lookup.c

早期freebsd实现

/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)lookup.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

#include "gprof.h"

    /*
     *	look up an address in a sorted-by-address namelist
     *	    this deals with misses by mapping them to the next lower 
     *	    entry point.
     */
nltype *
nllookup( address )
    unsigned long	address;
{
    register long	low;
    register long	middle;
    register long	high;
#   ifdef DEBUG
	register int	probes;

	probes = 0;
#   endif DEBUG
    for ( low = 0 , high = nname - 1 ; low != high ; ) {
#	ifdef DEBUG
	    probes += 1;
#	endif DEBUG
	middle = ( high + low ) >> 1;
	if ( nl[ middle ].value <= address && nl[ middle+1 ].value > address ) {
#	    ifdef DEBUG
		if ( debug & LOOKUPDEBUG ) {
		    printf( "[nllookup] %d (%d) probes\n" , probes , nname-1 );
		}
#	    endif DEBUG
	    return &nl[ middle ];
	}
	if ( nl[ middle ].value > address ) {
	    high = middle;
	} else {
	    low = middle + 1;
	}
    }
#   ifdef DEBUG
	if ( debug & LOOKUPDEBUG ) {
	    fprintf( stderr , "[nllookup] (%d) binary search fails\n" ,
		nname-1 );
	}
#   endif DEBUG
    return 0;
}

arctype *
arclookup( parentp , childp )
    nltype	*parentp;
    nltype	*childp;
{
    arctype	*arcp;

    if ( parentp == 0 || childp == 0 ) {
	fprintf( stderr, "[arclookup] parentp == 0 || childp == 0\n" );
	return 0;
    }
#   ifdef DEBUG
	if ( debug & LOOKUPDEBUG ) {
	    printf( "[arclookup] parent %s child %s\n" ,
		    parentp -> name , childp -> name );
	}
#   endif DEBUG
    for ( arcp = parentp -> children ; arcp ; arcp = arcp -> arc_childlist ) {
#	ifdef DEBUG
	    if ( debug & LOOKUPDEBUG ) {
		printf( "[arclookup]\t arc_parent %s arc_child %s\n" ,
			arcp -> arc_parentp -> name ,
			arcp -> arc_childp -> name );
	    }
#	endif DEBUG
	if ( arcp -> arc_childp == childp ) {
	    return arcp;
	}
    }
    return 0;
}