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+/*
+** License Applicability. Except to the extent portions of this file are
+** made subject to an alternative license as permitted in the SGI Free
+** Software License B, Version 1.1 (the "License"), the contents of this
+** file are subject only to the provisions of the License. You may not use
+** this file except in compliance with the License. You may obtain a copy
+** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
+** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
+**
+** http://oss.sgi.com/projects/FreeB
+**
+** Note that, as provided in the License, the Software is distributed on an
+** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
+** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
+** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
+** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
+**
+** Original Code. The Original Code is: OpenGL Sample Implementation,
+** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
+** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
+** Copyright in any portions created by third parties is as indicated
+** elsewhere herein. All Rights Reserved.
+**
+** Additional Notice Provisions: The application programming interfaces
+** established by SGI in conjunction with the Original Code are The
+** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
+** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
+** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
+** Window System(R) (Version 1.3), released October 19, 1998. This software
+** was created using the OpenGL(R) version 1.2.1 Sample Implementation
+** published by SGI, but has not been independently verified as being
+** compliant with the OpenGL(R) version 1.2.1 Specification.
+*/
+
+/*
+ * knotvector.c++
+ *
+ */
+
+#include "glimports.h"
+#include "mystdio.h"
+#include "myassert.h"
+#include "knotvector.h"
+#include "defines.h"
+
+#ifdef __WATCOMC__
+#pragma warning 726 10
+#endif
+
+void Knotvector::init( long _knotcount, long _stride, long _order, INREAL *_knotlist )
+{
+ knotcount = _knotcount;
+ stride = _stride;
+ order = _order;
+ knotlist = new Knot[_knotcount];
+ assert( knotlist != 0 );
+
+ for( int i = 0; i != _knotcount; i++ )
+ knotlist[i] = (Knot) _knotlist[i];
+}
+
+Knotvector::Knotvector( void )
+{
+ knotlist = 0;
+}
+
+Knotvector::~Knotvector( void )
+{
+ if( knotlist ) delete[] knotlist;
+}
+
+int Knotvector::validate( void )
+{
+ /* kindex is used as an array index so subtract one first,
+ * this propagates throughout the code so study carefully */
+ long kindex = knotcount-1;
+
+ if( order < 1 || order > MAXORDER ) {
+ // spline order un-supported
+ return( 1 );
+ }
+
+ if( knotcount < (2 * order) ) {
+ // too few knots
+ return( 2 );
+ }
+
+ if( identical( knotlist[kindex-(order-1)], knotlist[order-1]) ) {
+ // valid knot range is empty
+ return( 3 );
+ }
+
+ for( long i = 0; i < kindex; i++)
+ if( knotlist[i] > knotlist[i+1] ) {
+ // decreasing knot sequence
+ return( 4 );
+ }
+
+ /* check for valid multiplicity */
+
+ /* kindex is currently the index of the last knot.
+ * In the next loop it is decremented to ignore the last knot
+ * and the loop stops when kindex is 2 so as to ignore the first
+ * knot as well. These knots are not used in computing
+ * knot multiplicities.
+ */
+
+ long multi = 1;
+ for( ; kindex >= 1; kindex-- ) {
+ if( knotlist[kindex] - knotlist[kindex-1] < TOLERANCE ) {
+ multi++;
+ continue;
+ }
+ if ( multi > order ) {
+ // knot multiplicity greater than order of spline
+ return( 5 );
+ }
+ multi = 1;
+ }
+
+ if ( multi > order ) {
+ // knot multiplicity greater than order of spline
+ return( 5 );
+ }
+
+ return 0;
+}
+
+void Knotvector::show( const char *msg )
+{
+#ifndef NDEBUG
+ _glu_dprintf( "%s\n", msg );
+ _glu_dprintf( "order = %ld, count = %ld\n", order, knotcount );
+
+ for( int i=0; i<knotcount; i++ )
+ _glu_dprintf( "knot[%d] = %g\n", i, knotlist[i] );
+#endif
+}
+