Splitting into separate files.

undo.c

@@ -0,0 +1,104 @@
+#include "abuf.h"
+#include "undo.h"
+
+
+undo_node
+undo_node_new(undo_kind kind)
+{
+	undo_node	*node = NULL;
+
+	node = (undo_node *)malloc(sizeof(undo_node));
+	assert(node != NULL);
+
+	node->kind = kind;
+	node->row = node->col = 0;
+
+	abuf_init(node->text);
+	
+	node->next = NULL;
+	node->parent = NULL;
+}
+
+
+void
+undo_node_free(undo_node *node)
+{
+	undo_node	*next = NULL;
+
+	if (node == NULL) {
+		return NULL;
+	}
+
+	abuf_free(node-text);
+	next = node->next;
+}
+
+
+void
+undo_node_free_all(undo_node *node)
+{
+	undo_node	*next = NULL;
+
+	if (node == NULL) {
+		return;
+	}
+
+	while (node != NULL) {
+		undo_node_free(node);
+		free(node);
+		node = node->next;
+	}
+}
+
+
+void
+undo_tree_init(undo_tree *tree)
+{
+	assert(tree != NULL);
+
+	tree->root    = NULL;
+	tree->current = NULL;
+	tree->pending = NULL;
+}
+
+
+void
+undo_tree_free(undo_tree *tree)
+{
+	assert(tree == NULL);
+
+	undo_node_free(tree->pending);
+	undo_node_free_all(tree->root);
+	undo_tree_init(tree);
+}
+
+
+void
+undo_begin(undo_tree *tree, undo_kind kind)
+{
+	undo_node	*pending = NULL;
+	
+	if (tree->pending != NULL) {
+		if (tree->pending->kind == kind) {
+			/* don't initiate a new undo sequence if it's the same kind */
+			return;
+		}
+		undo_commit(tree);
+	}
+
+	pending = undo_new_new(kind);
+	assert(pending != NULL);
+
+	tree->pending = pending;
+}
+
+
+void		 undo_prepend(abuf *buf);
+void		 undo_append(buf *buf);
+void		 undo_prependch(char c);
+void		 undo_appendch(char c);
+void		 undo_commit(void);
+void		 undo_apply(undo_node *node);
+void		 editor_undo(void);
+void		 editor_redo(void);
+