strsearch.c revision 34f9b3eef6fdadbda0a846aa4d68691ac40eace5
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* Glenn Fowler
* AT&T Research
*/
#include <ast.h>
/*
* return a pointer to the element matching
* name in the (*comparf*)() sorted tab of num elements of
* size siz where the first member of each
* element is a char*
*
* 0 returned if name not found
*/
void*
strsearch(const void* tab, size_t num, size_t siz, Strcmp_f comparf, const char* name, void* context)
{
register char* lo = (char*)tab;
register char* hi = lo + (num - 1) * siz;
register char* mid;
register int v;
while (lo <= hi)
{
mid = lo + (((hi - lo) / siz) / 2) * siz;
if (!(v = context ? (*(Strcmp_context_f)comparf)(name, *((char**)mid), context) : (*comparf)(name, *((char**)mid))))
return (void*)mid;
else if (v > 0)
lo = mid + siz;
else hi = mid - siz;
}
return 0;
}