/includes/StringUtils.php
PHP | 432 lines | 251 code | 48 blank | 133 comment | 30 complexity | a7a7b138eaff8dc356eb5d8d7b1d5958 MD5 | raw file
Possible License(s): GPL-2.0, Apache-2.0, LGPL-3.0
- <?php
- /**
- * A collection of static methods to play with strings.
- */
- class StringUtils {
- /**
- * Perform an operation equivalent to
- *
- * preg_replace( "!$startDelim(.*?)$endDelim!", $replace, $subject );
- *
- * except that it's worst-case O(N) instead of O(N^2)
- *
- * Compared to delimiterReplace(), this implementation is fast but memory-
- * hungry and inflexible. The memory requirements are such that I don't
- * recommend using it on anything but guaranteed small chunks of text.
- *
- * @param $startDelim
- * @param $endDelim
- * @param $replace
- * @param $subject
- *
- * @return string
- */
- static function hungryDelimiterReplace( $startDelim, $endDelim, $replace, $subject ) {
- $segments = explode( $startDelim, $subject );
- $output = array_shift( $segments );
- foreach ( $segments as $s ) {
- $endDelimPos = strpos( $s, $endDelim );
- if ( $endDelimPos === false ) {
- $output .= $startDelim . $s;
- } else {
- $output .= $replace . substr( $s, $endDelimPos + strlen( $endDelim ) );
- }
- }
- return $output;
- }
- /**
- * Perform an operation equivalent to
- *
- * preg_replace_callback( "!$startDelim(.*)$endDelim!s$flags", $callback, $subject )
- *
- * This implementation is slower than hungryDelimiterReplace but uses far less
- * memory. The delimiters are literal strings, not regular expressions.
- *
- * If the start delimiter ends with an initial substring of the end delimiter,
- * e.g. in the case of C-style comments, the behaviour differs from the model
- * regex. In this implementation, the end must share no characters with the
- * start, so e.g. /*\/ is not considered to be both the start and end of a
- * comment. /*\/xy/*\/ is considered to be a single comment with contents /xy/.
- *
- * @param $startDelim String: start delimiter
- * @param $endDelim String: end delimiter
- * @param $callback Callback: function to call on each match
- * @param $subject String
- * @param $flags String: regular expression flags
- * @return string
- */
- static function delimiterReplaceCallback( $startDelim, $endDelim, $callback, $subject, $flags = '' ) {
- $inputPos = 0;
- $outputPos = 0;
- $output = '';
- $foundStart = false;
- $encStart = preg_quote( $startDelim, '!' );
- $encEnd = preg_quote( $endDelim, '!' );
- $strcmp = strpos( $flags, 'i' ) === false ? 'strcmp' : 'strcasecmp';
- $endLength = strlen( $endDelim );
- $m = array();
- while ( $inputPos < strlen( $subject ) &&
- preg_match( "!($encStart)|($encEnd)!S$flags", $subject, $m, PREG_OFFSET_CAPTURE, $inputPos ) )
- {
- $tokenOffset = $m[0][1];
- if ( $m[1][0] != '' ) {
- if ( $foundStart &&
- $strcmp( $endDelim, substr( $subject, $tokenOffset, $endLength ) ) == 0 )
- {
- # An end match is present at the same location
- $tokenType = 'end';
- $tokenLength = $endLength;
- } else {
- $tokenType = 'start';
- $tokenLength = strlen( $m[0][0] );
- }
- } elseif ( $m[2][0] != '' ) {
- $tokenType = 'end';
- $tokenLength = strlen( $m[0][0] );
- } else {
- throw new MWException( 'Invalid delimiter given to ' . __METHOD__ );
- }
- if ( $tokenType == 'start' ) {
- # Only move the start position if we haven't already found a start
- # This means that START START END matches outer pair
- if ( !$foundStart ) {
- # Found start
- $inputPos = $tokenOffset + $tokenLength;
- # Write out the non-matching section
- $output .= substr( $subject, $outputPos, $tokenOffset - $outputPos );
- $outputPos = $tokenOffset;
- $contentPos = $inputPos;
- $foundStart = true;
- } else {
- # Move the input position past the *first character* of START,
- # to protect against missing END when it overlaps with START
- $inputPos = $tokenOffset + 1;
- }
- } elseif ( $tokenType == 'end' ) {
- if ( $foundStart ) {
