The Tor Browser / file comparison
comparison: js/src/tests/ecma_6/Math/shell.js
js/src/tests/ecma_6/Math/shell.js
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
equal
deleted
inserted
replaced
| -1:000000000000 | 0:b549cf9fa77e |
|---|---|
| 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 | |
| 4 | |
| 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 }; | |
| 23 | |
| 24 var ENDIAN; // 0 for little-endian, 1 for big-endian. | |
| 25 | |
| 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 }; | |
| 44 | |
| 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); | |
| 53 | |
| 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 } |
