c3-lang/libtommath/bn_mp_grow.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_grow.c

• #include <tommath_private.h>
  #ifdef BN_MP_GROW_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
   */
  
  /* grow as required */
  int mp_grow (mp_int * a, int size)
  {
    int     i;
    mp_digit *tmp;
  
    /* if the alloc size is smaller alloc more ram */
    if (a->alloc < size) {
      /* ensure there are always at least MP_PREC digits extra on top */
      size += (MP_PREC * 2) - (size % MP_PREC);
  
      /* reallocate the array a->dp
       *
       * We store the return in a temporary variable
       * in case the operation failed we don't want
       * to overwrite the dp member of a.
       */
      tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size);
      if (tmp == NULL) {
        /* reallocation failed but "a" is still valid [can be freed] */
        return MP_MEM;
      }
  
      /* reallocation succeeded so set a->dp */
      a->dp = tmp;
  
      /* zero excess digits */
      i        = a->alloc;
      a->alloc = size;
      for (; i < a->alloc; i++) {
        a->dp[i] = 0;
      }
    }
    return MP_OKAY;
  }
  #endif
  
  /* $Source$ */
  /* $Revision$ */
  /* $Date$ */
  

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