devela 0.28.0

A development substrate of coherence.
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
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315

// devela::num::prob::rand::xyza8
//
//!

use crate::{ConstInit, Own, whilst};
use crate::{Infallible, InfallibleResult, RandQualities, RandSeedable, RandTry};

#[doc = crate::_tags!(rand)]
/// A simple 8-bit <abbr title="Pseudo-Random Number Generator">PRNG</abbr>
/// with 32-bit of state, based on the *XorShift* algorithm.
#[doc = crate::_doc_meta!{location("num/prob/rand")}]
///
/// It has a 0.8% chance of falling into a poor quality short chain,
/// a some degree of care is required to seed it. However, the quality of the
/// random numbers is excellent for such a small state (32 bits), and it passes
/// almost all of the die hard tests.
///
/// Its longest cycle is 4_261_412_736.
// (== u32::MAX + u16::MAX * 512 + 639).
#[doc = crate::_doc_vendor!("8bit_rng")]
#[must_use]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct Xyza8a {
    x: u8,
    y: u8,
    z: u8,
    a: u8,
}

/// Creates a new PRNG initialized with the default fixed seed.
impl Default for Xyza8a {
    fn default() -> Self {
        Self::INIT
    }
}
/// Creates a new PRNG initialized with the default fixed seed.
impl ConstInit for Xyza8a {
    const INIT: Self = Self::new(Self::DEFAULT_SEED);
}

// private associated items
impl Xyza8a {
    #[doc(hidden)]
    pub const DEFAULT_SEED: [u8; 4] = [0xDE, 0xFA, 0x00, 0x17];
}

impl Xyza8a {
    /// Returns a seeded `Xyza8a` generator from the given 4 × 8-bit seeds.
    pub const fn new(seeds: [u8; 4]) -> Self {
        Self { x: seeds[0], y: seeds[1], z: seeds[2], a: seeds[3] }
    }
    #[must_use]
    /// Returns the PRNG's inner state as a raw snapshot.
    pub const fn inner_state(self) -> [u8; 4] {
        [self.x, self.y, self.z, self.a]
    }
    /// Restores the PRNG from the given state.
    pub const fn from_state(state: [u8; 4]) -> Self {
        Self { x: state[0], y: state[1], z: state[2], a: state[3] }
    }
    #[must_use]
    /// Returns the current random `u8`.
    pub const fn current_u8(&self) -> u8 {
        self.a
    }
    /// Advances the state and returns the next random `u8`.
    pub const fn next_u8(&mut self) -> u8 {
        let t = self.x ^ (self.x << 4);
        self.x = self.y;
        self.y = self.z;
        self.z = self.a;
        self.a = self.z ^ t ^ (self.z >> 1) ^ (t << 1);
        self.a
    }
    /// Returns a copy of the next new random state.
    pub const fn peek_next_state(&self) -> Self {
        let mut new = *self;
        let t = new.x ^ (new.x << 4);
        new.x = new.y;
        new.y = new.z;
        new.z = new.a;
        new.a = new.z ^ t ^ (new.z >> 1) ^ (t << 1);
        new
    }
    /// Returns both the next random state and the `u8` value.
    pub const fn own_next_u8(self) -> Own<Self, u8> {
        let s = self.peek_next_state();
        let v = s.current_u8();
        Own::new(s, v)
    }
    /// Fills the buffer with generated bytes.
    pub const fn fill_bytes(&mut self, buffer: &mut [u8]) {
        whilst! { i in 0..buffer.len(); {
            buffer[i] = self.next_u8();
        }}
    }
}

