+ /**
+ * Recognise the 2-byte magic header for gzip streams
+ *
+ * https://recalll.co/ask/v/topic/java-How-to-check-if-InputStream-is-Gzipped/555aadd62bd27354438b90f6
+ *
+ * @param bytes
+ * - at least two bytes
+ * @return
+ * @throws IOException
+ */
+ public static boolean isGzipStream(InputStream input) throws IOException
+ {
+ if (!input.markSupported())
+ {
+ Console.error(
+ "FileParse.izGzipStream: input stream must support mark/reset");
+ return false;
+ }
+ input.mark(4);
+
+ // get first 2 bytes or return false
+ byte[] bytes = new byte[2];
+ int read = input.read(bytes);
+ input.reset();
+ if (read != bytes.length)
+ {
+ return false;
+ }
+
+ int header = (bytes[0] & 0xff) | ((bytes[1] << 8) & 0xff00);
+ return (GZIPInputStream.GZIP_MAGIC == header);
+ }
+
+ /**
+ * Returns a Reader for the given input after wrapping it in a buffered input
+ * stream, and then checking if it needs to be wrapped by a GZipInputStream
+ *
+ * @param input
+ * @return
+ */
+ private BufferedReader checkForGzipStream(InputStream input)
+ throws Exception
+ {
+ // NB: stackoverflow
+ // https://stackoverflow.com/questions/4818468/how-to-check-if-inputstream-is-gzipped
+ // could use a PushBackInputStream rather than a BufferedInputStream
+ if (!input.markSupported())
+ {
+ input = new BufferedInputStream(input, 16);
+ }
+ if (isGzipStream(input))
+ {
+ return getGzipReader(input);
+ }
+ // return a buffered reader for the stream.
+ InputStreamReader isReader = new InputStreamReader(input);
+ BufferedReader toReadFrom = new BufferedReader(isReader);
+ return toReadFrom;
+ }
+
+ /**
+ * Returns a {@code BufferedReader} which wraps the input stream with a
+ * GZIPInputStream. Throws a {@code ZipException} if a GZIP format error
+ * occurs or the compression method used is unsupported.
+ *
+ * @param inputStream
+ * @return
+ * @throws Exception
+ */
+ private BufferedReader getGzipReader(InputStream inputStream)