poulpy/poulpy-core/src/layouts/glwe_pt.rs

use std::fmt;

use poulpy_hal::layouts::{Data, DataMut, DataRef, VecZnx, VecZnxToMut, VecZnxToRef, ZnxInfos};

use crate::layouts::{
    Base2K, BuildError, Degree, GLWECiphertext, GLWECiphertextToMut, GLWECiphertextToRef, GLWEInfos, GLWELayoutSet, LWEInfos,
    Rank, TorusPrecision,
};

#[derive(PartialEq, Eq, Copy, Clone, Debug)]
pub struct GLWEPlaintextLayout {
    pub n: Degree,
    pub base2k: Base2K,
    pub k: TorusPrecision,
}

impl LWEInfos for GLWEPlaintextLayout {
    fn base2k(&self) -> Base2K {
        self.base2k
    }

    fn k(&self) -> TorusPrecision {
        self.k
    }

    fn n(&self) -> Degree {
        self.n
    }
}

impl GLWEInfos for GLWEPlaintextLayout {
    fn rank(&self) -> Rank {
        Rank(0)
    }
}

pub struct GLWEPlaintext<D: Data> {
    pub data: VecZnx<D>,
    pub base2k: Base2K,
    pub k: TorusPrecision,
}

impl<D: DataMut> GLWELayoutSet for GLWEPlaintext<D> {
    fn set_basek(&mut self, base2k: Base2K) {
        self.base2k = base2k
    }

    fn set_k(&mut self, k: TorusPrecision) {
        self.k = k
    }
}

impl<D: Data> LWEInfos for GLWEPlaintext<D> {
    fn base2k(&self) -> Base2K {
        self.base2k
    }

    fn k(&self) -> TorusPrecision {
        self.k
    }

    fn size(&self) -> usize {
        self.data.size()
    }

    fn n(&self) -> Degree {
        Degree(self.data.n() as u32)
    }
}

impl<D: Data> GLWEInfos for GLWEPlaintext<D> {
    fn rank(&self) -> Rank {
        Rank(self.data.cols() as u32 - 1)
    }
}

pub struct GLWEPlaintextBuilder<D: Data> {
    data: Option<VecZnx<D>>,
    base2k: Option<Base2K>,
    k: Option<TorusPrecision>,
}

impl<D: Data> GLWEPlaintext<D> {
    #[inline]
    pub fn builder() -> GLWEPlaintextBuilder<D> {
        GLWEPlaintextBuilder {
            data: None,
            base2k: None,
            k: None,
        }
    }
}

impl<D: Data> GLWEPlaintextBuilder<D> {
    #[inline]
    pub fn data(mut self, data: VecZnx<D>) -> Self {
        self.data = Some(data);
        self
    }
    #[inline]
    pub fn base2k(mut self, base2k: Base2K) -> Self {
        self.base2k = Some(base2k);
        self
    }
    #[inline]
    pub fn k(mut self, k: TorusPrecision) -> Self {
        self.k = Some(k);
        self
    }

    pub fn build(self) -> Result<GLWEPlaintext<D>, BuildError> {
        let data: VecZnx<D> = self.data.ok_or(BuildError::MissingData)?;
        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;

        if base2k.0 == 0 {
            return Err(BuildError::ZeroBase2K);
        }

        if k.0 == 0 {
            return Err(BuildError::ZeroTorusPrecision);
        }

        if data.n() == 0 {
            return Err(BuildError::ZeroDegree);
        }

        if data.cols() != 1 {
            return Err(BuildError::ZeroCols);
        }

        if data.size() == 0 {
            return Err(BuildError::ZeroLimbs);
        }

        Ok(GLWEPlaintext { data, base2k, k })
    }
}

impl<D: DataRef> fmt::Display for GLWEPlaintext<D> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "GLWEPlaintext: base2k={} k={}: {}",
            self.base2k().0,
            self.k().0,
            self.data
        )
    }
}

impl GLWEPlaintext<Vec<u8>> {
    pub fn alloc<A>(infos: &A) -> Self
    where
        A: GLWEInfos,
    {
        Self::alloc_with(infos.n(), infos.base2k(), infos.k(), Rank(0))
    }

    pub fn alloc_with(n: Degree, base2k: Base2K, k: TorusPrecision, rank: Rank) -> Self {
        debug_assert!(rank.0 == 0);
        Self {
            data: VecZnx::alloc(n.into(), (rank + 1).into(), k.0.div_ceil(base2k.0) as usize),
            base2k,
            k,
        }
    }

    pub fn alloc_bytes<A>(infos: &A) -> usize
    where
        A: GLWEInfos,
    {
        Self::alloc_bytes_with(infos.n(), infos.base2k(), infos.k(), Rank(0))
    }

    pub fn alloc_bytes_with(n: Degree, base2k: Base2K, k: TorusPrecision, rank: Rank) -> usize {
        debug_assert!(rank.0 == 0);
        VecZnx::alloc_bytes(n.into(), (rank + 1).into(), k.0.div_ceil(base2k.0) as usize)
    }
}

impl<D: DataRef> GLWECiphertextToRef for GLWEPlaintext<D> {
    fn to_ref(&self) -> GLWECiphertext<&[u8]> {
        GLWECiphertext::builder()
            .data(self.data.to_ref())
            .k(self.k())
            .base2k(self.base2k())
            .build()
            .unwrap()
    }
}

impl<D: DataMut> GLWECiphertextToMut for GLWEPlaintext<D> {
    fn to_mut(&mut self) -> GLWECiphertext<&mut [u8]> {
        GLWECiphertext::builder()
            .k(self.k())
            .base2k(self.base2k())
            .data(self.data.to_mut())
            .build()
            .unwrap()
    }
}