nut 0.1.1

use crate::utils::is_aligned;
use std::mem::size_of;

/// LeafPageElement represents a node on a leaf page.
#[derive(Debug)]
#[repr(C)]
pub struct LeafPageElement {
    pub flags: u32,
    pub pos: u32,
    pub ksize: u32,
    pub vsize: u32,
}

impl LeafPageElement {
    /// binary struct's size (16)
    pub const SIZE: usize = size_of::<LeafPageElement>();

    /// key returns a byte slice of the node key.
    pub fn key(&self) -> &[u8] {
        debug_assert!(is_aligned(self));
        unsafe {
            let optr = self as *const Self as *const u8;
            let ptr = optr.add(self.pos as usize);
            std::slice::from_raw_parts(ptr, self.ksize as usize)
        }
    }

    /// value returns a byte slice of the node value.
    pub fn value(&self) -> &[u8] {
        debug_assert!(is_aligned(self));
        unsafe {
            std::slice::from_raw_parts(
                (self as *const Self as *const u8).add((self.pos + self.ksize) as usize),
                self.vsize as usize,
            )
        }
    }
}