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/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#include <stdlib.h>
/* Perform a binary search for KEY in BASE which has NMEMB elements
of SIZE bytes each. The comparisons are done by (*COMPAR)(). */
PTR
DEFUN(bsearch, (key, base, nmemb, size, compar),
register CONST PTR key AND register CONST PTR base AND
size_t nmemb AND register size_t size AND
register int EXFUN((*compar), (CONST PTR, CONST PTR)))
{
register size_t l, u, idx;
register CONST PTR p;
register int comparison;
l = 0;
u = nmemb;
while (l < u)
{
idx = (l + u) / 2;
p = (PTR) (((CONST char *) base) + (idx * size));
comparison = (*compar)(key, p);
if (comparison < 0)
u = idx;
else if (comparison > 0)
l = idx + 1;
else
return (PTR) p;
}
return NULL;
}
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