Add tsearch and friends, and a test program

tsearch is missing from windows. use the netbsd version as it's
license-compatible.

lib/roken/tsearch-test.c

@@ -0,0 +1,125 @@
+/*
+ * 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 <config.h>
+
+#include "roken.h"
+#include "search.h"
+
+struct node {
+    char *string;
+    int order;
+};
+
+extern void *rk_tdelete(const void * __restrict, void ** __restrict,
+		 int (*)(const void *, const void *));
+extern void *rk_tfind(const void *, void * const *,
+	       int (*)(const void *, const void *));
+extern void *rk_tsearch(const void *, void **, int (*)(const void *, const void *));
+extern void rk_twalk(const void *, void (*)(const void *, VISIT, int));
+
+void *rootnode = NULL;
+int numerr = 0;
+
+/*
+ *  This routine compares two nodes, based on an
+ *  alphabetical ordering of the string field.
+ */
+int
+node_compare(const void *node1, const void *node2)
+{
+    return strcmp(((const struct node *) node1)->string,
+		  ((const struct node *) node2)->string);
+}
+
+static int walkorder = -1;
+
+void
+list_node(const void *ptr, VISIT order, int level)
+{
+    const struct node *p = *(const struct node **) ptr;
+
+    if (order == postorder || order == leaf)  {
+	walkorder++;
+	if (p->order != walkorder) {
+	    warnx("sort failed: expected %d next, got %d\n", walkorder,
+		  p->order);
+	    numerr++;
+	}
+    }
+}
+
+int
+main(int argc, char **argv)
+{
+    int numtest = 1;
+    struct node *t, *p, tests[] = {
+	{ "", 0 },
+	{ "ab", 3 },
+	{ "abc", 4 },
+	{ "abcdefg", 8 },
+	{ "abcd", 5 },
+	{ "a", 2 },
+	{ "abcdef", 7 },
+	{ "abcde", 6 },
+	{ "=", 1 },
+	{ NULL }
+    };
+    
+    for(t = tests; t->string; t++) {
+	/* Better not be there */
+	p = (struct node *)rk_tfind((void *)t, (void **)&rootnode,
+				    node_compare);
+	
+	if (p) {
+	    warnx("erroneous list: found %d\n", p->order);
+	    numerr++;
+	}
+	
+	/* Put node into the tree. */
+	p = (struct node *) rk_tsearch((void *)t, (void **)&rootnode,
+				       node_compare);
+	
+	if (!p) {
+	    warnx("erroneous list: missing %d\n", t->order);
+	    numerr++;
+	}
+    }
+    
+    rk_twalk(rootnode, list_node);
+    
+    for(t = tests; t->string; t++) {
+	/* Better be there */
+	p =  (struct node *) rk_tfind((void *)t, (void **)&rootnode,
+				      node_compare);
+	
+	if (!p) {
+	    warnx("erroneous list: missing %d\n", t->order);
+	    numerr++;
+	}
+	
+	/* pull out node */
+	(void) rk_tdelete((void *)t, (void **)&rootnode,
+			  node_compare);
+	
+	/* Better not be there */
+	p =  (struct node *) rk_tfind((void *)t, (void **)&rootnode,
+				      node_compare);
+	
+	if (p) {
+	    warnx("erroneous list: found %d\n", p->order);
+	    numerr++;
+	}
+	
+    }
+    
+    return numerr;
+}