From 28f540f45bbacd939bfd07f213bcad2bf730b1bf Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Sat, 18 Feb 1995 01:27:10 +0000 Subject: initial import --- stdlib/bsearch.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 stdlib/bsearch.c (limited to 'stdlib/bsearch.c') diff --git a/stdlib/bsearch.c b/stdlib/bsearch.c new file mode 100644 index 0000000000..d798eabd2b --- /dev/null +++ b/stdlib/bsearch.c @@ -0,0 +1,51 @@ +/* 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 +#include + + +/* 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; +} -- cgit 1.4.1