Math::BigInt::Calc(3pm) 				 Perl Programmers Reference Guide				   Math::BigInt::Calc(3pm)

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 sport the same functions can
       also be used to support Math::BigInt, like Math::BigInt::GMP or Math::BigInt::Pari.

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:

	       use Math::BigInt lib => 'libname';

       'libname' is either the long name ('Math::BigInt::Pari'), or only the short version like 'Pari'.

STORAGE

METHODS

       The following functions MUST be defined in order to support the use by Math::BigInt v1.70 or later:

	       api_version()   return API version, 1 for v1.70, 2 for v1.83
	       _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
	       _two()	       return a new object with value 2
	       _ten()	       return a new object with value 10

	       _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-dependent 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.
			       The second operand will be not be 0, so no need to
			       check for that.
	       _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!
	       _dec(obj)       decrement object by one (input is guaranteed to be > 0)
	       _inc(obj)       increment object by one

	       _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_two(obj)    return true if argument is 2
	       _is_ten(obj)    return true if argument is 10
	       _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

	       _from_hex(str)  return new object from a hexadecimal string
	       _from_bin(str)  return new object from a binary string
	       _from_oct(str)  return new object from an octal string

	       _as_hex(str)    return string containing the value as
			       unsigned hex string, with the '0x' prepended.
			       Leading zeros must be stripped.
	       _as_bin(str)    Like as_hex, only as binary string containing only
			       zeros and ones. Leading zeros must be stripped and a
			       '0b' must be prepended.

	       _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
			       Note: 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

	       _mod(obj1,obj2) Return remainder of div of the 1st by the 2nd object
	       _sqrt(obj)      return the square root of object (truncated to int)
	       _root(obj)      return the n'th (n >= 3) root of obj (truncated to int)
	       _fac(obj)       return factorial of object 1 (1*2*3*4..)
	       _pow(obj1,obj2) return object 1 to the power of object 2
			       return undef for NaN
	       _zeros(obj)     return number of trailing decimal zeros
	       _modinv	       return inverse modulus
	       _modpow	       return modulus of power ($x ** $y) % $z
	       _log_int(X,N)   calculate integer log() of X in base N
			       X >= 0, N >= 0 (return undef for NaN)
			       returns (RESULT, EXACT) where EXACT is:
				1     : result is exactly RESULT
				0     : result was truncated to RESULT
				undef : unknown whether result is exactly RESULT
	       _gcd(obj,obj)   return Greatest Common Divisor of two objects

       The following functions are REQUIRED for an api_version of 2 or greater:

	       _1ex($x)        create the number 1Ex where x >= 0
	       _alen(obj)      returns approximate count of the decimal digits of the
			       object. This estimate MUST always be greater or equal
			       to what _len() returns.
	       _nok(n,k)       calculate n over k (binomial coefficient)

       The following functions are optional, and can be defined if the underlying lib has a fast way to do them. If undefined, Math::BigInt will
       use pure Perl (hence slow) fallback routines to emulate these:

	       _signed_or
	       _signed_and
	       _signed_xor

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

       So the library needs only to deal with unsigned big integers. Testing of input parameter validity is done by the caller, so you need not
       worry about underflow (f.i. in "_sub()", "_dec()") nor about division by zero or similar cases.

       The first parameter can be modified, that includes the possibility that you return a reference to a completely different object instead.
       Although keeping the reference and just changing its contents is preferred over creating and returning a different reference.

       Return values are always references to objects, strings, or true/false for comparison routines.

WRAP YOUR OWN

       If you want to port your own favourite c-lib for big numbers to the Math::BigInt interface, you can take any of the already existing
       modules as a rough guideline. You should really wrap up the latest BigInt and BigFloat testsuites with your module, and replace in them any
       of the following:

	       use Math::BigInt;

       by this:

	       use Math::BigInt lib => 'yourlib';

       This way you ensure that your library really works 100% within Math::BigInt.

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.  Seperated from BigInt and shaped API with the
       help of John Peacock.

       Fixed, speed-up, streamlined and enhanced by Tels 2001 - 2007.

SEE ALSO

       Math::BigInt, Math::BigFloat, Math::BigInt::GMP, Math::BigInt::FastCalc and Math::BigInt::Pari.

perl v5.12.1							    2010-04-26						   Math::BigInt::Calc(3pm)