even betterer uuid stuff

Cargo.toml

@@ -1,8 +1,8 @@
 [package]
 name = "julid-rs"
 # 1.61803398874989484
-#--------------^
-version = "1.6.18033988749"
+#---------------^
+version = "1.6.180339887498"
 authors = ["Joe Ardent <code@ardent.nebcorp.com>"]
 edition = "2024"
 keywords = ["ulid", "sqlite", "julid", "uuid", "guid"]
@@ -41,7 +41,7 @@ uuid = { version = "1.17", default-features = false, optional = true }
 
 [dev-dependencies]
 divan = "0.1"
-uuid = { version = "1", default-features = false, features = ["v7"] }
+uuid = { version = "1", default-features = false, features = ["v7", "v4"] }
 julid-rs = { path = ".", features = ["uuid"] }
 
 [[bench]]

VERSION

@@ -1 +1 @@
-1.618033988749
+1.6180339887498

src/base32.rs

@@ -65,7 +65,7 @@ impl fmt::Display for DecodeError {
             DecodeError::InvalidLength(len) => format!("invalid length: {len}"),
             DecodeError::InvalidChar(c) => format!("invalid character: {c}"),
         };
-        write!(f, "{}", text)
+        write!(f, "{text}")
     }
 }
 

src/uuid.rs

@@ -2,7 +2,7 @@ use std::fmt;
 
 use uuid::{Uuid, Variant};
 
-use crate::Julid;
+use crate::{Julid, COUNTER_BITS};
 
 impl Julid {
     /// Convert to UUIDv7, possibly losing counter bits and altering the top
@@ -40,11 +40,32 @@ impl Julid {
             return Err(UuidError::UnsupportedVariant(var));
         }
 
-        Ok(id.as_u64_pair().into())
+        let (hi, lo) = id.as_u64_pair();
+        // zero out the high bits of the counter, which are "7" (0b0111) from the uuid
+        let mask = (1 << 12) - 1;
+        let counter = hi & mask;
+        let ts = hi >> COUNTER_BITS;
+        let hi = (ts << COUNTER_BITS) | counter;
+
+        Ok((hi, lo).into())
     }
 }
 
-#[derive(Debug)]
+impl From<Julid> for Uuid {
+    fn from(value: Julid) -> Self {
+        value.as_uuid()
+    }
+}
+
+impl TryFrom<Uuid> for Julid {
+    type Error = UuidError;
+
+    fn try_from(value: Uuid) -> Result<Self, Self::Error> {
+        Julid::from_uuid(value)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub enum UuidError {
     UnsupportedVersion(usize),
     UnsupportedVariant(uuid::Variant),
@@ -64,7 +85,9 @@ impl fmt::Display for UuidError {
 
 #[cfg(test)]
 mod test {
-    use crate::Julid;
+    use uuid::Uuid;
+
+    use crate::{uuid::UuidError, Julid};
 
     #[test]
     fn into_uuid() {
@@ -78,17 +101,23 @@ mod test {
     #[test]
     fn from_uuid() {
         let j1 = Julid::new();
-        let u1 = j1.as_uuid();
-        let ju1 = Julid::from_uuid(u1).unwrap();
-        // casting a julid to a uuid alters the counter and entropy bits slightly, so
-        // the original julid and one derived from a uuid made from it won't be the
-        // same.
-        assert_ne!(j1, ju1);
 
+        let u1: Uuid = j1.into();
+        let ju1: Julid = u1.try_into().unwrap();
+        assert_eq!(j1.timestamp(), ju1.timestamp());
+        assert_eq!(j1.counter(), ju1.counter());
+        assert_eq!(j1.random() << 2, ju1.random() << 2);
+        // once we've converted to uuid and then back to julid, we've reached the fixed
+        // point
         let u2 = ju1.as_uuid();
-        let ju2 = Julid::from_uuid(u2).unwrap();
-        // but once we've made that alteration, we've reached the fixed point
+        let ju2 = u2.try_into().unwrap();
         assert_eq!(ju1, ju2);
-        assert_eq!(u1, u2);
+    }
+
+    #[test]
+    fn cant_even_from_uuid_non_v7() {
+        let u = uuid::Uuid::new_v4();
+        let jr: Result<Julid, UuidError> = u.try_into();
+        assert_eq!(jr, Err(UuidError::UnsupportedVersion(4)));
     }
 }