lib/ccan/asearch/asearch.h

   1 /* Licensed under LGPLv2.1+ - see LICENSE file for details */
   2 #ifndef CCAN_ASEARCH_H
   3 #define CCAN_ASEARCH_H
   4 #include <stdlib.h>
   5 #include <ccan/typesafe_cb/typesafe_cb.h>
   6
   7 /**
   8  * asearch - search an array of elements
   9  * @key: pointer to item being searched for
  10  * @base: pointer to data to sort
  11  * @num: number of elements
  12  * @cmp: pointer to comparison function
  13  *
  14  * This function does a binary search on the given array.  The
  15  * contents of the array should already be in ascending sorted order
  16  * under the provided comparison function.
  17  *
  18  * Note that the key need not have the same type as the elements in
  19  * the array, e.g. key could be a string and the comparison function
  20  * could compare the string with the struct's name field.  However, if
  21  * the key and elements in the array are of the same type, you can use
  22  * the same comparison function for both sort() and asearch().
  23  */
  24 #if HAVE_TYPEOF
  25 #define asearch(key, base, num, cmp)                                    \
  26         ((__typeof__(*(base))*)(bsearch((key), (base), (num), sizeof(*(base)), \
  27                 typesafe_cb_cast(int (*)(const void *, const void *),   \
  28                                  int (*)(const __typeof__(*(key)) *,    \
  29                                          const __typeof__(*(base)) *),  \
  30                                  (cmp)))))
  31
  32 #else
  33 #define asearch(key, base, num, cmp)                            \
  34         (bsearch((key), (base), (num), sizeof(*(base)),         \
  35                  (int (*)(const void *, const void *))(cmp)))
  36 #endif
  37
  38 #endif /* CCAN_ASEARCH_H */