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File: [cvs.NetBSD.org] / src / lib / libc / stdlib / tdelete.c (download)
Revision 1.5, Wed May 18 19:36:36 2011 UTC (12 years, 11 months ago) by dsl
Remove __P() |
/* $NetBSD: tdelete.c,v 1.5 2011/05/18 19:36:36 dsl 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 1.5 2011/05/18 19:36:36 dsl Exp $"); #endif /* LIBC_SCCS and not lint */ #include <assert.h> #define _SEARCH_PRIVATE #include <search.h> #include <stdlib.h> /* delete node with given key */ void * tdelete(vkey, vrootp, compar) const void *vkey; /* key to be deleted */ void **vrootp; /* address of the root of tree */ 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; }