- # Found match
- $output .= call_user_func( $callback, array(
- substr( $subject, $outputPos, $tokenOffset + $tokenLength - $outputPos ),
- substr( $subject, $contentPos, $tokenOffset - $contentPos )
- ));
- $foundStart = false;
- } else {
- # Non-matching end, write it out
- $output .= substr( $subject, $inputPos, $tokenOffset + $tokenLength - $outputPos );
- }
- $inputPos = $outputPos = $tokenOffset + $tokenLength;
- } else {
- throw new MWException( 'Invalid delimiter given to ' . __METHOD__ );
- }
- }
- if ( $outputPos < strlen( $subject ) ) {
- $output .= substr( $subject, $outputPos );
- }
- return $output;
- }
- /**
- * Perform an operation equivalent to
- *
- * preg_replace( "!$startDelim(.*)$endDelim!$flags", $replace, $subject )
- *
- * @param $startDelim String: start delimiter regular expression
- * @param $endDelim String: end delimiter regular expression
- * @param $replace String: replacement string. May contain $1, which will be
- * replaced by the text between the delimiters
- * @param $subject String to search
- * @param $flags String: regular expression flags
- * @return String: The string with the matches replaced
- */
- static function delimiterReplace( $startDelim, $endDelim, $replace, $subject, $flags = '' ) {
- $replacer = new RegexlikeReplacer( $replace );
- return self::delimiterReplaceCallback( $startDelim, $endDelim,
- $replacer->cb(), $subject, $flags );
- }
- /**
- * More or less "markup-safe" explode()
- * Ignores any instances of the separator inside <...>
- * @param $separator String
- * @param $text String
- * @return array
- */
- static function explodeMarkup( $separator, $text ) {
- $placeholder = "\x00";
- // Remove placeholder instances
- $text = str_replace( $placeholder, '', $text );
- // Replace instances of the separator inside HTML-like tags with the placeholder
- $replacer = new DoubleReplacer( $separator, $placeholder );
- $cleaned = StringUtils::delimiterReplaceCallback( '<', '>', $replacer->cb(), $text );
- // Explode, then put the replaced separators back in
- $items = explode( $separator, $cleaned );
- foreach( $items as $i => $str ) {
- $items[$i] = str_replace( $placeholder, $separator, $str );
- }
- return $items;
- }
- /**
- * Escape a string to make it suitable for inclusion in a preg_replace()
- * replacement parameter.
- *
- * @param $string String
- * @return String
- */
- static function escapeRegexReplacement( $string ) {
- $string = str_replace( '\\', '\\\\', $string );
- $string = str_replace( '$', '\\$', $string );
- return $string;
- }
- /**
- * Workalike for explode() with limited memory usage.
- * Returns an Iterator
- * @param $separator
- * @param $subject
- * @return \ArrayIterator|\ExplodeIterator
- */
- static function explode( $separator, $subject ) {
- if ( substr_count( $subject, $separator ) > 1000 ) {
- return new ExplodeIterator( $separator, $subject );
- } else {
- return new ArrayIterator( explode( $separator, $subject ) );
- }
- }
- }
- /**
- * Base class for "replacers", objects used in preg_replace_callback() and
- * StringUtils::delimiterReplaceCallback()
- */
- class Replacer {
- function cb() {
- return array( &$this, 'replace' );
- }
- }
- /**
- * Class to replace regex matches with a string similar to that used in preg_replace()
- */
- class RegexlikeReplacer extends Replacer {
- var $r;
- function __construct( $r ) {
- $this->r = $r;
- }
- function replace( $matches ) {
- $pairs = array();
- foreach ( $matches as $i => $match ) {
- $pairs["\$$i"] = $match;
- }
- return strtr( $this->r, $pairs );
- }
- }
- /**
- * Class to perform secondary replacement within each replacement string
- */
- class DoubleReplacer extends Replacer {
- function __construct( $from, $to, $index = 0 ) {
- $this->from = $from;
- $this->to = $to;
- $this->index = $index;
- }
- function replace( $matches ) {
- return str_replace( $this->from, $this->to, $matches[$this->index] );
