lib/util/tsort.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    typesafe qsort
   5
   6    Copyright (C) Andrew Tridgell 2010
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #ifndef _TSORT_H
  23 #define _TSORT_H
  24 #include <assert.h>
  25
  26 /*
  27   a wrapper around qsort() that ensures the comparison function is
  28   type safe.
  29  */
  30 #ifndef TYPESAFE_QSORT
  31 #define TYPESAFE_QSORT(base, numel, comparison) \
  32 do { \
  33         if (numel > 1) { \
  34                 qsort(base, numel, sizeof((base)[0]), (int (*)(const void *, const void *))comparison); \
  35                 assert(comparison(&((base)[0]), &((base)[1])) <= 0); \
  36         } \
  37 } while (0)
  38 #endif
  39
  40
  41 #ifndef NUMERIC_CMP
  42 /*
  43  * NUMERIC_CMP is a safe replacement for `a - b` in comparison
  44  * functions. It will work on integers, pointers, and floats.
  45  *
  46  * Rather than
  47  *
  48  *      return a - b;
  49  *
  50  * use
  51  *
  52  *     return NUMERIC_CMP(a, b);
  53  *
  54  * and you won't have any troubles if a - b would overflow.
  55  */
  56 #define NUMERIC_CMP(a, b) (((a) > (b)) - ((a) < (b)))
  57 #endif
  58
  59 #endif