From 74c3ae52f84d988b8bf3f0affe143d2cd2d8143a Mon Sep 17 00:00:00 2001
From: mat <github@matdoes.dev>
Date: Thu, 16 Jun 2022 23:38:51 -0500
Subject: azalea-world uses azalea-block

---
 azalea-block/src/lib.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

(limited to 'azalea-block/src')

diff --git a/azalea-block/src/lib.rs b/azalea-block/src/lib.rs
index 01c86b11..95e8ce37 100644
--- a/azalea-block/src/lib.rs
+++ b/azalea-block/src/lib.rs
@@ -4,3 +4,44 @@ mod blocks;
 pub use behavior::BlockBehavior;
 pub use blocks::*;
 
+use std::mem;
+
+impl BlockState {
+	/// Transmutes a u32 to a block state. UB if the value is not a valid block
+	/// state.
+	#[inline]
+	pub unsafe fn from_u32_unsafe(state_id: u32) -> Self {
+		mem::transmute::<u32, BlockState>(state_id)
+	}
+
+	#[inline]
+	pub fn is_valid_state(state_id: u32) -> bool {
+		state_id <= Self::max_state()
+	}
+}
+
+impl TryFrom<u32> for BlockState {
+	type Error = ();
+
+	/// Safely converts a state id to a block state.
+	fn try_from(state_id: u32) -> Result<Self, Self::Error> {
+		if Self::is_valid_state(state_id) {
+			Ok(unsafe { Self::from_u32_unsafe(state_id) })
+		} else {
+			Err(())
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn test_from_u32() {
+		assert_eq!(BlockState::try_from(0).unwrap(), BlockState::Air);
+
+		assert!(BlockState::try_from(BlockState::max_state()).is_ok());
+		assert!(BlockState::try_from(BlockState::max_state() + 1).is_err());
+	}
+}
-- 
cgit v1.2.3