quantities 0.10.0

Unit-safe computations with quantities.
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

// ---------------------------------------------------------------------------
// Copyright:   (c) 2022 ff. Michael Amrhein (michael@adrhinum.de)
// License:     This program is part of a larger application. For license
//              details please read the file LICENSE.TXT provided together
//              with the application.
// ---------------------------------------------------------------------------
// $Source: src/rate.rs $
// $Revision: 2022-04-17T17:08:57+02:00 $

use core::{
    fmt,
    ops::{Div, Mul},
};

use crate::{AmountT, Quantity, Unit, AMNT_ONE};

/// The ratio between two related quantity values.
#[derive(Copy, Clone, Debug)]
pub struct Rate<TQ: Quantity, PQ: Quantity> {
    term_amount: AmountT,
    term_unit: TQ::UnitType,
    per_unit_multiple: AmountT,
    per_unit: PQ::UnitType,
}

impl<TQ: Quantity, PQ: Quantity> Rate<TQ, PQ> {
    /// Returns a new instance of `Rate` with attributes equal to given params.
    #[inline(always)]
    pub const fn new(
        term_amount: AmountT,
        term_unit: TQ::UnitType,
        per_unit_multiple: AmountT,
        per_unit: PQ::UnitType,
    ) -> Self {
        Self {
            term_amount,
            term_unit,
            per_unit_multiple,
            per_unit,
        }
    }

    /// Returns a new instance of `Rate` with attributes extracted from the
    /// given quantity values.
    #[inline(always)]
    pub fn from_qty_vals(term: TQ, per: PQ) -> Self {
        Self {
            term_amount: term.amount(),
            term_unit: term.unit(),
            per_unit_multiple: per.amount(),
            per_unit: per.unit(),
        }
    }

    /// Returns the term amount of `self`.
    #[inline(always)]
    pub const fn term_amount(&self) -> AmountT {
        self.term_amount
    }

    /// Returns the term unit of `self`.
    #[inline(always)]
    pub const fn term_unit(&self) -> TQ::UnitType {
        self.term_unit
    }

    /// Returns the per unit multiple of `self`.
    #[inline(always)]
    pub const fn per_unit_multiple(&self) -> AmountT {
        self.per_unit_multiple
    }

    /// Returns the per unit of `self`.
    #[inline(always)]
    pub const fn per_unit(&self) -> PQ::UnitType {
        self.per_unit
    }

    /// Returns the multiplicative inverse of `self`
    pub const fn reciprocal(&self) -> Rate<PQ, TQ> {
        Rate::<PQ, TQ>::new(
            self.per_unit_multiple(),
            self.per_unit(),
            self.term_amount(),
            self.term_unit(),
        )
    }
}

impl<TQ: Quantity, PQ: Quantity> fmt::Display for Rate<TQ, PQ> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        if self.term_unit().symbol() == "" {
            write!(f, "{} / ", self.term_amount())?;
        } else {
            write!(
                f,
                "{} {} / ",
                self.term_amount(),
                self.term_unit().symbol()
            )?;
        };
        if self.per_unit().symbol() == "" {
            write!(f, "{}", self.per_unit_multiple())
        } else if self.per_unit_multiple() == AMNT_ONE {
            write!(f, "{}", self.per_unit().symbol())
        } else {
            write!(
                f,
                "{} {}",
                self.per_unit_multiple(),
                self.per_unit().symbol()
            )
        }
    }
}

impl<TQ: Quantity, PQ: Quantity> Mul<PQ> for Rate<TQ, PQ>
where
    PQ: Div<PQ, Output = AmountT>,
{
    type Output = TQ;

    fn mul(self, rhs: PQ) -> Self::Output {
        let amnt: AmountT =
            (rhs / self.per_unit().as_qty()) / self.per_unit_multiple();
        Self::Output::new(amnt * self.term_amount(), self.term_unit())
    }
}