BigInteger 1.0

BigInteger is an arbitrary length integer extension module for Perl. SYNOPSIS use Math::BigInteger; The BigInteger extension module gives access to Eric Youngs bignum library. This provides a faster alternative to the Math::BigInt library. The basic object in this library is a BigInteger. It is used to hold a single large integer. It is not intended that this package be used directly, but instead be used by a wrapper package, such as the Math::BigInteger class. FUNCTIONS Many of the following functions can be used in two styles, by calling the function on an object, or by calling the function explicitly; for example, here are two ways of assigning to $a the sum of $b and $c: $a->add($b, $c); or BigInteger::add($a, $b, $c); Creation/Destruction routines. new my $bi = new BigInteger; # Create a new BigInteger object. clone my $b = $a->clone(); Create a new BigInteger object from another BigInteger object. copy copy($a, $b); Copy one BigInteger object to another. save my $data = $bi->save(); Save a BigInteger object as a MSB-first string. restore my $bi = restore BigInteger $data; Create a new BigInteger object from a MSB-first string. Comparison functions ucmp ucmp($a, $b); Return -1 if $a is less than $b, 0 if $a and $b are the same and 1 is $a is greater than $b. This is an unsigned comparison. cmp cmp($a, $b); Return -1 if $a is less than $b, 0 if $a and $b are the same and 1 is $a is greater than $b. This is a signed comparison. Arithmetic Functions inc $bi->inc(); Increment $bi by one: dec $bi->dec(); Decrement $bi by one: add $r->add($a, $b); Add $a and $b and return the result in $r. mul $r->mul($a, $b); Multiply $a by $b and return the result in $r. Note that $r must not be the same object as $a or $b. div div($dv, $rem, $m, $d); Divide $m by $d and return the result in $dv and the remainder in $rem. Either of $dv or $rem can be undef, in which case that value is not returned. mod $rem->mod($m, $d); Find the remainder of $m divided by $d and return it in $rem. This function is more efficient than div. lshift $r->lshift($a, $n); Shift $a left by $n bits. lshift1 $r->lshift1($a); Shift $a left by 1 bit. This form is more efficient than lshift($r, $a, 1). rshift $r->rshift($a, $n); Shift $a right by $n bits. rshift1 $r->rshift1($a); Shift $a right by 1 bit. This form is more efficient than rshift($r, $a, 1). mod_exp $r->mod_exp($a, $p, $mod); Raise $a to the $p power and return the remainder into $r when divided by $m. modmul_recip modmul_recip($r, $x, $y, $m, $i, $nb); This function is used to perform an efficient mod_mul operation. If one is going to repeatedly perform mod_mul with the same modulus is worth calculating the reciprocal of the modulus and then using this function. This operation uses the fact that a/b == a*r where r is the reciprocal of b. On modern computers multiplication is very fast and big number division is very slow. $x is multiplied by $y and then divided by $m and the remainder is returned in $r. $i is the reciprocal of $m and $nb is the number of bits as returned from reciprocal. This function is used in mod_exp. mul_mod $r->mul_mod($a, $b, $m); Multiply $a by $b and return the remainder into $r when divided by $m. reciprical $r->reciprical($m); Return the reciprocal of $m into $r. Miscellaneous Routines num_bits my $size = $bi->numbits(); Return the size (in bits) of the BigInteger. gcd $r->gcd($a, $b); $r has the greatest common divisor of $a and $b. inverse_modn $r->inverse_modn($a, $n); This function creates a new BigInteger and returns it in $r. This number is the inverse mod $n of $a. By this it is meant that the returned value $r satisfies (a*r)%n == 1. This function is used in the generation of RSA keys..

Requirements:	No special requirements
Platforms:	Linux
Keyword:	B And,  Biginteger,  Libraries,  Mod,  More Efficient Than,  Programming,  R-,  Return
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