c3-lang/libtommath/bn_mp_fread.c

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• Hash : 4e3f1344
  Author :
  Date : 2015-11-12T01:49:07
  

  provide tommath_private.h tommath.h contains declarations for the public part of the library. tommath_private.h contains the functions which are private to ltm and should not be exposed to the public.

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• bn_mp_fread.c

• #include <tommath_private.h>
  #ifdef BN_MP_FREAD_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis
   *
   * LibTomMath is a library that provides multiple-precision
   * integer arithmetic as well as number theoretic functionality.
   *
   * The library was designed directly after the MPI library by
   * Michael Fromberger but has been written from scratch with
   * additional optimizations in place.
   *
   * The library is free for all purposes without any express
   * guarantee it works.
   *
   * Tom St Denis, tstdenis82@gmail.com, http://libtom.org
   */
  
  /* read a bigint from a file stream in ASCII */
  int mp_fread(mp_int *a, int radix, FILE *stream)
  {
     int err, ch, neg, y;
     
     /* clear a */
     mp_zero(a);
     
     /* if first digit is - then set negative */
     ch = fgetc(stream);
     if (ch == '-') {
        neg = MP_NEG;
        ch = fgetc(stream);
     } else {
        neg = MP_ZPOS;
     }
     
     for (;;) {
        /* find y in the radix map */
        for (y = 0; y < radix; y++) {
            if (mp_s_rmap[y] == ch) {
               break;
            }
        }
        if (y == radix) {
           break;
        }
        
        /* shift up and add */
        if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
           return err;
        }
        if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
           return err;
        }
        
        ch = fgetc(stream);
     }
     if (mp_cmp_d(a, 0) != MP_EQ) {
        a->sign = neg;
     }
     
     return MP_OKAY;
  }
  
  #endif
  
  /* $Source$ */
  /* $Revision$ */
  /* $Date$ */
  

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