/**
* SeekQuarry/Yioop --
* Open Source Pure PHP Search Engine, Crawler, and Indexer
*
* Copyright (C) 2009 - 2026 Chris Pollett chris@pollett.org
*
* LICENSE:
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* END LICENSE
*
* @author Akash Patel (edited by Chris Pollett chris@pollett.org)
* Ideas adapted Leemon Baird's bigint.js
* @license https://www.gnu.org/licenses/ GPL3
* @link https://www.seekquarry.com/
* @copyright 2009 - 2026
* @filesource
*/
/*
* Constant for number of bits per element
*/
var bits_per_element = 15;
/*
* Constant to mask the overflow value
*/
var mask = 32767;
/*
* Constant to define radix
*/
var radix = mask + 1;
/*
* To add BigInt and int number
*
* @param BigInt x first operand
* @param int n second operand
* @return BigInt result
*/
function addInteger(x, n)
{
var new_x = expandBigInt(x, x.length + 1);
addBigIntToInt(new_x, n);
return trimBigInt(new_x, 1);
}
/*
* Returns the BigInt with given number of leading zeroes
*
* @param BigInt x input number
* @param int k expected number of leading zeroes
* @return BigInt result
*/
function trimBigInt(x, k)
{
var i = x.length;
while(i > 0 && !x[i - 1]) {
i--;
}
var y = new Array(i + k);
copyBigIntFromBigInt(y, x);
return y;
}
/*
* Expands a BigInt to at least an n element array,
* adding zeroes if needed
*
* @param BigInt x first operand
* @param int n expected number of elements
* @return BigInt result
*/
function expandBigInt(x, n)
{
var bits = (x.length > n ? x.length : n) * bits_per_element;
var result = int2BigInt(0, bits, 0);
copyBigIntFromBigInt(result, x);
return result;
}
/*
* Converts a normal int to BigInt. It pads the array with leading zeros so
* that it has at least minSize elements
*
* @param int t input number
* @param int bits expected number of bits
* @param int min_size minimum size of the BigInt.
* @return Array stores the BigInt in bits_per_element-bit chunks,
* little endian
*/
function int2BigInt(t, bits, min_size)
{
var size_of_array = Math.max(
Math.ceil(bits / bits_per_element) + 1, min_size);
var buffer = new Array(size_of_array);
copyBigIntFromInt(buffer, t);
return buffer;
}
/*
* Copies one BigInt to another BigInt
* x must be an array at least as big as y
*
* @param BigInt x input number
* @param BigInt bits expected number of bits
* @return BigInt result
*/
function copyBigIntFromBigInt(x, y)
{
var len = (x.length < y.length) ? x.length : y.length;
for (var i = 0; i < len; i++) {
x[i] = y[i];
}
for (var i = len; i < x.length ; i++) {
x[i] = 0;
}
}
/*
* Makes a Big Integer out of the supplied int
*
* @param BigInt x input number
* @param int n input number
* @return BigInt result
*/
function copyBigIntFromInt(x, n)
{
var c = n;
for (var i = 0; i < x.length; i++) {
x[i] = c & mask;
c >>= bits_per_element;
}
}
/*
* To perform x = x + n where x is a BigInt and n is an integer
*
* @param BigInt x input number
* @param int n input number
* @return BigInt result of the summation
*/
function addBigIntToInt(x, n)
{
var i, c, b;
x[0] += n;
c = 0;
for (i = 0; i < x.length; i++) {
c += x[i];
b = 0;
if (c < 0) {
b =- (c >> bits_per_element);
c += b * radix;
}
x[i] = c & mask;
c = (c >> bits_per_element) - b;
if (!c) {
return;
}
}
}
/*
* Converts a string into a BigInt. It pads the array with leading zeros
* so that it has at least min_size elements.
