feat: Move bounded_vec into the noir stdlib (#4197)

# Description

Partially resolves #4020. 

Need to then remove from `aztec-packages` and move to this
implementation.

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*



## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [ ] I have tested the changes locally.
- [ ] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

Signed-off-by: Kevaundray Wedderburn <[email protected]>
Co-authored-by: vezenovm <[email protected]>

noir_stdlib/src/collections.nr

@@ -1 +1,2 @@
 mod vec;
+mod bounded_vec;

noir_stdlib/src/collections/bounded_vec.nr

@@ -0,0 +1,88 @@
+struct BoundedVec<T, MaxLen> {
+    storage: [T; MaxLen],
+    // TODO: change this to return a u64 as Noir now
+    // uses u64 for indexing
+    len: Field,
+    empty_value: T,
+}
+
+impl<T, MaxLen> BoundedVec<T, MaxLen> {
+    pub fn new(initial_value: T) -> Self {
+        BoundedVec { storage: [initial_value; MaxLen], len: 0, empty_value: initial_value }
+    }
+
+    pub fn get(mut self: Self, index: Field) -> T {
+        assert(index as u64 < self.len as u64);
+        self.storage[index]
+    }
+
+    pub fn get_unchecked(mut self: Self, index: Field) -> T {
+        self.storage[index]
+    }
+
+    pub fn push(&mut self, elem: T) {
+        assert(self.len as u64 < MaxLen as u64, "push out of bounds");
+
+        self.storage[self.len] = elem;
+        self.len += 1;
+    }
+
+    pub fn len(self) -> Field {
+        self.len
+    }
+
+    pub fn max_len(_self: BoundedVec<T, MaxLen>) -> Field {
+        MaxLen
+    }
+
+    // This is a intermediate method, while we don't have an
+    // .extend method
+    pub fn storage(self) -> [T; MaxLen] {
+        self.storage
+    }
+
+    pub fn extend_from_array<Len>(&mut self, array: [T; Len]) {
+        let new_len = self.len + array.len();
+        assert(new_len as u64 <= MaxLen as u64, "extend_from_array out of bounds");
+        for i in 0..array.len() {
+            self.storage[self.len + i] = array[i];
+        }
+        self.len = new_len;
+    }
+
+    pub fn extend_from_bounded_vec<Len>(&mut self, vec: BoundedVec<T, Len>) {
+        let append_len = vec.len();
+        let new_len = self.len + append_len;
+        assert(new_len as u64 <= MaxLen as u64, "extend_from_bounded_vec out of bounds");
+
+        let mut exceeded_len = false;
+        for i in 0..Len {
+            exceeded_len |= i == append_len;
+            if !exceeded_len {
+                self.storage[self.len + (i as Field)] = vec.get_unchecked(i as Field);
+            }
+        }
+        self.len = new_len;
+    }
+
+    pub fn pop(&mut self) -> T {
+        assert(self.len as u64 > 0);
+        self.len -= 1;
+
+        let elem = self.storage[self.len];
+        self.storage[self.len] = self.empty_value;
+        elem
+    }
+
+    pub fn any<Env>(self, predicate: fn[Env](T) -> bool) -> bool {
+        let mut ret = false;
+        let mut exceeded_len = false;
+        for i in 0..MaxLen {
+            exceeded_len |= i == self.len;
+            if (!exceeded_len) {
+                ret |= predicate(self.storage[i]);
+            }
+        }
+        ret
+    }
+}

noir_stdlib/src/prelude.nr

@@ -1,4 +1,5 @@
 use crate::collections::vec::Vec;
+use crate::collections::bounded_vec::BoundedVec;
 use crate::option::Option;
 use crate::{print, println, assert_constant};
 use crate::uint128::U128;

test_programs/noir_test_success/bounded_vec/Nargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "bounded_vec"
+type = "bin"
+authors = [""]
+compiler_version = ">=0.23.0"
+
+[dependencies]

test_programs/noir_test_success/bounded_vec/src/main.nr

@@ -0,0 +1,105 @@
+#[test]
+fn test_vec_push_pop() {
+    let mut vec: BoundedVec<Field, 3> = BoundedVec::new(0);
+    assert(vec.len == 0);
+    vec.push(2);
+    assert(vec.len == 1);
+    vec.push(4);
+    assert(vec.len == 2);
+    vec.push(6);
+    assert(vec.len == 3);
+    let x = vec.pop();
+    assert(x == 6);
+    assert(vec.len == 2);
+    assert(vec.get(0) == 2);
+    assert(vec.get(1) == 4);
+}
+
+#[test]
+fn test_vec_extend_from_array() {
+    let mut vec: BoundedVec<Field, 3> = BoundedVec::new(0);
+    vec.extend_from_array([2, 4]);
+    assert(vec.len == 2);
+    assert(vec.get(0) == 2);
+    assert(vec.get(1) == 4);
+}
+
+#[test(should_fail_with="extend_from_array out of bounds")]
+fn test_vec_extend_from_array_out_of_bound() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+    vec.extend_from_array([2, 4, 6]);
+}
+
+#[test(should_fail_with="extend_from_array out of bounds")]
+fn test_vec_extend_from_array_twice_out_of_bound() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+    vec.extend_from_array([2]);
+    assert(vec.len == 1);
+    vec.extend_from_array([4, 6]);
+}
+
+#[test(should_fail)]
+fn test_vec_get_out_of_bound() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+    vec.extend_from_array([2, 4]);
+    let _x = vec.get(2);
+}
+
+#[test(should_fail)]
+fn test_vec_get_not_declared() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+    vec.extend_from_array([2]);
+    let _x = vec.get(1);
+}
+
+#[test(should_fail)]
+fn test_vec_get_uninitialized() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+    let _x = vec.get(0);
+}
+
+#[test(should_fail_with="push out of bounds")]
+fn test_vec_push_out_of_bound() {
+    let mut vec: BoundedVec<Field, 1> = BoundedVec::new(0);
+    vec.push(1);
+    vec.push(2);
+}
+
+#[test(should_fail_with="extend_from_bounded_vec out of bounds")]
+fn test_vec_extend_from_bounded_vec_out_of_bound() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+
+    let mut another_vec: BoundedVec<Field, 3> = BoundedVec::new(0);
+    another_vec.extend_from_array([1, 2, 3]);
+
+    vec.extend_from_bounded_vec(another_vec);
+}
+
+#[test(should_fail_with="extend_from_bounded_vec out of bounds")]
+fn test_vec_extend_from_bounded_vec_twice_out_of_bound() {
+    let mut vec: BoundedVec<Field, 2> = BoundedVec::new(0);
+    vec.extend_from_array([1, 2]);
+
+    let mut another_vec: BoundedVec<Field, 1> = BoundedVec::new(0);
+    another_vec.push(3);
+
+    vec.extend_from_bounded_vec(another_vec);
+}
+
+#[test]
+fn test_vec_any() {
+    let mut vec: BoundedVec<Field, 3> = BoundedVec::new(0);
+    vec.extend_from_array([2, 4, 6]);
+    assert(vec.any(|v| v == 2) == true);
+    assert(vec.any(|v| v == 4) == true);
+    assert(vec.any(|v| v == 6) == true);
+    assert(vec.any(|v| v == 3) == false);
+}
+
+#[test]
+fn test_vec_any_not_default() {
+    let default_value = 1;
+    let mut vec: BoundedVec<Field, 3> = BoundedVec::new(default_value);
+    vec.extend_from_array([2, 4]);
+    assert(vec.any(|v| v == default_value) == false);
+}