string $flags Regular expression flags
201 * @return string The string with the matches replaced
203 static function delimiterReplace( $startDelim, $endDelim, $replace, $subject, $flags = '' ) {
204 $replacer = new RegexlikeReplacer( $replace );
206 return self
::delimiterReplaceCallback( $startDelim, $endDelim,
207 $replacer->cb(), $subject, $flags );
211 * More or less "markup-safe" explode()
212 * Ignores any instances of the separator inside `<...>`
213 * @param string $separator
214 * @param string $text
217 static function explodeMarkup( $separator, $text ) {
218 $placeholder = "\x00";
220 // Remove placeholder instances
221 $text = str_replace( $placeholder, '', $text );
223 // Replace instances of the separator inside HTML-like tags with the placeholder
224 $replacer = new DoubleReplacer( $separator, $placeholder );
225 $cleaned = StringUtils
::delimiterReplaceCallback( '<', '>', $replacer->cb(), $text );
227 // Explode, then put the replaced separators back in
228 $items = explode( $separator, $cleaned );
229 foreach ( $items as $i => $str ) {
230 $items[$i] = str_replace( $placeholder, $separator, $str );
237 * More or less "markup-safe" str_replace()
238 * Ignores any instances of the separator inside `<...>`
239 * @param string $search
240 * @param string $replace
241 * @param string $text
244 static function replaceMarkup( $search, $replace, $text ) {
245 $placeholder = "\x00";
247 // Remove placeholder instances
248 $text = str_replace( $placeholder, '', $text );
250 // Replace instances of the separator inside HTML-like tags with the placeholder
251 $replacer = new DoubleReplacer( $search, $placeholder );
252 $cleaned = StringUtils
::delimiterReplaceCallback( '<', '>', $replacer->cb(), $text );
254 // Explode, then put the replaced separators back in
255 $cleaned = str_replace( $search, $replace, $cleaned );
256 $text = str_replace( $placeholder, $search, $cleaned );
262 * Escape a string to make it suitable for inclusion in a preg_replace()
263 * replacement parameter.
265 * @param string $string
268 static function escapeRegexReplacement( $string ) {
269 $string = str_replace( '\\', '\\\\', $string );
270 $string = str_replace( '$', '\\$', $string );
275 * Workalike for explode() with limited memory usage.
277 * @param string $separator
278 * @param string $subject
279 * @return ArrayIterator|ExplodeIterator
281 static function explode( $separator, $subject ) {
282 if ( substr_count( $subject, $separator ) > 1000 ) {
283 return new ExplodeIterator( $separator, $subject );
285 return new ArrayIterator( explode( $separator, $subject ) );