bit-int 0.2.1

An arbitrary fixed bit-width integer 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
144
145
146
147
148
149
150
151

// SPDX-FileCopyrightText: 2024 Shun Sakai
//
// SPDX-License-Identifier: Apache-2.0 OR MIT

//! Constants for [`BitInt`].

use super::BitInt;

macro_rules! impl_consts {
    ($T:ty) => {
        impl<const N: u32> BitInt<$T, N> {
            /// The smallest value that can be represented by this `BitInt`.
            ///
            /// # Examples
            ///
            /// ```
            /// # use bit_int::BitInt;
            /// #
            #[doc = concat!("assert_eq!(BitInt::<", stringify!($T), ", 7>::MIN.get(), -64);")]
            /// ```
            // SAFETY: because `MIN` must be the smallest value of a `N`-bit signed integer.
            pub const MIN: Self =
                unsafe { Self::new_unchecked(<$T>::MIN >> (<$T>::BITS - Self::BITS)) };

            /// The largest value that can be represented by this `BitInt`.
            ///
            /// # Examples
            ///
            /// ```
            /// # use bit_int::BitInt;
            /// #
            #[doc = concat!("assert_eq!(BitInt::<", stringify!($T), ", 7>::MAX.get(), 63);")]
            /// ```
            // SAFETY: because `MAX` must be the largest value of a `N`-bit signed integer.
            pub const MAX: Self =
                unsafe { Self::new_unchecked(<$T>::MAX >> (<$T>::BITS - Self::BITS)) };

            /// The size of this `BitInt` in bits.
            ///
            /// # Examples
            ///
            /// ```
            /// # use bit_int::BitInt;
            /// #
            #[doc = concat!("assert_eq!(BitInt::<", stringify!($T), ", 7>::BITS, 7);")]
            /// ```
            pub const BITS: u32 = N;
        }
    };
}
impl_consts!(i8);
impl_consts!(i16);
impl_consts!(i32);
impl_consts!(i64);
impl_consts!(i128);
impl_consts!(isize);

#[cfg(test)]
mod tests {
    use super::super::{BitI8, BitI16, BitI32, BitI64, BitI128, BitIsize};

    #[test]
    fn min() {
        assert_eq!(BitI8::<7>::MIN.get(), i8::MIN >> 1);
        assert_eq!(BitI16::<15>::MIN.get(), i16::MIN >> 1);
        assert_eq!(BitI32::<31>::MIN.get(), i32::MIN >> 1);
        assert_eq!(BitI64::<63>::MIN.get(), i64::MIN >> 1);
        assert_eq!(BitI128::<127>::MIN.get(), i128::MIN >> 1);
        assert_eq!(BitIsize::<{ isize::BITS - 1 }>::MIN.get(), isize::MIN >> 1);
    }

    #[test]
    fn min_when_one_bit() {
        assert_eq!(BitI8::<1>::MIN.get(), -1);
        assert_eq!(BitI16::<1>::MIN.get(), -1);
        assert_eq!(BitI32::<1>::MIN.get(), -1);
        assert_eq!(BitI64::<1>::MIN.get(), -1);
        assert_eq!(BitI128::<1>::MIN.get(), -1);
        assert_eq!(BitIsize::<1>::MIN.get(), -1);
    }

    #[test]
    fn min_when_max_bits() {
        assert_eq!(BitI8::<{ i8::BITS }>::MIN.get(), i8::MIN);
        assert_eq!(BitI16::<{ i16::BITS }>::MIN.get(), i16::MIN);
        assert_eq!(BitI32::<{ i32::BITS }>::MIN.get(), i32::MIN);
        assert_eq!(BitI64::<{ i64::BITS }>::MIN.get(), i64::MIN);
        assert_eq!(BitI128::<{ i128::BITS }>::MIN.get(), i128::MIN);
        assert_eq!(BitIsize::<{ isize::BITS }>::MIN.get(), isize::MIN);
    }

    #[test]
    fn max() {
        assert_eq!(BitI8::<7>::MAX.get(), i8::MAX >> 1);
        assert_eq!(BitI16::<15>::MAX.get(), i16::MAX >> 1);
        assert_eq!(BitI32::<31>::MAX.get(), i32::MAX >> 1);
        assert_eq!(BitI64::<63>::MAX.get(), i64::MAX >> 1);
        assert_eq!(BitI128::<127>::MAX.get(), i128::MAX >> 1);
        assert_eq!(BitIsize::<{ isize::BITS - 1 }>::MAX.get(), isize::MAX >> 1);
    }

    #[test]
    fn max_when_one_bit() {
        assert_eq!(BitI8::<1>::MAX.get(), 0);
        assert_eq!(BitI16::<1>::MAX.get(), 0);
        assert_eq!(BitI32::<1>::MAX.get(), 0);
        assert_eq!(BitI64::<1>::MAX.get(), 0);
        assert_eq!(BitI128::<1>::MAX.get(), 0);
        assert_eq!(BitIsize::<1>::MAX.get(), 0);
    }

    #[test]
    fn max_when_max_bits() {
        assert_eq!(BitI8::<{ i8::BITS }>::MAX.get(), i8::MAX);
        assert_eq!(BitI16::<{ i16::BITS }>::MAX.get(), i16::MAX);
        assert_eq!(BitI32::<{ i32::BITS }>::MAX.get(), i32::MAX);
        assert_eq!(BitI64::<{ i64::BITS }>::MAX.get(), i64::MAX);
        assert_eq!(BitI128::<{ i128::BITS }>::MAX.get(), i128::MAX);
        assert_eq!(BitIsize::<{ isize::BITS }>::MAX.get(), isize::MAX);
    }

    #[test]
    fn bits() {
        assert_eq!(BitI8::<7>::BITS, 7);
        assert_eq!(BitI16::<15>::BITS, 15);
        assert_eq!(BitI32::<31>::BITS, 31);
        assert_eq!(BitI64::<63>::BITS, 63);
        assert_eq!(BitI128::<127>::BITS, 127);
        assert_eq!(BitIsize::<{ isize::BITS - 1 }>::BITS, isize::BITS - 1);
    }

    #[test]
    fn bits_when_one_bit() {
        assert_eq!(BitI8::<1>::BITS, 1);
        assert_eq!(BitI16::<1>::BITS, 1);
        assert_eq!(BitI32::<1>::BITS, 1);
        assert_eq!(BitI64::<1>::BITS, 1);
        assert_eq!(BitI128::<1>::BITS, 1);
        assert_eq!(BitIsize::<1>::BITS, 1);
    }

    #[test]
    fn bits_when_max_bits() {
        assert_eq!(BitI8::<{ i8::BITS }>::BITS, i8::BITS);
        assert_eq!(BitI16::<{ i16::BITS }>::BITS, i16::BITS);
        assert_eq!(BitI32::<{ i32::BITS }>::BITS, i32::BITS);
        assert_eq!(BitI64::<{ i64::BITS }>::BITS, i64::BITS);
        assert_eq!(BitI128::<{ i128::BITS }>::BITS, i128::BITS);
        assert_eq!(BitIsize::<{ isize::BITS }>::BITS, isize::BITS);
    }
}