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

Revision 1.8, Wed Jan 20 20:47:41 2016 UTC (6 years, 3 months ago) by christos
Branch: MAIN
CVS Tags: prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, cjep_sun2x-base1, cjep_sun2x-base, cjep_sun2x, cjep_staticlib_x-base1, cjep_staticlib_x-base, cjep_staticlib_x, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, HEAD
Changes since 1.7: +2 -4 lines

Don't return NULL when we are freeing the root node; return a free'd pointer
instead.

/*	$NetBSD: tdelete.c,v 1.8 2016/01/20 20:47:41 christos 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 1.8 2016/01/20 20:47:41 christos 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;
		}
	}
	free(*rootp);				/* D4: Free node */
	*rootp = q;				/* link parent to new node */
	return p;
}