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<?php
namespace TextExtracts;
use MWTidy;
/**
* This class needs to understand HTML as well as plain text. It tries to not break HTML tags, but
* might break pairs of tags, leaving unclosed tags behind. We can tidy the output to fix
* this.
*
* @license GPL-2.0-or-later
*/
class TextTruncator {
/**
* @var bool Whether to tidy the output
*/
private $useTidy;
/**
* @param bool $useTidy
*/
public function __construct( bool $useTidy ) {
$this->useTidy = $useTidy;
}
/**
* Returns no more than the given number of sentences
*
* @param string $text Source text to extract from
* @param int $requestedSentenceCount Maximum number of sentences to extract
* @return string
*/
public function getFirstSentences( $text, $requestedSentenceCount ) {
if ( $requestedSentenceCount <= 0 ) {
return '';
}
// Based on code from OpenSearchXml by Brion Vibber
$endchars = [
// regular ASCII
'\P{Lu}\.(?=[ \n]|$)',
'[!?](?=[ \n]|$)',
// full-width ideographic full-stop
'。',
// double-width roman forms
'．',
'！',
'？',
// half-width ideographic full stop
'｡',
];
$regexp = '/(?:' . implode( '|', $endchars ) . ')+/u';
$res = preg_match_all( $regexp, $text, $matches, PREG_OFFSET_CAPTURE );
if ( !$res ) {
// Just return the first line
$lines = explode( "\n", $text, 2 );
return trim( $lines[0] );
}
$index = min( $requestedSentenceCount, $res ) - 1;
list( $tail, $length ) = $matches[0][$index];
// PCRE returns raw offsets, so using substr() instead of mb_substr()
$text = substr( $text, 0, $length ) . $tail;
return $this->tidy( $text );
}
/**
* Returns no more than a requested number of characters, preserving words
*
* @param string $text Source text to extract from
* @param int $requestedLength Maximum number of characters to return
* @return string
*/
public function getFirstChars( $text, $requestedLength ) {
if ( $requestedLength <= 0 ) {
return '';
}
$length = mb_strlen( $text );
if ( $length <= $requestedLength ) {
return $text;
}
// This ungreedy pattern always matches, just might return an empty string
$pattern = '/^[\w\/]*>?/su';
preg_match( $pattern, mb_substr( $text, $requestedLength ), $m );
$text = mb_substr( $text, 0, $requestedLength ) . $m[0];
return $this->tidy( $text );
}
/**
* @param string $text
* @return string
*/
private function tidy( $text ) {
if ( $this->useTidy ) {
$text = MWTidy::tidy( $text );
}
return trim( $text );
}
}
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