change version format

src/version.rs

@@ -2,7 +2,7 @@
 // This source code is licensed under both the Apache 2.0 and MIT License
 // (found in the LICENSE-* files in the repository)
 
-use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
+use byteorder::WriteBytesExt;
 
 /// Disk format version
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -13,21 +13,21 @@ pub enum Version {
 
 impl std::fmt::Display for Version {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "{}", u16::from(*self))
+        write!(f, "{}", u8::from(*self))
     }
 }
 
-impl From<Version> for u16 {
+impl From<Version> for u8 {
     fn from(value: Version) -> Self {
         match value {
             Version::V1 => 1,
         }
     }
 }
 
-impl TryFrom<u16> for Version {
+impl TryFrom<u8> for Version {
     type Error = ();
-    fn try_from(value: u16) -> Result<Self, Self::Error> {
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
         match value {
             1 => Ok(Self::V1),
             _ => Err(()),
@@ -48,14 +48,8 @@ impl Version {
         let first_three = bytes.get(0..3)?;
 
         if first_three == MAGIC_BYTES {
-            let next_two = bytes.get(3..5)?;
-
-            let mut bytes = [0; 2];
-            bytes.copy_from_slice(next_two);
-            let mut bytes: &[u8] = &bytes;
-
-            let value = bytes.read_u16::<BigEndian>().ok()?;
-            let version = Self::try_from(value).ok()?;
+            let version = *bytes.get(3)?;
+            let version = Self::try_from(version).ok()?;
 
             Some(version)
         } else {
@@ -68,7 +62,7 @@ impl Version {
         writer: &mut W,
     ) -> std::io::Result<usize> {
         writer.write_all(&MAGIC_BYTES)?;
-        writer.write_u16::<BigEndian>(u16::from(self))?;
+        writer.write_u8(u8::from(self))?;
         Ok(5)
     }
 }
@@ -83,21 +77,21 @@ mod tests {
     pub fn version_serialize() -> crate::Result<()> {
         let mut bytes = vec![];
         Version::V1.write_file_header(&mut bytes)?;
-        assert_eq!(bytes, &[b'V', b'L', b'G', 0, 1]);
+        assert_eq!(bytes, &[b'V', b'L', b'G', 1]);
         Ok(())
     }
 
     #[test]
     #[allow(clippy::expect_used)]
     pub fn version_deserialize_success() {
-        let version = Version::parse_file_header(&[b'V', b'L', b'G', 0, 1]);
+        let version = Version::parse_file_header(&[b'V', b'L', b'G', 1]);
         assert_eq!(version, Some(Version::V1));
     }
 
     #[test]
     #[allow(clippy::expect_used)]
     pub fn version_deserialize_fail() {
-        let version = Version::parse_file_header(&[b'F', b'J', b'X', 0, 1]);
+        let version = Version::parse_file_header(&[b'F', b'J', b'X', 1]);
         assert!(version.is_none());
     }