ais 0.12.0

An Automatic Identification System (AIS) parser library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

//! Assignment Mode Command (type 16)

use super::parsers::*;
use super::AisMessageType;
use crate::errors::Result;
use nom::bits::{bits, complete::take as take_bits};
use nom::IResult;

#[derive(Debug, PartialEq, Eq)]
pub struct AssignmentModeCommand {
    pub message_type: u8,
    pub repeat_indicator: u8,
    pub mmsi: u32,
    pub mmsi1: u32,
    pub offset1: u16,
    pub increment1: u16,
    pub mmsi2: Option<u32>,
    pub offset2: Option<u16>,
    pub increment2: Option<u16>,
}

impl<'a> AisMessageType<'a> for AssignmentModeCommand {
    fn name(&self) -> &'static str {
        "Assignment Mode Command"
    }

    fn parse(data: &'a [u8]) -> Result<Self> {
        let (_, report) = parse_base(data)?;
        Ok(report)
    }
}

fn parse_base(data: &[u8]) -> IResult<&[u8], AssignmentModeCommand> {
    bits(move |data| -> IResult<_, _> {
        let (data, message_type) = take_bits(6u8)(data)?;
        let (data, repeat_indicator) = take_bits(2u8)(data)?;
        let (data, mmsi) = take_bits(30u32)(data)?;
        let (data, _spare) = take_bits::<_, u8, _, _>(2u8)(data)?;

        let (data, mmsi1) = take_bits(30u32)(data)?;
        let (data, offset1) = take_bits(12u16)(data)?;
        let (data, increment1) = take_bits(10u16)(data)?;

        // Check for remaining bits, if there are enough bits for the second station
        let remaining_bits = remaining_bits(data);

        if remaining_bits >= 52 {
            let (data, mmsi2) = take_bits(30u32)(data)?;
            let (data, offset2) = take_bits(12u16)(data)?;
            let (data, increment2) = take_bits(10u16)(data)?;

            Ok((
                data,
                AssignmentModeCommand {
                    message_type,
                    repeat_indicator,
                    mmsi,
                    mmsi1,
                    offset1,
                    increment1,
                    mmsi2: Some(mmsi2),
                    offset2: Some(offset2),
                    increment2: Some(increment2),
                },
            ))
        } else {
            // Only one station assignment
            Ok((
                data,
                AssignmentModeCommand {
                    message_type,
                    repeat_indicator,
                    mmsi,
                    mmsi1,
                    offset1,
                    increment1,
                    mmsi2: None,
                    offset2: None,
                    increment2: None,
                },
            ))
        }
    })(data)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_type16_example_1_single_station() {
        let bytestream = b"@01uEO@mMk7P<P00";
        let bitstream = crate::messages::unarmor(bytestream, 0).unwrap();
        let report = AssignmentModeCommand::parse(bitstream.as_ref()).unwrap();

        assert_eq!(report.message_type, 16);
        assert_eq!(report.repeat_indicator, 0);
        assert_eq!(report.mmsi, 2053501);
        assert_eq!(report.mmsi1, 224251000);
        assert_eq!(report.offset1, 200);
        assert_eq!(report.increment1, 0);
        assert_eq!(report.mmsi2, None);
        assert_eq!(report.offset2, None);
        assert_eq!(report.increment2, None);
    }

    #[test]
    fn test_type16_example_2_single_station() {
        let bytestream = b"@01uEO@hsqJ0<P00";
        let bitstream = crate::messages::unarmor(bytestream, 0).unwrap();
        let report = AssignmentModeCommand::parse(bitstream.as_ref()).unwrap();

        assert_eq!(report.message_type, 16);
        assert_eq!(report.repeat_indicator, 0);
        assert_eq!(report.mmsi, 2053501);
        assert_eq!(report.mmsi1, 205252000);
        assert_eq!(report.offset1, 200);
        assert_eq!(report.increment1, 0);
        assert_eq!(report.mmsi2, None);
        assert_eq!(report.offset2, None);
        assert_eq!(report.increment2, None);
    }

    #[test]
    fn test_type16_example_with_two_stations() {
        let bytestream = b"@6STUk004lQ206bCKNOBAb6SJ@5s";
        let bitstream = crate::messages::unarmor(bytestream, 0).unwrap();
        let report = AssignmentModeCommand::parse(bitstream.as_ref()).unwrap();

        assert_eq!(report.message_type, 16);
        assert_eq!(report.repeat_indicator, 0);
        assert_eq!(report.mmsi, 439952844);
        assert_eq!(report.mmsi1, 315920);
        assert_eq!(report.offset1, 2049);
        assert_eq!(report.increment1, 681);
        assert_eq!(report.mmsi2, Some(230137673));
        assert_eq!(report.offset2, Some(424));
        assert_eq!(report.increment2, Some(419));
    }
}