/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0.If a copy of the MPL was not distributed with this
 * file, You can obtain one at http ://mozilla.org/MPL/2.0/.
 */
#pragma once

#include "ESPReader.h"

typedef struct meta_node MetaNode;

/* Meta Nodes are used for constructing a more flexible tree structure 
 * on top of the natural structure of ESP/ESM files.
 * 
 * Meta Nodes do not create a pure tree structure, rather they have pointers to
 * their parent and first child, and children have pointers backwards and 
 * forward through a linked list of all of the children of the parent node.
 * 
 * There is no root node as such, rather there is a root linked list for which
 * all of the Meta Nodes have no parents.
 * 
 * While the ESP/ESM buffer can be modified in-place, any modification that
 * changes the size of the stored data cannot be directly written to the buffer
 * without first shifting all of the data after the point of modification. 
 * 
 * Modifications that change data size are:
 * - Adding or deleting a group or record
 * - Adding or deleting a field in a record
 * - Changing a variable length field with data of different length
 * 
 * With a Meta Node you can instead allocate new, arbitrarily sized memory for 
 * the node data. The Meta Node tree can then be walked to reconstruct a
 * contiguous view of discontiguous memory.
 */
struct meta_node {
    Node n;
    MetaNode *parent;
    MetaNode *child;
    MetaNode *prev;
    MetaNode *next;
};