kc3-lang/libtommath/bn_mp_unpack.c

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• Hash : b6813a41
  Author :
  Date : 2019-09-27T03:40:08
  

  replace mp_export/import by mp_pack/unpack

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• bn_mp_unpack.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
  

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