bounded principal

ic-stable-structures/Cargo.toml

@@ -4,6 +4,7 @@ version.workspace = true
 edition.workspace = true
 
 [dependencies]
+candid = { workspace = true }
 dfinity-stable-structures = { workspace = true }
 memmap2 = { workspace = true, optional = true }
 parking_lot = { workspace = true }
@@ -12,7 +13,6 @@ thiserror = { workspace = true }
 
 [dev-dependencies]
 anyhow = { workspace = true }
-candid = { workspace = true }
 criterion = { workspace = true }
 did = { path = "./tests/did" }
 ic-cdk = { workspace = true }

ic-stable-structures/src/structure/common/mod.rs

@@ -1,5 +1,6 @@
 pub mod ring_buffer;
 
+use candid::Principal;
 pub use ring_buffer::{StableRingBuffer, StableRingBufferIndices};
 
 /// A trait for types that have a minimum and maximum value.
@@ -82,3 +83,35 @@ impl<const N: usize> Bounded for [u8; N] {
     const MIN: [u8; N] = [u8::MIN; N];
     const MAX: [u8; N] = [u8::MAX; N];
 }
+
+/// Principal sorted by two fields:
+/// 1) `len: u8` -> min = 0, max = 29;
+/// 2) `bytes: [u8; Self::MAX_LENGTH_IN_BYTES]` -> min = [], max = [0xFF; 29];
+impl Bounded for Principal {
+    const MIN: Self = Principal::from_slice(&[]); // Management canister principal;
+    const MAX: Self = Principal::from_slice(&[0xFF; 29]);
+}
+
+#[cfg(test)]
+mod tests {
+    use candid::Principal;
+
+    use crate::Bounded;
+
+    #[test]
+    fn correct_principal_bounds() {
+        let min_principal = Principal::MIN;
+        let max_principal = Principal::MAX;
+
+        let mut some_principals = vec![Principal::anonymous(), Principal::management_canister()];
+
+        let other_principals_iter =
+            (1..30).map(|i| Principal::from_slice(&vec![i as u8; i as usize]));
+        some_principals.extend(other_principals_iter);
+
+        for principal in some_principals {
+            assert!(principal >= min_principal);
+            assert!(principal <= max_principal);
+        }
+    }
+}