Code enhancements

src/smartcontracts/code.spec.ts

@@ -0,0 +1,38 @@
+import { assert } from "chai";
+import { Code } from "./code";
+import { Hash } from "../hash";
+
+describe("Code Class Tests", function() {
+    const sampleHex = "abcdef0123456789";
+    const sampleBuffer = Buffer.from(sampleHex, "hex");
+
+    it("should create Code from buffer", function() {
+        const code = Code.fromBuffer(sampleBuffer);
+
+        assert.instanceOf(code, Code);
+        assert.equal(code.toString(), sampleHex);
+    });
+
+    it("should create Code from hex string", function() {
+        const code = Code.fromHex(sampleHex);
+
+        assert.instanceOf(code, Code);
+        assert.equal(code.toString(), sampleHex);
+    });
+
+    it("should return the correct buffer from valueOf", function() {
+        const code = Code.fromHex(sampleHex);
+        const buffer = code.valueOf();
+
+        assert.isTrue(Buffer.isBuffer(buffer));
+        assert.equal(buffer.toString("hex"), sampleHex);
+    });
+
+    it("should compute hash correctly", function() {
+        const code = Code.fromHex(sampleHex);
+        const hash = code.computeHash();
+
+        assert.instanceOf(hash, Buffer);
+        assert.equal(hash.toString('hex'), 'ac86b78afd9bdda3641a47a4aff2a7ee26acd40cc534d63655e9dfbf3f890a02')
+    });
+});

src/smartcontracts/code.ts

@@ -1,3 +1,8 @@
+import { Hash } from "../hash";
+
+const createHasher = require('blake2b')
+const CODE_HASH_LENGTH = 32
+
 /**
  * Bytecode of a Smart Contract, as an abstraction.
  */
@@ -15,6 +20,13 @@ export class Code {
         return new Code(code.toString("hex"));
     }
 
+    /**
+     * Creates a Code object from a hex-encoded string.
+     */
+    static fromHex(hex: string): Code {
+        return new Code(hex)
+    }
+
     /**
      * Returns the bytecode as a hex-encoded string.
      */
@@ -25,4 +37,12 @@ export class Code {
     valueOf(): Buffer {
         return Buffer.from(this.hex, "hex");
     }
+
+    computeHash(): Buffer {
+        const hash = createHasher(CODE_HASH_LENGTH)
+            .update(this.valueOf())
+            .digest();
+
+        return Buffer.from(hash)
+    }
 }