114 lines
3.0 KiB
JavaScript
114 lines
3.0 KiB
JavaScript
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// Big integer base-10 printing library
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// Copyright (c) 2008-2020 Lapo Luchini <lapo@lapo.it>
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice appear in all copies.
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//
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// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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(typeof define != 'undefined' ? define : function (factory) { 'use strict';
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if (typeof module == 'object') module.exports = factory();
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else window.int10 = factory();
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})(function () {
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"use strict";
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var max = 10000000000000; // biggest 10^n integer that can still fit 2^53 when multiplied by 256
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/**
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* Arbitrary length base-10 value.
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* @param {number} value - Optional initial value (will be 0 otherwise).
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*/
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function Int10(value) {
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this.buf = [+value || 0];
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}
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/**
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* Multiply value by m and add c.
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* @param {number} m - multiplier, must be < =256
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* @param {number} c - value to add
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*/
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Int10.prototype.mulAdd = function (m, c) {
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// assert(m <= 256)
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var b = this.buf,
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l = b.length,
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i, t;
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for (i = 0; i < l; ++i) {
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t = b[i] * m + c;
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if (t < max)
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c = 0;
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else {
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c = 0|(t / max);
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t -= c * max;
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}
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b[i] = t;
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}
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if (c > 0)
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b[i] = c;
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};
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/**
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* Subtract value.
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* @param {number} c - value to subtract
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*/
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Int10.prototype.sub = function (c) {
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var b = this.buf,
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l = b.length,
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i, t;
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for (i = 0; i < l; ++i) {
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t = b[i] - c;
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if (t < 0) {
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t += max;
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c = 1;
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} else
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c = 0;
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b[i] = t;
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}
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while (b[b.length - 1] === 0)
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b.pop();
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};
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/**
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* Convert to decimal string representation.
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* @param {*} base - optional value, only value accepted is 10
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*/
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Int10.prototype.toString = function (base) {
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if ((base || 10) != 10)
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throw 'only base 10 is supported';
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var b = this.buf,
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s = b[b.length - 1].toString();
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for (var i = b.length - 2; i >= 0; --i)
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s += (max + b[i]).toString().substring(1);
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return s;
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};
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/**
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* Convert to Number value representation.
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* Will probably overflow 2^53 and thus become approximate.
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*/
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Int10.prototype.valueOf = function () {
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var b = this.buf,
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v = 0;
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for (var i = b.length - 1; i >= 0; --i)
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v = v * max + b[i];
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return v;
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};
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/**
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* Return value as a simple Number (if it is <= 10000000000000), or return this.
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*/
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Int10.prototype.simplify = function () {
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var b = this.buf;
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return (b.length == 1) ? b[0] : this;
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};
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return Int10;
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});
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