Bignum(3) User Contributed Perl Documentation Bignum(3)NAMECrypt::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";
}
DESCRIPTIONCrypt::OpenSSL::Bignum provides access to OpenSSL multiprecision inte-
ger arithmetic libraries. Presently, many though not all of the arith-
metic operations that OpenSSL provides are exposed to perl. In addi-
tion, this module can be used to provide access to bignum values pro-
duced 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; oth-
erwise, the value of second argument is set to the result and
returned.
mul This method returns the product of this object and the first argu-
ment, 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; oth-
erwise, 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 argu-
ment 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 argu-
ment, 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@cpan.org
SEE ALSO
perl, bn(3ssl)perl v5.8.8 2003-02-18 Bignum(3)
