source/libs/gmp/gmp-src/mpz/cmp_si.c

   1 /* mpz_cmp_si(u,v) -- Compare an integer U with a single-word int V.
   2    Return positive, zero, or negative based on if U > V, U == V, or U < V.
   3
   4 Copyright 1991, 1993-1996, 2000-2002, 2012, 2013 Free Software Foundation, Inc.
   5
   6 This file is part of the GNU MP Library.
   7
   8 The GNU MP Library is free software; you can redistribute it and/or modify
   9 it under the terms of either:
  10
  11   * the GNU Lesser General Public License as published by the Free
  12     Software Foundation; either version 3 of the License, or (at your
  13     option) any later version.
  14
  15 or
  16
  17   * the GNU General Public License as published by the Free Software
  18     Foundation; either version 2 of the License, or (at your option) any
  19     later version.
  20
  21 or both in parallel, as here.
  22
  23 The GNU MP Library is distributed in the hope that it will be useful, but
  24 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  25 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  26 for more details.
  27
  28 You should have received copies of the GNU General Public License and the
  29 GNU Lesser General Public License along with the GNU MP Library.  If not,
  30 see https://www.gnu.org/licenses/.  */
  31
  32 #include "gmp.h"
  33 #include "gmp-impl.h"
  34
  35 int
  36 _mpz_cmp_si (mpz_srcptr u, signed long int v_digit) __GMP_NOTHROW
  37 {
  38 #if GMP_NAIL_BITS != 0
  39   /* FIXME.  This isn't very pretty.  */
  40   mpz_t tmp;
  41   mp_limb_t tt[2];
  42   PTR(tmp) = tt;
  43   ALLOC(tmp) = 2;
  44   mpz_set_si (tmp, v_digit);
  45   return mpz_cmp (u, tmp);
  46 #else
  47
  48   mp_size_t vsize, usize;
  49
  50   usize = SIZ (u);
  51   vsize = (v_digit > 0) - (v_digit < 0);
  52
  53   if ((usize == 0) | (usize != vsize))
  54     return usize - vsize;
  55   else {
  56     mp_limb_t u_digit, absv_digit;
  57
  58     u_digit = PTR (u)[0];
  59     absv_digit = ABS_CAST (unsigned long, v_digit);
  60
  61     if (u_digit == absv_digit)
  62       return 0;
  63
  64     if (u_digit > absv_digit)
  65       return usize;
  66     else
  67       return -usize;
  68   }
  69 #endif
  70 }