module builtin

pub struct array {
pub:
    data         voidptr
    len          int
    cap          int
    element_size int
}

// for now off the stack
fn new_array_from_c_array(len int, cap int, elm_size int, c_array voidptr) array {
    arr := array{
        len:          len
        cap:          cap
        element_size: elm_size
        data:         c_array
    }
    return arr
}

// Private function. Used to implement array[] operator
fn (a array) get(i int) voidptr {
    if i < 0 || i >= a.len {
        panic('array.get: index out of range') // FIXME: (i == ${i}, a.len == ${a.len})')
    }
    return a.data + i * a.element_size
}

// Private function. Used to implement assignment to the array element.
fn (mut a array) set(i int, val voidptr) {
    if i < 0 || i >= a.len {
        panic('array.set: index out of range') // FIXME: (i == ${i}, a.len == ${a.len})')
    }
    mem_copy(a.data + a.element_size * i, val, a.element_size)
}

// array.repeat returns new array with the given array elements
// repeated `nr_repeat` times
pub fn (a array) repeat(nr_repeats int) array {
    assert nr_repeats >= 0

    arr := array{
        len:          nr_repeats * a.len
        cap:          nr_repeats * a.len
        element_size: a.element_size
        data:         malloc(nr_repeats * a.len * a.element_size)
    }
    for i in 0 .. nr_repeats {
        mem_copy(arr.data + i * a.len * a.element_size, a.data, a.len * a.element_size)
    }
    return arr
}