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/*
* 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.
*/
/*LINTLIBRARY*/
#include <search.h>
typedef struct node_t
{
char *key;
struct node_t *llink, *rlink;
} node;
/* find a node, or return 0 */
void *
tfind(vkey, vrootp, compar)
const void *vkey; /* key to be found */
void *const *vrootp; /* address of the tree root */
int (*compar)(const void *, const void *);
{
char *key = (char *)vkey;
node **rootp = (node **)vrootp;
if (rootp == (struct node_t **)0)
return ((struct node_t *)0);
while (*rootp != (struct node_t *)0) { /* T1: */
int r;
if ((r = (*compar)(key, (*rootp)->key)) == 0) /* T2: */
return (*rootp); /* key found */
rootp = (r < 0) ?
&(*rootp)->llink : /* T3: follow left branch */
&(*rootp)->rlink; /* T4: follow right branch */
}
return (node *)0;
}
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