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
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);
DESCRIPTION
BN_set_bit() sets bit n in a to
1 (a|=(1<<n)). The
number is expanded if necessary.
BN_clear_bit() sets bit n in a to
0 (a&=~(1<<n)). An
error occurs if a is shorter than n bits.
BN_is_bit_set() tests if bit n in a is
set.
BN_mask_bits() truncates a to an n bit
number (a&=~((~0)>>n)).
An error occurs if a already is shorter than n bits.
BN_lshift() shifts a left by n bits
and places the result in r (r=a*2^n).
BN_lshift1() shifts a left by one and places
the result in r (r=2*a).
BN_rshift() shifts a right by n bits
and places the result in r (r=a/2^n).
BN_rshift1() shifts a right by one and places
the result in r (r=a/2).
For the shift functions, r and a may
be the same variable.
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 ERR_get_error(3).
SEE ALSO
bn(3), BN_num_bytes(3), BN_add(3)
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.
