rssn 0.2.9

A comprehensive scientific computing library for Rust, aiming for feature parity with NumPy and SymPy.
Documentation 
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//! Handle-based FFI API for numerical number theory operations.

use std::ptr;

use crate::numerical::number_theory as nt;

/// Computes the greatest common divisor (GCD).
#[unsafe(no_mangle)]
pub extern "C" fn rssn_num_nt_gcd(
    a: u64,
    b: u64,
) -> u64 {
    nt::gcd(a, b)
}

/// Computes the least common multiple (LCM).
#[unsafe(no_mangle)]
pub extern "C" fn rssn_num_nt_lcm(
    a: u64,
    b: u64,
) -> u64 {
    nt::lcm(a, b)
}

/// Computes (base^exp) % modulus.
#[unsafe(no_mangle)]
pub extern "C" fn rssn_num_nt_mod_pow(
    base: u128,
    exp: u64,
    modulus: u64,
) -> u64 {
    nt::mod_pow(base, exp, modulus)
}

/// Finds the modular multiplicative inverse.
/// Returns 0 if no inverse exists (modulus cannot be 0).
#[unsafe(no_mangle)]
pub extern "C" fn rssn_num_nt_mod_inverse(
    a: i64,
    m: i64,
) -> i64 {
    nt::mod_inverse(a, m).unwrap_or(0)
}

/// Tests if a number is prime using Miller-Rabin.
#[unsafe(no_mangle)]
pub extern "C" fn rssn_num_nt_is_prime(n: u64) -> bool {
    nt::is_prime_miller_rabin(n)
}

/// Computes Euler's totient function φ(n).
#[unsafe(no_mangle)]
pub const extern "C" fn rssn_num_nt_phi(n: u64) -> u64 {
    nt::phi(n)
}

/// Returns the number of prime factors and writes them to `out_factors`.
/// `out_factors` must be large enough.
///
/// # Safety
///
/// This function is unsafe because it dereferences raw pointers as part of the FFI boundary.
/// The caller must ensure:
/// 1. All pointer arguments are valid and point to initialized memory.
/// 2. The memory layout of passed structures matches the expected C-ABI layout.
/// 3. Any pointers returned by this function are managed according to the API's ownership rules.
#[unsafe(no_mangle)]
pub unsafe extern "C" fn rssn_num_nt_factorize(
    n: u64,
    out_factors: *mut u64,
) -> usize {
    unsafe {
        let factors = nt::factorize(n);

        if !out_factors.is_null() {
            ptr::copy_nonoverlapping(factors.as_ptr(), out_factors, factors.len());
        }

        factors.len()
    }
}