/// # Extras
impl Xyza8a {
    /// Returns a seeded `Xyza8a` generator from the given 32-bit seed.
    ///
    /// The seeds will be split in little endian order.
    pub const fn new1_u32(seed: u32) -> Self {
        Self::new(seed.to_le_bytes())
    }
    /// Returns a seeded `Xyza8a` generator from the given 2 × 16-bit seeds.
    ///
    /// The seeds will be split in little endian order.
    pub const fn new2_u16(seeds: [u16; 2]) -> Self {
        let [x, y] = seeds[0].to_le_bytes();
        let [z, a] = seeds[1].to_le_bytes();
        Self::new([x, y, z, a])
    }
    /// Returns a seeded `Xyza8b` generator from the given 4 × 8-bit seeds.
    /// This is an alias of [`new`][Self#method.new].
    pub const fn new4_u8(seeds: [u8; 4]) -> Self {
        Self::new(seeds)
    }
    /// Returns the next 2 × random `u8` combined as a single `u16`.
    fn next_u16(&mut self) -> u16 {
        u16::from_le_bytes([self.next_u8(), self.next_u8()])
    }
    /// Returns the next 4 × random `u8` combined as a single `u32`.
    fn next_u32(&mut self) -> u32 {
        u32::from_le_bytes([self.next_u8(), self.next_u8(), self.next_u8(), self.next_u8()])
    }
    /// Returns the next 8 × random `u8` combined as a single `u64`.
    fn next_u64(&mut self) -> u64 {
        u64::from_le_bytes([
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
        ])
    }
}

// -----------------------------------------------------------------------------

#[doc = crate::_tags!(rand)]
/// A simple 8-bit <abbr title="Pseudo-Random Number Generator">PRNG</abbr>
/// with 32-bit of state, based on the *XorShift* algorithm.
#[doc = crate::_doc_meta!{location("num/prob/rand")}]
///
/// It has an almost optimal cycle so no real care is required
/// for seeding except avoiding all zeros, but it fails many of the die hard
/// random number tests.
///
/// Its longest cycle is 4,294,967,294.
#[doc = crate::_doc_vendor!("8bit_rng")]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct Xyza8b {
    x: u8,
    y: u8,
    z: u8,
    a: u8,
}

impl Default for Xyza8b {
    fn default() -> Self {
        Self::INIT
    }
}
impl ConstInit for Xyza8b {
    const INIT: Self = Self::new(Self::DEFAULT_SEED);
}

// private associated items
impl Xyza8b {
    #[doc(hidden)]
    pub const DEFAULT_SEED: [u8; 4] = [0xDE, 0xFA, 0x00, 0x17];
}

impl Xyza8b {
    /// Returns a seeded `Xyza8b` generator from the given 4 × 8-bit seeds.
    /// This is the fastest constructor.
    pub const fn new(seeds: [u8; 4]) -> Self {
        Self { x: seeds[0], y: seeds[1], z: seeds[2], a: seeds[3] }
    }
    #[must_use]
    /// Returns the PRNG's inner state as a raw snapshot.
    pub const fn inner_state(self) -> [u8; 4] {
        [self.x, self.y, self.z, self.a]
    }
    /// Restores the PRNG from the given state.
    pub const fn from_state(state: [u8; 4]) -> Self {
        Self { x: state[0], y: state[1], z: state[2], a: state[3] }
    }
    /// Returns the current random `u8`.
    pub const fn current_u8(&self) -> u8 {
        self.a
    }
    /// Returns the next random `u8`.
    pub const fn next_u8(&mut self) -> u8 {
        let t = self.x ^ (self.x >> 1);
        self.x = self.y;
        self.y = self.z;
        self.z = self.a;
        self.a = self.z ^ t ^ (self.z >> 3) ^ (t << 1);
        self.a
    }
    /// Returns a copy of the next new random state.
    pub const fn peek_next_state(&self) -> Self {
        let mut new = *self;
        let t = new.x ^ (new.x >> 1);
        new.x = new.y;
        new.y = new.z;
        new.z = new.a;
        new.a = new.z ^ t ^ (new.z >> 3) ^ (t << 1);
        new
    }
    /// Returns both the next random state and the `u8` value.
    pub const fn own_next_u8(self) -> Own<Self, u8> {
        let s = self.peek_next_state();
        let v = s.current_u8();
        Own::new(s, v)
    }
    /// Fills the buffer with generated bytes.
    pub const fn fill_bytes(&mut self, buffer: &mut [u8]) {
        whilst! { i in 0..buffer.len(); {
            buffer[i] = self.next_u8();
        }}
    }
}

