You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
66 lines
1.8 KiB
66 lines
1.8 KiB
=pod
|
|
|
|
=head1 NAME
|
|
|
|
BN_set_bit, BN_clear_bit, BN_is_bit_set, BN_mask_bits, BN_lshift,
|
|
BN_lshift1, BN_rshift, BN_rshift1 - bit operations on BIGNUMs
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/bn.h>
|
|
|
|
int BN_set_bit(BIGNUM *a, int n);
|
|
int BN_clear_bit(BIGNUM *a, int n);
|
|
|
|
int BN_is_bit_set(const BIGNUM *a, int n);
|
|
|
|
int BN_mask_bits(BIGNUM *a, int n);
|
|
|
|
int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
|
|
int BN_lshift1(BIGNUM *r, BIGNUM *a);
|
|
|
|
int BN_rshift(BIGNUM *r, BIGNUM *a, int n);
|
|
int BN_rshift1(BIGNUM *r, BIGNUM *a);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
BN_set_bit() sets bit B<n> in B<a> to 1 (C<a|=(1E<lt>E<lt>n)>). The
|
|
number is expanded if necessary.
|
|
|
|
BN_clear_bit() sets bit B<n> in B<a> to 0 (C<a&=~(1E<lt>E<lt>n)>). An
|
|
error occurs if B<a> is shorter than B<n> bits.
|
|
|
|
BN_is_bit_set() tests if bit B<n> in B<a> is set.
|
|
|
|
BN_mask_bits() truncates B<a> to an B<n> bit number
|
|
(C<a&=~((~0)E<gt>E<gt>n)>). An error occurs if B<a> already is
|
|
shorter than B<n> bits.
|
|
|
|
BN_lshift() shifts B<a> left by B<n> bits and places the result in
|
|
B<r> (C<r=a*2^n>). BN_lshift1() shifts B<a> left by one and places
|
|
the result in B<r> (C<r=2*a>).
|
|
|
|
BN_rshift() shifts B<a> right by B<n> bits and places the result in
|
|
B<r> (C<r=a/2^n>). BN_rshift1() shifts B<a> right by one and places
|
|
the result in B<r> (C<r=a/2>).
|
|
|
|
For the shift functions, B<r> and B<a> may be the same variable.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
BN_is_bit_set() returns 1 if the bit is set, 0 otherwise.
|
|
|
|
All other functions return 1 for success, 0 on error. The error codes
|
|
can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<bn(3)|bn(3)>, L<BN_num_bytes(3)|BN_num_bytes(3)>, L<BN_add(3)|BN_add(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
BN_set_bit(), BN_clear_bit(), BN_is_bit_set(), BN_mask_bits(),
|
|
BN_lshift(), BN_lshift1(), BN_rshift(), and BN_rshift1() are available
|
|
in all versions of SSLeay and OpenSSL.
|
|
|
|
=cut
|
|
|