tree: Adding N-tree module.

src/tree.c

@@ -0,0 +1,119 @@
+/* tree.c - N-tree implementation
+ *
+ *   Copyright (C) 2011   Henrik Hautakoski <henrik@fiktivkod.org>
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Generic implementation of a N-tree
+ */
+
+#include "xalloc.h"
+#include "tree.h"
+
+struct tree* tree_new() {
+
+    return xmallocz(sizeof(struct tree));
+}
+
+struct tree* tree_link(struct tree *parent, struct tree *tree) {
+
+    if (parent->child) {
+        struct tree *it = parent->child;
+        while(it->next)
+            it = it->next;
+        it->next = tree;
+    } else {
+        parent->child = tree;
+    }
+    tree->parent = parent;
+    return tree;
+}
+
+void tree_unlink(struct tree *tree) {
+
+    if (tree_is_root(tree))
+        return;
+
+    /* remove the node from the tree */
+    if (tree->parent->child == tree) {
+        tree->parent->child = tree->next;
+    } else {
+        struct tree *prev = tree->parent->child;
+        while(prev->next && prev->next != tree)
+            prev = prev->next;
+        prev->next = tree->next;
+    }
+
+    /* move the children to node's old parent */
+    if (tree->child) {
+        struct tree *it = tree->parent->child;
+        if (tree->parent->child) {
+            while(it->next)
+                it = it->next;
+            it->next = tree->child;
+        } else {
+            tree->parent->child = tree->child;
+        }
+
+        /* Update parent */
+        for(it = tree->child; it; it = it->next)
+            it->parent = tree->parent;
+    }
+
+    tree->parent = NULL;
+    tree->next = NULL;
+    tree->child = NULL;
+}
+
+void tree_move(struct tree *dest, struct tree *src) {
+
+    if (src->parent == dest)
+        /* node are already in place */
+        return;
+
+    /* detach and attach att the new node */
+    tree_detach(src);
+    tree_link(dest, src);
+}
+
+void tree_detach(struct tree *tree) {
+
+    if (tree_is_root(tree))
+        return;
+
+    if (tree->parent->child == tree) {
+        tree->parent->child = tree->next;
+    } else if (tree->parent->child) {
+        struct tree *prev = tree->parent->child;
+        while(prev->next && prev->next != tree)
+            prev = prev->next;
+        prev->next = tree->next;
+    }
+    tree->parent = NULL;
+    tree->next = NULL;
+}
+
+void tree_traverse(struct tree *tree, tree_traverse_fn fn, void *data) {
+
+    while(tree) {
+        struct tree *next = tree->next;
+        fn(tree, data);
+        if (tree->child)
+            tree_traverse(tree->child, fn, data);
+        tree = next;
+    }
+}
+
+size_t tree_parent_count(struct tree *tree) {
+
+    size_t count = 0;
+    
+    if (tree) {
+        for(; tree->parent; count++)
+            tree = tree->parent;
+    }
+    return count;
+}

src/tree.h

@@ -0,0 +1,48 @@
+/* tree.c - N-tree implementation
+ *
+ *   Copyright (C) 2011   Henrik Hautakoski <henrik@fiktivkod.org>
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ */
+ 
+#ifndef __TREE_H
+#define __TREE_H
+
+#include <stddef.h>
+
+struct tree {
+    struct tree *next;
+    struct tree *parent;
+    struct tree *child;
+};
+
+typedef void (*tree_traverse_fn)(struct tree *tree, void *data);
+
+#define tree_is_root(n)      \
+    ((n) &&                  \
+     (n)->parent == NULL &&  \
+     (n)->next == NULL)
+
+#define tree_is_leaf(n) \
+    ((n) && (n)->child == NULL)
+
+#define TREE_INIT { NULL }
+
+struct tree* tree_new();
+
+struct tree* tree_link(struct tree *parent, struct tree *tree);
+
+void tree_unlink(struct tree *tree);
+
+void tree_move(struct tree *dest, struct tree *src); 
+
+void tree_detach(struct tree *tree);
+
+void tree_traverse(struct tree *tree, tree_traverse_fn fn, void *data);
+
+size_t tree_parent_count(struct tree *tree);
+
+#endif /* __TREE_H */