fastnum 0.7.4

Fast decimal numbers 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
141
142
143

use core::{
    fmt,
    fmt::{Display, Formatter},
};

use crate::{bint::UInt, decimal::dec::ControlBlock};

#[inline]
pub(crate) fn debug_print<const N: usize>(
    digits: &UInt<N>,
    cb: &ControlBlock,
    ty: &str,
    f: &mut Formatter,
) -> fmt::Result {
    if f.alternate() {
        debug_print_alternate(digits, cb, ty, f)
    } else {
        debug_print_default(digits, cb, ty, f)
    }
}

fn debug_print_alternate<const N: usize>(
    digits: &UInt<N>,
    cb: &ControlBlock,
    ty: &str,
    f: &mut Formatter,
) -> fmt::Result {
    if cb.is_nan() {
        return write!(f, "{ty}(NaN)");
    } else if cb.is_infinity() {
        return write!(f, "{ty}({}Inf)", cb.get_sign());
    }

    let alert = if cb.is_op_ok() { "" } else { "! " };
    write!(
        f,
        "{}({}{}{}e{})",
        ty,
        alert,
        cb.get_sign(),
        digits,
        cb.get_exponent()
    )
}

fn debug_print_default<const N: usize>(
    digits: &UInt<N>,
    cb: &ControlBlock,
    ty: &str,
    f: &mut Formatter,
) -> fmt::Result {
    write!(
        f,
        "{}(digits=[{:?}], exp=[{}], flags=[{}], signals=[{}], ctx=[{}], extra=[{}])",
        ty,
        digits,
        cb.get_exponent(),
        Flags(*cb),
        cb.get_signals(),
        cb.get_context(),
        cb.get_extra_precision()
    )
}

struct Flags(ControlBlock);

macro_rules! delimiter {
    ($delimiter: ident, $f: ident) => {
        #[allow(unused_assignments)]
        match $delimiter {
            true => {
                write!($f, ", ")?;
            }
            false => {
                $delimiter = true;
            }
        }
    };
}

impl Display for Flags {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        let mut delimiter = false;

        if self.0.is_nan() {
            write!(f, "NAN")?;
            delimiter = true;
        }

        if self.0.is_negative() {
            delimiter!(delimiter, f);
            write!(f, "S")?;
        }

        if self.0.is_infinity() {
            delimiter!(delimiter, f);
            write!(f, "INF")?;
        }

        Ok(())
    }
}

macro_rules! type_name {
    ($t: literal) => {
        const {
            const PREFIX: &'static [u8] = $t.as_bytes();

            let buffer: &[u8] = &const {
                let mut buffer = [0; PREFIX.len() + usize::MAX.ilog10() as usize + 1];

                let mut i = buffer.len();
                let mut n = N * 64;

                while 0 < i && n != 0 {
                    i -= 1;

                    buffer[i] = (n % 10) as u8 + b'0';
                    n /= 10;
                }

                let mut j = PREFIX.len();
                while 0 < i && 0 < j {
                    i -= 1;
                    j -= 1;

                    buffer[i] = PREFIX[j];
                }

                buffer
            };

            let buffer_len = PREFIX.len() + (N * 64).ilog10() as usize + 1;

            match core::str::from_utf8(buffer.split_at(buffer.len() - buffer_len).1) {
                Ok(x) => x,
                Err(_) => panic!("buffer is always ascii"),
            }
        }
    };
}

pub(crate) use type_name;