//! Utils

pub trait NewCapacity: Sized
{
    fn new() -> Self;
    fn with_capacity(cap: usize) -> Self;
}

impl NewCapacity for String
{
    fn new() -> Self
    {
	Self::new()
    }
    
    fn with_capacity(cap: usize) -> Self
    {
	Self::with_capacity(cap)
    }
}

impl<T> NewCapacity for Vec<T>
{
    fn new() -> Self
    {
	Self::new()
    }
    
    fn with_capacity(cap: usize) -> Self
    {
	Self::with_capacity(cap)
    }
}

pub fn hint_cap<T: NewCapacity, I: Iterator>(iter: &I) -> T
{
    match iter.size_hint() {
	(0, Some(0)) | (0, None) => T::new(),
	(_, Some(x)) | (x, _) => T::with_capacity(x)
    }
}