* The array will always have at least one leading zero, unless base=-1
* If base is less than 36 we use the digit_str below to convert (say for hex
* or decimal numbers). Otherwise, we assume the base is 256 and just use
* charCode
*
* @param String s input string
* @param int base base of the output number
* @param int min_size minimum size of the BigInt
* @return BigInt
*/
function str2BigInt(s, base, min_size)
{
var d, i, j, x, y, kk;
var digits_str =
'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
var k = s.length;
var x = int2BigInt(0, base * k, 0);
for (i = 0; i < k; i++) {
d = (base > 36) ? s.charCodeAt(i) :
digits_str.indexOf(s.substring(i, i + 1), 0);
if (base <= 36 && d >= 36) {
d -= 26; //lower to upper
}
if (d >= base || d < 0) {
break;
}
multInt(x, base);
addBigIntToInt(x, d);
}
k = x.length;
while(k > 0 && !x[k - 1]) {
k--;
}
k = min_size > k + 1 ? min_size : k + 1;
y = new Array(k);
kk = k < x.length ? k : x.length;
for (i = 0; i < kk; i++){
y[i] = x[i];
}
// copy rest as 0
for (j = i; j < k; j++) {
y[j] = 0;
}
return y;
}
/*
* Converts a BigInt into a string in a given base, from base 2 up to base 95
*
* @param BigInt x input number
* @param int base base of the output number
* @return String result
*/
function bigInt2Str(x, base)
{
var i = "";
var t = "";
var s = "";
var digits_str =
'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
var temp_array = new Array();
if (temp_array.length != x.length){
temp_array = dup(x);
} else {
copyBigIntFromBigInt(temp_array, x);
}
while (!isZero(temp_array)) {
t = divInt(temp_array, base); //t=s % base; s=floor(s/base);
s = digits_str.substring(t, t + 1) + s;
}
if (s.length == 0){
s = "0";
}
return s;
}
/*
* Makes a copy of a BigInt
*
* @param BigInt x input number
* @return BigInt buffer copy of the BigInt x
*/
function dup(x)
{
var buffer = new Array(x.length);
copyBigIntFromBigInt(buffer, x);
return buffer;
}
/*
* Checks whether BigInt is zero or not.
* Returns 0 if the BigInt is zero otherwise return 1
* @param BigInt x input number
* @return int
*/
function isZero(x) {
for (var i = 0; i < x.length; i++){
if (x[i]) {
return 0;
}
}
return 1;
}
/*
* Computes x = floor(x/n) for BigInt x and integer n, and
*
* @param BigInt x numerator
* @param int n denomenator
* @return int r reminder
*/
function divInt(x, n)
{
var r = 0;
var s;
for (var i = x.length - 1; i >= 0; i--) {
s = r*radix + x[i];
x[i] = Math.floor(s/n);
r = s % n;
}
return r;
}
/*
* Multiplies BigInt with Int.
*
* @param BigInt x input number
* @param int n input number
*/
function multInt(x, n)
{
if (n == 0){
return;
}
var i, carry, borrow;
carry = 0;
for (i = 0; i < x.length ; i++) {
carry += x[i] * n;
borrow = 0;
if (carry < 0) {
borrow =- (carry >> bits_per_element);
carry += borrow * radix;
}
x[i] = carry & mask;
carry = (carry >> bits_per_element) - borrow;
}
}
/*
* Performs x * y on BigInt's.
*
* @param BigInt x input number
* @param BigInt y input number
* @return BigInt ans result of multiplication
*/
function mult(x, y)
{
var ans = expandBigInt(x, x.length + y.length);
multEquals(ans, y);
return trimBigInt(ans, 1);
}
/*
* Performs x *= y (so the result is x)
*
* @param BigInt x input number
* @param BigInt y input number
*/
function multEquals(x, y)
{
var result = new Array(2 * x.length);
copyBigIntFromInt(result, 0);
for (var i = 0; i< y.length; i++) {
if (y[i]) {
linearCombShift(result, x, y[i], i);
}
}
copyBigIntFromBigInt(x, result);
}
/*
* Computes x += y*b*d^{ys}, where d is our base.
