Copy include/bbcode functions to src methods

- Add Core\Network class

src/Content/Text/Plaintext.php

@@ -34,4 +34,41 @@ class Plaintext
 
 		return $msg;
 	}
+
+	/**
+	 * Returns the character positions of the provided boundaries, optionally skipping a number of first occurrences
+	 *
+	 * @param string $text        Text to search
+	 * @param string $open        Left boundary
+	 * @param string $close       Right boundary
+	 * @param int    $occurrences Number of first occurrences to skip
+	 * @return boolean|array
+	 */
+	public static function getBoundariesPosition($text, $open, $close, $occurrences = 0)
+	{
+		if ($occurrences < 0) {
+			$occurrences = 0;
+		}
+
+		$start_pos = -1;
+		for ($i = 0; $i <= $occurrences; $i++) {
+			if ($start_pos !== false) {
+				$start_pos = strpos($text, $open, $start_pos + 1);
+			}
+		}
+
+		if ($start_pos === false) {
+			return false;
+		}
+
+		$end_pos = strpos($text, $close, $start_pos);
+
+		if ($end_pos === false) {
+			return false;
+		}
+
+		$res = ['start' => $start_pos, 'end' => $end_pos];
+
+		return $res;
+	}
 }