From 7fe4942b9c2f1f6023eda0fc613be7eff747dcc2 Mon Sep 17 00:00:00 2001
From: soruh <mail@soruh.de>
Date: Thu, 24 Aug 2023 21:52:12 +0200
Subject: [PATCH] add boolean and optional

---
 src/datastructures/boolean.rs  | 27 ++++++++++++++++
 src/datastructures/mod.rs      |  2 ++
 src/datastructures/optional.rs | 58 ++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 src/datastructures/boolean.rs
 create mode 100644 src/datastructures/optional.rs

diff --git a/src/datastructures/boolean.rs b/src/datastructures/boolean.rs
new file mode 100644
index 0000000..8b073a1
--- /dev/null
+++ b/src/datastructures/boolean.rs
@@ -0,0 +1,27 @@
+use zerocopy::{AsBytes, FromBytes, FromZeroes, Unaligned};
+
+#[derive(Clone, Copy, FromBytes, FromZeroes, AsBytes, Unaligned)]
+#[repr(transparent)]
+pub struct Boolean(u8);
+
+impl From<bool> for Boolean {
+    fn from(value: bool) -> Self {
+        Self::new(value)
+    }
+}
+
+impl From<Boolean> for bool {
+    fn from(value: Boolean) -> Self {
+        value.get()
+    }
+}
+
+impl Boolean {
+    pub fn get(self) -> bool {
+        self.0 != 0
+    }
+
+    pub fn new(value: bool) -> Self {
+        Self(value as u8)
+    }
+}
diff --git a/src/datastructures/mod.rs b/src/datastructures/mod.rs
index 0637479..601be13 100644
--- a/src/datastructures/mod.rs
+++ b/src/datastructures/mod.rs
@@ -1,4 +1,6 @@
+pub mod boolean;
 pub mod btree;
+pub mod optional;
 pub mod queue;
 pub mod string;
 pub mod vector;
diff --git a/src/datastructures/optional.rs b/src/datastructures/optional.rs
new file mode 100644
index 0000000..9a3ab80
--- /dev/null
+++ b/src/datastructures/optional.rs
@@ -0,0 +1,58 @@
+use zerocopy::{AsBytes, FromBytes, FromZeroes, Unaligned};
+
+use super::boolean::Boolean;
+
+#[derive(Clone, Copy, FromBytes, FromZeroes, AsBytes, Unaligned)]
+#[repr(packed)]
+pub struct Optional<T> {
+    present: Boolean,
+    value: T,
+}
+
+impl<T: FromZeroes> From<Option<T>> for Optional<T> {
+    fn from(value: Option<T>) -> Self {
+        match value {
+            Some(value) => Optional::some(value),
+            None => Optional::none(),
+        }
+    }
+}
+
+impl<T: FromZeroes> Default for Optional<T> {
+    fn default() -> Self {
+        Self::none()
+    }
+}
+
+impl<T> Optional<T> {
+    pub fn none() -> Self
+    where
+        T: FromZeroes,
+    {
+        Self {
+            present: Boolean::new(false),
+            value: T::new_zeroed(),
+        }
+    }
+    pub fn some(value: T) -> Self {
+        Self {
+            present: Boolean::new(true),
+            value,
+        }
+    }
+    pub fn get(self) -> Option<T> {
+        if self.present.get() {
+            Some(self.value)
+        } else {
+            None
+        }
+    }
+
+    pub fn is_some(&self) -> bool {
+        self.present.get()
+    }
+
+    pub fn is_none(&self) -> bool {
+        !self.is_some()
+    }
+}