48 lines
1.2 KiB
C
48 lines
1.2 KiB
C
/* $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $ */
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/* $FreeBSD$ */
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/*
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* Tree search generalized from Knuth (6.2.2) Algorithm T just like
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* the AT&T man page says.
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*
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* The node_t structure is for internal use only, lint doesn't grok it.
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*
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* Written by reading the System V Interface Definition, not the code.
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*
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* Totally public domain.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
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#endif /* LIBC_SCCS and not lint */
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#include <assert.h>
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#define _SEARCH_PRIVATE
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#include <stdlib.h>
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#include <search.h>
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/* find a node, or return 0 */
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void *
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tfind(vkey, vrootp, compar)
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const void *vkey; /* key to be found */
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void **vrootp; /* address of the tree root */
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int (*compar) __P((const void *, const void *));
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{
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node_t **rootp = (node_t **)vrootp;
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if (rootp == NULL)
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return NULL;
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while (*rootp != NULL) { /* T1: */
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int r;
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if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */
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return *rootp; /* key found */
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rootp = (r < 0) ?
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&(*rootp)->llink : /* T3: follow left branch */
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&(*rootp)->rlink; /* T4: follow right branch */
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}
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return NULL;
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}
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