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simplesshd/dropbear/libtommath/bn_mp_copy.c
2020-12-28 16:40:37 -05:00

48 lines
900 B
C

#include "tommath_private.h"
#ifdef BN_MP_COPY_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* copy, b = a */
mp_err mp_copy(const mp_int *a, mp_int *b)
{
int n;
mp_digit *tmpa, *tmpb;
mp_err err;
/* if dst == src do nothing */
if (a == b) {
return MP_OKAY;
}
/* grow dest */
if (b->alloc < a->used) {
if ((err = mp_grow(b, a->used)) != MP_OKAY) {
return err;
}
}
/* zero b and copy the parameters over */
/* pointer aliases */
/* source */
tmpa = a->dp;
/* destination */
tmpb = b->dp;
/* copy all the digits */
for (n = 0; n < a->used; n++) {
*tmpb++ = *tmpa++;
}
/* clear high digits */
MP_ZERO_DIGITS(tmpb, b->used - n);
/* copy used count and sign */
b->used = a->used;
b->sign = a->sign;
return MP_OKAY;
}
#endif