libtommath/bn_mp_incr.c
2019-04-12 14:55:08 +02:00

31 lines
708 B
C

#include "tommath_private.h"
#ifdef BN_MP_INCR_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* Increment "a" by one like "a++". Changes input! */
int mp_incr(mp_int *a)
{
int e = MP_OKAY;
if (MP_IS_ZERO(a)) {
mp_set(a,1uL);
return MP_OKAY;
} else if (a->sign == MP_NEG) {
a->sign = MP_ZPOS;
if ((e = mp_decr(a)) != MP_OKAY) {
return e;
}
/* There is no -0 in LTM */
if (!MP_IS_ZERO(a)) {
a->sign = MP_NEG;
}
return MP_OKAY;
} else if (a->dp[0] < MP_MASK) {
a->dp[0]++;
return MP_OKAY;
} else {
return mp_add_d(a, 1uL,a);
}
}
#endif