il2-test-utils 0.1.1

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//! This module contains functions that can be used to create sample values
//! to be used in tests.
use std::ops::AddAssign;

#[cfg(test)]
mod tests;

/// Fills the mutable slice with the specified value.
///
/// Arguments:
/// - `target`: The slice to be filled;
/// - `value`: The value;
pub fn fill_with_value<T: Copy>(target: &mut [T], value: T) {
    for t in target {
        *t = value;
    }
}

/// Fills the mutable slice with a sequence of values.
///
/// Arguments:
/// - `target`: The slice to be filled;
/// - `initial`: The initial value;
/// - `inc`: The increment;
pub fn fill_with_seq<T: AddAssign + Copy>(target: &mut [T], initial: T, inc: T) {
    let mut curr = initial;
    for t in target {
        *t = curr;
        curr += inc;
    }
}

/// Fills the mutable slice with a sequence of values generated by a generetor
/// function.
///
/// This function receives the current value and must return the next value of the
/// sequence.
///
/// ```
/// let mut v: [u32; 6] = [0; 6];
/// // Using a generator based on the Collatz conjecture.
/// fill_with_seq_gen(&mut v, 5, |v| if v % 2 == 0 { v / 2 } else { 3 * v + 1 });
/// let exp: [u32; 6] = [5, 16, 8, 4, 2, 1];
/// assert_eq!(&v, &exp);
/// ```
///
/// Arguments:
/// - `target`: The slice to be filled;
/// - `initial`: The initial value;
/// - `gen`: The function used to generate the next state;
pub fn fill_with_seq_gen<T: Copy>(target: &mut [T], initial: T, gen: fn(T) -> T) {
    let mut curr = initial;
    for t in target {
        *t = curr;
        curr = gen(curr);
    }
}

/// Fills the mutable slice with a sequence of values generated by a generetor.
/// This function extracts the next value form the generator.
///
/// ```
/// struct Gen(u32, u32);
/// let mut v: [u32; 6] = [0; 6];
/// let mut g: Gen = Gen { 0: 0, 1: 1 };
///
/// // Using Fibonacci generator
/// fill_with_generator(&mut v, &mut g, |g| {
///     let r = g.0;
///     g.0 = g.1;
///     g.1 += r;
///     r
/// });
/// let exp: [u32; 6] = [0, 1, 1, 2, 3, 5];
/// assert_eq!(&v, &exp);
/// ```
///
/// Arguments:
/// - `target`: The slice to be filled;
/// - `generator`: The generator;
/// - `next`: The function used to extract the next value from the generator;
pub fn fill_with_generator<T: Copy, G>(target: &mut [T], generator: &mut G, next: fn(&mut G) -> T) {
    for t in target {
        *t = next(generator);
    }
}