* This corresponds to one row of table needed to compute x*y
*
* @param BigInt x to store the result
* @param BigInt y input number
* @param integer b digit position in the second number
* @param integer ys to get bit shift operator
*/
function linearCombShift(x, y, b, ys)
{
var i, c, k;
k = x.length < ys + y.length ? x.length : ys + y.length;
for (c = 0, i = ys; i < k; i++) {
c += x[i] + b * y[i - ys];
x[i] = c & mask;
c >>= bits_per_element;
}
for (i = k; c && i < x.length; i++) {
c += x[i];
x[i] = c & mask;
c >>= bits_per_element;
}
}
/*
* Performs BigInt divide operation
*
* @param BigInt x Dividend
* @param BigInt y Divisor
* @param BigInt q to store the quotient
* @param BigInt r to store the reminder
*/
function divide(x, y, q, r)
{
var kx, ky;
var i, j, y1, y2, c, a, b;
var tmp, out_check;
copyBigIntFromBigInt(r, x);
ky = y.length;
while(y[ky - 1] == 0) { // find first non-zero position
ky--;
}
b = y[ky - 1];
a = 0;
while(b > 0) {
b >>= 1;
a++;
}
a = bits_per_element - a;
leftShift(y, a);
leftShift(r, a);
kx = r.length;
while(r[kx - 1] == 0 && kx > ky) { // find first non-zero position
kx--;
}
copyBigIntFromInt(q, 0, x.length);
while (!greaterShift(y, r, kx - ky)) {
subShift(r, y, kx-ky);
q[kx - ky]++;
}
for (i = kx - 1; i >= ky; i--) {
if (r[i] == y[ky-1]) {
q[i - ky] = mask;
} else {
q[i - ky] = Math.floor((r[i] * radix + r[i-1]) / y[ky-1]);
}
while(true) {
y2 = (ky > 1 ? y[ky - 2] : 0) * q[i-ky];
c = y2 >> bits_per_element;
y2 = y2 & mask;
y1 =c + q[i-ky] * y[ky-1];
c = y1 >> bits_per_element;
y1 = y1 & mask;
if (c == r[i]) {
if (y1 == r[i - 1]) {
tmp = (i > 1) ? r[i - 2] : 0
out_check = (y2 > tmp);
} else {
out_check = (y1 > r[i - 1]);
}
} else {
out_check = (c > r[i]);
}
if (out_check) {
q[i - ky]--;
} else {
break;
}
}
linearCombShift(r, y, -q[i - ky], i - ky);
if (negative(r)) {
addShift(r, y, i - ky);
q[i-ky]--;
}
}
rightShift(y, a);
rightShift(r, a);
}
/*
* Performs left shift operation on BigInt by given number of bits
*
* @param BigInt x input number
* @param integer n number of bits to be shifted
*/
function leftShift(x, n)
{
var i;
var len = Math.floor(n / bits_per_element);
if (len) {
for (i = x.length; i >= len; i--){
x[i] = x[i - len];
}
for (;i >= 0; i--) {
x[i] = 0;
}
n %= bits_per_element;
}
if (!n) { return; }
for (i = x.length - 1; i > 0; i--) {
x[i] = mask & ((x[i] << n) | (x[i-1] >> (bits_per_element - n)));
}
x[i] = mask & (x[i] << n);
}
/*
* Performs right shift operation on BigInt by given number of bits
* @param BigInt x input number
* @param integer n number of bits to be shifted
*/
function rightShift(x, n)
{
var i;
var len = Math.floor(n / bits_per_element);
if (len) {
for (i = 0; i< x.length - len; i++) {
x[i] = x[i + len];
}
for (; i< x.length; i++){
x[i] = 0;
}
n %= bits_per_element;
}
for (i = 0; i < x.length - 1; i++) {
x[i] = mask & ((x[i + 1] <<(bits_per_element - n)) | (x[i] >> n));
}
x[i] >>= n;
}
/*
* Used to check whether BigInt is negative or not
*
* @return integer output 1 if it is negative otherwise 0
*/
function negative(x)
{
var result = (x[x.length - 1] >> (bits_per_element - 1)) & 1;
return result;
}
/*
* Used to perform a shift operation on y and add it to the x
*
* @param BigInt x first input number
* @param BigInt y second input number
* @return integer output 1 if it is negative otherwise 0
*/
function addShift(x, y, ys)
{
var i, sum;
len = x.length < ys + y.length ? x.length : ys + y.length;
for (i = ys; i < len; i++) {
sum += x[i] + y[i-ys];
x[i] = sum & mask;
sum >>= bits_per_element;
}
for (i = len; sum && i < x.length; i++) {
sum += x[i];
