1use std::fmt;
  2
  3use poulpy_hal::{
  4    api::ZnFillUniform,
  5    layouts::{
  6        Backend, Data, DataMut, DataRef, FillUniform, Module, ReaderFrom, WriterTo, Zn, ZnToMut, ZnToRef, ZnxInfos, ZnxView,
  7        ZnxViewMut,
  8    },
  9    source::Source,
 10};
 11
 12use crate::layouts::{Base2K, Degree, LWE, LWEInfos, LWEToMut, TorusPrecision};
 13
 14#[derive(PartialEq, Eq, Clone)]
 15pub struct LWECompressed<D: Data> {
 16    pub(crate) data: Zn<D>,
 17    pub(crate) k: TorusPrecision,
 18    pub(crate) base2k: Base2K,
 19    pub(crate) seed: [u8; 32],
 20}
 21
 22impl<D: Data> LWEInfos for LWECompressed<D> {
 23    fn base2k(&self) -> Base2K {
 24        self.base2k
 25    }
 26
 27    fn k(&self) -> TorusPrecision {
 28        self.k
 29    }
 30
 31    fn n(&self) -> Degree {
 32        Degree(self.data.n() as u32)
 33    }
 34
 35    fn size(&self) -> usize {
 36        self.data.size()
 37    }
 38}
 39
 40impl<D: DataRef> fmt::Debug for LWECompressed<D> {
 41    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 42        write!(f, "{self}")
 43    }
 44}
 45
 46impl<D: DataRef> fmt::Display for LWECompressed<D> {
 47    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 48        write!(
 49            f,
 50            "LWECompressed: base2k={} k={} seed={:?}: {}",
 51            self.base2k(),
 52            self.k(),
 53            self.seed,
 54            self.data
 55        )
 56    }
 57}
 58
 59impl<D: DataMut> FillUniform for LWECompressed<D> {
 60    fn fill_uniform(&mut self, log_bound: usize, source: &mut Source) {
 61        self.data.fill_uniform(log_bound, source);
 62    }
 63}
 64
 65impl LWECompressed<Vec<u8>> {
 66    pub fn alloc_from_infos<A>(infos: &A) -> Self
 67    where
 68        A: LWEInfos,
 69    {
 70        Self::alloc(infos.base2k(), infos.k())
 71    }
 72
 73    pub fn alloc(base2k: Base2K, k: TorusPrecision) -> Self {
 74        LWECompressed {
 75            data: Zn::alloc(1, 1, k.0.div_ceil(base2k.0) as usize),
 76            k,
 77            base2k,
 78            seed: [0u8; 32],
 79        }
 80    }
 81
 82    pub fn bytes_of_from_infos<A>(infos: &A) -> usize
 83    where
 84        A: LWEInfos,
 85    {
 86        Self::bytes_of(infos.base2k(), infos.k())
 87    }
 88
 89    pub fn bytes_of(base2k: Base2K, k: TorusPrecision) -> usize {
 90        Zn::bytes_of(1, 1, k.0.div_ceil(base2k.0) as usize)
 91    }
 92}
 93
 94use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 95
 96impl<D: DataMut> ReaderFrom for LWECompressed<D> {
 97    fn read_from<R: std::io::Read>(&mut self, reader: &mut R) -> std::io::Result<()> {
 98        self.k = TorusPrecision(reader.read_u32::<LittleEndian>()?);
 99        self.base2k = Base2K(reader.read_u32::<LittleEndian>()?);
100        reader.read_exact(&mut self.seed)?;
101        self.data.read_from(reader)
102    }
103}
104
105impl<D: DataRef> WriterTo for LWECompressed<D> {
106    fn write_to<W: std::io::Write>(&self, writer: &mut W) -> std::io::Result<()> {
107        writer.write_u32::<LittleEndian>(self.k.into())?;
108        writer.write_u32::<LittleEndian>(self.base2k.into())?;
109        writer.write_all(&self.seed)?;
110        self.data.write_to(writer)
111    }
112}
113
114pub trait LWEDecompress
115where
116    Self: ZnFillUniform,
117{
118    fn decompress_lwe<R, O>(&self, res: &mut R, other: &O)
119    where
120        R: LWEToMut,
121        O: LWECompressedToRef,
122    {
123        let res: &mut LWE<&mut [u8]> = &mut res.to_mut();
124        let other: &LWECompressed<&[u8]> = &other.to_ref();
125
126        assert_eq!(res.lwe_layout(), other.lwe_layout());
127
128        let mut source: Source = Source::new(other.seed);
129        self.zn_fill_uniform(
130            res.n().into(),
131            other.base2k().into(),
132            &mut res.data,
133            0,
134            &mut source,
135        );
136        for i in 0..res.size() {
137            res.data.at_mut(0, i)[0] = other.data.at(0, i)[0];
138        }
139    }
140}
141
142impl<B: Backend> LWEDecompress for Module<B> where Self: ZnFillUniform {}
143
144impl<D: DataMut> LWE<D> {
145    pub fn decompress<O, M>(&mut self, module: &M, other: &O)
146    where
147        O: LWECompressedToRef,
148        M: LWEDecompress,
149    {
150        module.decompress_lwe(self, other);
151    }
152}
153
154pub trait LWECompressedToRef {
155    fn to_ref(&self) -> LWECompressed<&[u8]>;
156}
157
158impl<D: DataRef> LWECompressedToRef for LWECompressed<D> {
159    fn to_ref(&self) -> LWECompressed<&[u8]> {
160        LWECompressed {
161            k: self.k,
162            base2k: self.base2k,
163            seed: self.seed,
164            data: self.data.to_ref(),
165        }
166    }
167}
168
169pub trait LWECompressedToMut {
170    fn to_mut(&mut self) -> LWECompressed<&mut [u8]>;
171}
172
173impl<D: DataMut> LWECompressedToMut for LWECompressed<D> {
174    fn to_mut(&mut self) -> LWECompressed<&mut [u8]> {
175        LWECompressed {
176            k: self.k,
177            base2k: self.base2k,
178            seed: self.seed,
179            data: self.data.to_mut(),
180        }
181    }
182}