140 lines
3.7 KiB
JavaScript
140 lines
3.7 KiB
JavaScript
var Random = {
|
|
twister: null,
|
|
|
|
init: function (seed) {
|
|
if (seed == null || seed === undefined) {
|
|
seed = new Date().getTime();
|
|
}
|
|
this.twister = new MersenneTwister();
|
|
this.twister.seed(seed);
|
|
},
|
|
number: function (limit) {
|
|
// Returns an integer in [0, limit]. Uniform distribution.
|
|
if (limit == 0) {
|
|
return limit;
|
|
}
|
|
if (limit == null || limit === undefined) {
|
|
limit = 0xffffffff;
|
|
}
|
|
return (this.twister.int32() >>> 0) % limit;
|
|
},
|
|
float: function () {
|
|
// Returns a float in [0, 1]. Uniform distribution.
|
|
return this.twister.real2() >>> 0;
|
|
},
|
|
range: function (start, limit) {
|
|
// Returns an integer in [start, limit]. Uniform distribution.
|
|
if (isNaN(start) || isNaN(limit)) {
|
|
Utils.traceback();
|
|
throw new TypeError("Random.range() received a non number type: '" + start + "', '" + limit + "')");
|
|
}
|
|
return Random.number(limit - start + 1) + start;
|
|
},
|
|
ludOneTo: function(limit) {
|
|
// Returns a float in [1, limit]. The logarithm has uniform distribution.
|
|
return Math.exp(Random.float() * Math.log(limit));
|
|
},
|
|
index: function (list) {
|
|
if (!(list instanceof Array || (typeof list != "string" && "length" in list))) {
|
|
Utils.traceback();
|
|
throw new TypeError("Random.index() received a non array type: '" + list + "'");
|
|
}
|
|
return list[this.number(list.length)];
|
|
},
|
|
key: function (obj) {
|
|
var list = [];
|
|
for (var i in obj) {
|
|
list.push(i);
|
|
}
|
|
return this.index(list);
|
|
},
|
|
bool: function () {
|
|
return this.index([true, false]);
|
|
},
|
|
pick: function (obj) {
|
|
if (typeof obj == "function") {
|
|
return obj();
|
|
}
|
|
if (obj instanceof Array) {
|
|
return this.pick(this.index(obj));
|
|
}
|
|
return obj;
|
|
},
|
|
chance: function (limit) {
|
|
if (limit == null || limit === undefined) {
|
|
limit = 2;
|
|
}
|
|
if (isNaN(limit)) {
|
|
Utils.traceback();
|
|
throw new TypeError("Random.chance() received a non number type: '" + limit + "'");
|
|
}
|
|
return this.number(limit) == 1;
|
|
},
|
|
choose: function (list, flat) {
|
|
if (!(list instanceof Array)) {
|
|
Utils.traceback();
|
|
throw new TypeError("Random.choose() received a non-array type: '" + list + "'");
|
|
}
|
|
var total = 0;
|
|
for (var i = 0; i < list.length; i++) {
|
|
total += list[i][0];
|
|
}
|
|
var n = this.number(total);
|
|
for (var i = 0; i < list.length; i++) {
|
|
if (n < list[i][0]) {
|
|
if (flat == true) {
|
|
return list[i][1];
|
|
} else {
|
|
return this.pick([list[i][1]]);
|
|
}
|
|
}
|
|
n = n - list[i][0];
|
|
}
|
|
if (flat == true) {
|
|
return list[0][1];
|
|
}
|
|
return this.pick([list[0][1]]);
|
|
},
|
|
weighted: function (wa) {
|
|
// More memory-hungry but hopefully faster than Random.choose$flat
|
|
var a = [];
|
|
for (var i = 0; i < wa.length; ++i) {
|
|
for (var j = 0; j < wa[i].w; ++j) {
|
|
a.push(wa[i].v);
|
|
}
|
|
}
|
|
return a;
|
|
},
|
|
use: function (obj) {
|
|
return Random.bool() ? obj : "";
|
|
},
|
|
shuffle: function (arr) {
|
|
var len = arr.length;
|
|
var i = len;
|
|
while (i--) {
|
|
var p = Random.number(i + 1);
|
|
var t = arr[i];
|
|
arr[i] = arr[p];
|
|
arr[p] = t;
|
|
}
|
|
},
|
|
shuffled: function (arr) {
|
|
var newArray = arr.slice();
|
|
Random.shuffle(newArray);
|
|
return newArray;
|
|
},
|
|
some: function (list, limit) {
|
|
if (!(list instanceof Array)) {
|
|
Utils.traceback();
|
|
throw new TypeError("Random.some() received a non-array type: '" + list + "'");
|
|
}
|
|
if (typeof limit == 'number') {
|
|
limit = this.range(0, list.length);
|
|
}
|
|
var result = [];
|
|
for (var i = 0; i < limit; i++) {
|
|
result.push(this.pick(list));
|
|
}
|
|
return result;
|
|
}
|
|
};
|