0029769: Uninitialized data with BSplCLib_Cache, BSplSLib_Cache

[occt.git] / src / BSplCLib / BSplCLib_CacheParams.hxx

diff --git a/src/BSplCLib/BSplCLib_CacheParams.hxx b/src/BSplCLib/BSplCLib_CacheParams.hxx
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+++ b/src/BSplCLib/BSplCLib_CacheParams.hxx
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+// Copyright (c) 2018 OPEN CASCADE SAS
+//
+// This file is part of Open CASCADE Technology software library.
+//
+// This library is free software; you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License version 2.1 as published
+// by the Free Software Foundation, with special exception defined in the file
+// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
+// distribution for complete text of the license and disclaimer of any warranty.
+//
+// Alternatively, this file may be used under the terms of Open CASCADE
+// commercial license or contractual agreement.
+
+#ifndef _BSplCLib_CacheParams_Headerfile
+#define _BSplCLib_CacheParams_Headerfile
+
+#include <Standard_Real.hxx>
+#include <TColStd_Array1OfReal.hxx>
+
+#include <BSplCLib.hxx>
+
+//! Simple structure containing parameters describing parameterization
+//! of a B-spline curve or a surface in one direction (U or V),
+//! and data of the current span for its caching
+struct BSplCLib_CacheParams
+{
+  const Standard_Integer Degree;      ///< degree of Bezier/B-spline
+  const Standard_Boolean IsPeriodic;  ///< true of the B-spline is periodic
+  const Standard_Real FirstParameter; ///< first valid parameter
+  const Standard_Real LastParameter;  ///< last valid parameter
+
+  const Standard_Integer SpanIndexMin; ///< minimal index of span
+  const Standard_Integer SpanIndexMax; ///< maximal index of span
+
+  Standard_Real    SpanStart;    ///< parameter for the frst point of the span
+  Standard_Real    SpanLength;   ///< length of the span
+  Standard_Integer SpanIndex;    ///< index of the span
+
+  //! Constructor, prepares data structures for caching.
+  //! \param theDegree     degree of the B-spline (or Bezier)
+  //! \param thePeriodic   identify whether the B-spline is periodic
+  //! \param theFlatKnots  knots of Bezier / B-spline parameterization
+  BSplCLib_CacheParams (Standard_Integer theDegree, Standard_Boolean thePeriodic,
+                        const TColStd_Array1OfReal& theFlatKnots)
+  : Degree(theDegree),
+    IsPeriodic(thePeriodic),
+    FirstParameter(theFlatKnots.Value(theFlatKnots.Lower() + theDegree)),
+    LastParameter(theFlatKnots.Value(theFlatKnots.Upper() - theDegree)),
+    SpanIndexMin(theFlatKnots.Lower() + theDegree),
+    SpanIndexMax(theFlatKnots.Upper() - theDegree - 1),
+    SpanStart(0.),
+    SpanLength(0.),
+    SpanIndex(0)
+  {}
+
+  //! Normalizes the parameter for periodic B-splines
+  //! \param theParameter the value to be normalized into the knots array
+  Standard_Real PeriodicNormalization (Standard_Real theParameter) const
+  {
+    if (IsPeriodic)
+    {
+      if (theParameter < FirstParameter)
+      {
+        Standard_Real aPeriod = LastParameter - FirstParameter;
+        Standard_Real aScale = IntegerPart ((FirstParameter - theParameter) / aPeriod);
+        return theParameter + aPeriod * (aScale + 1.0);
+      }
+      if (theParameter > LastParameter)
+      {
+        Standard_Real aPeriod = LastParameter - FirstParameter;
+        Standard_Real aScale = IntegerPart ((theParameter - LastParameter) / aPeriod);
+        return theParameter - aPeriod * (aScale + 1.0);
+      }
+    }
+    return theParameter;
+  }
+
+  //! Verifies validity of the cache using flat parameter of the point
+  //! \param theParameter parameter of the point placed in the span
+  Standard_Boolean IsCacheValid (Standard_Real theParameter) const
+  {
+    Standard_Real aNewParam = PeriodicNormalization  (theParameter);
+    Standard_Real aDelta = aNewParam - SpanStart;
+    return ((aDelta >= 0.0 || SpanIndex == SpanIndexMin) &&
+            (aDelta < SpanLength || SpanIndex == SpanIndexMax));
+  }
+
+  //! Computes span for the specified parameter
+  //! \param theParameter parameter of the point placed in the span
+  //! \param theFlatKnots  knots of Bezier / B-spline parameterization
+  void LocateParameter (Standard_Real& theParameter, const TColStd_Array1OfReal& theFlatKnots)
+  {
+    SpanIndex = 0;
+    BSplCLib::LocateParameter (Degree, theFlatKnots, BSplCLib::NoMults(), 
+                               theParameter, IsPeriodic, SpanIndex, theParameter);
+    SpanStart  = theFlatKnots.Value(SpanIndex);
+    SpanLength = theFlatKnots.Value(SpanIndex + 1) - SpanStart;
+  }
+
+private:
+  // copying is prohibited
+  BSplCLib_CacheParams (const BSplCLib_CacheParams&);
+  void operator = (const BSplCLib_CacheParams&);
+};
+
+#endif