rssn 0.2.9

A comprehensive scientific computing library for Rust, aiming for feature parity with NumPy and SymPy.
Documentation 
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//! Bincode-based FFI API for classical mechanics functions.

use std::os::raw::c_char;

use crate::ffi_apis::common::BincodeBuffer;
use crate::ffi_apis::common::from_bincode_buffer;
use crate::ffi_apis::common::to_bincode_buffer;
use crate::symbolic::classical_mechanics;
use crate::symbolic::core::Expr;

/// Calculates kinetic energy using Bincode.
#[unsafe(no_mangle)]
pub extern "C" fn rssn_bincode_kinetic_energy(
    mass_buf: BincodeBuffer,
    velocity_buf: BincodeBuffer,
) -> BincodeBuffer {
    let mass: Option<Expr> = from_bincode_buffer(&mass_buf);

    let velocity: Option<Expr> = from_bincode_buffer(&velocity_buf);

    match (mass, velocity) {
        | (Some(m), Some(v)) => to_bincode_buffer(&classical_mechanics::kinetic_energy(&m, &v)),
        | _ => BincodeBuffer::empty(),
    }
}

/// Computes Euler-Lagrange equation using Bincode.
#[unsafe(no_mangle)]
pub extern "C" fn rssn_bincode_euler_lagrange_equation(
    lagrangian_buf: BincodeBuffer,
    q: *const c_char,
    q_dot: *const c_char,
    t_var: *const c_char,
) -> BincodeBuffer {
    let lagrangian: Option<Expr> = from_bincode_buffer(&lagrangian_buf);

    let q_str = unsafe {
        if q.is_null() {
            None
        } else {
            std::ffi::CStr::from_ptr(q).to_str().ok()
        }
    };

    let q_dot_str = unsafe {
        if q_dot.is_null() {
            None
        } else {
            std::ffi::CStr::from_ptr(q_dot).to_str().ok()
        }
    };

    let t_str = unsafe {
        if t_var.is_null() {
            None
        } else {
            std::ffi::CStr::from_ptr(t_var).to_str().ok()
        }
    };

    match (lagrangian, q_str, q_dot_str, t_str) {
        | (Some(l), Some(qs), Some(qds), Some(ts)) => {
            to_bincode_buffer(&classical_mechanics::euler_lagrange_equation(
                &l, qs, qds, ts,
            ))
        },
        | _ => BincodeBuffer::empty(),
    }
}