Implement .indexOf() and .lastIndexOf() on typed arrays

test/mjsunit/harmony/typedarrays-lastindexof.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-arrays --allow-natives-syntax
+
+var typedArrayConstructors = [
+  Uint8Array,
+  Int8Array,
+  Uint16Array,
+  Int16Array,
+  Uint32Array,
+  Int32Array,
+  Uint8ClampedArray,
+  Float32Array,
+  Float64Array];
+
+function CheckTypedArrayIsNeutered(array) {
+  assertEquals(0, array.byteLength);
+  assertEquals(0, array.byteOffset);
+  assertEquals(0, array.length);
+}
+
+function TestTypedArrayLastIndexOf(constructor) {
+  assertEquals(1, constructor.prototype.lastIndexOf.length);
+
+  // Negative cases.
+  assertEquals(-1, constructor.of().lastIndexOf(1));
+  var a = constructor.of(1, 2, 3, 1, 2, 3, 1);
+  assertEquals(-1, a.lastIndexOf(4));
+
+  assertEquals(5, a.lastIndexOf(3));
+  // Index out of range.
+  assertEquals(4, a.lastIndexOf(2, a.length));
+  // Index in range.
+  assertEquals(1, a.lastIndexOf(2, 2));
+  // Negative index in range.
+  assertEquals(0, a.lastIndexOf(1, -5));
+  // Negative index out of range.
+  assertEquals(-1, a.lastIndexOf(1, -10));
+
+  // Typed arrays cannot store "undefined", so even when creating one
+  // with "undefined" values, those are coerced to numbers, which means
+  // .lastIndexOf() cannot ever return a valid index for "undefined".
+  assertEquals(-1, a.lastIndexOf(undefined));
+  assertEquals(-1, constructor.of(undefined).lastIndexOf(undefined));
+
+  // Neutering the buffer backing the typed array should make
+  // .lastIndexOf() always return -1 afterwards.
+  a = constructor.of(1, 2, 3, 4, 5, 6);
+  %ArrayBufferNeuter(a.buffer);
+  CheckTypedArrayIsNeutered(a);
+  assertEquals(-1, a.lastIndexOf(4));
+
+  // The method must work for typed arrays created from ArrayBuffer.
+  // The length of the ArrayBuffer is chosen so it is a multiple of
+  // all lengths of the typed array items.
+  a = new constructor(new ArrayBuffer(64));
+  a[4] = 42;
+  assertEquals(4, a.lastIndexOf(42));
+
+  // Externalizing the array by using the .buffer property should not
+  // affect operation of .lastIndexOf().
+  a = constructor.of(1, 2, 3, 4, 5, 6);
+  var buffer = a.buffer;
+  assertTrue(!!buffer);
+  assertEquals("ArrayBuffer", %_ClassOf(buffer));
+  assertSame(buffer, a.buffer);
+  assertEquals(2, a.lastIndexOf(3));
+
+  // The %TypedArray%.prototype.lastIndexOf() method should not work
+  // when transplanted to objects that are not typed arrays.
+  assertThrows(function () { constructor.prototype.lastIndexOf.call([1, 2, 3], 0); }, TypeError);
+  assertThrows(function () { constructor.prototype.lastIndexOf.call("abc", 0); }, TypeError);
+  assertThrows(function () { constructor.prototype.lastIndexOf.call({}, 0); }, TypeError);
+  assertThrows(function () { constructor.prototype.lastIndexOf.call(0, 0); }, TypeError);
+
+  // Method must be useable on instances of other typed arrays.
+  for (var otherConstructor of typedArrayConstructors) {
+    a = otherConstructor.of(1, 2, 3, 4);
+    assertEquals(2, constructor.prototype.lastIndexOf.call(a, 3));
+  }
+}
+
+for (var constructor of typedArrayConstructors) {
+  TestTypedArrayLastIndexOf(constructor);
+}