libtommath/bn_mp_to_unsigned_bin.c
2019-02-02 07:39:23 +01:00

46 lines
1.1 KiB
C

#include "tommath_private.h"
#ifdef BN_MP_TO_UNSIGNED_BIN_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
* LibTomMath is a library that provides multiple-precision
* integer arithmetic as well as number theoretic functionality.
*
* The library was designed directly after the MPI library by
* Michael Fromberger but has been written from scratch with
* additional optimizations in place.
*
* SPDX-License-Identifier: Unlicense
*/
/* store in unsigned [big endian] format */
int mp_to_unsigned_bin(const mp_int *a, unsigned char *b)
{
int x, res;
mp_int t;
if ((res = mp_init_copy(&t, a)) != MP_OKAY) {
return res;
}
x = 0;
while (!IS_ZERO(&t)) {
#ifndef MP_8BIT
b[x++] = (unsigned char)(t.dp[0] & 255u);
#else
b[x++] = (unsigned char)(t.dp[0] | ((t.dp[1] & 1u) << 7));
#endif
if ((res = mp_div_2d(&t, 8, &t, NULL)) != MP_OKAY) {
mp_clear(&t);
return res;
}
}
bn_reverse(b, x);
mp_clear(&t);
return MP_OKAY;
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */