1use crate::ffi::svp::{self, bytes_of_svp_ppol};
  2use crate::{alias_mut_slice_to_vec, is_aligned, Module, VecZnxApi, VecZnxDft};
  3
  4use crate::{alloc_aligned, cast, Infos};
  5use rand::seq::SliceRandom;
  6use rand_core::RngCore;
  7use rand_distr::{Distribution, WeightedIndex};
  8use sampling::source::Source;
  9
 10pub struct Scalar(pub Vec<i64>);
 11
 12impl Module {
 13    pub fn new_scalar(&self) -> Scalar {
 14        Scalar::new(self.n())
 15    }
 16}
 17
 18impl Scalar {
 19    pub fn new(n: usize) -> Self {
 20        Self(alloc_aligned::<i64>(n))
 21    }
 22
 23    pub fn n(&self) -> usize {
 24        self.0.len()
 25    }
 26
 27    pub fn buffer_size(n: usize) -> usize {
 28        n
 29    }
 30
 31    pub fn from_buffer(&mut self, n: usize, buf: &mut [u8]) {
 32        let size: usize = Self::buffer_size(n);
 33        debug_assert!(
 34            buf.len() >= size,
 35            "invalid buffer: buf.len()={} < self.buffer_size(n={})={}",
 36            buf.len(),
 37            n,
 38            size
 39        );
 40        debug_assert!(is_aligned(buf.as_ptr()));
 41        self.0 = alias_mut_slice_to_vec(cast::<u8, i64>(&buf[..size]))
 42    }
 43
 44    pub fn as_ptr(&self) -> *const i64 {
 45        self.0.as_ptr()
 46    }
 47
 48    pub fn fill_ternary_prob(&mut self, prob: f64, source: &mut Source) {
 49        let choices: [i64; 3] = [-1, 0, 1];
 50        let weights: [f64; 3] = [prob / 2.0, 1.0 - prob, prob / 2.0];
 51        let dist: WeightedIndex<f64> = WeightedIndex::new(&weights).unwrap();
 52        self.0
 53            .iter_mut()
 54            .for_each(|x: &mut i64| *x = choices[dist.sample(source)]);
 55    }
 56
 57    pub fn fill_ternary_hw(&mut self, hw: usize, source: &mut Source) {
 58        assert!(hw <= self.n());
 59        self.0[..hw]
 60            .iter_mut()
 61            .for_each(|x: &mut i64| *x = (((source.next_u32() & 1) as i64) << 1) - 1);
 62        self.0.shuffle(source);
 63    }
 64}
 65
 66pub struct SvpPPol(pub *mut svp::svp_ppol_t, pub usize);
 67
 68/// A prepared [crate::Scalar] for [SvpPPolOps::svp_apply_dft].
 69/// An [SvpPPol] an be seen as a [VecZnxDft] of one limb.
 70/// The backend array of an [SvpPPol] is allocated in C and must be freed manually.
 71impl SvpPPol {
 72    /// Returns the ring degree of the [SvpPPol].
 73    pub fn n(&self) -> usize {
 74        self.1
 75    }
 76
 77    pub fn from_bytes(size: usize, bytes: &mut [u8]) -> SvpPPol {
 78        debug_assert!(is_aligned(bytes.as_ptr()));
 79        debug_assert!(bytes.len() << 3 >= size);
 80        SvpPPol(bytes.as_mut_ptr() as *mut svp::svp_ppol_t, size)
 81    }
 82
 83    /// Returns the number of cols of the [SvpPPol], which is always 1.
 84    pub fn cols(&self) -> usize {
 85        1
 86    }
 87}
 88
 89pub trait SvpPPolOps {
 90    /// Allocates a new [SvpPPol].
 91    fn new_svp_ppol(&self) -> SvpPPol;
 92
 93    /// Returns the minimum number of bytes necessary to allocate
 94    /// a new [SvpPPol] through [SvpPPol::from_bytes].
 95    fn bytes_of_svp_ppol(&self) -> usize;
 96
 97    /// Prepares a [crate::Scalar] for a [SvpPPolOps::svp_apply_dft].
 98    fn svp_prepare(&self, svp_ppol: &mut SvpPPol, a: &Scalar);
 99
100    /// Applies the [SvpPPol] x [VecZnxDft] product, where each limb of
101    /// the [VecZnxDft] is multiplied with [SvpPPol].
102    fn svp_apply_dft<T: VecZnxApi + Infos>(
103        &self,
104        c: &mut VecZnxDft,
105        a: &SvpPPol,
106        b: &T,
107        b_cols: usize,
108    );
109}
110
111impl SvpPPolOps for Module {
112    fn new_svp_ppol(&self) -> SvpPPol {
113        unsafe { SvpPPol(svp::new_svp_ppol(self.0), self.n()) }
114    }
115
116    fn bytes_of_svp_ppol(&self) -> usize {
117        unsafe { svp::bytes_of_svp_ppol(self.0) as usize }
118    }
119
120    fn svp_prepare(&self, svp_ppol: &mut SvpPPol, a: &Scalar) {
121        unsafe { svp::svp_prepare(self.0, svp_ppol.0, a.as_ptr()) }
122    }
123
124    fn svp_apply_dft<T: VecZnxApi + Infos>(
125        &self,
126        c: &mut VecZnxDft,
127        a: &SvpPPol,
128        b: &T,
129        b_cols: usize,
130    ) {
131        debug_assert!(
132            c.cols() >= b_cols,
133            "invalid c_vector: c_vector.cols()={} < b.cols()={}",
134            c.cols(),
135            b_cols
136        );
137        unsafe {
138            svp::svp_apply_dft(
139                self.0,
140                c.0,
141                b_cols as u64,
142                a.0,
143                b.as_ptr(),
144                b_cols as u64,
145                b.n() as u64,
146            )
147        }
148    }
149}