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      1 // Copyright 2013 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 "use strict";
      6 
      7 var $ArrayBuffer = global.ArrayBuffer;
      8 
      9 // -------------------------------------------------------------------
     10 
     11 function ArrayBufferConstructor(length) { // length = 1
     12   if (%_IsConstructCall()) {
     13     var byteLength = ToPositiveInteger(length, 'invalid_array_buffer_length');
     14     %ArrayBufferInitialize(this, byteLength);
     15   } else {
     16     throw MakeTypeError('constructor_not_function', ["ArrayBuffer"]);
     17   }
     18 }
     19 
     20 function ArrayBufferGetByteLen() {
     21   if (!IS_ARRAYBUFFER(this)) {
     22     throw MakeTypeError('incompatible_method_receiver',
     23                         ['ArrayBuffer.prototype.byteLength', this]);
     24   }
     25   return %_ArrayBufferGetByteLength(this);
     26 }
     27 
     28 // ES6 Draft 15.13.5.5.3
     29 function ArrayBufferSlice(start, end) {
     30   if (!IS_ARRAYBUFFER(this)) {
     31     throw MakeTypeError('incompatible_method_receiver',
     32                         ['ArrayBuffer.prototype.slice', this]);
     33   }
     34 
     35   var relativeStart = TO_INTEGER(start);
     36   if (!IS_UNDEFINED(end)) {
     37     end = TO_INTEGER(end);
     38   }
     39   var first;
     40   var byte_length = %_ArrayBufferGetByteLength(this);
     41   if (relativeStart < 0) {
     42     first = MathMax(byte_length + relativeStart, 0);
     43   } else {
     44     first = MathMin(relativeStart, byte_length);
     45   }
     46   var relativeEnd = IS_UNDEFINED(end) ? byte_length : end;
     47   var fin;
     48   if (relativeEnd < 0) {
     49     fin = MathMax(byte_length + relativeEnd, 0);
     50   } else {
     51     fin = MathMin(relativeEnd, byte_length);
     52   }
     53 
     54   if (fin < first) {
     55     fin = first;
     56   }
     57   var newLen = fin - first;
     58   // TODO(dslomov): implement inheritance
     59   var result = new $ArrayBuffer(newLen);
     60 
     61   %ArrayBufferSliceImpl(this, result, first);
     62   return result;
     63 }
     64 
     65 function ArrayBufferIsViewJS(obj) {
     66   return %ArrayBufferIsView(obj);
     67 }
     68 
     69 function SetUpArrayBuffer() {
     70   %CheckIsBootstrapping();
     71 
     72   // Set up the ArrayBuffer constructor function.
     73   %SetCode($ArrayBuffer, ArrayBufferConstructor);
     74   %FunctionSetPrototype($ArrayBuffer, new $Object());
     75 
     76   // Set up the constructor property on the ArrayBuffer prototype object.
     77   %AddNamedProperty(
     78       $ArrayBuffer.prototype, "constructor", $ArrayBuffer, DONT_ENUM);
     79 
     80   InstallGetter($ArrayBuffer.prototype, "byteLength", ArrayBufferGetByteLen);
     81 
     82   InstallFunctions($ArrayBuffer, DONT_ENUM, $Array(
     83       "isView", ArrayBufferIsViewJS
     84   ));
     85 
     86   InstallFunctions($ArrayBuffer.prototype, DONT_ENUM, $Array(
     87       "slice", ArrayBufferSlice
     88   ));
     89 }
     90 
     91 SetUpArrayBuffer();
     92