arrayfire 3.5.0

use std::fmt;
use std::ops::Index;

/// Dim4 is used to store [Array](./struct.Array.html) dimensions
#[derive(Copy, Clone, PartialEq, Debug)]
pub struct Dim4 {
    dims: [u64; 4],
}

/// Default trait for Dim4 returns an Array of dimensions [1, 1, 1, 1]
impl Default for Dim4 {
    fn default() -> Dim4 {
        Dim4 { dims:[1, 1, 1, 1] }
    }
}

/// Enables index operation for Dim4
///
/// # Examples
///
/// ```rust
/// use arrayfire::Dim4;
///
/// let dims = Dim4::new(&[4, 4, 2, 1]);
/// println!("0th Dimension length is {}", dims[0]); // -> 4
/// println!("1th Dimension length is {}", dims[1]); // -> 4
/// println!("2th Dimension length is {}", dims[2]); // -> 2
/// println!("3th Dimension length is {}", dims[3]); // -> 1
/// ```
impl Index<usize> for Dim4 {
    type Output = u64;

    fn index<'a>(&'a self, _index: usize) ->&'a u64 {
        &self.dims[_index]
    }
}

/// Enables use of Dim4 objects for printing it to display
///
/// # Examples
///
/// ```rust
/// use arrayfire::Dim4;
///
/// let dims = Dim4::new(&[4, 4, 2, 1]);
/// println!("0th Dimension length is {}", dims[0]); // -> 4
/// ```
impl fmt::Display for Dim4 {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "[{} {} {} {}]", self.dims[0], self.dims[1], self.dims[2], self.dims[3])
    }
}

impl Dim4 {
    /// Create Dim4 object
    ///
    /// # Examples
    ///
    /// ```rust
    /// use arrayfire::Dim4;
    /// let dims = Dim4::new(&[4, 4, 2, 1]);
    /// ```
    pub fn new(dims: &[u64; 4]) -> Dim4 {
        Dim4 { dims: dims.clone(), }
    }

    /// Get the number of elements represented by Dim4 object
    pub fn elements(&self) -> u64 {
        self.dims[0]*self.dims[1]*self.dims[2]*self.dims[3]
    }

    /// Get the number of dimensions of Dim4
    pub fn ndims(&self) -> usize {
        let nelems = self.elements();
        match nelems {
            0 => 0,
            1 => 1,
            _ => {
                if self.dims[3] != 1 { 4 }
                else if self.dims[2] != 1 { 3 }
                else if self.dims[1] != 1 { 2 }
                else { 1 }
            },
        }
    }

    /// Get the dimensions as a slice of 4 values
    pub fn get(&self) -> &[u64; 4] {
        &self.dims
    }
}