@ton/core
Version:
Core TypeScript library that implements low level primitives for TON blockchain.
191 lines (186 loc) • 8.03 kB
JavaScript
"use strict";
/**
The MIT License (MIT)
Copyright (c) 2016 Zeh Fernando
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.Prando = void 0;
class Prando {
// ================================================================================================================
// CONSTRUCTOR ----------------------------------------------------------------------------------------------------
/**
* Generate a new Prando pseudo-random number generator.
*
* @param seed - A number or string seed that determines which pseudo-random number sequence will be created. Defaults to a random seed based on `Math.random()`.
*/
constructor(seed) {
this._value = NaN;
if (typeof seed === "string") {
// String seed
this._seed = this.hashCode(seed);
}
else if (typeof seed === "number") {
// Numeric seed
this._seed = this.getSafeSeed(seed);
}
else {
// Pseudo-random seed
this._seed = this.getSafeSeed(Prando.MIN +
Math.floor((Prando.MAX - Prando.MIN) * Math.random()));
}
this.reset();
}
// ================================================================================================================
// PUBLIC INTERFACE -----------------------------------------------------------------------------------------------
/**
* Generates a pseudo-random number between a lower (inclusive) and a higher (exclusive) bounds.
*
* @param min - The minimum number that can be randomly generated.
* @param pseudoMax - The maximum number that can be randomly generated (exclusive).
* @return The generated pseudo-random number.
*/
next(min = 0, pseudoMax = 1) {
this.recalculate();
return this.map(this._value, Prando.MIN, Prando.MAX, min, pseudoMax);
}
/**
* Generates a pseudo-random integer number in a range (inclusive).
*
* @param min - The minimum number that can be randomly generated.
* @param max - The maximum number that can be randomly generated.
* @return The generated pseudo-random number.
*/
nextInt(min = 10, max = 100) {
this.recalculate();
return Math.floor(this.map(this._value, Prando.MIN, Prando.MAX, min, max + 1));
}
/**
* Generates a pseudo-random string sequence of a particular length from a specific character range.
*
* Note: keep in mind that creating a random string sequence does not guarantee uniqueness; there is always a
* 1 in (char_length^string_length) chance of collision. For real unique string ids, always check for
* pre-existing ids, or employ a robust GUID/UUID generator.
*
* @param length - Length of the string to be generated.
* @param chars - Characters that are used when creating the random string. Defaults to all alphanumeric chars (A-Z, a-z, 0-9).
* @return The generated string sequence.
*/
nextString(length = 16, chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") {
let str = "";
while (str.length < length) {
str += this.nextChar(chars);
}
return str;
}
/**
* Generates a pseudo-random string of 1 character specific character range.
*
* @param chars - Characters that are used when creating the random string. Defaults to all alphanumeric chars (A-Z, a-z, 0-9).
* @return The generated character.
*/
nextChar(chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") {
return chars.substr(this.nextInt(0, chars.length - 1), 1);
}
/**
* Picks a pseudo-random item from an array. The array is left unmodified.
*
* Note: keep in mind that while the returned item will be random enough, picking one item from the array at a time
* does not guarantee nor imply that a sequence of random non-repeating items will be picked. If you want to
* *pick items in a random order* from an array, instead of *pick one random item from an array*, it's best to
* apply a *shuffle* transformation to the array instead, then read it linearly.
*
* @param array - Array of any type containing one or more candidates for random picking.
* @return An item from the array.
*/
nextArrayItem(array) {
return array[this.nextInt(0, array.length - 1)];
}
/**
* Generates a pseudo-random boolean.
*
* @return A value of true or false.
*/
nextBoolean() {
this.recalculate();
return this._value > 0.5;
}
/**
* Skips ahead in the sequence of numbers that are being generated. This is equivalent to
* calling next() a specified number of times, but faster since it doesn't need to map the
* new random numbers to a range and return it.
*
* @param iterations - The number of items to skip ahead.
*/
skip(iterations = 1) {
while (iterations-- > 0) {
this.recalculate();
}
}
/**
* Reset the pseudo-random number sequence back to its starting seed. Further calls to next()
* will then produce the same sequence of numbers it had produced before. This is equivalent to
* creating a new Prando instance with the same seed as another Prando instance.
*
* Example:
* let rng = new Prando(12345678);
* console.log(rng.next()); // 0.6177754114889017
* console.log(rng.next()); // 0.5784605181725837
* rng.reset();
* console.log(rng.next()); // 0.6177754114889017 again
* console.log(rng.next()); // 0.5784605181725837 again
*/
reset() {
this._value = this._seed;
}
// ================================================================================================================
// PRIVATE INTERFACE ----------------------------------------------------------------------------------------------
recalculate() {
this._value = this.xorshift(this._value);
}
xorshift(value) {
// Xorshift*32
// Based on George Marsaglia's work: http://www.jstatsoft.org/v08/i14/paper
value ^= value << 13;
value ^= value >> 17;
value ^= value << 5;
return value;
}
map(val, minFrom, maxFrom, minTo, maxTo) {
return (((val - minFrom) / (maxFrom - minFrom)) * (maxTo - minTo) + minTo);
}
hashCode(str) {
let hash = 0;
if (str) {
const l = str.length;
for (let i = 0; i < l; i++) {
hash = (hash << 5) - hash + str.charCodeAt(i);
hash |= 0;
hash = this.xorshift(hash);
}
}
return this.getSafeSeed(hash);
}
getSafeSeed(seed) {
if (seed === 0)
return 1;
return seed;
}
}
exports.Prando = Prando;
Prando.MIN = -2147483648; // Int32 min
Prando.MAX = 2147483647; // Int32 max