poulpy_hal/layouts/
module.rs

1use std::{
2    fmt::{Debug, Display},
3    marker::PhantomData,
4    ptr::NonNull,
5};
6
7use bytemuck::Pod;
8use rand_distr::num_traits::Zero;
9
10use crate::{
11    GALOISGENERATOR,
12    api::{ModuleLogN, ModuleN},
13};
14
15#[allow(clippy::missing_safety_doc)]
16pub trait Backend: Sized {
17    type ScalarBig: Copy + Zero + Display + Debug + Pod;
18    type ScalarPrep: Copy + Zero + Display + Debug + Pod;
19    type Handle: 'static;
20    fn layout_prep_word_count() -> usize;
21    fn layout_big_word_count() -> usize;
22    unsafe fn destroy(handle: NonNull<Self::Handle>);
23}
24
25pub struct Module<B: Backend> {
26    ptr: NonNull<B::Handle>,
27    n: u64,
28    _marker: PhantomData<B>,
29}
30
31unsafe impl<B: Backend> Sync for Module<B> {}
32unsafe impl<B: Backend> Send for Module<B> {}
33
34impl<B: Backend> Module<B> {
35    #[allow(clippy::missing_safety_doc)]
36    #[inline]
37    pub fn new_marker(n: u64) -> Self {
38        Self {
39            ptr: NonNull::dangling(),
40            n,
41            _marker: PhantomData,
42        }
43    }
44
45    #[allow(clippy::missing_safety_doc)]
46    #[inline]
47    pub unsafe fn from_nonnull(ptr: NonNull<B::Handle>, n: u64) -> Self {
48        Self {
49            ptr,
50            n,
51            _marker: PhantomData,
52        }
53    }
54
55    /// Construct from a raw pointer managed elsewhere.
56    /// SAFETY: `ptr` must be non-null and remain valid for the lifetime of this Module.
57    #[inline]
58    #[allow(clippy::missing_safety_doc)]
59    pub unsafe fn from_raw_parts(ptr: *mut B::Handle, n: u64) -> Self {
60        Self {
61            ptr: NonNull::new(ptr).expect("null module ptr"),
62            n,
63            _marker: PhantomData,
64        }
65    }
66
67    #[allow(clippy::missing_safety_doc)]
68    #[inline]
69    pub unsafe fn ptr(&self) -> *mut <B as Backend>::Handle {
70        self.ptr.as_ptr()
71    }
72
73    #[inline]
74    pub fn n(&self) -> usize {
75        self.n as usize
76    }
77    #[inline]
78    pub fn as_mut_ptr(&self) -> *mut B::Handle {
79        self.ptr.as_ptr()
80    }
81
82    #[inline]
83    pub fn log_n(&self) -> usize {
84        (usize::BITS - (self.n() - 1).leading_zeros()) as _
85    }
86}
87
88pub trait CyclotomicOrder
89where
90    Self: ModuleN,
91{
92    fn cyclotomic_order(&self) -> i64 {
93        (self.n() << 1) as _
94    }
95}
96
97impl<BE: Backend> ModuleLogN for Module<BE> where Self: ModuleN {}
98
99impl<BE: Backend> CyclotomicOrder for Module<BE> where Self: ModuleN {}
100
101#[inline(always)]
102pub fn galois_element(generator: i64, cyclotomic_order: i64) -> i64 {
103    if generator == 0 {
104        return 1;
105    }
106
107    let g_exp: u64 = mod_exp_u64(GALOISGENERATOR, generator.unsigned_abs() as usize) & (cyclotomic_order - 1) as u64;
108    g_exp as i64 * generator.signum()
109}
110
111pub trait GaloisElement
112where
113    Self: CyclotomicOrder,
114{
115    // Returns GALOISGENERATOR^|generator| * sign(generator)
116    fn galois_element(&self, generator: i64) -> i64 {
117        galois_element(generator, self.cyclotomic_order())
118    }
119
120    // Returns gen^-1
121    fn galois_element_inv(&self, gal_el: i64) -> i64 {
122        if gal_el == 0 {
123            panic!("cannot invert 0")
124        }
125
126        let g_exp: u64 = mod_exp_u64(
127            gal_el.unsigned_abs(),
128            (self.cyclotomic_order() - 1) as usize,
129        ) & (self.cyclotomic_order() - 1) as u64;
130        g_exp as i64 * gal_el.signum()
131    }
132}
133
134impl<BE: Backend> GaloisElement for Module<BE> where Self: CyclotomicOrder {}
135
136impl<B: Backend> Drop for Module<B> {
137    fn drop(&mut self) {
138        unsafe { B::destroy(self.ptr) }
139    }
140}
141
142pub fn mod_exp_u64(x: u64, e: usize) -> u64 {
143    let mut y: u64 = 1;
144    let mut x_pow: u64 = x;
145    let mut exp = e;
146    while exp > 0 {
147        if exp & 1 == 1 {
148            y = y.wrapping_mul(x_pow);
149        }
150        x_pow = x_pow.wrapping_mul(x_pow);
151        exp >>= 1;
152    }
153    y
154}
poulpy_hal/layouts/module.rs

poulpy_hal/layouts/
module.rs
