variant-rs 0.4.0

VARIANT support for Rust. Clean, idiomatic handling of WinAPI/COM results.
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

//! Wrapper type for COM dates (stored as [`f64`])

use chrono::{Duration, NaiveDate, NaiveDateTime, NaiveTime};
use std::fmt::{Debug, Display};
use std::ops::Sub;

/// Transparent wrapper around a COM date stored as an [`f64`]
#[derive(Clone, Copy, PartialEq, PartialOrd)]
pub struct ComDate(pub f64);

impl Display for ComDate {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(
            f,
            "{}",
            match TryInto::<NaiveDateTime>::try_into(*self) {
                Ok(s) => s.to_string(),
                Err(_) => "<invalid>".to_owned(),
            }
        )
    }
}

impl Debug for ComDate {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "ComDate({:?}, {})", self.0, self)
    }
}

macro_rules! com_epoch {
    () => {
        NaiveDateTime::new(
            NaiveDate::from_ymd_opt(1899, 12, 30).unwrap(),
            NaiveTime::from_hms_opt(0, 0, 0).unwrap(),
        )
    };
}

impl From<NaiveDateTime> for ComDate {
    fn from(date: NaiveDateTime) -> Self {
        ComDate(date.sub(com_epoch!()).num_milliseconds() as f64 / 24.0 / 60.0 / 60.0 / 1000.0)
    }
}

impl From<ComDate> for NaiveDateTime {
    fn from(date: ComDate) -> Self {
        com_epoch!() + Duration::milliseconds((date.0 * 24.0 * 60.0 * 60.0 * 1000.0) as i64)
    }
}

impl From<*mut f64> for &mut ComDate {
    fn from(ptr: *mut f64) -> Self {
        unsafe { &mut *(ptr as *mut ComDate) }
    }
}

impl ComDate {
    pub fn as_mut_ptr(&mut self) -> *mut f64 {
        (&mut self.0) as *mut f64
    }
}