Function create_string_view_array_with_len

arrow/src/util/bench_util.rs:417–450

Creates a random (but fixed-seeded) array of a given size, null density and length

(
    size: usize,
    null_density: f32,
    str_len: usize,
    mixed: bool,
)

/// Creates a random (but fixed-seeded) array of a given size, null density and length
pub fn create_string_view_array_with_len(
    size: usize,
    null_density: f32,
    str_len: usize,
    mixed: bool,
) -> StringViewArray {
    let rng = &mut seedable_rng();

    let mut lengths = Vec::with_capacity(size);

    // if mixed, we creates first half that string length small than 12 bytes and second half large than 12 bytes
    if mixed {
        for _ in 0..size / 2 {
            lengths.push(rng.random_range(1..12));
        }
        for _ in size / 2..size {
            lengths.push(rng.random_range(12..=std::cmp::max(30, str_len)));
        }
    } else {
        lengths.resize(size, str_len);
    }

    lengths
        .into_iter()
        .map(|len| {
            if rng.random::<f32>() < null_density {
                None
            } else {
                let value: Vec<u8> = rng.sample_iter(&Alphanumeric).take(len).collect();
                Some(String::from_utf8(value).unwrap())
            }
        })
        .collect()
}

/// Creates an random (but fixed-seeded) array of a given size and null density
/// consisting of random 4 character alphanumeric strings