From b5b80a6edd03728fed6be3b638ce9201dd2e9e7a Mon Sep 17 00:00:00 2001
From: Gabriel Rondon <grondon@gmail.com>
Date: Mon, 23 Mar 2026 23:45:07 +0000
Subject: [PATCH 1/2] feat(vec): add extend() method for batch element
 insertion

Add `BaseVec::extend()` and `Vec::extend()` for appending multiple items
in a single operation. Writes all items sequentially and updates the
length once, reducing stable memory writes compared to repeated push().

Closes #349
---
 src/base_vec.rs  | 16 ++++++++++++++++
 src/vec.rs       |  9 +++++++++
 src/vec/tests.rs | 42 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/src/base_vec.rs b/src/base_vec.rs
index 78cdb4b6..634c280a 100644
--- a/src/base_vec.rs
+++ b/src/base_vec.rs
@@ -227,6 +227,22 @@ impl<T: Storable, M: Memory> BaseVec<T, M> {
         Ok(())
     }
 
+    /// Adds multiple items at the end of the vector.
+    ///
+    /// Complexity: O(n * max_size(T))
+    pub fn extend(&self, items: &[T]) -> Result<(), GrowFailed> {
+        let start_index = self.len();
+        let slot = slot_size::<T>() as u64;
+        for (i, item) in items.iter().enumerate() {
+            let offset = DATA_OFFSET + slot * (start_index + i as u64);
+            let bytes = item.to_bytes_checked();
+            let data_offset = self.write_entry_size(offset, bytes.len() as u32)?;
+            safe_write(&self.memory, data_offset, bytes.borrow())?;
+        }
+        self.set_len(start_index + items.len() as u64);
+        Ok(())
+    }
+
     /// Removes the item at the end of the vector.
     ///
     /// Complexity: O(max_size(T))
diff --git a/src/vec.rs b/src/vec.rs
index d2cb984f..cf0b27b4 100644
--- a/src/vec.rs
+++ b/src/vec.rs
@@ -89,6 +89,15 @@ impl<T: Storable, M: Memory> Vec<T, M> {
             .expect("Failed to push item to the vector");
     }
 
+    /// Adds multiple items at the end of the vector.
+    ///
+    /// Complexity: O(n * max_size(T))
+    pub fn extend(&self, items: &[T]) {
+        self.0
+            .extend(items)
+            .expect("Failed to extend the vector");
+    }
+
     /// Removes the item at the end of the vector.
     ///
     /// Complexity: O(max_size(T))
diff --git a/src/vec/tests.rs b/src/vec/tests.rs
index cb6e676f..c53d5f63 100644
--- a/src/vec/tests.rs
+++ b/src/vec/tests.rs
@@ -350,3 +350,45 @@ fn set_last_element_to_large_blob() {
     // Store a large blob that would require growing the memory.
     sv.set(0, &Blob::try_from(vec![1; 65536].as_slice()).unwrap());
 }
+
+#[test]
+fn extend_empty_slice() {
+    let sv = StableVec::<u64, M>::new(M::default());
+    sv.extend(&[]);
+    assert_eq!(sv.len(), 0);
+    assert!(sv.is_empty());
+}
+
+#[test]
+fn extend_basic() {
+    let sv = StableVec::<u64, M>::new(M::default());
+    sv.extend(&[1, 2, 3]);
+    assert_eq!(sv.len(), 3);
+    assert_eq!(sv.to_vec(), vec![1, 2, 3]);
+}
+
+#[test]
+fn extend_after_push() {
+    let sv = StableVec::<u64, M>::new(M::default());
+    sv.push(&0);
+    sv.extend(&[1, 2, 3]);
+    assert_eq!(sv.len(), 4);
+    assert_eq!(sv.to_vec(), vec![0, 1, 2, 3]);
+}
+
+#[test]
+fn extend_multiple_calls() {
+    let sv = StableVec::<u64, M>::new(M::default());
+    sv.extend(&[1, 2]);
+    sv.extend(&[3, 4]);
+    assert_eq!(sv.to_vec(), vec![1, 2, 3, 4]);
+}
+
+#[test]
+fn extend_persistence() {
+    let sv = StableVec::<u64, M>::new(M::default());
+    sv.extend(&[10, 20, 30]);
+    let mem = sv.into_memory();
+    let sv = StableVec::<u64, M>::init(mem);
+    assert_eq!(sv.to_vec(), vec![10, 20, 30]);
+}

From d0d32dc6d8f713e2e9e40ba7f775471b00d7727a Mon Sep 17 00:00:00 2001
From: Gabriel Rondon <grondon@gmail.com>
Date: Tue, 24 Mar 2026 10:16:47 +0000
Subject: [PATCH 2/2] chore: retrigger CI after CLA signing