lapo.it
1// Big integer base-10 printing library
2// Copyright (c) 2014 Lapo Luchini <lapo@lapo.it>
3
4// Permission to use, copy, modify, and/or distribute this software for any
5// purpose with or without fee is hereby granted, provided that the above
6// copyright notice and this permission notice appear in all copies.
7//
8// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15
16/*jshint browser: true, strict: true, immed: true, latedef: true, undef: true, regexdash: false */
17(function () {
18"use strict";
19
20var max = 10000000000000; // biggest integer that can still fit 2^53 when multiplied by 256
21
22function Int10(value) {
23 this.buf = [+value || 0];
24}
25
26Int10.prototype.mulAdd = function (m, c) {
27 // assert(m <= 256)
28 var b = this.buf,
29 l = b.length,
30 i, t;
31 for (i = 0; i < l; ++i) {
32 t = b[i] * m + c;
33 if (t < max)
34 c = 0;
35 else {
36 c = 0|(t / max);
37 t -= c * max;
38 }
39 b[i] = t;
40 }
41 if (c > 0)
42 b[i] = c;
43};
44
45Int10.prototype.toString = function (base) {
46 if ((base || 10) != 10)
47 throw 'only base 10 is supported';
48 var b = this.buf,
49 s = b[b.length - 1].toString();
50 for (var i = b.length - 2; i >= 0; --i)
51 s += (max + b[i]).toString().substring(1);
52 return s;
53};
54
55Int10.prototype.valueOf = function () {
56 var b = this.buf,
57 v = 0;
58 for (var i = b.length - 1; i >= 0; --i)
59 v = v * max + b[i];
60 return v;
61};
62
63Int10.prototype.simplify = function () {
64 var b = this.buf;
65 return (b.length == 1) ? b[0] : this;
66};
67
68// export globals
69if (typeof module !== 'undefined') { module.exports = Int10; } else { window.Int10 = Int10; }
70})();