Online PHP editor | output for NnOk1

<?php function doCharDiff($from_text, $to_text) { $result = []; $jobs = [[0, strlen($from_text), 0, strlen($to_text)]]; while ($job = array_pop($jobs)) { // get the segments which must be diff'ed list($from_segment_start, $from_segment_end, $to_segment_start, $to_segment_end) = $job; $from_segment_len = $from_segment_end - $from_segment_start; $to_segment_len = $to_segment_end - $to_segment_start; // catch easy cases first if (!$from_segment_len || !$to_segment_len) { if ($from_segment_len) $result[$from_segment_start * 4 + 0] = new FineDiffDeleteOp($from_segment_len); else if ($to_segment_len) $result[$from_segment_start * 4 + 1] = new FineDiffInsertOp(substr($to_text, $to_segment_start, $to_segment_len)); continue; } if ($from_segment_len >= $to_segment_len) { $copy_len = $to_segment_len; while ($copy_len) { $to_copy_start = $to_segment_start; $to_copy_start_max = $to_segment_end - $copy_len; while ($to_copy_start <= $to_copy_start_max) { $from_copy_start = strpos(substr($from_text, $from_segment_start, $from_segment_len), substr($to_text, $to_copy_start, $copy_len)); if ($from_copy_start !== false) { $from_copy_start += $from_segment_start; break 2; } $to_copy_start++; } $copy_len--; } } else { $copy_len = $from_segment_len; while ($copy_len) { $from_copy_start = $from_segment_start; $from_copy_start_max = $from_segment_end - $copy_len; while ($from_copy_start <= $from_copy_start_max) { $to_copy_start = strpos(substr($to_text, $to_segment_start, $to_segment_len), substr($from_text, $from_copy_start, $copy_len)); if ($to_copy_start !== false) { $to_copy_start += $to_segment_start; break 2; } $from_copy_start++; } $copy_len--; } } // match found if ($copy_len) { $jobs[] = [$from_segment_start, $from_copy_start, $to_segment_start, $to_copy_start]; $result[$from_copy_start * 4 + 2] = new FineDiffCopyOp($copy_len); $jobs[] = [$from_copy_start + $copy_len, $from_segment_end, $to_copy_start + $copy_len, $to_segment_end]; } // no match, so delete all, insert all else { $result[$from_segment_start * 4] = new FineDiffReplaceOp($from_segment_len, substr($to_text, $to_segment_start, $to_segment_len)); } } ksort($result, SORT_NUMERIC); return array_values($result); }