Introduce ChunkArray type

A generic array for per-chunk data, indexed by ChunkCoords.

src/types.rs

@@ -1,4 +1,9 @@
-use std::fmt::Debug;
+use std::{
+	fmt::Debug,
+	ops::{Index, IndexMut},
+};
+
+use itertools::iproduct;
 
 pub const CHUNKS_PER_REGION: u8 = 32;
 
@@ -22,3 +27,37 @@ impl Debug for ChunkCoords {
 		write!(f, "({}, {})", self.x.0, self.z.0)
 	}
 }
+
+#[derive(Debug, Clone, Copy, Default)]
+pub struct ChunkArray<T>(pub [[T; CHUNKS_PER_REGION as usize]; CHUNKS_PER_REGION as usize]);
+
+impl<T> ChunkArray<T> {
+	pub fn keys() -> impl Iterator<Item = ChunkCoords> {
+		iproduct!(0..CHUNKS_PER_REGION, 0..CHUNKS_PER_REGION).map(|(z, x)| ChunkCoords {
+			x: ChunkX(x),
+			z: ChunkZ(z),
+		})
+	}
+
+	pub fn values(&self) -> impl Iterator<Item = &T> {
+		Self::keys().map(|k| &self[k])
+	}
+
+	pub fn iter(&self) -> impl Iterator<Item = (ChunkCoords, &T)> {
+		Self::keys().map(|k| (k, &self[k]))
+	}
+}
+
+impl<T> Index<ChunkCoords> for ChunkArray<T> {
+	type Output = T;
+
+	fn index(&self, index: ChunkCoords) -> &Self::Output {
+		&self.0[index.z.0 as usize][index.x.0 as usize]
+	}
+}
+
+impl<T> IndexMut<ChunkCoords> for ChunkArray<T> {
+	fn index_mut(&mut self, index: ChunkCoords) -> &mut Self::Output {
+		&mut self.0[index.z.0 as usize][index.x.0 as usize]
+	}
+}