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1 | // Copyright (c) 2014 OPEN CASCADE SAS |
2 | // |
3 | // This file is part of Open CASCADE Technology software library. |
4 | // |
5 | // This library is free software; you can redistribute it and/or modify it under |
6 | // the terms of the GNU Lesser General Public License version 2.1 as published |
7 | // by the Free Software Foundation, with special exception defined in the file |
8 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
9 | // distribution for complete text of the license and disclaimer of any warranty. |
10 | // |
11 | // Alternatively, this file may be used under the terms of Open CASCADE |
12 | // commercial license or contractual agreement. |
13 | |
14 | #ifndef _Graphic3d_BufferRange_HeaderFile |
15 | #define _Graphic3d_BufferRange_HeaderFile |
16 | |
17 | #include <Graphic3d_Vec.hxx> |
18 | #include <Standard_Integer.hxx> |
19 | |
20 | //! Range of values defined as Start + Length pair. |
21 | struct Graphic3d_BufferRange |
22 | { |
23 | Standard_Integer Start; //!< first element within the range |
24 | Standard_Integer Length; //!< number of elements within the range |
25 | |
26 | //! Empty constructor. |
27 | Graphic3d_BufferRange() : Start (0), Length (0) {} |
28 | |
29 | //! Constructor. |
30 | Graphic3d_BufferRange (Standard_Integer theStart, Standard_Integer theLength) : Start (theStart), Length (theLength) {} |
31 | |
32 | //! Return TRUE if range is empty. |
33 | Standard_Boolean IsEmpty() const { return Length == 0; } |
34 | |
35 | //! Return the Upper element within the range |
36 | Standard_Integer Upper() const { return Start + Length - 1; } |
37 | |
38 | //! Clear the range. |
39 | void Clear() |
40 | { |
41 | Start = 0; |
42 | Length = 0; |
43 | } |
44 | |
45 | //! Add another range to this one. |
46 | void Unite (const Graphic3d_BufferRange& theRange) |
47 | { |
48 | if (IsEmpty()) |
49 | { |
50 | *this = theRange; |
51 | return; |
52 | } |
53 | else if (theRange.IsEmpty()) |
54 | { |
55 | return; |
56 | } |
57 | |
58 | const Standard_Integer aStart = Min (Start, theRange.Start); |
59 | const Standard_Integer aLast = Max (Upper(), theRange.Upper()); |
60 | Start = aStart; |
61 | Length = aLast - aStart + 1; |
62 | } |
63 | }; |
64 | |
65 | #endif // _Graphic3d_BufferRange_HeaderFile |