Adding toBytes and fromBytes to Nat32

src/Nat32.mo

@@ -2,6 +2,7 @@
 ///
 /// Most operations are available as built-in operators (e.g. `1 + 1`).
 import Nat "Nat";
+import Nat8 "Nat8";
 import Prim "mo:⛔";
 
 module {
@@ -143,4 +144,20 @@ module {
   /// Returns `x` to the power of `y`, `x **% y`. Wraps on overflow.
   public func powWrap(x : Nat32, y : Nat32) : Nat32 { x **% y };
 
+  /// Returns [Nat8] of size 4 of the Nat32
+  public func toBytes(x : Nat32) : [Nat8] {
+    [ Prim.natToNat8(Prim.nat32ToNat((x >> 24) & (255))), 
+      Prim.natToNat8(Prim.nat32ToNat((x >> 16) & (255))), 
+      Prim.natToNat8(Prim.nat32ToNat((x >> 8) & (255))), 
+      Prim.natToNat8(Prim.nat32ToNat((x & 255))) ];
+  };
+
+  /// Returns  Nat32 for a four byte array
+  public func fromBytes(x : [Nat8] : Nat32] {
+    (Prim.natToNat32(Prim.nat8ToNat(x[0])) << 24) + 
+    (Prim.natToNat32(Prim.nat8ToNat(x[1])) << 16) +
+    (Prim.natToNat32(Prim.nat8ToNat(x[2])) << 8) +
+    (Prim.natToNat32(Prim.nat8ToNat(x[3])));
+  };
+
 }

test/nat32Test.mo

@@ -0,0 +1,18 @@
+import Debug "mo:base/Debug";
+import Nat "mo:base/Nat";
+import Nat8 "mo:base/Nat8";
+import Nat32 "mo:base/Nat32";
+
+Debug.print("Nat32");
+
+do {
+  Debug.print("  toBytes");
+
+  assert(Nat32.toBytes((4_123_435_857:Nat32)) == [(245:Nat8), (198:Nat8), (163:Nat8), (81:Nat8)]);
+};
+
+do {
+  Debug.print("  fromBytes");
+
+  assert(Nat32.fromBytes([(245:Nat8), (198:Nat8), (163:Nat8), (81:Nat8)]) == (4_123_435_857:Nat32))
+};