js/src/tests/ecma_6/Math/shell.js@129ffea94266
js/src/tests/ecma_6/Math/shell.js
Sat, 03 Jan 2015 20:18:00 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Sat, 03 Jan 2015 20:18:00 +0100
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
- permissions
- -rw-r--r--
Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.
1 // The nearest representable values to +1.0.
2 const ONE_PLUS_EPSILON = 1 + Math.pow(2, -52); // 0.9999999999999999
3 const ONE_MINUS_EPSILON = 1 - Math.pow(2, -53); // 1.0000000000000002
5 {
6 var fail = function (msg) {
7 var exc = new Error(msg);
8 try {
9 // Try to improve on exc.fileName and .lineNumber; leave exc.stack
10 // alone. We skip two frames: fail() and its caller, an assertX()
11 // function.
12 var frames = exc.stack.trim().split("\n");
13 if (frames.length > 2) {
14 var m = /@([^@:]*):([0-9]+)$/.exec(frames[2]);
15 if (m) {
16 exc.fileName = m[1];
17 exc.lineNumber = +m[2];
18 }
19 }
20 } catch (ignore) { throw ignore;}
21 throw exc;
22 };
24 var ENDIAN; // 0 for little-endian, 1 for big-endian.
26 // Return the difference between the IEEE 754 bit-patterns for a and b.
27 //
28 // This is meaningful when a and b are both finite and have the same
29 // sign. Then the following hold:
30 //
31 // * If a === b, then diff(a, b) === 0.
32 //
33 // * If a !== b, then diff(a, b) === 1 + the number of representable values
34 // between a and b.
35 //
36 var f = new Float64Array([0, 0]);
37 var u = new Uint32Array(f.buffer);
38 var diff = function (a, b) {
39 f[0] = a;
40 f[1] = b;
41 //print(u[1].toString(16) + u[0].toString(16) + " " + u[3].toString(16) + u[2].toString(16));
42 return Math.abs((u[3-ENDIAN] - u[1-ENDIAN]) * 0x100000000 + u[2+ENDIAN] - u[0+ENDIAN]);
43 };
45 // Set ENDIAN to the platform's endianness.
46 ENDIAN = 0; // try little-endian first
47 if (diff(2, 4) === 0x100000) // exact wrong answer we'll get on a big-endian platform
48 ENDIAN = 1;
49 assertEq(diff(2,4), 0x10000000000000);
50 assertEq(diff(0, Number.MIN_VALUE), 1);
51 assertEq(diff(1, ONE_PLUS_EPSILON), 1);
52 assertEq(diff(1, ONE_MINUS_EPSILON), 1);
54 var assertNear = function assertNear(a, b, tolerance=1) {
55 if (!Number.isFinite(b)) {
56 fail("second argument to assertNear (expected value) must be a finite number");
57 } else if (Number.isNaN(a)) {
58 fail("got NaN, expected a number near " + b);
59 } else if (!Number.isFinite(a)) {
60 if (b * Math.sign(a) < Number.MAX_VALUE)
61 fail("got " + a + ", expected a number near " + b);
62 } else {
63 // When the two arguments do not have the same sign bit, diff()
64 // returns some huge number. So if b is positive or negative 0,
65 // make target the zero that has the same sign bit as a.
66 var target = b === 0 ? a * 0 : b;
67 var err = diff(a, target);
68 if (err > tolerance) {
69 fail("got " + a + ", expected a number near " + b +
70 " (relative error: " + err + ")");
71 }
72 }
73 };
74 }
