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Giac_maj/libtommath-0.39/bn_mp_read_signed_bin.c 1.11 KB
6663b6c9   adorian   projet complet av...
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  #include <tommath.h>
  #ifdef BN_MP_READ_SIGNED_BIN_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, tomstdenis@gmail.com, http://math.libtomcrypt.com
   */
  
  /* read signed bin, big endian, first byte is 0==positive or 1==negative */
  int mp_read_signed_bin (mp_int * a, const unsigned char *b, int c)
  {
    int     res;
  
    /* read magnitude */
    if ((res = mp_read_unsigned_bin (a, b + 1, c - 1)) != MP_OKAY) {
      return res;
    }
  
    /* first byte is 0 for positive, non-zero for negative */
    if (b[0] == 0) {
       a->sign = MP_ZPOS;
    } else {
       a->sign = MP_NEG;
    }
  
    return MP_OKAY;
  }
  #endif
  
  /* $Source: /cvs/libtom/libtommath/bn_mp_read_signed_bin.c,v $ */
  /* $Revision: 1.4 $ */
  /* $Date: 2006/03/31 14:18:44 $ */