c3-lang/libtommath/bn_s_mp_get_bit.c

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• Hash : a8239c24
  Author :
  Date : 2019-05-13T11:32:42
  

  deprecate mp_get_bit The return type of mp_get_bit was imprecise (either mp_err or mp_bool), therefore this function is deprecated in favor of s_mp_get_bit for now. If we need s_mp_get_bit to be public, we should add it under a different name. However since mp_set_bit is not available, I don't think there any downstream users (ab)using mp_int as bitsets.

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• bn_s_mp_get_bit.c

• #include "tommath_private.h"
  #ifdef BN_S_MP_GET_BIT_C
  
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  /* Get bit at position b and return MP_YES if the bit is 1, MP_NO if it is 0 */
  mp_bool s_mp_get_bit(const mp_int *a, unsigned int b)
  {
     mp_digit bit;
     int limb = (int)(b / MP_DIGIT_BIT);
  
     if (limb >= a->used) {
        return MP_NO;
     }
  
     bit = (mp_digit)1 << (b % MP_DIGIT_BIT);
     return ((a->dp[limb] & bit) != 0u) ? MP_YES : MP_NO;
  }
  
  #endif
  

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