Cannot access underlying data

[tiphaineruy]

Issue: When parsing an AIS frame. you sometime might want to access the raw data.

example: VesselDynamicData.nav_status is an enum constructed from an u8 field. If you need to use the parser as an intermediate parser for other tool, you might want to use the underlying u8 and not manipulate the enum

solutions:

• for fields store the raw value in the object and only parse the enum when requested.
• do not store the raw value and impl "to_value" for enums and accept dataloss for enums mapping different values to one enum field -> ex: ShipType ' 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 => ShipType::HighSpeedCraft,'

[tiphaineruy]

Simplest would be

/// Navigation status for VesselDynamicData

[derive(Clone, Copy, Debug, PartialEq)]

pub enum NavigationStatus { UnderWayUsingEngine = 0, // 0 AtAnchor = 1, // 1 NotUnderCommand = 2, // 2 .... }

allowing let nav_status = NavigationStatus::UnderWayUsingEngine as u8