Merge pull request #288 from contractormario/task/g278_key_generator

Implement KeyGenerator

Author: rg911

src/core/format/KeyGenerator.ts

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2019 NEM
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { UInt64 } from '../../model/UInt64';
+import { sha3_256 } from 'js-sha3';
+
+export class KeyGenerator {
+    /**
+     * Generate UInt64 from a string
+     * @param {string} input Input string
+     * @returns {UInt64} Deterministic uint64 value for the given string
+     */
+    public static generateUInt64Key(input: string): UInt64 {
+        if (input.length === 0) {
+            throw Error(`Input must not be empty`);
+        }
+        const buf = sha3_256.arrayBuffer(input);
+        const result = new Uint32Array(buf);
+        return new UInt64([result[0], (result[1] | 0x80000000) >>> 0]);
+    }
+}

src/core/format/index.ts

@@ -18,4 +18,5 @@ export * from './RawAddress';
 export * from './RawArray';
 export * from './Convert';
 export * from './IdGenerator';
+export * from './KeyGenerator';
 export * from './RawUInt64';

test/core/format/KeyGenerator.spec.ts

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2019 NEM
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import { expect } from 'chai';
+import { UInt64 } from '../../../src/model/UInt64';
+import { KeyGenerator } from '../../../src/core/format/KeyGenerator';
+
+describe('key generator', () => {
+    describe('generate key from string', () => {
+        it('throws if input is empty', () => {
+            expect(() => KeyGenerator.generateUInt64Key('')).to.throw(Error, 'Input must not be empty');
+        })
+        it('returns UInt64', () => {
+            expect(KeyGenerator.generateUInt64Key('a')).to.be.instanceOf(UInt64);
+        })
+        it('generates correct keys', () => {
+            expect(KeyGenerator.generateUInt64Key('a').toHex()).to.equal('F524A0FBF24B0880');
+        })
+        it('generates keys deterministically', () => {
+            expect(KeyGenerator.generateUInt64Key('abc').toHex()).to.equal('B225E24FA75D983A');
+            expect(KeyGenerator.generateUInt64Key('abc').toHex()).to.equal('B225E24FA75D983A');
+            expect(KeyGenerator.generateUInt64Key('def').toHex()).to.equal('B0AC5222678F0D8E');
+            expect(KeyGenerator.generateUInt64Key('def').toHex()).to.equal('B0AC5222678F0D8E');
+            expect(KeyGenerator.generateUInt64Key('abc').toHex()).to.equal('B225E24FA75D983A');
+        })
+    })
+});