kc3-lang/libtommath/mp_fread.c

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• Hash : bbb17808
  Author :
  Date : 2019-10-30T14:19:50
  

  mp_radix off-by-one error and other related code-cleanup

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• mp_fread.c

• #include "tommath_private.h"
  #ifdef MP_FREAD_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  #ifndef MP_NO_FILE
  /* read a bigint from a file stream in ASCII */
  mp_err mp_fread(mp_int *a, int radix, FILE *stream)
  {
     mp_err err;
     mp_sign neg = MP_ZPOS;
     int ch;
  
     /* make sure the radix is ok */
     if ((radix < 2) || (radix > 64)) {
        return MP_VAL;
     }
  
     /* if first digit is - then set negative */
     ch = fgetc(stream);
     if (ch == (int)'-') {
        neg = MP_NEG;
        ch = fgetc(stream);
     }
  
     /* no digits, return error */
     if (ch == EOF) {
        return MP_ERR;
     }
  
     /* clear a */
     mp_zero(a);
  
     do {
        uint8_t y;
        unsigned pos;
        ch = (radix <= 36) ? MP_TOUPPER(ch) : ch;
        pos = (unsigned)(ch - (int)'+');
        if (MP_RMAP_REVERSE_SIZE <= pos) {
           break;
        }
  
        y = s_mp_rmap_reverse[pos];
  
        if (y >= radix) {
           break;
        }
  
        /* shift up and add */
        if ((err = mp_mul_d(a, (mp_digit)radix, a)) != MP_OKAY) {
           return err;
        }
        if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
           return err;
        }
     } while ((ch = fgetc(stream)) != EOF);
  
     if (!mp_iszero(a)) {
        a->sign = neg;
     }
  
     return MP_OKAY;
  }
  #endif
  
  #endif
  

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