libtommath/mp_from_sbin.c
2019-11-11 21:52:20 +01:00

22 lines
579 B
C

#include "tommath_private.h"
#ifdef MP_FROM_SBIN_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* read signed bin, big endian, first byte is 0==positive or 1==negative */
mp_err mp_from_sbin(mp_int *a, const uint8_t *buf, size_t size)
{
mp_err err;
/* read magnitude */
if ((err = mp_from_ubin(a, buf + 1, size - 1u)) != MP_OKAY) {
return err;
}
/* first byte is 0 for positive, non-zero for negative */
a->sign = (buf[0] != (uint8_t)0) ? MP_NEG : MP_ZPOS;
return MP_OKAY;
}
#endif