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a528d4f0a9
If something was "present in all versions" of SSLeay, or if it was added to a version of SSLeay (and therefore predates OpenSSL), remove mention of it. Documentation history now starts with OpenSSL. Remove mention of all history before OpenSSL 0.9.8, inclusive. Remove all AUTHOR sections. Reviewed-by: Tim Hudson <tjh@openssl.org>
61 lines
1.6 KiB
Plaintext
61 lines
1.6 KiB
Plaintext
=pod
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=head1 NAME
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BN_set_bit, BN_clear_bit, BN_is_bit_set, BN_mask_bits, BN_lshift,
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BN_lshift1, BN_rshift, BN_rshift1 - bit operations on BIGNUMs
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=head1 SYNOPSIS
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#include <openssl/bn.h>
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int BN_set_bit(BIGNUM *a, int n);
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int BN_clear_bit(BIGNUM *a, int n);
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int BN_is_bit_set(const BIGNUM *a, int n);
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int BN_mask_bits(BIGNUM *a, int n);
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int BN_lshift(BIGNUM *r, const BIGNUM *a, int n);
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int BN_lshift1(BIGNUM *r, BIGNUM *a);
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int BN_rshift(BIGNUM *r, BIGNUM *a, int n);
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int BN_rshift1(BIGNUM *r, BIGNUM *a);
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=head1 DESCRIPTION
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BN_set_bit() sets bit B<n> in B<a> to 1 (C<a|=(1E<lt>E<lt>n)>). The
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number is expanded if necessary.
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BN_clear_bit() sets bit B<n> in B<a> to 0 (C<a&=~(1E<lt>E<lt>n)>). An
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error occurs if B<a> is shorter than B<n> bits.
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BN_is_bit_set() tests if bit B<n> in B<a> is set.
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BN_mask_bits() truncates B<a> to an B<n> bit number
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(C<a&=~((~0)E<gt>E<gt>n)>). An error occurs if B<a> already is
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shorter than B<n> bits.
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BN_lshift() shifts B<a> left by B<n> bits and places the result in
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B<r> (C<r=a*2^n>). Note that B<n> must be non-negative. BN_lshift1() shifts
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B<a> left by one and places the result in B<r> (C<r=2*a>).
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BN_rshift() shifts B<a> right by B<n> bits and places the result in
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B<r> (C<r=a/2^n>). Note that B<n> must be non-negative. BN_rshift1() shifts
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B<a> right by one and places the result in B<r> (C<r=a/2>).
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For the shift functions, B<r> and B<a> may be the same variable.
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=head1 RETURN VALUES
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BN_is_bit_set() returns 1 if the bit is set, 0 otherwise.
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All other functions return 1 for success, 0 on error. The error codes
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can be obtained by L<ERR_get_error(3)>.
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=head1 SEE ALSO
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L<bn(3)>, L<BN_num_bytes(3)>, L<BN_add(3)>
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=cut
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