kc3-lang/libtommath/bn_mp_dr_is_modulus.c

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• Hash : 4534056c
  Author :
  Date : 2019-05-13T00:22:18
  

  use enums mp_err, mp_ord, mp_bool, mp_sign * MP_USE_ENUMS enables enums * Wc++-compat catches some implicit conversions if MP_USE_ENUMS is defined * 100% backwards compatible API/ABI if MP_USE_ENUMS is not defined

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• bn_mp_dr_is_modulus.c

• #include "tommath_private.h"
  #ifdef BN_MP_DR_IS_MODULUS_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  /* determines if a number is a valid DR modulus */
  mp_bool mp_dr_is_modulus(const mp_int *a)
  {
     int ix;
  
     /* must be at least two digits */
     if (a->used < 2) {
        return MP_NO;
     }
  
     /* must be of the form b**k - a [a <= b] so all
      * but the first digit must be equal to -1 (mod b).
      */
     for (ix = 1; ix < a->used; ix++) {
        if (a->dp[ix] != MP_MASK) {
           return MP_NO;
        }
     }
     return MP_YES;
  }
  
  #endif
  

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