ruint 1.19.0

Unsigned integer type with const-generic bit length
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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263

/// Wrapper for [`ruint_macro::uint!`]. See its documentation for details.
#[macro_export]
#[cfg(not(doc))] // Show the actual macro in docs.
#[doc(hidden)]
macro_rules! uint {
    ($($t:tt)*) => {
        $crate::__private::ruint_macro::uint_with_path! { [$crate] $($t)* }
    }
}

macro_rules! impl_bin_op {
    ($trait:ident, $fn:ident, $trait_assign:ident, $fn_assign:ident, $fdel:ident) => {
        impl<const BITS: usize, const LIMBS: usize> $trait_assign<Uint<BITS, LIMBS>>
            for Uint<BITS, LIMBS>
        {
            #[inline(always)]
            #[track_caller]
            fn $fn_assign(&mut self, rhs: Uint<BITS, LIMBS>) {
                *self = self.$fdel(rhs);
            }
        }
        impl<const BITS: usize, const LIMBS: usize> $trait_assign<&Uint<BITS, LIMBS>>
            for Uint<BITS, LIMBS>
        {
            #[inline(always)]
            #[track_caller]
            fn $fn_assign(&mut self, rhs: &Uint<BITS, LIMBS>) {
                *self = self.$fdel(*rhs);
            }
        }
        impl<const BITS: usize, const LIMBS: usize> $trait<Uint<BITS, LIMBS>>
            for Uint<BITS, LIMBS>
        {
            type Output = Uint<BITS, LIMBS>;

            #[inline(always)]
            #[track_caller]
            fn $fn(self, rhs: Uint<BITS, LIMBS>) -> Self::Output {
                self.$fdel(rhs)
            }
        }
        impl<const BITS: usize, const LIMBS: usize> $trait<&Uint<BITS, LIMBS>>
            for Uint<BITS, LIMBS>
        {
            type Output = Uint<BITS, LIMBS>;

            #[inline(always)]
            #[track_caller]
            fn $fn(self, rhs: &Uint<BITS, LIMBS>) -> Self::Output {
                self.$fdel(*rhs)
            }
        }
        impl<const BITS: usize, const LIMBS: usize> $trait<Uint<BITS, LIMBS>>
            for &Uint<BITS, LIMBS>
        {
            type Output = Uint<BITS, LIMBS>;

            #[inline(always)]
            #[track_caller]
            fn $fn(self, rhs: Uint<BITS, LIMBS>) -> Self::Output {
                self.$fdel(rhs)
            }
        }
        impl<const BITS: usize, const LIMBS: usize> $trait<&Uint<BITS, LIMBS>>
            for &Uint<BITS, LIMBS>
        {
            type Output = Uint<BITS, LIMBS>;

            #[inline(always)]
            #[track_caller]
            fn $fn(self, rhs: &Uint<BITS, LIMBS>) -> Self::Output {
                self.$fdel(*rhs)
            }
        }
    };
}

macro_rules! assume {
    ($e:expr $(,)?) => {
        if !$e {
            debug_unreachable!(stringify!($e));
        }
    };

    ($e:expr, $($t:tt)+) => {
        if !$e {
            debug_unreachable!($($t)+);
        }
    };
}

macro_rules! debug_unreachable {
    ($($t:tt)*) => {
        if cfg!(debug_assertions) {
            panic!($($t)*);
        } else {
            unsafe { core::hint::unreachable_unchecked() };
        }
    };
}

macro_rules! const_range_for {
    ($p:pat in $start:tt.. $end:expr => $x:block) => {
        const_range_for!(@range $p, $start, $end, $x)
    };
    ($p:pat in ($start:expr).. $end:expr => $x:block) => {
        const_range_for!(@range $p, $start, $end, $x)
    };
    (@range $p:pat, $start:expr, $end:expr, $x:block) => {{
        let mut iter = $start;
        while iter < $end {
            // This mirrors `core::ops::IndexRange::next_unchecked` until const
            // fns can use normal `for` loops again.
            let $p = iter;
            // SAFETY: The range was checked to be non-empty, so adding one
            // cannot overflow.
            iter = unsafe { iter.unchecked_add(1) };
            $x
        }
    }};
    ($p:pat in ref $slice:expr => $x:block) => {{
        let slice = $slice;
        let range = slice.as_ptr_range();
        let mut ptr = range.start;
        let end = range.end;
        // This mirrors the non-ZST `core::slice::Iter::next` pointer walk until
        // const fns can use normal `for` loops again.
        while unsafe { end.offset_from(ptr) } != 0 {
            let old = ptr;
            // SAFETY: `ptr` is not `end`, so advancing by one stays within the
            // slice range or reaches the one-past-end pointer.
            ptr = unsafe { ptr.add(1) };
            // SAFETY: `old` came from `slice.as_ptr_range()` and was checked to
            // be before `end`, so it points to a live element.
            let $p = unsafe { &*old };
            $x
        }
    }};
    ($p:pat in rev ref $slice:expr => $x:block) => {{
        let slice = $slice;
        let range = slice.as_ptr_range();
        let start = range.start;
        let mut ptr = range.end;
        // This mirrors the non-ZST `core::slice::Iter::next_back` pointer walk
        // until const fns can use normal `for` loops again.
        while unsafe { ptr.offset_from(start) } != 0 {
            // SAFETY: `ptr` is after `start`, so moving back by one stays within
            // the slice range and points to the next element from the back.
            ptr = unsafe { ptr.sub(1) };
            // SAFETY: `ptr` came from `slice.as_ptr_range()` and was moved back
            // into the slice range before dereferencing.
            let $p = unsafe { &*ptr };
            $x
        }
    }};
    ($p:pat in mut $slice:expr => $x:block) => {{
        let slice = &mut $slice;
        let range = slice.as_mut_ptr_range();
        let mut ptr = range.start;
        let end = range.end;
        // This mirrors the non-ZST `core::slice::IterMut::next` pointer walk
        // until const fns can use normal `for` loops again.
        while unsafe { end.offset_from(ptr) } != 0 {
            let old = ptr;
            // SAFETY: `ptr` is not `end`, so advancing by one stays within the
            // slice range or reaches the one-past-end pointer.
            ptr = unsafe { ptr.add(1) };
            // SAFETY: `old` came from `slice.as_mut_ptr_range()` and was checked
            // to be before `end`. The pointer is advanced before yielding, which
            // matches `IterMut` and avoids yielding the same element twice.
            let $p = unsafe { &mut *old };
            $x
        }
    }};
}

