lib: Add B-tree implementation

Adds an implementation of B-trees of order k (k children, min fill is
k/2, max fill k - 1). Useful to implement indexes for faster lookups.

1 files changed, 80 insertions, 0 deletions

diff --git a/src/lib/tests/btree_test.c b/src/lib/tests/btree_test.c
new file mode 100644
index 00000000..257a7e37
--- /dev/null
+++ b/src/lib/tests/btree_test.c
@@ -0,0 +1,80 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * Test of the B-tree implementation
+ *
+ *    Dimitri Staessens <dimitri.staessens@intec.ugent.be>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+
+#include "btree.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX_BTREE_KEY 10000
+
+int btree_test(int     argc,
+               char ** argv)
+{
+        struct btree * tree;
+
+        int i;
+
+        (void) argc;
+        (void) argv;
+
+        tree = btree_create(32);
+        if (tree == NULL)
+                return -1;
+
+        if (btree_search(tree, 8) != NULL) {
+                btree_destroy(tree);
+                return -1;
+        }
+
+        for(i = 0; i < MAX_BTREE_KEY; ++i)
+                if (btree_insert(tree, i, &argv)) {
+                        printf("Failed to add element.\n");
+                        btree_destroy(tree);
+                        return -1;
+                }
+
+        for (i = 0; i < MAX_BTREE_KEY / 10; ++i)
+                if (btree_search(tree, rand() % MAX_BTREE_KEY) != &argv) {
+                        printf("Added element not in tree.\n");
+                        btree_destroy(tree);
+                        return -1;
+                }
+
+        for (i = 0; i < MAX_BTREE_KEY / 10; ++i)
+                if (btree_remove(tree, i)) {
+                        printf("Failed to remove element.\n");
+                        btree_destroy(tree);
+                        return -1;
+                }
+
+        for (i = 0; i < MAX_BTREE_KEY / 10; ++i)
+                if (btree_search(tree, rand() % MAX_BTREE_KEY / 10) != &argv) {
+                        printf("Removed element found in tree.\n");
+                        btree_destroy(tree);
+                        return -1;
+                }
+
+        btree_destroy(tree);
+
+        return 0;
+}