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

use core::ops::{ControlFlow, FromResidual, Try};

pub const ERROR_BIT: usize = 1 << (usize::BITS - 1);

#[derive(Copy, Clone, Debug, Eq, PartialEq)]
#[repr(usize)]
pub enum Error {
    Success,
    LoadError,
    InvalidParameter,
    Unsupported,
    BadBufferSize,
    BufferTooSmall,
    NotReady,
    DeviceError,
    WriteProtected,
    OutOfResources,
    VolumeCorrupted,
    VolumeFull,
    NoMedia,
    MediaChanged,
    NotFound,
    AccessDenied,
    NoResponse,
    NoMapping,
    Timeout,
    NotStarted,
    AlreadyStarted,
    Aborted,
    IcmpError,
    TftpError,
    ProtocolError,
    IncompatibleVersion,
    SecurityViolation,
    CrcError,
    EndOfMedia,
    Error29,
    Error30,
    EndOfFile,
    InvalidLanguage,
    CompromisedData,
    Error34,
    HttpError,
    Unknown,
}

impl From<usize> for Error {
    fn from(value: usize) -> Self {
        use self::Error::*;
        match value {
            0 => Success,
            1 => LoadError,
            2 => InvalidParameter,
            3 => Unsupported,
            4 => BadBufferSize,
            5 => BufferTooSmall,
            6 => NotReady,
            7 => DeviceError,
            8 => WriteProtected,
            9 => OutOfResources,
            10 => VolumeCorrupted,
            11 => VolumeFull,
            12 => NoMedia,
            13 => MediaChanged,
            14 => NotFound,
            15 => AccessDenied,
            16 => NoResponse,
            17 => NoMapping,
            18 => Timeout,
            19 => NotStarted,
            20 => AlreadyStarted,
            21 => Aborted,
            22 => IcmpError,
            23 => TftpError,
            24 => ProtocolError,
            25 => IncompatibleVersion,
            26 => SecurityViolation,
            27 => CrcError,
            28 => EndOfMedia,
            29 => Error29,
            30 => Error30,
            31 => EndOfFile,
            32 => InvalidLanguage,
            33 => CompromisedData,
            34 => Error34,
            35 => HttpError,
            _ => Unknown,
        }
    }
}

pub type Result<T> = ::core::result::Result<T, Error>;

#[derive(Copy, Clone, Debug, Eq, PartialEq)]
#[must_use]
#[repr(transparent)]
pub struct Status(pub usize);

impl Status {
    pub fn new(value: usize) -> Self {
        Status(value)
    }
}

impl Try for Status {
    type Output = usize;
    type Residual = Error;

    fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {
        if self.0 & ERROR_BIT == 0 {
            ControlFlow::Continue(self.0)
        } else {
            ControlFlow::Break(Error::from(self.0 & !ERROR_BIT))
        }
    }

    fn from_output(v: Self::Output) -> Self {
        Self(v & !ERROR_BIT)
    }
}

impl FromResidual for Status {
    fn from_residual(v: Error) -> Self {
        Self(v as usize | ERROR_BIT)
    }
}

impl<T> FromResidual<Error> for Result<T> {
    fn from_residual(err: Error) -> Self {
        Err(err)
    }
}