Add Memory utility library (#5189)

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
Co-authored-by: Arr00 <13561405+arr00@users.noreply.github.com>

test/utils/Memory.test.js

@@ -0,0 +1,39 @@
+const { ethers } = require('hardhat');
+const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
+async function fixture() {
+  const mock = await ethers.deployContract('$Memory');
+  return { mock };
+}
+
+describe('Memory', function () {
+  beforeEach(async function () {
+    Object.assign(this, await loadFixture(fixture));
+  });
+
+  describe('free pointer', function () {
+    it('sets free memory pointer', async function () {
+      const ptr = ethers.toBeHex(0xa0, 32);
+      await expect(this.mock.$setFreeMemoryPointer(ptr)).to.not.be.reverted;
+    });
+
+    it('gets free memory pointer', async function () {
+      await expect(this.mock.$getFreeMemoryPointer()).to.eventually.equal(
+        ethers.toBeHex(0x80, 32), // Default pointer
+      );
+    });
+  });
+
+  describe('pointer conversions', function () {
+    it('asBytes32', async function () {
+      const ptr = ethers.toBeHex('0x1234', 32);
+      await expect(this.mock.$asBytes32(ptr)).to.eventually.equal(ptr);
+    });
+
+    it('asPointer', async function () {
+      const ptr = ethers.toBeHex('0x1234', 32);
+      await expect(this.mock.$asPointer(ptr)).to.eventually.equal(ptr);
+    });
+  });
+});