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//
// A rust binding for the GSL library by Guillaume Gomez (guillaume1.gomez@gmail.com)
//

//! The following functions are equivalent to the function gsl_pow_int (see
//! [Small integer powers](Pow.html)) with an error estimate.

use crate::Value;
use std::mem::MaybeUninit;

/// This routine computes the power x^n for integer n. The power is computed using the minimum
/// number of multiplications. For example, x^8 is computed as ((x^2)^2)^2, requiring only 3
/// multiplications. For reasons of efficiency, these functions do not check for overflow or
/// underflow conditions.
///
/// ```rust
/// use rgsl::power::pow_int;
///
/// /* compute 3.0**12 */
/// println!("{}", pow_int(3., 12));
/// ```
#[doc(alias = "gsl_sf_pow_int")]
pub fn pow_int(x: f64, n: i32) -> f64 {
    unsafe { sys::gsl_sf_pow_int(x, n) }
}

/// This routine computes the power x^n for integer n. The power is computed using the minimum
/// number of multiplications. For example, x^8 is computed as ((x^2)^2)^2, requiring only 3
/// multiplications. For reasons of efficiency, these functions do not check for overflow or
/// underflow conditions.
///
/// ```rust
/// use rgsl::power::pow_int_e;
///
/// /* compute 3.0**12 */
/// println!("{:?}", pow_int_e(3., 12));
/// ```
#[doc(alias = "gsl_sf_pow_int_e")]
pub fn pow_int_e(x: f64, n: i32) -> (Value, ::types::Result) {
    let mut result = MaybeUninit::<sys::gsl_sf_result>::uninit();
    let ret = unsafe { sys::gsl_sf_pow_int_e(x, n, result.as_mut_ptr()) };

    (Value::from(ret), unsafe { result.assume_init() }.into())
}