field, followed
			// immediately by data
			list(, $general_purpose_flag) = unpack('v', substr($gz_data, 6, 2));

			// If the file has been compressed on the fly, 0x08 bit is set of
			// the general purpose field. We can use this to differentiate
			// between a compressed document, and a ZIP file
			$zip_compressed_on_the_fly = ((0x08 & $general_purpose_flag) === 0x08);

			if (!$zip_compressed_on_the_fly) {
				// Don't attempt to decode a compressed zip file
				return $gz_data;
			}

			// Determine the first byte of data, based on the above ZIP header
			// offsets:
			$first_file_start = array_sum(unpack('v2', substr($gz_data, 26, 4)));
			$decompressed     = @gzinflate(substr($gz_data, 30 + $first_file_start));
			if ($decompressed !== false) {
				return $decompressed;
			}

			return false;
		}

		// Finally fall back to straight gzinflate
		$decompressed = @gzinflate($gz_data);
		if ($decompressed !== false) {
			return $decompressed;
		}

		// Fallback for all above failing, not expected, but included for
		// debugging and preventing regressions and to track stats
		$decompressed = @gzinflate(substr($gz_data, 2));
		if ($decompressed !== false) {
			return $decompressed;
		}

		return false;
	}
}