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1 // Copyright 2012 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 (function(global, utils) { | |
6 "use strict"; | |
7 | |
8 %CheckIsBootstrapping(); | |
9 | |
10 // ------------------------------------------------------------------- | |
11 // Imports | |
12 | |
13 // The first two slots are reserved to persist PRNG state. | |
14 define kRandomNumberStart = 2; | |
15 | |
16 var GlobalMath = global.Math; | |
17 var NaN = %GetRootNaN(); | |
18 var nextRandomIndex = 0; | |
19 var randomNumbers = UNDEFINED; | |
20 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol"); | |
21 | |
22 //------------------------------------------------------------------- | |
23 // ECMA 262 - 15.8.2.14 | |
24 function MathRandom() { | |
25 // While creating a startup snapshot, %GenerateRandomNumbers returns a | |
26 // normal array containing a single random number, and has to be called for | |
27 // every new random number. | |
28 // Otherwise, it returns a pre-populated typed array of random numbers. The | |
29 // first two elements are reserved for the PRNG state. | |
30 if (nextRandomIndex <= kRandomNumberStart) { | |
31 randomNumbers = %GenerateRandomNumbers(randomNumbers); | |
32 if (%_IsTypedArray(randomNumbers)) { | |
33 nextRandomIndex = %_TypedArrayGetLength(randomNumbers); | |
34 } else { | |
35 nextRandomIndex = randomNumbers.length; | |
36 } | |
37 } | |
38 return randomNumbers[--nextRandomIndex]; | |
39 } | |
40 | |
41 // ------------------------------------------------------------------- | |
42 | |
43 %AddNamedProperty(GlobalMath, toStringTagSymbol, "Math", READ_ONLY | DONT_ENUM); | |
44 | |
45 // Set up non-enumerable functions of the Math object and | |
46 // set their names. | |
47 utils.InstallFunctions(GlobalMath, DONT_ENUM, [ | |
48 "random", MathRandom, | |
49 ]); | |
50 | |
51 %SetForceInlineFlag(MathRandom); | |
52 | |
53 // ------------------------------------------------------------------- | |
54 // Exports | |
55 | |
56 utils.Export(function(to) { | |
57 to.MathRandom = MathRandom; | |
58 }); | |
59 | |
60 }) | |
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