libtommath/mp_to_ubin.c
2019-10-29 17:40:59 +01:00

38 lines
768 B
C

#include "tommath_private.h"
#ifdef MP_TO_UBIN_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* store in unsigned [big endian] format */
mp_err mp_to_ubin(const mp_int *a, uint8_t *buf, size_t maxlen, size_t *written)
{
size_t x, count;
mp_err err;
mp_int t;
count = mp_ubin_size(a);
if (count > maxlen) {
return MP_BUF;
}
if ((err = mp_init_copy(&t, a)) != MP_OKAY) {
return err;
}
for (x = count; x --> 0u;) {
buf[x] = (uint8_t)(t.dp[0] & 255u);
if ((err = mp_div_2d(&t, 8, &t, NULL)) != MP_OKAY) {
goto LBL_ERR;
}
}
if (written != NULL) {
*written = count;
}
LBL_ERR:
mp_clear(&t);
return err;
}
#endif