Libc-498.tar.gz

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

diff --git a/stdlib/tsearch-fbsd.c b/stdlib/tsearch-fbsd.c
new file mode 100644 (file)
index 0000000..edeccde
--- /dev/null
+++ b/stdlib/tsearch-fbsd.c
@@ -0,0 +1,58 @@
+/*     $NetBSD: tsearch.c,v 1.3 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: tsearch.c,v 1.3 1999/09/16 11:45:37 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+#endif
+__FBSDID("$FreeBSD: src/lib/libc/stdlib/tsearch.c,v 1.4 2003/01/05 02:43:18 tjr Exp $");
+
+#define _SEARCH_PRIVATE
+#include <search.h>
+#include <stdlib.h>
+
+/* find or insert datum into search tree */
+void *
+tsearch(vkey, vrootp, compar)
+       const void *vkey;               /* key to be located */
+       void **vrootp;                  /* address of tree root */
+       int (*compar)(const void *, const void *);
+{
+       node_t *q;
+       node_t **rootp = (node_t **)vrootp;
+
+       if (rootp == NULL)
+               return NULL;
+
+       while (*rootp != NULL) {        /* Knuth's T1: */
+               int r;
+
+               if ((r = (*compar)(vkey, (*rootp)->key)) == 0)  /* T2: */
+                       return *rootp;          /* we found it! */
+
+               rootp = (r < 0) ?
+                   &(*rootp)->llink :          /* T3: follow left branch */
+                   &(*rootp)->rlink;           /* T4: follow right branch */
+       }
+
+       q = malloc(sizeof(node_t));             /* T5: key not found */
+       if (q != 0) {                           /* make new node */
+               *rootp = q;                     /* link new node to old */
+               /* LINTED const castaway ok */
+               q->key = (void *)vkey;          /* initialize new node */
+               q->llink = q->rlink = NULL;
+       }
+       return q;
+}