private function extractRelevant($words, $fulltext, $relLength = 300)
{
if (!is_array($words)) {
$words = explode(' ', $words);
}
// 1/6 ratio on prevcount tends to work pretty well and puts the terms
// in the middle of the extract
$prevCount = floor($relLength / 6);
$indicator = '…';
$textlength = strlen($fulltext);
if ($textlength <= $relLength) {
return $fulltext;
}
$locations = $this->extractLocations($words, $fulltext);
$startPos = $this->determineSnipLocation($locations, $prevCount);
// if we are going to snip too much...
if ($textlength - $startPos < $relLength) {
$startPos = $startPos - ($textlength - $startPos) / 2;
}
$relText = substr($fulltext, $startPos, $relLength);
// check to ensure we dont snip the last word if thats the match
if ($startPos + $relLength < $textlength) {
$relText = substr($relText, 0, strrpos($relText, ' ')) . $indicator;
// remove last word
}
// If we trimmed from the front add '…'
if ($startPos != 0) {
$relText = $indicator . substr($relText, strpos($relText, ' ') + 1);
// remove first word
}
// Highlight the words, using the `<mark>` tag.
foreach ($words as $word) {
$relText = preg_replace('/\\b(' . $word . ')\\b/i', '<mark>$1</mark>', $relText);
}
return $relText;
}
