qfall-math 0.2.0

// Copyright 2023 Marvin Beckmann
//
// This file is part of qFALL-math.
//
// qFALL-math is free software: you can redistribute it and/or modify it under
// the terms of the Mozilla Public License Version 2.0 as published by the
// Mozilla Foundation. See <https://mozilla.org/en-US/MPL/2.0/>.

//! [`Modulus`] is a type of a positive integer larger than `1` that is used in
//! order to do modulus operations. The modulus type itself is also used for
//! optimizations.
//! A [`Modulus`] of `1` is not allowed, since operations would always just
//! return `0`. This way, checks later in the code can be avoided.
//!
//! This implementation uses the [FLINT](https://flintlib.org/) library.

use crate::integer::debug_fmpz;
use flint3_sys::{fmpz_mod_ctx, nmod_t};
use std::{fmt, rc::Rc};

mod cmp;
mod distance;
mod fmpz_helpers;
mod from;
mod get;
mod ownership;
mod properties;
mod serialize;
mod to_string;
mod unsafe_functions;

/// [`Modulus`] is a type of a positive integer larger than `1` that is used
/// to do modulus operations.
///
/// Attributes:
/// - `modulus`: holds the value of the modulus
///
/// # Examples
/// Create [`Modulus`] from [`str`]:
/// ```
/// use qfall_math::integer_mod_q::Modulus;
/// use std::str::FromStr;
/// use qfall_math::integer::Z;
/// let value = Z::from(10);
///
/// // instantiations
/// let _ = Modulus::from(10);
/// let a = Modulus::from_str("42").unwrap();
/// let b: Modulus = (&value).try_into().unwrap();
///
/// // clone
/// let clone = a.clone();
///
/// // properties
/// let is_prime: bool = a.is_prime();
///
/// // to_string incl. (de-)serialization
/// assert_eq!("42", &a.to_string());
/// assert_eq!(
///     "{\"modulus\":\"42\"}",
///     serde_json::to_string(&a).unwrap()
/// );
///
/// // comparison
/// assert_eq!(a, clone);
/// ```
pub struct Modulus {
    pub(crate) modulus: Rc<fmpz_mod_ctx>,
}

impl fmt::Debug for Modulus {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "Modulus {{ modulus: {}, storage: {{ modulus: {}}}}}",
            self,
            debug_fmpz_mod_ctx(&self.modulus)
        )
    }
}

macro_rules! debug_fn_ptr {
    ($opt_fn:expr) => {
        match $opt_fn {
            Some(f) => format!("Some({:#x})", f as usize),
            None => "None".to_string(),
        }
    };
}

fn debug_fmpz_mod_ctx(value: &fmpz_mod_ctx) -> String {
    format!(
        "fmpz_mod_ctx {{ n: [{}], add_fxn: {}, sub_fxn: {}, mul_fxn: {}, mod_: {}, n_limbs: {:?}, ninv_limbs: {:?}}}",
        debug_fmpz(&value.n[0]),
        debug_fn_ptr!(value.add_fxn),
        debug_fn_ptr!(value.sub_fxn),
        debug_fn_ptr!(value.mul_fxn),
        debug_nmod_t(&value.mod_),
        value.n_limbs,
        value.ninv_limbs
    )
}

fn debug_nmod_t(value: &nmod_t) -> String {
    format!(
        "nmod_t {{ n: {}, ninv: {}, norm: {} }}",
        value.n, value.ninv, value.norm
    )
}