Line data    Source code

       1             : #include "tommath_private.h"
       2             : #ifdef BN_MP_READ_RADIX_C
       3             : /* LibTomMath, multiple-precision integer library -- Tom St Denis */
       4             : /* SPDX-License-Identifier: Unlicense */
       5             : 
       6             : #define MP_TOUPPER(c) ((((c) >= 'a') && ((c) <= 'z')) ? (((c) + 'A') - 'a') : (c))
       7             : 
       8             : /* read a string [ASCII] in a given radix */
       9           0 : mp_err mp_read_radix(mp_int *a, const char *str, int radix)
      10             : {
      11           0 :    mp_err   err;
      12           0 :    int      y;
      13           0 :    mp_sign  neg;
      14           0 :    unsigned pos;
      15           0 :    char     ch;
      16             : 
      17             :    /* zero the digit bignum */
      18           0 :    mp_zero(a);
      19             : 
      20             :    /* make sure the radix is ok */
      21           0 :    if ((radix < 2) || (radix > 64)) {
      22           0 :       return MP_VAL;
      23             :    }
      24             : 
      25             :    /* if the leading digit is a
      26             :     * minus set the sign to negative.
      27             :     */
      28           0 :    if (*str == '-') {
      29           0 :       ++str;
      30           0 :       neg = MP_NEG;
      31             :    } else {
      32           0 :       neg = MP_ZPOS;
      33             :    }
      34             : 
      35             :    /* set the integer to the default of zero */
      36           0 :    mp_zero(a);
      37             : 
      38             :    /* process each digit of the string */
      39           0 :    while (*str != '\0') {
      40             :       /* if the radix <= 36 the conversion is case insensitive
      41             :        * this allows numbers like 1AB and 1ab to represent the same  value
      42             :        * [e.g. in hex]
      43             :        */
      44           0 :       ch = (radix <= 36) ? (char)MP_TOUPPER((int)*str) : *str;
      45           0 :       pos = (unsigned)(ch - '(');
      46           0 :       if (mp_s_rmap_reverse_sz < pos) {
      47           0 :          break;
      48             :       }
      49           0 :       y = (int)mp_s_rmap_reverse[pos];
      50             : 
      51             :       /* if the char was found in the map
      52             :        * and is less than the given radix add it
      53             :        * to the number, otherwise exit the loop.
      54             :        */
      55           0 :       if ((y == 0xff) || (y >= radix)) {
      56             :          break;
      57             :       }
      58           0 :       if ((err = mp_mul_d(a, (mp_digit)radix, a)) != MP_OKAY) {
      59           0 :          return err;
      60             :       }
      61           0 :       if ((err = mp_add_d(a, (mp_digit)y, a)) != MP_OKAY) {
      62           0 :          return err;
      63             :       }
      64           0 :       ++str;
      65             :    }
      66             : 
      67             :    /* if an illegal character was found, fail. */
      68           0 :    if (!((*str == '\0') || (*str == '\r') || (*str == '\n'))) {
      69           0 :       mp_zero(a);
      70           0 :       return MP_VAL;
      71             :    }
      72             : 
      73             :    /* set the sign only if a != 0 */
      74           0 :    if (!MP_IS_ZERO(a)) {
      75           0 :       a->sign = neg;
      76             :    }
      77           0 :    return MP_OKAY;
      78             : }
      79             : #endif