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/* $NetBSD: tfind.c,v 1.3.18.2 2005/03/23 11:12:21 tron 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 <assert.h>
#define _SEARCH_PRIVATE
#include <stdlib.h>
#include <search.h>
/* find a node, or return 0 */
void *
tfind (const void *vkey, void * const *vrootp,
int (*compar) (const void *, const void *))
{
node_t * const *rootp = (node_t * const*)vrootp;
if (rootp == NULL)
return NULL;
while (*rootp != NULL)
{
/* T1: */
int r;
if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
return *rootp; /* key found */
rootp = (r < 0) ?
&(*rootp)->llink : /* T3: follow left branch */
&(*rootp)->rlink; /* T4: follow right branch */
}
return NULL;
}
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