wmmon/ulllib.c

   1 /*
   2  *  Unsigned long long arithmetic limited library, tailored for wmmon's
   3  *  specific needs.
   4  *
   5  *  Copyright (c) 2014 Pedro Gimeno Fortea
   6  *
   7  *  This file is part of wmmon.
   8  *
   9  *  wmmon is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  wmmon is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with wmmon; if not, write to the Free Software Foundation, Inc.,
  21  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 #ifndef HAVE_LONG_LONG_INT
  25
  26 #include "ulllib.h"
  27
  28 void ullreset(ullong *target) {
  29         target->H = target->L = 0;
  30 }
  31
  32 void ulladd(ullong *target, const ullong *toadd) {
  33         unsigned long tmpL = toadd->L, tmpH = toadd->H;
  34         target->L += tmpL;
  35
  36         /* Carry if the result is less than one of the operands */
  37         target->H += tmpH + (target->L < tmpL);
  38 }
  39
  40 long ullsub(const ullong *a, const ullong *b) {
  41         /* Will wrap around correctly if necessary. Result is assumed to
  42            fit a signed long. */
  43         /* assert((a->H == b->H && a->L >= b->L)
  44                   || (a->H == b->H + 1 && a->L < b->L)); */
  45         return a->L - b->L;
  46 }
  47
  48 void ullparse(ullong *target, const char *str) {
  49         ullong tmp;
  50
  51         ullreset(target);
  52         while (*str >= '0' && *str <= '9') {
  53                 tmp = *target;
  54                 ulladd(target, target); /* *2 */
  55                 ulladd(target, target); /* *4 */
  56                 ulladd(target, &tmp);   /* *5 */
  57                 ulladd(target, target); /* *10 */
  58                 tmp.H = 0;
  59                 tmp.L = *str - '0';
  60                 ulladd(target, &tmp);   /* + digit */
  61                 ++str;
  62         }
  63 }
  64
  65 #endif /* HAVE_LONG_LONG_INT */
  66
  67 typedef int make_iso_compilers_happy;
  68