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1 |
| -// seedrandom.js version 2.0. |
2 |
| -// Author: David Bau 4/2/2011 |
3 |
| -// |
4 |
| -// Defines a method Math.seedrandom() that, when called, substitutes |
5 |
| -// an explicitly seeded RC4-based algorithm for Math.random(). Also |
6 |
| -// supports automatic seeding from local or network sources of entropy. |
7 |
| -// |
8 |
| -// Usage: |
9 |
| -// |
10 |
| -// <script src=http://davidbau.com/encode/seedrandom-min.js></script> |
11 |
| -// |
12 |
| -// Math.seedrandom('yipee'); Sets Math.random to a function that is |
13 |
| -// initialized using the given explicit seed. |
14 |
| -// |
15 |
| -// Math.seedrandom(); Sets Math.random to a function that is |
16 |
| -// seeded using the current time, dom state, |
17 |
| -// and other accumulated local entropy. |
18 |
| -// The generated seed string is returned. |
19 |
| -// |
20 |
| -// Math.seedrandom('yowza', true); |
21 |
| -// Seeds using the given explicit seed mixed |
22 |
| -// together with accumulated entropy. |
23 |
| -// |
24 |
| -// <script src="http://bit.ly/srandom-512"></script> |
25 |
| -// Seeds using physical random bits downloaded |
26 |
| -// from random.org. |
27 |
| -// |
28 |
| -// <script src="https://jsonlib.appspot.com/urandom?callback=Math.seedrandom"> |
29 |
| -// </script> Seeds using urandom bits from call.jsonlib.com, |
30 |
| -// which is faster than random.org. |
31 |
| -// |
32 |
| -// Examples: |
33 |
| -// |
34 |
| -// Math.seedrandom("hello"); // Use "hello" as the seed. |
35 |
| -// document.write(Math.random()); // Always 0.5463663768140734 |
36 |
| -// document.write(Math.random()); // Always 0.43973793770592234 |
37 |
| -// var rng1 = Math.random; // Remember the current prng. |
38 |
| -// |
39 |
| -// var autoseed = Math.seedrandom(); // New prng with an automatic seed. |
40 |
| -// document.write(Math.random()); // Pretty much unpredictable. |
41 |
| -// |
42 |
| -// Math.random = rng1; // Continue "hello" prng sequence. |
43 |
| -// document.write(Math.random()); // Always 0.554769432473455 |
44 |
| -// |
45 |
| -// Math.seedrandom(autoseed); // Restart at the previous seed. |
46 |
| -// document.write(Math.random()); // Repeat the 'unpredictable' value. |
47 |
| -// |
48 |
| -// Notes: |
49 |
| -// |
50 |
| -// Each time seedrandom('arg') is called, entropy from the passed seed |
51 |
| -// is accumulated in a pool to help generate future seeds for the |
52 |
| -// zero-argument form of Math.seedrandom, so entropy can be injected over |
53 |
| -// time by calling seedrandom with explicit data repeatedly. |
54 |
| -// |
55 |
| -// On speed - This javascript implementation of Math.random() is about |
56 |
| -// 3-10x slower than the built-in Math.random() because it is not native |
57 |
| -// code, but this is typically fast enough anyway. Seeding is more expensive, |
58 |
| -// especially if you use auto-seeding. Some details (timings on Chrome 4): |
59 |
| -// |
60 |
| -// Our Math.random() - avg less than 0.002 milliseconds per call |
61 |
| -// seedrandom('explicit') - avg less than 0.5 milliseconds per call |
62 |
| -// seedrandom('explicit', true) - avg less than 2 milliseconds per call |
63 |
| -// seedrandom() - avg about 38 milliseconds per call |
64 |
| -// |
65 |
| -// LICENSE (BSD): |
66 |
| -// |
67 |
| -// Copyright 2010 David Bau, all rights reserved. |
68 |
| -// |
69 |
| -// Redistribution and use in source and binary forms, with or without |
70 |
| -// modification, are permitted provided that the following conditions are met: |
71 |
| -// |
72 |
| -// 1. Redistributions of source code must retain the above copyright |
73 |
| -// notice, this list of conditions and the following disclaimer. |
74 |
| -// |
75 |
| -// 2. Redistributions in binary form must reproduce the above copyright |
76 |
| -// notice, this list of conditions and the following disclaimer in the |
77 |
| -// documentation and/or other materials provided with the distribution. |
78 |
| -// |
79 |
| -// 3. Neither the name of this module nor the names of its contributors may |
80 |
| -// be used to endorse or promote products derived from this software |
81 |
| -// without specific prior written permission. |
82 |
| -// |
83 |
| -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
84 |
| -// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
85 |
| -// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
86 |
| -// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
87 |
| -// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
88 |
| -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
89 |
| -// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
90 |
| -// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
91 |
| -// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
92 |
| -// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
93 |
| -// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
94 |
| -// |
| 1 | +/** |
| 2 | + * @fileoverview |
| 3 | + * seedrandom.js version 2.0. |
