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File: [cvs.NetBSD.org] / src / lib / libc / stdlib / tdelete.c (download)

Revision 1.6, Mon Jun 25 22:32:45 2012 UTC (11 years, 9 months ago) by abs
Branch: MAIN
CVS Tags: yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, tls-maxphys-base, tls-maxphys, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, agc-symver-base, agc-symver
Changes since 1.5: +5 -7 lines 

Update old-style definitions to ANSI, remove a couple of register
definitions along the way. Fixed gcc 4.1 build (thank you vax)

/*	$NetBSD: tdelete.c,v 1.6 2012/06/25 22:32:45 abs Exp $	*/

/*
 * Tree search generalized from Knuth (6.2.2) Algorithm T just like
 * the AT&T man page says.
 *
 * The node_t structure is for internal use only, lint doesn't grok it.
 *
 * Written by reading the System V Interface Definition, not the code.
 *
 * Totally public domain.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: tdelete.c,v 1.6 2012/06/25 22:32:45 abs Exp $");
#endif /* LIBC_SCCS and not lint */

#include <assert.h>
#define _SEARCH_PRIVATE
#include <search.h>
#include <stdlib.h>


/* find a node with key "vkey" in tree "vrootp" */
void *
tdelete(const void *vkey, void **vrootp,
    int (*compar)(const void *, const void *))
{
	node_t **rootp = (node_t **)vrootp;
	node_t *p, *q, *r;
	int  cmp;

	_DIAGASSERT(vkey != NULL);
	_DIAGASSERT(compar != NULL);

	if (rootp == NULL || (p = *rootp) == NULL)
		return NULL;

	while ((cmp = (*compar)(vkey, (*rootp)->key)) != 0) {
		p = *rootp;
		rootp = (cmp < 0) ?
		    &(*rootp)->llink :		/* follow llink branch */
		    &(*rootp)->rlink;		/* follow rlink branch */
		if (*rootp == NULL)
			return NULL;		/* key not found */
	}
	r = (*rootp)->rlink;			/* D1: */
	if ((q = (*rootp)->llink) == NULL)	/* Left NULL? */
		q = r;
	else if (r != NULL) {			/* Right link is NULL? */
		if (r->llink == NULL) {		/* D2: Find successor */
			r->llink = q;
			q = r;
		} else {			/* D3: Find NULL link */
			for (q = r->llink; q->llink != NULL; q = r->llink)
				r = q;
			r->llink = q->rlink;
			q->llink = (*rootp)->llink;
			q->rlink = (*rootp)->rlink;
		}
	}
	if (p != *rootp)
		free(*rootp);			/* D4: Free node */
	*rootp = q;				/* link parent to new node */
	return p;
}