1 files changed, 81 insertions, 0 deletions
diff --git a/Src/Plugins/Visualization/vis_avs/undo.h b/Src/Plugins/Visualization/vis_avs/undo.h
new file mode 100644
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+++ b/Src/Plugins/Visualization/vis_avs/undo.h
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+/*
+  LICENSE
+  -------
+Copyright 2005 Nullsoft, Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification, 
+are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright notice,
+    this list of conditions and the following disclaimer. 
+
+  * Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution. 
+
+  * Neither the name of Nullsoft nor the names of its contributors may be used to 
+    endorse or promote products derived from this software without specific prior written permission. 
+ 
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR 
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 
+FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 
+OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+#ifndef _UNDO_H_
+#define _UNDO_H_
+
+class C_UndoStack;
+
+class C_UndoItem
+{
+  friend C_UndoStack;
+  public:
+    C_UndoItem();
+    ~C_UndoItem();
+    C_UndoItem(const C_UndoItem& T);
+    C_UndoItem(void *data, int length, bool isdirty);
+
+    C_UndoItem & operator = (const C_UndoItem& T);
+    bool operator == (const C_UndoItem& T) const;
+
+    void set(void *data, int length, bool isdirty);
+    void *get() const { return data; }
+    int size() const { return length; }
+
+  private:
+    void *data;
+    int length;
+    bool isdirty;
+};
+
+class C_UndoStack
+{
+  public:
+    static void saveundo(int is2=0);
+    static void cleardirty();
+    static bool isdirty();
+
+    static void undo();
+    static void redo();
+
+    static int can_undo();
+    static int can_redo();
+
+    static void clear();
+
+  private:
+
+    // sorry to do this mig, but that doubly linked lists made me scared. I think it
+    // wasn't actually the source of my bug (I later fixed it), but doubly linked lists
+    // are just plain hard to get right. :)
+    static int list_pos;
+    static C_UndoItem *list[256]; // only keep 256 elements in list at a time
+};
+
+#endif//_UNDO_H_
+\ No newline at end of file