f14fb60209
* Updating common/lib * Updating lib/csu * Updating lib/libc * Updating libexec/ld.elf_so * Corrected test on __minix in featuretest to actually follow the meaning of the comment. * Cleaned up _REENTRANT-related defintions. * Disabled -D_REENTRANT for libfetch * Removing some unneeded __NBSD_LIBC defines and tests Change-Id: Ic1394baef74d11b9f86b312f5ff4bbc3cbf72ce2
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
/* $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;
|
|
}
|