source: rtems/c/src/lib/libbsp/arm/nds/tools/ndstool/include/ndstree.h @ adada0d

inline int cmp(const char *a, bool a_isdir, const char *b, bool b_isdir)
{
        // oh... directory sort doesn't matter since we write out dir- and filenames seperately
        //if (a_isdir && !b_isdir) return -1;
        //if (b_isdir && !a_isdir) return +1;
        return strcmp(a, b);
}

struct TreeNode
{
        unsigned int dir_id;            // directory ID in case of directory entry
        const char *name;               // file or directory name
        TreeNode *directory;            // nonzero indicates directory. first directory node is a dummy
        TreeNode *prev, *next;          // linked list

        TreeNode()
        {
                dir_id = 0;
                name = "";
                directory = 0;
                prev = next = 0;
        }
        
        // new entry in same directory
        TreeNode *New(const char *name, bool isdir)
        {
                TreeNode *newNode = new TreeNode();
                newNode->name = strdup(name);

                TreeNode *node = this;

                if (cmp(name, isdir, node->name, node->dir_id) < 0)     // prev
                {
                        while (cmp(name, isdir, node->name, node->dir_id) < 0)
                        {
                                if (node->prev)
                                        node = node->prev;
                                else
                                        break;          // insert after dummy node
                        }
                }
                else
                {
                        while (node->next && (cmp(name, isdir, node->next->name, node->next->dir_id) >= 0))
                        {
                                node = node->next;
                        }
                }

                // insert after current node
                newNode->prev = node;
                newNode->next = node->next;
                if (node->next) node->next->prev = newNode;
                node->next = newNode;

                return newNode;
        }
};

TreeNode *ReadDirectory(TreeNode *node, char *path);