bring in binary search tree code.

Obtained from: NetBSD

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/libc/stdlib/tfind.c b/lib/libc/stdlib/tfind.c
new file mode 100644
index 0000000..b2c4b96
--- /dev/null
+++ b/lib/libc/stdlib/tfind.c
@@ -0,0 +1,47 @@
+/*	$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $	*/
+/* $FreeBSD$ */
+
+/*
+ * 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: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+
+#include <assert.h>
+#define _SEARCH_PRIVATE
+#include <stdlib.h>
+#include <search.h>
+
+/* find a node, or return 0 */
+void *
+tfind(vkey, vrootp, compar)
+	const void *vkey;		/* key to be found */
+	void **vrootp;			/* address of the tree root */
+	int (*compar) __P((const void *, const void *));
+{
+	node_t **rootp = (node_t **)vrootp;
+
+	if (rootp == NULL)
+		return NULL;
+
+	while (*rootp != NULL) {		/* T1: */
+		int r;
+
+		if ((r = (*compar)(vkey, (*rootp)->key)) == 0)	/* T2: */
+			return *rootp;		/* key found */
+		rootp = (r < 0) ?
+		    &(*rootp)->llink :		/* T3: follow left branch */
+		    &(*rootp)->rlink;		/* T4: follow right branch */
+	}
+	return NULL;
+}