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

use crate::common::Segment;

const THERMAL_ASSERT_BIT: u8 = 1 << 0;
const CURRENT_MOD_SEGMENT_BIT: u8 = 1 << 1;
const CURRENT_STM_SEGMENT_BIT: u8 = 1 << 2;
const CURRENT_GAIN_SEGMENT_BIT: u8 = 1 << 2;
const IS_GAIN_MODE_BIT: u8 = 1 << 3;

/// FPGA state
#[repr(C)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct FPGAState {
    pub(crate) state: u8,
}

impl FPGAState {
    /// Check if thermal sensor is asserted
    pub const fn is_thermal_assert(&self) -> bool {
        (self.state & THERMAL_ASSERT_BIT) != 0
    }

    /// Current mod segment
    pub const fn current_mod_segment(&self) -> Segment {
        match self.state & CURRENT_MOD_SEGMENT_BIT {
            0 => Segment::S0,
            _ => Segment::S1,
        }
    }

    /// Current stm segment
    pub const fn current_stm_segment(&self) -> Option<Segment> {
        if !self.is_stm_mode() {
            return None;
        }
        match self.state & CURRENT_STM_SEGMENT_BIT {
            0 => Some(Segment::S0),
            _ => Some(Segment::S1),
        }
    }

    /// Current gain segment
    pub const fn current_gain_segment(&self) -> Option<Segment> {
        if !self.is_gain_mode() {
            return None;
        }
        match self.state & CURRENT_GAIN_SEGMENT_BIT {
            0 => Some(Segment::S0),
            _ => Some(Segment::S1),
        }
    }

    /// Check if gain mode
    pub const fn is_gain_mode(&self) -> bool {
        (self.state & IS_GAIN_MODE_BIT) != 0
    }

    /// Check if stm mode
    pub const fn is_stm_mode(&self) -> bool {
        !self.is_gain_mode()
    }

    pub const fn state(&self) -> u8 {
        self.state
    }
}

#[cfg(test)]
mod tests {
    use std::mem::size_of;

    use super::*;

    #[test]
    fn test_size() {
        assert_eq!(1, size_of::<FPGAState>());
        assert_eq!(0, std::mem::offset_of!(FPGAState, state));
    }

    #[rstest::rstest]
    #[test]
    #[case(false, 0b0)]
    #[case(true, 0b1)]
    fn test_is_thermal_assert(#[case] expected: bool, #[case] state: u8) {
        assert_eq!(expected, FPGAState { state }.is_thermal_assert());
    }

    #[rstest::rstest]
    #[test]
    #[case(Segment::S0, 0b00)]
    #[case(Segment::S1, 0b10)]
    fn test_current_mod_segment(#[case] expected: Segment, #[case] state: u8) {
        assert_eq!(expected, FPGAState { state }.current_mod_segment());
    }

    #[rstest::rstest]
    #[test]
    #[case(false, 0b0000)]
    #[case(true, 0b1000)]
    fn test_is_gain_mode(#[case] expected: bool, #[case] state: u8) {
        assert_eq!(expected, FPGAState { state }.is_gain_mode());
    }

    #[rstest::rstest]
    #[test]
    #[case(false, 0b1000)]
    #[case(true, 0b0000)]
    fn test_is_stm_mode(#[case] expected: bool, #[case] state: u8) {
        assert_eq!(expected, FPGAState { state }.is_stm_mode());
    }

    #[rstest::rstest]
    #[test]
    #[case(None, 0b1000)]
    #[case(Some(Segment::S0), 0b0000)]
    #[case(Some(Segment::S1), 0b0100)]
    fn test_current_stm_segment(#[case] expected: Option<Segment>, #[case] state: u8) {
        assert_eq!(expected, FPGAState { state }.current_stm_segment());
    }

    #[rstest::rstest]
    #[test]
    #[case(None, 0b0000)]
    #[case(Some(Segment::S0), 0b1000)]
    #[case(Some(Segment::S1), 0b1100)]
    fn test_current_gain_segment(#[case] expected: Option<Segment>, #[case] state: u8) {
        assert_eq!(expected, FPGAState { state }.current_gain_segment());
    }
}