b902641d73
I've also added insque(3) and remque(3) (from NetBSD because the OpenBSD ones are currently broken for non-circular lists). I've not added the three hash table functions that should be in this header because they operate on a single global hash table and thus aren't likely to be useful. Bug: https://code.google.com/p/android/issues/detail?id=73719 (cherry picked from commit 3e424d0a241f8ae5194514dabc4ad899f5a5416d) Change-Id: I5882a6b48c80fea8ac6b9c27e7b9de10b202b4ff
42 lines
1.0 KiB
C
42 lines
1.0 KiB
C
/* $OpenBSD: tfind.c,v 1.6 2014/03/16 18:38:30 guenther Exp $ */
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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
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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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/*LINTLIBRARY*/
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#include <search.h>
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typedef struct node_t
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{
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char *key;
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struct node_t *llink, *rlink;
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} node;
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/* find a node, or return 0 */
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void *
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tfind(const void *vkey, void * const *vrootp,
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int (*compar)(const void *, const void *))
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{
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char *key = (char *)vkey;
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node **rootp = (node **)vrootp;
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if (rootp == (struct node_t **)0)
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return ((struct node_t *)0);
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while (*rootp != (struct node_t *)0) { /* T1: */
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int r;
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if ((r = (*compar)(key, (*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 (node *)0;
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}
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