kc3-lang/libtommath/mp_read_radix.c

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• Hash : 7a68f128
  Author :
  Date : 2019-10-19T16:24:39
  

  Execute move.sh - Rename files from bn_* to match the function names. * git blame <renamed-file> is not affected * git log --follow <renamed-file> can be used to show log across renames

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• mp_read_radix.c

• #include "tommath_private.h"
  #ifdef MP_READ_RADIX_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  #define MP_TOUPPER(c) ((((c) >= 'a') && ((c) <= 'z')) ? (((c) + 'A') - 'a') : (c))
  
  /* read a string [ASCII] in a given radix */
  mp_err mp_read_radix(mp_int *a, const char *str, int radix)
  {
     mp_err   err;
     int      y;
     mp_sign  neg;
     unsigned pos;
     char     ch;
  
     /* zero the digit bignum */
     mp_zero(a);
  
     /* make sure the radix is ok */
     if ((radix < 2) || (radix > 64)) {
        return MP_VAL;
     }
  
     /* if the leading digit is a
      * minus set the sign to negative.
      */
     if (*str == '-') {
        ++str;
        neg = MP_NEG;
     } else {
        neg = MP_ZPOS;
     }
  
     /* set the integer to the default of zero */
     mp_zero(a);
  
     /* process each digit of the string */
     while (*str != '\0') {
        /* if the radix <= 36 the conversion is case insensitive
         * this allows numbers like 1AB and 1ab to represent the same  value
         * [e.g. in hex]
         */
        ch = (radix <= 36) ? (char)MP_TOUPPER((int)*str) : *str;
        pos = (unsigned)(ch - '(');
        if (MP_RMAP_REVERSE_SIZE < pos) {
           break;
        }
        y = (int)s_mp_rmap_reverse[pos];
  
        /* if the char was found in the map
         * and is less than the given radix add it
         * to the number, otherwise exit the loop.
         */
        if ((y == 0xff) || (y >= radix)) {
           break;
        }
        if ((err = mp_mul_d(a, (mp_digit)radix, a)) != MP_OKAY) {
           return err;
        }
        if ((err = mp_add_d(a, (mp_digit)y, a)) != MP_OKAY) {
           return err;
        }
        ++str;
     }
  
     /* if an illegal character was found, fail. */
     if (!((*str == '\0') || (*str == '\r') || (*str == '\n'))) {
        mp_zero(a);
        return MP_VAL;
     }
  
     /* set the sign only if a != 0 */
     if (!MP_IS_ZERO(a)) {
        a->sign = neg;
     }
     return MP_OKAY;
  }
  #endif
  

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