x[i] = sum & mask;
sum >>= bits_per_element;
}
}
/*
* Right shifts the x by given number of bits and check
* whether it is greater than y
*
* @param BigInt x nonnegative input number
* @param BigInt y nonnegative input number
* @param integer shift nonnegative integer
* @return integer output 1 if the check passes otherwise returns 0
*/
function greaterShift(x, y, shift)
{
var i;
var len = ((x.length + shift) < y.length) ? (x.length + shift):y.length;
for (i = y.length - 1 - shift; i < x.length && i >= 0; i++)
{
if (x[i] > 0) {
return 1;
}
}
for (i = x.length - 1 + shift; i < y.length; i++)
{
if (y[i] > 0) {
return 0;
}
}
for (i = len - 1; i >= shift; i--)
{
if (x[i-shift] > y[i]) {
return 1;
} else if (x[i-shift] < y[i]) {
return 0;
}
}
return 0;
}
/*
* Left shift y by given number of bits and performs
* subtraction operation. The result is stored in x
*
* @param BigInt x BigInt number
* @param BigInt y BigInt number
* @param integer shift number of shift bits
*/
function subShift(x, y, ys)
{
var i, sum;
var len = x.length < ys + y.length ? x.length : ys + y.length;
for (i = ys; i < len; i++) {
sum += x[i] - y[i - ys];
x[i] = sum & mask;
sum >>= bits_per_element;
}
for (i = len; sum && i < x.length; i++) {
sum += x[i];
x[i] = sum & mask;
sum >>= bits_per_element;
}
}
/*
* Computes x mod n
*
* @param BigInt x argument to modr
* @param integer n modulus
* @return result which equals x mod n
*/
function bigMod(x, n)
{
var ans = dup(x);
modCalculation(ans, n);
var result = trim(ans, 1);
return result;
}
/*
* Computes x mod n with the result stored in x
*
* @param BigInt x argument to mod
* @param BigInt n modulus
*/
function modCalculation(x, n)
{
var dividend = new Array(0);
var divisor = new Array(0);
if (dividend.length != x.length) {
dividend = dup(x);
} else {
copyBigIntFromBigInt(dividend, x);
}
if (divisor.length != x.length) {
divisor = dup(x);
}
divide(dividend, n, divisor, x);
}
/*
* Returns x with exactly k leading zeroes
*
* @param BigInt x BigInt number
* @param integer k expected number of leading zeroes in x
* @return result result=x mod n
*/
function trim(x, k)
{
var i, y;
for (i= x.length; i > 0 && !x[i-1]; i--);
y = new Array(i + k);
copyBigIntFromBigInt(y, x);
return y;
}
/*
* Computes modulus x*y mod n using BigInt's
*
* @param BigInt x first parameter in above expression
* @param BigInt y second parameter in above expression
* @param BigInt n modulus
* @return BigInt x * y mod n
*/
function multMod(x, y, n)
{
var result = expand(x, n.length);
multModOperation(result, y, n);
return trim(result, 1);
}
/*
* Computes modulus x*y mod n using BigInt's stores the result in x potential
* leaving the output untrimmed (this is an auxiliary method for multMod)
*
* @param BigInt x first parameter in above expression
* @param BigInt y second parameter in above expression
* @param BigInt n modulus
* @return BigInt x * y mod n
*/
function multModOperation(x, y, n)
{
var input_number = new Array(2 * x.length);
copyBigIntFromInt(input_number, 0);
for (var i = 0; i < y.length; i++){
if (y[i]) {
linearCombShift(input_number, x, y[i], i);
}
}
modCalculation(input_number, n);
copyBigIntFromBigInt(x, input_number);
}
/*
* Expands BigInt to the given number of elements.
* Leading zeros are added
*
* @param BigInt x BigInt number
* @param integer n expected number of elements
* @return ans x * y mod n
*/
function expand(x, n)
{
var ans = int2BigInt(0,
(x.length > n ? x.length : n) * bits_per_element, 0);
copyBigIntFromBigInt(ans, x);
return ans;
}
(c) 2026 Seekquarry - Open Source Search Engine Software