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Bignum(3)             User Contributed Perl Documentation            Bignum(3)

NAME
       Crypt::OpenSSL::Bignum - OpenSSL's multiprecision integer arithmetic
SYNOPSIS
         use Crypt::OpenSSL::Bignum;
         my $bn = Crypt::OpenSSL::Bignum->new_from_decimal( "1000" );
         # or
         my $bn = Crypt::OpenSSL::Bignum->new_from_word( 1000 );
         # or
         my $bn = Crypt::OpenSSL::Bignum->new_from_hex("0x3e8");
         # or
         my $bn = Crypt::OpenSSL::Bignum->new_from_bin(pack( "C*", 3, 232 ))
         use Crypt::OpenSSL::Bignum::CTX;
         sub print_factorial
         {
           my( $n ) = @_;
           my $fac = Crypt::OpenSSL::Bignum->one();
           my $ctx = Crypt::OpenSSL::Bignum::CTX->new();
           foreach my $i (1 .. $n)
           {
             $fac->mul( Crypt::OpenSSL::Bignum->new_from_word( $i ), $ctx, $fac );
           }
           print "$n factorial is ", $fac->to_decimal(), "\n";
         }
DESCRIPTION
       Crypt::OpenSSL::Bignum provides access to OpenSSL multiprecision
       integer arithmetic libraries.  Presently, many though not all of the
       arithmetic operations that OpenSSL provides are exposed to perl.  In
       addition, this module can be used to provide access to bignum values
       produced by other OpenSSL modules, such as key parameters from
       Crypt::OpenSSL::RSA.
       NOTE: Many of the methods in this package can croak, so use eval, or
       Error.pm's try/catch mechanism to capture errors.
Class Methods
       new_from_word
           Create a new Crypt::OpenSSL::Bignum object whose value will be the
           word given.  Note that numbers represneted by objects created using
           this method are necessarily between 0 and 2^32 - 1.
       new_from_decimal
           Create a new Crypt::OpenSSL::Bignum object whose value is specified
           by the given decimal representation.
       new_from_hex
           Create a new Crypt::OpenSSL::Bignum object whose value is specified
           by the given hexidecimal representation.
       new_from_bin
           Create a new Crypt::OpenSSL::Bignum object whose value is specified
           by the given packed binary string.  Note that objects created using
           this method are necessarily nonnegative.
       zero
           Returns a new Crypt::OpenSSL::Bignum object representing 0
       one Returns a new Crypt::OpenSSL::Bignum object representing 1
       bless_pointer
           Given a pointer to a OpenSSL BIGNUM object in memory, construct and
           return Crypt::OpenSSL::Bignum object around this.  Note that the
           underlying BIGNUM object will be destroyed (via
           BN_clear_free(3ssl)) when the returned Crypt::OpenSSL::Bignum
           object is no longer referenced, so the pointer passed to this
           method should only be referenced via the returned perl object after
           calling bless_pointer.
           This method is intended only for use by XSUB writers writing code
           that interfaces with OpenSSL library methods, and who wish to be
           able to return a BIGNUM structure to perl as a
           Crypt::OpenSSL::Bignum object.
Instance Methods
       to_decimal
           Return a decimal string representation of this object.
       to_hex
           Return a hexidecimal string representation of this object.
       to_bin
           Return a packed binary string representation of this object.  Note
           that sign is ignored, so that to bin called on a
           Crypt::OpenSSL::Bignum object representing a negative number
           returns the same value as it would called on an object representing
           that number's absolute value.
       get_word
           Return a scalar integer representation of this object, if it can be
           represented as an unsigned long.
       is_zero
           Returns true of this object represents 0.
       is_one
           Returns true of this object represents 1.
       is_odd
           Returns true of this object represents an odd number.
       copy
           Returns a copy of this object.
       add This method returns the sum of this object and the first argument.
           If only one argument is passed, a new Crypt::OpenSSL::Bignum object
           is created for the return value; otherwise, the value of second
           argument is set to the result and returned.
       sub This method returns the difference of this object and the first
           argument.  If only one argument is passed, a new
           Crypt::OpenSSL::Bignum object is created for the return value;
           otherwise, the value of second argument is set to the result and
           returned.
       mul This method returns the product of this object and the first
           argument, using the second argument, a Crypt::OpenSSL::Bignum::CTX
           object, as a scratchpad.  If only two arguments are passed, a new
           Crypt::OpenSSL::Bignum object is created for the return value;
           otherwise, the value of third argument is set to the result and
           returned.
       div This method returns a list consisting of quotient and the remainder
           obtained by dividing this object by the first argument, using the
           second argument, a Crypt::OpenSSL::Bignum::CTX object, as a
           scratchpad.  If only two arguments are passed, new
           Crypt::OpenSSL::Bignum objects is created for both return values.
           If a third argument is passed, otherwise, the value of third
           argument is set to the quotient.  If a fourth argument is passed,
           the value of the fourth argument is set to the remainder.
       exp This method returns the product of this object exponeniated by the
           first argument, using the second argument, a
           Crypt::OpenSSL::Bignum::CTX object, as a scratchpad.
       mod_exp
           This method returns the product of this object exponeniated by the
           first argument, modulo the second argument, using the third
           argument, a Crypt::OpenSSL::Bignum::CTX object, as a scratchpad.
       pointer_copy
           This method is intended only for use by XSUB writers wanting to
           have access to the underlying BIGNUM structure referenced by a
           Crypt::OpenSSL::Bignum perl object so that they can pass them to
           other routines in the OpenSSL library.  It returns a perl scalar
           whose IV can be cast to a BIGNUM* value.  This can then be passed
           to an XSUB which can work with the BIGNUM directly.  Note that the
           BIGNUM object pointed to will be a copy of the BIGNUM object
           wrapped by the instance; it is thus the responsiblity of the client
           to free space allocated by this BIGNUM object if and when it is
           done with it. See also bless_pointer.
AUTHOR
       Ian Robertson, iroberts AT cpan.org
SEE ALSO
       perl, bn(3ssl)

perl v5.16.3                      2007-05-20                         Bignum(3)