*
* preg_replace_callback( "!$startDelim(.*)$endDelim!s$flags", $callback, $subject )
*
- * This implementation is slower than staticDelimiterReplace but uses far less
- * memory and allows regular expression delimiters.
+ * This implementation is slower than hungryDelimiterReplace but uses far less
+ * memory. The delimiters are literal strings, not regular expressions.
*
* @param string $flags Regular expression flags
*/
+ # 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/.
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 );
while ( $inputPos < strlen( $subject ) &&
- preg_match( "!($startDelim)|($endDelim)!$flags", $subject, $m, PREG_OFFSET_CAPTURE, $inputPos ) )
+ preg_match( "!($encStart)|($encEnd)!S$flags", $subject, $m, PREG_OFFSET_CAPTURE, $inputPos ) )
{
+ $tokenOffset = $m[0][1];
if ( $m[1][0] != '' ) {
- # Found start
- # Write out the non-matching section
- $output .= substr( $subject, $outputPos, $m[1][1] - $outputPos );
- $foundStart = true;
- $inputPos = $contentPos = $m[1][1] + strlen( $m[1][0] );
- $outputPos = $m[1][1];
+ 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] != '' ) {
- # Found end
+ $tokenType = 'end';
+ $tokenLength = strlen( $m[0][0] );
+ } else {
+ throw new MWException( 'Invalid delimiter given to ' . __METHOD__ );
+ }
+
+ if ( $tokenType == 'start' ) {
+ $inputPos = $tokenOffset + $tokenLength;
+ # Only move the start position if we haven't already found a start
+ # This means that START START END matches outer pair
+ if ( !$foundStart ) {
+ # Found start
+ # Write out the non-matching section
+ $output .= substr( $subject, $outputPos, $tokenOffset - $outputPos );
+ $outputPos = $tokenOffset;
+ $contentPos = $inputPos;
+ $foundStart = true;
+ }
+ } elseif ( $tokenType == 'end' ) {
if ( $foundStart ) {
# Found match
$output .= call_user_func( $callback, array(
- substr( $subject, $outputPos, $m[2][1] + strlen( $m[2][0] ) - $outputPos ),
- substr( $subject, $contentPos, $m[2][1] - $contentPos )
+ substr( $subject, $outputPos, $tokenOffset + $tokenLength - $outputPos ),
+ substr( $subject, $contentPos, $tokenOffset - $contentPos )
));
$foundStart = false;
} else {
# Non-matching end, write it out
- $output .= substr( $subject, $inputPos, $m[2][1] + strlen( $m[2][0] ) - $outputPos );
+ $output .= substr( $subject, $inputPos, $tokenOffset + $tokenLength - $outputPos );
}
- $inputPos = $outputPos = $m[2][1] + strlen( $m[2][0] );
+ $inputPos = $outputPos = $tokenOffset + $tokenLength;
} else {
throw new MWException( 'Invalid delimiter given to ' . __METHOD__ );
}