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authorNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
committerNorbert Preining <norbert@preining.info>2019-09-02 13:46:59 +0900
commite0c6872cf40896c7be36b11dcc744620f10adf1d (patch)
tree60335e10d2f4354b0674ec22d7b53f0f8abee672 /graphics/epix/interval.cc
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+/*
+ * interval.cc -- ePiX::interval class functions
+ *
+ * This file is part of ePiX, a C++ library for creating high-quality
+ * figures in LaTeX
+ *
+ * Version 1.2.0-2
+ * Last Change: September 26, 2007
+ *
+ *
+ * Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
+ * Andrew D. Hwang <rot 13 nujnat at zngupf dot ubylpebff dot rqh>
+ * Department of Mathematics and Computer Science
+ * College of the Holy Cross
+ * Worcester, MA, 01610-2395, USA
+ *
+ *
+ * ePiX is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * ePiX is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with ePiX; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+#include <cstdlib>
+#include <string>
+
+#include "functions.h"
+#include "interval.h"
+
+namespace ePiX {
+
+ // expect arg of the form (a,b), [a,b), (a,b], or [a,b]
+ interval::interval(std::string arg)
+ : m_closed_l(true), m_closed_r(true)
+ {
+ std::string::size_type i(arg.find_first_of("[("));
+
+ if (i == std::string::npos) // return "empty interval"
+ {
+ m_rmin=1;
+ m_rmax=0;
+ return;
+ }
+
+ // else
+ arg.erase(0, i);
+
+ if (arg.at(0) == '(')
+ m_closed_l = false;
+
+ // expect numerical argument
+ i = arg.find_first_of("-0123456789.");
+ if (i == std::string::npos)
+ {
+ m_rmin=1;
+ m_rmax=0;
+ return;
+ }
+
+ arg.erase(0, i);
+
+ // get left endpoint
+ const char* tmp1(arg.c_str());
+ char* new_arg;
+ m_rmin = strtod(tmp1, &new_arg);
+ arg=new_arg;
+
+ i = arg.find_first_of(",");
+ if (i == std::string::npos)
+ {
+ m_rmax=0;
+ m_rmin=1;
+ return;
+ }
+
+ arg.erase(0, i);
+
+ // expect another numerical argument
+ i = arg.find_first_of("-0123456789.");
+ if (i == std::string::npos)
+ {
+ m_rmax=0;
+ m_rmin=1;
+ return;
+ }
+
+ arg.erase(0, i);
+
+ const char* tmp2(arg.c_str());
+ m_rmax = strtod(tmp2, &new_arg);
+ arg=new_arg;
+
+ i = arg.find_first_of(")]");
+
+ if (i == std::string::npos)
+ {
+ m_rmax=0;
+ m_rmin=1;
+ return;
+ }
+
+ if (arg.at(0) == ')')
+ m_closed_r = false;
+ } // end of interval(std::string)
+
+
+ interval::interval(double a, double b)
+ : m_rmin(ePiX::min(a, b)), m_rmax(ePiX::max(a, b)),
+ m_closed_l(true), m_closed_r(true) { }
+
+ interval interval::literal(double a, double b)
+ {
+ interval value(a, a);
+ value.m_rmax = b;
+ return value;
+ }
+
+ interval interval::emptyset(literal(1,0));
+
+ double interval::min() const
+ {
+ return m_rmin;
+ }
+
+ double interval::max() const
+ {
+ return m_rmax;
+ }
+
+ double interval::avg() const
+ {
+ return 0.5*(m_rmin + m_rmax);
+ }
+
+
+ // Magic number
+ const double EPS(1.0e-10);
+
+ bool interval::contains(double x) const
+ {
+ // check bounds at each endpoint
+ return ( (m_closed_l ? (m_rmin - EPS <= x) : (m_rmin + EPS < x))
+ && (m_closed_r ? (x <= m_rmax + EPS) : (x < m_rmax - EPS)) );
+ }
+
+ // Minkowski sum
+ interval& interval::operator +=(const interval& I)
+ {
+ if (is_empty())
+ ;
+
+ else if (I.is_empty())
+ *this = interval::emptyset;
+
+ else
+ {
+ m_rmin += I.m_rmin;
+ m_rmax += I.m_rmax;
+
+ // sum contains endpoint iff both arguments do
+ m_closed_l &= I.m_closed_l;
+ m_closed_r &= I.m_closed_r;
+ }
+
+ return *this;
+ }
+
+ // intersection
+ interval& interval::operator *=(const interval& I)
+ {
+ if (!is_empty())
+ {
+ m_rmin = ePiX::max(m_rmin, I.m_rmin);
+ m_rmax = ePiX::min(m_rmax, I.m_rmax);
+
+ m_closed_l &= I.m_closed_l;
+ m_closed_r &= I.m_closed_r;
+ }
+
+ return *this;
+ }
+
+ bool interval::operator== (const interval& I) const
+ {
+ if (is_empty())
+ return (I.is_empty()); // both empty?
+
+ else
+ return ((m_rmin == I.m_rmin) && (m_rmax == I.m_rmax)
+ && (m_closed_l == I.m_closed_l) && (m_closed_r == I.m_closed_r));
+ }
+
+ bool interval::operator!= (const interval& I) const
+ {
+ return !(*this == I);
+ }
+
+ bool interval::is_empty() const
+ {
+ if ( (m_rmin < m_rmax)
+ || ( (m_rmin == m_rmax) && m_closed_l && m_closed_r ) )
+ return false;
+
+ else
+ return true;
+ }
+
+ // non-members
+ interval operator+ (interval I1, const interval& I2)
+ {
+ return I1 += I2;
+ }
+
+ interval operator* (interval I1, const interval& I2)
+ {
+ return I1 *= I2;
+ }
+
+} // end of namespace