/// # Extras
impl Xyza8b {
    /// Returns a seeded `Xyza8a` generator from the given 32-bit seed.
    ///
    /// The seeds will be split in little endian order.
    pub const fn new1_u32(seed: u32) -> Self {
        Self::new(seed.to_le_bytes())
    }
    /// Returns a seeded `Xyza8a` generator from the given 2 × 16-bit seeds.
    ///
    /// The seeds will be split in little endian order.
    pub const fn new2_u16(seeds: [u16; 2]) -> Self {
        let [x, y] = seeds[0].to_le_bytes();
        let [z, b] = seeds[1].to_le_bytes();
        Self::new([x, y, z, b])
    }
    /// Returns a seeded `Xyza8b` generator from the given 4 × 8-bit seeds.
    /// This is an alias of [`new`][Self#method.new].
    pub const fn new4_u8(seeds: [u8; 4]) -> Self {
        Self::new(seeds)
    }
    /// Returns the next 2 × random `u8` combined as a single `u16`.
    fn next_u16(&mut self) -> u16 {
        u16::from_le_bytes([self.next_u8(), self.next_u8()])
    }
    /// Returns the next 4 × random `u8` combined as a single `u32`.
    fn next_u32(&mut self) -> u32 {
        u32::from_le_bytes([self.next_u8(), self.next_u8(), self.next_u8(), self.next_u8()])
    }
    /// Returns the next 8 × random `u8` combined as a single `u64`.
    fn next_u64(&mut self) -> u64 {
        u64::from_le_bytes([
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
            self.next_u8(),
        ])
    }
}

crate::items! {
    impl RandTry for Xyza8a {
        type Error = Infallible;
        const RAND_OUTPUT_BITS: u32 = 8;
        const RAND_STATE_BITS: u32 = 32;
        const RAND_QUALITIES: RandQualities = RandQualities::WEAK_PRNG;
        fn rand_try_next_u8(&mut self) -> InfallibleResult<u8> { Ok(self.next_u8()) }
        fn rand_try_next_u16(&mut self) -> InfallibleResult<u16> { Ok(self.next_u16()) }
        fn rand_try_next_u32(&mut self) -> InfallibleResult<u32> { Ok(self.next_u32()) }
        fn rand_try_next_u64(&mut self) -> InfallibleResult<u64> { Ok(self.next_u64()) }
        fn rand_try_fill_bytes(&mut self, buffer: &mut [u8]) -> InfallibleResult<()> {
            self.fill_bytes(buffer);
            Ok(())
        }
    }
    impl RandTry for Xyza8b {
        type Error = Infallible;
        const RAND_OUTPUT_BITS: u32 = 8;
        const RAND_STATE_BITS: u32 = 32;
        const RAND_QUALITIES: RandQualities = RandQualities::WEAK_PRNG;
        fn rand_try_next_u8(&mut self) -> InfallibleResult<u8> { Ok(self.next_u8()) }
        fn rand_try_next_u16(&mut self) -> InfallibleResult<u16> { Ok(self.next_u16()) }
        fn rand_try_next_u32(&mut self) -> InfallibleResult<u32> { Ok(self.next_u32()) }
        fn rand_try_next_u64(&mut self) -> InfallibleResult<u64> { Ok(self.next_u64()) }
        fn rand_try_fill_bytes(&mut self, buffer: &mut [u8]) -> InfallibleResult<()> {
            self.fill_bytes(buffer);
            Ok(())
        }
    }
    impl RandSeedable for Xyza8a {
        type RandSeed = [u8; 4];
        fn rand_from_seed(seed: Self::RandSeed) -> Self { Self::new(seed) }
    }
    impl RandSeedable for Xyza8b {
        type RandSeed = [u8; 4];
        #[inline(always)]
        fn rand_from_seed(seed: Self::RandSeed) -> Self { Self::new(seed) }
    }
}
crate::__impl_dep_rand_core!(Xyza8a);
crate::__impl_dep_rand_core!(Xyza8b);