- }
- }
- /**
- * Class to perform replacement based on a simple hashtable lookup
- */
- class HashtableReplacer extends Replacer {
- var $table, $index;
- function __construct( $table, $index = 0 ) {
- $this->table = $table;
- $this->index = $index;
- }
- function replace( $matches ) {
- return $this->table[$matches[$this->index]];
- }
- }
- /**
- * Replacement array for FSS with fallback to strtr()
- * Supports lazy initialisation of FSS resource
- */
- class ReplacementArray {
- /*mostly private*/ var $data = false;
- /*mostly private*/ var $fss = false;
- /**
- * Create an object with the specified replacement array
- * The array should have the same form as the replacement array for strtr()
- */
- function __construct( $data = array() ) {
- $this->data = $data;
- }
- function __sleep() {
- return array( 'data' );
- }
- function __wakeup() {
- $this->fss = false;
- }
- /**
- * Set the whole replacement array at once
- */
- function setArray( $data ) {
- $this->data = $data;
- $this->fss = false;
- }
- function getArray() {
- return $this->data;
- }
- /**
- * Set an element of the replacement array
- */
- function setPair( $from, $to ) {
- $this->data[$from] = $to;
- $this->fss = false;
- }
- function mergeArray( $data ) {
- $this->data = array_merge( $this->data, $data );
- $this->fss = false;
- }
- function merge( $other ) {
- $this->data = array_merge( $this->data, $other->data );
- $this->fss = false;
- }
- function removePair( $from ) {
- unset($this->data[$from]);
- $this->fss = false;
- }
- function removeArray( $data ) {
- foreach( $data as $from => $to )
- $this->removePair( $from );
- $this->fss = false;
- }
- function replace( $subject ) {
- if ( function_exists( 'fss_prep_replace' ) ) {
- wfProfileIn( __METHOD__.'-fss' );
- if ( $this->fss === false ) {
- $this->fss = fss_prep_replace( $this->data );
- }
- $result = fss_exec_replace( $this->fss, $subject );
- wfProfileOut( __METHOD__.'-fss' );
- } else {
- wfProfileIn( __METHOD__.'-strtr' );
- $result = strtr( $subject, $this->data );
- wfProfileOut( __METHOD__.'-strtr' );
- }
- return $result;
- }
- }
- /**
- * An iterator which works exactly like:
- *
- * foreach ( explode( $delim, $s ) as $element ) {
- * ...
- * }
- *
- * Except it doesn't use 193 byte per element
- */
- class ExplodeIterator implements Iterator {
- // The subject string
- var $subject, $subjectLength;
- // The delimiter
- var $delim, $delimLength;
- // The position of the start of the line
- var $curPos;
- // The position after the end of the next delimiter
- var $endPos;
- // The current token
- var $current;
- /**
- * Construct a DelimIterator
- */
- function __construct( $delim, $s ) {
- $this->subject = $s;
- $this->delim = $delim;
- // Micro-optimisation (theoretical)
- $this->subjectLength = strlen( $s );
- $this->delimLength = strlen( $delim );
- $this->rewind();
- }
- function rewind() {
- $this->curPos = 0;
- $this->endPos = strpos( $this->subject, $this->delim );
- $this->refreshCurrent();
- }
- function refreshCurrent() {
- if ( $this->curPos === false ) {
- $this->current = false;
- } elseif ( $this->curPos >= $this->subjectLength ) {
- $this->current = '';
- } elseif ( $this->endPos === false ) {
- $this->current = substr( $this->subject, $this->curPos );
- } else {
- $this->current = substr( $this->subject, $this->curPos, $this->endPos - $this->curPos );
- }
- }
- function current() {
- return $this->current;
- }
- function key() {
- return $this->curPos;
- }
- function next() {
- if ( $this->endPos === false ) {
- $this->curPos = false;
- } else {
- $this->curPos = $this->endPos + $this->delimLength;
- if ( $this->curPos >= $this->subjectLength ) {
- $this->endPos = false;
- } else {
- $this->endPos = strpos( $this->subject, $this->delim, $this->curPos );
- }
- }
- $this->refreshCurrent();
- return $this->current;
- }
- function valid() {
- return $this->curPos !== false;
- }
- }