Dogcows Code - chaz/openbox/blob - obt/bsearch.h

   1 /* -*- indent-tabs-mode: nil; tab-width: 4; c-basic-offset: 4; -*-
   2
   3    obt/bsearch.h for the Openbox window manager
   4    Copyright (c) 2010        Dana Jansens
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    See the COPYING file for a copy of the GNU General Public License.
  17 */
  18
  19 #ifndef __obt_bsearch_h
  20 #define __obt_bsearch_h
  21
  22 #include <glib.h>
  23
  24 G_BEGIN_DECLS
  25
  26 /*! Setup to do a binary search on an array. */
  27 #define BSEARCH_SETUP() \
  28     register guint l_BSEARCH, r_BSEARCH, out_BSEARCH;
  29
  30 /*! Helper macro that just returns the input */
  31 #define BSEARCH_IS_T(t) (t)
  32
  33 /*! Search an array @ar holding elements of type @t, starting at index @start,
  34   with @size elements, looking for value @val. */
  35 #define BSEARCH(t, ar, start, size, val) \
  36     BSEARCH_CMP(t, ar, start, size, val, BSEARCH_IS_T)
  37
  38 /*! Search an array @ar, starting at index @start,
  39   with @size elements, looking for value @val of type @t,
  40   using the macro @to_t to convert values in the arrau @ar to type @t.*/
  41 #define BSEARCH_CMP(t, ar, start, size, val, to_t)  \
  42 { \
  43     l_BSEARCH = (start);              \
  44     r_BSEARCH = (start)+(size)-1;     \
  45     while (l_BSEARCH <= r_BSEARCH) { \
  46         /* m is in the middle, but to the left if there's an even number \
  47            of elements */ \
  48         out_BSEARCH = l_BSEARCH + (r_BSEARCH - l_BSEARCH)/2;      \
  49         if ((val) == to_t((ar)[out_BSEARCH])) {             \
  50             break; \
  51         } \
  52         else if ((val) < to_t((ar)[out_BSEARCH]) && out_BSEARCH > 0) {   \
  53             r_BSEARCH = out_BSEARCH-1; /* search to the left side */ \
  54         } \
  55         else \
  56             l_BSEARCH = out_BSEARCH+1; /* search to the left side */ \
  57     } \
  58 }
  59
  60 /*! Returns true if the element last searched for was found in the array */
  61 #define BSEARCH_FOUND() (l_BSEARCH <= r_BSEARCH)
  62 /*! Returns the position in the array at which the element last searched for
  63   was found. */
  64 #define BSEARCH_AT() (out_BSEARCH)
  65
  66
  67
  68 G_END_DECLS
  69
  70 #endif