Add PlatformAddress and its tests

src/PlatformAddress.ts

@@ -0,0 +1,50 @@
+import { H160 } from "./primitives/H160";
+import { toWords, encode, decode, fromWords } from "./bech32";
+import { toHex } from "./utils";
+
+/**
+ * Substitutes for platform token owner which consists of network id and account
+ * id. . The network id is represented with prefix "ccc"(mainnet) or
+ * "tcc"(testnet). Currently version 0 exists only.
+ *
+ * Refer to the wiki for the details about PlatformAddress.
+ * https://github.com/CodeChain-io/codechain/wiki/CodeChain-Address
+ */
+export class PlatformAddress {
+    accountId: H160;
+
+    value: string;
+
+    private constructor(accountId: H160, address: string) {
+        this.accountId = accountId;
+        this.value = address;
+    }
+
+    static fromAccountId(accountId: H160, options: { isTestnet?: boolean, version?: number } = {}) {
+        const { isTestnet = false, version = 0 } = options;
+
+        if (version !== 0) {
+            throw `Unsupported version for platform address: ${version}`;
+        }
+
+        const words = toWords(Buffer.from([version, ...Buffer.from(accountId.value, "hex")]));
+        return new PlatformAddress(accountId, encode(isTestnet ? "tcc" : "ccc", words));
+    }
+
+    static fromAddress(address: string) {
+        if (!address.startsWith("ccc") && !address.startsWith("tcc")) {
+            throw `The prefix is unknown for platform address: ${address}`;
+        }
+
+        const { words } = decode(address, address.substr(0, 3));
+        const bytes = fromWords(words);
+        const version = bytes[0];
+
+        if (version !== 0) {
+            throw `Unsupported version for platform address: ${version}`;
+        }
+
+        const accountId = toHex(Buffer.from(bytes.slice(1)));
+        return new PlatformAddress(new H160(accountId), address);
+    }
+}

src/__test__/PlatformAddress.spec.ts

@@ -0,0 +1,44 @@
+import { PlatformAddress } from "../PlatformAddress";
+import { H160 } from "../primitives/H160";
+
+test("PlatformAddress.fromAccountId - mainnet (default)", () => {
+    const accountId = new H160("7b5e0ee8644c6f585fc297364143280a45844502");
+    const address = PlatformAddress.fromAccountId(accountId);
+    expect(address.value).toMatch(/^ccc[a-z0-9]+$/);
+});
+
+test("PlatformAddress.fromAccountId - testnet", () => {
+    const accountId = new H160("7b5e0ee8644c6f585fc297364143280a45844502");
+    const address = PlatformAddress.fromAccountId(accountId, { isTestnet: true });
+    expect(address.value).toMatch(/^tcc[a-z0-9]+$/);
+});
+
+test("PlatformAddress.fromAccountId - valid version", () => {
+    const accountId = new H160("7b5e0ee8644c6f585fc297364143280a45844502");
+    expect(() => {
+        PlatformAddress.fromAccountId(accountId, { version: 0 });
+    }).not.toThrow();
+});
+
+test("PlatformAddress.fromAccountId - invalid version", () => {
+    const accountId = new H160("7b5e0ee8644c6f585fc297364143280a45844502");
+    expect(() => {
+        PlatformAddress.fromAccountId(accountId, { version: 1 });
+    }).toThrow("Unsupported version for platform address: 1");
+});
+
+test("PlatformAddress.fromAddress - mainnet", () => {
+    const address = PlatformAddress.fromAddress("cccqpa4urhgv3xx7kzlc2tnvs2r9q9ytpz9qg4aw2qm");
+    expect(address.accountId).toEqual(new H160("7b5e0ee8644c6f585fc297364143280a45844502"));
+});
+
+test("PlatformAddress.fromAddress - testnet", () => {
+    const address = PlatformAddress.fromAddress("tccqpa4urhgv3xx7kzlc2tnvs2r9q9ytpz9qga6ufnz");
+    expect(address.accountId).toEqual(new H160("7b5e0ee8644c6f585fc297364143280a45844502"));
+});
+
+test("PlatformAddress.fromAddress - invalid checksum", () => {
+    expect(() => {
+        PlatformAddress.fromAddress("cccqpa4urhgv3xx7kzlc2tnvs2r9q9ytpz9qgqqqqqq");
+    }).toThrow();
+});

src/bech32.ts

@@ -141,6 +141,6 @@ export function toWords (bytes: any) {
 }
 
 // FIXME: any
-function fromWords (words: any) {
+export function fromWords (words: any) {
     return convert(words, 5, 8, false);
-}
+}

src/utils.ts

@@ -17,7 +17,7 @@ const secp256k1 = new EC("secp256k1");
 
 const toHexByte = (byte: number) => byte < 0x10 ? `0${byte.toString(16)}` : byte.toString(16);
 
-const toHex = (buffer: Buffer): string => {
+export const toHex = (buffer: Buffer): string => {
     return Array.from(buffer).map(toHexByte).join("");
 };