Issue 147 - [Typed objects] Implement object types

lib/typedObjects/primitiveTypes.js

+/*
+ * This file is part of Adblock Plus <http://adblockplus.org/>,
+ * Copyright (C) 2006-2014 Eyeo GmbH
+ *
+ * Adblock Plus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ *
+ * Adblock Plus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+"use strict";
+
+let {log2} = require("typedObjects/utils");
+
+function createGetter(shift, offset, view)
+{
+  shift = shift | 0;
+  offset = offset | 0;
+  offset >>= shift;
+  return function()
+  {
+    return view[this.bufferIndex][((this.byteOffset | 0) >> shift) + offset];
+  };
+}
+
+function createSetter(shift, offset, view)
+{
+  shift = shift | 0;
+  offset = offset | 0;
+  offset >>= shift;
+  return function(value)
+  {
+    view[this.bufferIndex][((this.byteOffset | 0) >> shift) + offset] = value;
+  };
+}
+
+function PrimitiveType(viewType)
+{
+  let result = Object.create(PrimitiveType.prototype);
+  result.viewTypes = [viewType];
+  result.byteLength = result.referenceLength = viewType.BYTES_PER_ELEMENT | 0;
+
+  let offsetShift = log2(result.byteLength) | 0;
+  result.createGetter = createGetter.bind(null, offsetShift);
+  result.createSetter = createSetter.bind(null, offsetShift);
+  Object.freeze(result);
+  return result;
+}
+
+exports.uint8 = exports.boolean = new PrimitiveType(Uint8Array);
+exports.uint8clamped = new PrimitiveType(Uint8ClampedArray);
+exports.int8 = new PrimitiveType(Int8Array);
+exports.uint16 = new PrimitiveType(Uint16Array);
+exports.int16 = new PrimitiveType(Int16Array);
+exports.uint32 = new PrimitiveType(Uint32Array);
+exports.int32 = new PrimitiveType(Int32Array);
+exports.float32 = new PrimitiveType(Float32Array);
+exports.float64 = new PrimitiveType(Float64Array);