github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpz/aors_ui.h (about)

     1  /* mpz_add_ui, mpz_sub_ui -- Add or subtract an mpz_t and an unsigned
     2     one-word integer.
     3  
     4  Copyright 1991, 1993, 1994, 1996, 1999-2002, 2004, 2012, 2013 Free Software
     5  Foundation, Inc.
     6  
     7  This file is part of the GNU MP Library.
     8  
     9  The GNU MP Library is free software; you can redistribute it and/or modify
    10  it under the terms of either:
    11  
    12    * the GNU Lesser General Public License as published by the Free
    13      Software Foundation; either version 3 of the License, or (at your
    14      option) any later version.
    15  
    16  or
    17  
    18    * the GNU General Public License as published by the Free Software
    19      Foundation; either version 2 of the License, or (at your option) any
    20      later version.
    21  
    22  or both in parallel, as here.
    23  
    24  The GNU MP Library is distributed in the hope that it will be useful, but
    25  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    26  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    27  for more details.
    28  
    29  You should have received copies of the GNU General Public License and the
    30  GNU Lesser General Public License along with the GNU MP Library.  If not,
    31  see https://www.gnu.org/licenses/.  */
    32  
    33  #include "gmp.h"
    34  #include "gmp-impl.h"
    35  
    36  
    37  #ifdef OPERATION_add_ui
    38  #define FUNCTION          mpz_add_ui
    39  #define FUNCTION2         mpz_add
    40  #define VARIATION_CMP     >=
    41  #define VARIATION_NEG
    42  #define VARIATION_UNNEG   -
    43  #endif
    44  
    45  #ifdef OPERATION_sub_ui
    46  #define FUNCTION          mpz_sub_ui
    47  #define FUNCTION2         mpz_sub
    48  #define VARIATION_CMP     <
    49  #define VARIATION_NEG     -
    50  #define VARIATION_UNNEG
    51  #endif
    52  
    53  #ifndef FUNCTION
    54  Error, need OPERATION_add_ui or OPERATION_sub_ui
    55  #endif
    56  
    57  
    58  void
    59  FUNCTION (mpz_ptr w, mpz_srcptr u, unsigned long int vval)
    60  {
    61    mp_srcptr up;
    62    mp_ptr wp;
    63    mp_size_t usize, wsize;
    64    mp_size_t abs_usize;
    65  
    66  #if BITS_PER_ULONG > GMP_NUMB_BITS  /* avoid warnings about shift amount */
    67    if (vval > GMP_NUMB_MAX)
    68      {
    69        mpz_t v;
    70        mp_limb_t vl[2];
    71        PTR(v) = vl;
    72        vl[0] = vval & GMP_NUMB_MASK;
    73        vl[1] = vval >> GMP_NUMB_BITS;
    74        SIZ(v) = 2;
    75        FUNCTION2 (w, u, v);
    76        return;
    77      }
    78  #endif
    79  
    80    usize = SIZ (u);
    81    if (usize == 0)
    82      {
    83        PTR (w)[0] = vval;
    84        SIZ (w) = VARIATION_NEG (vval != 0);
    85        return;
    86      }
    87  
    88    abs_usize = ABS (usize);
    89  
    90    /* If not space for W (and possible carry), increase space.  */
    91    wp = MPZ_REALLOC (w, abs_usize + 1);
    92  
    93    /* These must be after realloc (U may be the same as W).  */
    94    up = PTR (u);
    95  
    96    if (usize VARIATION_CMP 0)
    97      {
    98        mp_limb_t cy;
    99        cy = mpn_add_1 (wp, up, abs_usize, (mp_limb_t) vval);
   100        wp[abs_usize] = cy;
   101        wsize = VARIATION_NEG (abs_usize + cy);
   102      }
   103    else
   104      {
   105        /* The signs are different.  Need exact comparison to determine
   106  	 which operand to subtract from which.  */
   107        if (abs_usize == 1 && up[0] < vval)
   108  	{
   109  	  wp[0] = vval - up[0];
   110  	  wsize = VARIATION_NEG 1;
   111  	}
   112        else
   113  	{
   114  	  mpn_sub_1 (wp, up, abs_usize, (mp_limb_t) vval);
   115  	  /* Size can decrease with at most one limb.  */
   116  	  wsize = VARIATION_UNNEG (abs_usize - (wp[abs_usize - 1] == 0));
   117  	}
   118      }
   119  
   120    SIZ (w) = wsize;
   121  }