/// `let $id = &mut [0u64; nlimbs(2 * BITS)][..]`
macro_rules! let_double_bits {
    ($id:ident) => {
        // This array casting is a workaround for `generic_const_exprs` not being
        // stable.
        let mut double = [[0u64; 2]; LIMBS];
        let double_len = crate::nlimbs(2 * BITS);
        debug_assert!(2 * LIMBS >= double_len);
        // SAFETY: `[[u64; 2]; LIMBS] == [u64; 2 * LIMBS] >= [u64; nlimbs(2 * BITS)]`.
        let $id = unsafe {
            core::slice::from_raw_parts_mut(double.as_mut_ptr().cast::<u64>(), double_len)
        };
    };
}

/// Specialize an operation for u64, u128, u256 ([u128; 2])...
macro_rules! as_primitives {
    ($($uints:expr),* $(,)?; $($rest:tt)*) => {
        as_primitives!(@inner ($($uints),*); $($rest)*);
    };

    (@inner $uints:tt; { $($arm:ident $t:tt => $e:expr),* $(,)? }) => {
        $(
            as_primitives!(@arm $uints; $arm $t => $e);
        )*
    };

    (@arm ($($uint:expr),*); u64($($n:pat),*) => $e:expr) => {
        if LIMBS == 1 {
            $(
                let $n = $uint.limbs[0];
            )*
            $e
        }
    };
    (@arm ($($uint:expr),*); u128($($n:pat),*) => $e:expr) => {
        if LIMBS == 2 {
            $(
                let $n = $uint.as_double_words()[0].get();
            )*
            $e
        }
    };
    (@arm ($($uint:expr),*); u256($(($lo:pat, $hi:pat)),*) => $e:expr) => {
        if LIMBS == 4 {
            $(
                let &[lo, hi] = $uint.as_double_words() else { unreachable!() };
                let $lo = lo.get();
                let $hi = hi.get();
            )*
            $e
        }
    };
}

#[cfg(test)]
mod tests {
    // https://github.com/alloy-rs/ruint/issues/359
    ruint_macro::uint_with_path! {
        [crate]
        const _A: [crate::aliases::U256; 2] = [
            0x00006f85d6f68a85ec10345351a23a3aaf07f38af8c952a7bceca70bd2af7ad5_U256,
            0x00004b4110c9ae997782e1509b1d0fdb20a7c02bbd8bea7305462b9f8125b1e8_U256,
        ];
    }

    crate::uint! {
        const _B: [crate::aliases::U256; 2] = [
            0x00006f85d6f68a85ec10345351a23a3aaf07f38af8c952a7bceca70bd2af7ad5_U256,
            0x00004b4110c9ae997782e1509b1d0fdb20a7c02bbd8bea7305462b9f8125b1e8_U256,
        ];
    }

    #[test]
    fn test_uint_macro_with_paths() {
        extern crate self as aaa;
        use crate as ruint;
        use crate as __ruint;
        let value = crate::aliases::U256::from(0x10);
        assert_eq!(value, uint!(0x10U256));
        assert_eq!(value, ruint_macro::uint_with_path!([crate] 0x10U256));
        assert_eq!(value, ruint_macro::uint_with_path!([aaa] 0x10U256));
        assert_eq!(value, ruint_macro::uint_with_path!([aaa] 0x10U256));
        assert_eq!(value, ruint_macro::uint_with_path!([ruint] 0x10U256));
        assert_eq!(value, ruint_macro::uint_with_path!([__ruint] 0x10U256));
    }
}