50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
|
#include "tommath_private.h"
|
||
|
|
#ifdef BN_MP_UNPACK_C
|
||
|
|
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
|
||
|
|
/* SPDX-License-Identifier: Unlicense */
|
||
|
|
|
||
|
|
/* based on gmp's mpz_import.
|
||
|
|
* see http://gmplib.org/manual/Integer-Import-and-Export.html
|
||
|
|
*/
|
||
|
|
mp_err mp_unpack(mp_int *rop, size_t count, mp_order order, size_t size,
|
||
|
|
mp_endian endian, size_t nails, const void *op)
|
||
|
|
{
|
||
|
|
mp_err err;
|
||
|
|
size_t odd_nails, nail_bytes, i, j;
|
||
|
|
unsigned char odd_nail_mask;
|
||
|
|
|
||
|
|
mp_zero(rop);
|
||
|
|
|
||
|
|
if (endian == MP_NATIVE_ENDIAN) {
|
||
|
|
MP_GET_ENDIANNESS(endian);
|
||
|
|
}
|
||
|
|
|
||
|
|
odd_nails = (nails % 8u);
|
||
|
|
odd_nail_mask = 0xff;
|
||
|
|
for (i = 0; i < odd_nails; ++i) {
|
||
|
|
odd_nail_mask ^= (unsigned char)(1u << (7u - i));
|
||
|
|
}
|
||
|
|
nail_bytes = nails / 8u;
|
||
|
|
|
||
|
|
for (i = 0; i < count; ++i) {
|
||
|
|
for (j = 0; j < (size - nail_bytes); ++j) {
|
||
|
|
unsigned char byte = *((const unsigned char *)op +
|
||
|
|
(((order == MP_MSB_FIRST) ? i : ((count - 1u) - i)) * size) +
|
||
|
|
((endian == MP_BIG_ENDIAN) ? (j + nail_bytes) : (((size - 1u) - j) - nail_bytes)));
|
||
|
|
|
||
|
|
if ((err = mp_mul_2d(rop, (j == 0u) ? (int)(8u - odd_nails) : 8, rop)) != MP_OKAY) {
|
||
|
|
return err;
|
||
|
|
}
|
||
|
|
|
||
|
|
rop->dp[0] |= (j == 0u) ? (mp_digit)(byte & odd_nail_mask) : (mp_digit)byte;
|
||
|
|
rop->used += 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
mp_clamp(rop);
|
||
|
|
|
||
|
|
return MP_OKAY;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif
|