NAME

Math::BigInt::Calc - Pure Perl module to support Math::BigInt

SYNOPSIS

Provides support for big integer calculations. Not intended to be used by other modules. Other modules which export the same functions can also be used to support Math::Bigint

DESCRIPTION

In order to allow for multiple big integer libraries, Math::BigInt was rewritten to use library modules for core math routines. Any module which follows the same API as this can be used instead by using the following call:

        use Math::BigInt Calc => BigNum;

EXPORT

The following functions MUST be exported in order to support the use by Math::BigInt:

        _new(string)    return ref to new object from ref to decimal string
        _zero()         return a new object with value 0
        _one()          return a new object with value 1

        _str(obj)       return ref to a string representing the object
        _num(obj)       returns a Perl integer/floating point number
                        NOTE: because of Perl numeric notation defaults,
                        the _num'ified obj may lose accuracy due to 
                        machine-dependend floating point size limitations
                    
        _add(obj,obj)   Simple addition of two objects
        _mul(obj,obj)   Multiplication of two objects
        _div(obj,obj)   Division of the 1st object by the 2nd
                        In list context, returns (result,remainder).
                        NOTE: this is integer math, so no
                        fractional part will be returned.
        _sub(obj,obj)   Simple subtraction of 1 object from another
                        a third, optional parameter indicates that the params
                        are swapped. In this case, the first param needs to
                        be preserved, while you can destroy the second.
                        sub (x,y,1) => return x - y and keep x intact!

        _acmp(obj,obj)  <=> operator for objects (return -1, 0 or 1)

        _len(obj)       returns count of the decimal digits of the object
        _digit(obj,n)   returns the n'th decimal digit of object

        _is_one(obj)    return true if argument is +1
        _is_zero(obj)   return true if argument is 0
        _is_even(obj)   return true if argument is even (0,2,4,6..)
        _is_odd(obj)    return true if argument is odd (1,3,5,7..)

        _copy           return a ref to a true copy of the object

        _check(obj)     check whether internal representation is still intact
                        return 0 for ok, otherwise error message as string

The following functions are optional, and can be exported if the underlying lib has a fast way to do them. If not defined, Math::BigInt will use a pure, but slow, Perl function as fallback to emulate these:

        _from_hex(str)  return ref to new object from ref to hexadecimal string
        _from_bin(str)  return ref to new object from ref to binary string
        
        _rsft(obj,N,B)  shift object in base B by N 'digits' right
        _lsft(obj,N,B)  shift object in base B by N 'digits' left
        
        _xor(obj1,obj2) XOR (bit-wise) object 1 with object 2
                        Mote: XOR, AND and OR pad with zeros if size mismatches
        _and(obj1,obj2) AND (bit-wise) object 1 with object 2
        _or(obj1,obj2)  OR (bit-wise) object 1 with object 2

        _sqrt(obj)      return the square root of object
        _pow(obj,obj)   return object 1 to the power of object 2
        _gcd(obj,obj)   return Greatest Common Divisor of two objects
        
        _zeros(obj)     return number of trailing decimal zeros

        _dec(obj)       decrement object by one (input is >= 1)
        _inc(obj)       increment object by one

Input strings come in as unsigned but with prefix (i.e. as '123', '0xabc' or '0b1101').

Testing of input parameter validity is done by the caller, so you need not worry about underflow (_sub(), _dec()) nor about division by zero or similar cases.

LICENSE

This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.

AUTHORS

Original math code by Mark Biggar, rewritten by Tels http://bloodgate.com/ in late 2000, 2001. Seperated from BigInt and shaped API with the help of John Peacock.

SEE ALSO

Math::BigInt, Math::BigFloat.