libtommath/bn_mp_to_sbin.c

23 lines
606 B
C

#include "tommath_private.h"
#ifdef BN_MP_TO_SBIN_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* store in signed [big endian] format */
mp_err mp_to_sbin(const mp_int *a, unsigned char *buf, size_t maxlen, size_t *written)
{
mp_err err;
if (maxlen == 0u) {
return MP_BUF;
}
if ((err = mp_to_ubin(a, buf + 1, maxlen - 1u, written)) != MP_OKAY) {
return err;
}
if (written != NULL) {
(*written)++;
}
buf[0] = (a->sign == MP_ZPOS) ? (unsigned char)0 : (unsigned char)1;
return MP_OKAY;
}
#endif