Libc-498.tar.gz

[apple/libc.git] / stdlib / tdelete-fbsd.c

diff --git a/stdlib/tdelete-fbsd.c b/stdlib/tdelete-fbsd.c
new file mode 100644 (file)
index 0000000..7fb6893
--- /dev/null
+++ b/stdlib/tdelete-fbsd.c
@@ -0,0 +1,71 @@
+/*     $NetBSD: tdelete.c,v 1.2 1999/09/16 11:45:37 lukem 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 0
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: tdelete.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+#endif
+__FBSDID("$FreeBSD: src/lib/libc/stdlib/tdelete.c,v 1.6 2003/01/05 02:43:18 tjr Exp $");
+
+#define _SEARCH_PRIVATE
+#include <search.h>
+#include <stdlib.h>
+
+
+/*
+ * delete node with given key
+ *
+ * vkey:   key to be deleted
+ * vrootp: address of the root of the tree
+ * compar: function to carry out node comparisons
+ */
+void *
+tdelete(const void * __restrict vkey, void ** __restrict vrootp,
+    int (*compar)(const void *, const void *))
+{
+       node_t **rootp = (node_t **)vrootp;
+       node_t *p, *q, *r;
+       int cmp;
+
+       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;
+               }
+       }
+       free(*rootp);                           /* D4: Free node */
+       *rootp = q;                             /* link parent to new node */
+       return p;
+}