Implement RedbValue and RedbKey for char

src/types.rs

@@ -393,6 +393,41 @@ impl RedbKey for &str {
     }
 }
 
+impl RedbValue for char {
+    type SelfType<'a> = char;
+    type AsBytes<'a> = [u8; 3] where Self: 'a;
+
+    fn fixed_width() -> Option<usize> {
+        Some(3)
+    }
+
+    fn from_bytes<'a>(data: &'a [u8]) -> char
+    where
+        Self: 'a,
+    {
+        char::from_u32(u32::from_le_bytes([data[0], data[1], data[2], 0])).unwrap()
+    }
+
+    fn as_bytes<'a, 'b: 'a>(value: &'a Self::SelfType<'b>) -> [u8; 3]
+    where
+        Self: 'a,
+        Self: 'b,
+    {
+        let bytes = u32::from(*value).to_le_bytes();
+        [bytes[0], bytes[1], bytes[2]]
+    }
+
+    fn type_name() -> TypeName {
+        TypeName::internal(stringify!(char))
+    }
+}
+
+impl RedbKey for char {
+    fn compare(data1: &[u8], data2: &[u8]) -> Ordering {
+        Self::from_bytes(data1).cmp(&Self::from_bytes(data2))
+    }
+}
+
 macro_rules! le_value {
     ($t:ty) => {
         impl RedbValue for $t {

tests/basic_tests.rs

@@ -1606,3 +1606,29 @@ fn generic_signature_lifetimes() {
         read_key_generic(table, key, db);
     }
 }
+
+#[test]
+fn char_type() {
+    let tmpfile = create_tempfile();
+    let db = Database::create(tmpfile.path()).unwrap();
+
+    let definition: TableDefinition<char, char> = TableDefinition::new("x");
+
+    let write_txn = db.begin_write().unwrap();
+    {
+        let mut table = write_txn.open_table(definition).unwrap();
+        table.insert('a', &'b').unwrap();
+        table.insert(&'b', 'a').unwrap();
+    }
+    write_txn.commit().unwrap();
+
+    let read_txn = db.begin_read().unwrap();
+    let table = read_txn.open_table(definition).unwrap();
+    assert_eq!('a', table.get(&'b').unwrap().unwrap().value());
+    assert_eq!('b', table.get(&'a').unwrap().unwrap().value());
+
+    let mut iter = table.iter().unwrap();
+    assert_eq!(iter.next().unwrap().unwrap().0.value(), 'a');
+    assert_eq!(iter.next().unwrap().unwrap().0.value(), 'b');
+    assert!(iter.next().is_none());
+}