/**********************************************************\
| |
| The implementation of PHPRPC Protocol 3.0 |
| |
| powmod.js |
| |
| Release 3.0.0 beta 9 |
| Copyright (c) 2005-2007 by Team-PHPRPC |
| |
| WebSite: http://www.phprpc.org/ |
| http://www.phprpc.com/ |
| http://sourceforge.net/projects/php-rpc/ |
| |
| Authors: Ma Bingyao <andot@ujn.edu.cn> |
| |
| This file may be distributed and/or modified under the |
| terms of the GNU Lesser General Public License (LGPL) |
| version 2.1 as published by the Free Software Foundation |
| and appearing in the included file LICENSE. |
| |
\**********************************************************/
/* PowMod BigInt library.
*
* Copyright (C) 2006 Alexander Valyalkin <valyala@tut.by>
* 2006 Ma Bingyao <andot@ujn.edu.cn>
* Version: 3.0
* LastModified: Dec 5, 2006
* This library is free. You can redistribute it and/or modify it.
*/
// result = a * b
function mul(a, b) {
var n = a.length, m = b.length, nm = n + m, i, j, c = Array(nm);
for (i = 0; i < nm; i++) c[i] = 0;
for (i = 0; i < n; i++) {
for (j = 0; j < m; j++) {
c[i + j] += a[i] * b[j];
c[i + j + 1] += (c[i + j] >> 16) & 0xffff;
c[i + j] &= 0xffff;
}
}
return c;
}
// is_mod = 0, result = a / b
// is_mod = 1, result = a mod b
function div(a, b, is_mod) {
var n = a.length, m = b.length, i, j, d, tmp, qq, rr, c = Array();
d = Math.floor(0x10000 / (b[m - 1] + 1));
a = mul(a, [d]);
b = mul(b, [d]);
for (j = n - m; j >= 0; j--) {
tmp = a[j + m] * 0x10000 + a[j + m - 1];
rr = tmp % b[m - 1];
qq = Math.round((tmp - rr) / b[m - 1]);
if (qq == 0x10000 || (m > 1 && qq * b[m - 2] > 0x10000 * rr + a[j + m - 2])) {
qq--;
rr += b[m - 1];
if (rr < 0x10000 && qq * b[m - 2] > 0x10000 * rr + a[j + m - 2]) qq--;
}
for (i = 0; i < m; i++) {
tmp = i + j;
a[tmp] -= b[i] * qq;
a[tmp + 1] += Math.floor(a[tmp] / 0x10000);
a[tmp] &= 0xffff;
}
c[j] = qq;
if (a[tmp + 1] < 0) {
c[j]--;
for (i = 0; i < m; i++) {
tmp = i + j;
a[tmp] += b[i];
if (a[tmp] > 0xffff) {
a[tmp + 1]++;
a[tmp] &= 0xffff;
}
}
}
}
if (!is_mod) return c;
b = Array();
for (i = 0; i < m; i++) b[i] = a[i];
return div(b, [d]);
}
// result = a^b mod c
function pow_mod(a, b, c) {
var n = b.length, p = [1], i, j, tmp;
for (i = 0; i < n - 1; i++) {
tmp = b[i];
for (j = 0; j < 0x10; j++) {
if (tmp & 1) p = div(mul(p, a), c, 1);
tmp >>= 1;
a = div(mul(a, a), c, 1);
}
}
tmp = b[i];
while (tmp) {
if (tmp & 1) p = div(mul(p, a), c, 1);
tmp >>= 1;
a = div(mul(a, a), c, 1);
}
return p;
}
/*************************************************************/
// PadLefts with 0
function zerofill(str, num) {
var n = num - str.toString().length, i, s = '';
for (i = 0; i < n; i++) s += '0';
return s + str;
}
// Converts decimal string to BigInt number.
function dec2num(str) {
var n = str.length, a = [0], i, j, m;
n += 4 - (n % 4);
str = zerofill(str, n);
n >>= 2;
for (i = 0; i < n; i++) {
a = mul(a, [10000]);
a[0] += parseInt(str.substring(4 * i, 4 * (i + 1)), 10);
m = a.length;
j = a[m] = 0;
while (j < m && a[j] > 0xffff) {
a[j++] &= 0xffff;
a[j]++;
}
while (a.length > 1 && !a[a.length - 1]) a.length--;
}
return a;
}
// Converts BigInt number to decimal string.
function num2dec(a) {
var n = 2 * a.length, b = Array(), i;
for (i = 0; i < n; i++) {
b[i] = zerofill(div(a, [10000], 1)[0], 4);
a = div(a, [10000]);
}
while (b.length > 1 && !parseInt(b[b.length - 1], 10)) b.length--;
n = b.length - 1;
b[n] = parseInt(b[n], 10);
b = b.reverse().join('');
return b;
}
/*************************************************************/
// Converts binary string to BigInt number.
function str2num(str) {
var len = str.length;
if (len & 1) {
str = "\0" + str;
len++;
}
len >>= 1;
var result = Array();
for (var i = 0; i < len; i++) {
result[len - i - 1] = str.charCodeAt(i << 1) << 8 | str.charCodeAt((i << 1) + 1);
}
return result;
}
// Converts BigInt number to binary string.
function num2str(num) {
var n = num.length;
var s = Array();
for (var i = 0; i < n; i++) {
s[n - i - 1] = String.fromCharCode(num[i] >> 8 & 0xff, num[i] & 0xff);
}
return s.join('');
}
// Generates n-bit Random Number, if s = true, sets bit number n - 1.
function rand(n, s) {
var lowBitMasks = new Array(0x0000, 0x0001, 0x0003, 0x0007,
0x000f, 0x001f, 0x003f, 0x007f,
0x00ff, 0x01ff, 0x03ff, 0x07ff,
0x0fff, 0x1fff, 0x3fff, 0x7fff);
var r = n % 16;
var q = n >> 4;
var result = Array();
for (var i = 0; i < q; i++) {
result[i] = Math.floor(Math.random() * 0xffff);
}
if (r != 0) {
result[q] = Math.floor(Math.random() * lowBitMasks[r]);
if (s) {
result[q] |= 1 << (r - 1);
}
}
else if (s) {
result[q - 1] |= 0x8000;
}
return result;
}
