bigjs/src/myBig.js

A big integer library for JS, based on Leemon, with focus on prime numbers and cryptography

function BI(number,base){
	//This is where the bigint number will go
	this.num;

	switch(typeof number){
		case 'number':
			this.num = int2bigInt(number,64);
		break;
		case 'string':
			this.num = str2bigInt(number,base,64);
		break;
		case 'object':
			if(number instanceof BI){
				this.num = number.num.slice(0);
			}
		break;
	}
	return this;
}


/* CONSTANTS */
BI.ONE = new BI(1);
BI.ZERO = new BI(0);


/*
*	This function is called whenever the big int is used as an integer
* e.g. var b = new BI(10)
*	b * 1 should return 10
*/
BI.prototype.valueOf = function(){
	return parseInt(bigInt2str(this.num,10),10)
}


/*
*	BI.toString - returns the true number represented by this bigInt as a string
*		@param base {Number} - the base you want the number encoded in
*/
BI.prototype.toString = function(base){
	return bigInt2str(this.num,base);
}


/*
*	BI.add - this function adds the current big int with another
*		@param num {Number | BI} - the number you want to add to
*		@param me {Boolean} - set to true if you want the addition to happen on the current object, else make a new obj
*/
BI.prototype.add = function(num, me){
	var _this = (me ? this : new BI(this));

	if(num instanceof BI){
		_this.num = add(_this.num, num.num);
	}else{
		_this.num = addInt(_this.num, num);
	}

	return _this;
}


/*
* BI.subtract - this function subtracts the current big int with another
* 	@param num {Number | BI} - the number you want to subtract from
*		@oaram me {Boolean}
*/
BI.prototype.subtract = function(num, me){
	var _this = (me ? this : new BI(this));

	//Subtraction is the same as adding the negative
	if(num instanceof BI){
		_this.num = sub(_this.num, num.num);
	}else{
		_this.num = addInt(_this.num, -num);
	}

	return _this;
}


/*
* BI.multiply - this function multiplies the current big int with another
* 	@param num {Number | BI} - the number you want to multiply with
*		@oaram me {Boolean}
*/
BI.prototype.times = BI.prototype.multiply = function(num, me){
	var _this = (me ? this : new BI(this));

	if(num instanceof BI){
		_this.num = mult(_this.num, num.num);
	}else{
		//this function automatically modifies the array
		multInt_(_this.num,num);
	}

	return _this;
}


/*
* BI.prime - this function uses Maurer's algorithm to generate a true prime
*		@param bits {Number}  - number of bits in the prime
*		@param probable {Boolean} - where this is a probable prime or a true one
* Note: Since this is a true prime it might take a long time on large bitsizes
*/
BI.prime = function(bits,probable){
	var p = new BI(0);
	p.num = (probable ? randProbPrime(bits) : randTruePrime(bits));
	return p;
}

//For npm
module&&module.exports = BI;