| 4 | + * Author: David Bau 4/2/2011 |
| 5 | + * |
| 6 | + * Defines a method Math.seedrandom() that, when called, substitutes |
| 7 | + * an explicitly seeded RC4-based algorithm for Math.random(). Also |
| 8 | + * supports automatic seeding from local or network sources of entropy. |
| 9 | + * |
| 10 | + * Usage: |
| 11 | + * |
| 12 | + * <script src=http://davidbau.com/encode/seedrandom-min.js></script> |
| 13 | + * |
| 14 | + * Math.seedrandom('yipee'); Sets Math.random to a function that is |
| 15 | + * initialized using the given explicit seed. |
| 16 | + * |
| 17 | + * Math.seedrandom(); Sets Math.random to a function that is |
| 18 | + * seeded using the current time, dom state, |
| 19 | + * and other accumulated local entropy. |
| 20 | + * The generated seed string is returned. |
| 21 | + * |
| 22 | + * Math.seedrandom('yowza', true); |
| 23 | + * Seeds using the given explicit seed mixed |
| 24 | + * together with accumulated entropy. |
| 25 | + * |
| 26 | + * <script src="http://bit.ly/srandom-512"></script> |
| 27 | + * Seeds using physical random bits downloaded |
| 28 | + * from random.org. |
| 29 | + * |
| 30 | + * <script src="https://jsonlib.appspot.com/urandom?callback=Math.seedrandom"> |
| 31 | + * </script> Seeds using urandom bits from call.jsonlib.com, |
| 32 | + * which is faster than random.org. |
| 33 | + * |
| 34 | + * Examples: |
| 35 | + * |
| 36 | + * Math.seedrandom("hello"); // Use "hello" as the seed. |
| 37 | + * document.write(Math.random()); // Always 0.5463663768140734 |
| 38 | + * document.write(Math.random()); // Always 0.43973793770592234 |
| 39 | + * var rng1 = Math.random; // Remember the current prng. |
| 40 | + * |
| 41 | + * var autoseed = Math.seedrandom(); // New prng with an automatic seed. |
| 42 | + * document.write(Math.random()); // Pretty much unpredictable. |
| 43 | + * |
| 44 | + * Math.random = rng1; // Continue "hello" prng sequence. |
| 45 | + * document.write(Math.random()); // Always 0.554769432473455 |
| 46 | + * |
| 47 | + * Math.seedrandom(autoseed); // Restart at the previous seed. |
| 48 | + * document.write(Math.random()); // Repeat the 'unpredictable' value. |
| 49 | + * |
| 50 | + * Notes: |
| 51 | + * |
| 52 | + * Each time seedrandom('arg') is called, entropy from the passed seed |
| 53 | + * is accumulated in a pool to help generate future seeds for the |
| 54 | + * zero-argument form of Math.seedrandom, so entropy can be injected over |
| 55 | + * time by calling seedrandom with explicit data repeatedly. |
| 56 | + * |
| 57 | + * On speed - This javascript implementation of Math.random() is about |
| 58 | + * 3-10x slower than the built-in Math.random() because it is not native |
| 59 | + * code, but this is typically fast enough anyway. Seeding is more expensive, |
| 60 | + * especially if you use auto-seeding. Some details (timings on Chrome 4): |
| 61 | + * |
| 62 | + * Our Math.random() - avg less than 0.002 milliseconds per call |
| 63 | + * seedrandom('explicit') - avg less than 0.5 milliseconds per call |
| 64 | + * seedrandom('explicit', true) - avg less than 2 milliseconds per call |
| 65 | + * seedrandom() - avg about 38 milliseconds per call |
| 66 | + * |
| 67 | + * @license |
| 68 | + * seedrandom.js |
| 69 | + * Copyright 2010 David Bau, all rights reserved. |
| 70 | + * |
| 71 | + * Redistribution and use in source and binary forms, with or without |
| 72 | + * modification, are permitted provided that the following conditions are met: |
| 73 | + * |
| 74 | + * 1. Redistributions of source code must retain the above copyright |
| 75 | + * notice, this list of conditions and the following disclaimer. |
| 76 | + * |
| 77 | + * 2. Redistributions in binary form must reproduce the above copyright |
| 78 | + * notice, this list of conditions and the following disclaimer in the |
| 79 | + * documentation and/or other materials provided with the distribution. |
| 80 | + * |
| 81 | + * 3. Neither the name of this module nor the names of its contributors may |
| 82 | + * be used to endorse or promote products derived from this software |
| 83 | + * without specific prior written permission. |
| 84 | + * |
| 85 | + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 86 | + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 87 | + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 88 | + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 89 | + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 90 | + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 91 | + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 92 | + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 93 | + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 94 | + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 95 | + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 96 | + */ |
| 97 | + |
95 | 98 | /**
|
96 | 99 | * All code is in an anonymous closure to keep the global namespace clean.
|
97 | 100 | *
|
|
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