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/**
* \file
* \brief Simple closed interval class
*
* Copyright 2007 Michael Sloan <mgsloan@gmail.com>
*
* Original Rect/Range code by:
* Lauris Kaplinski <lauris@kaplinski.com>
* Nathan Hurst <njh@mail.csse.monash.edu.au>
* bulia byak <buliabyak@users.sf.net>
* MenTaLguY <mental@rydia.net>
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
* License version 2.1 as published by the Free Software Foundation
* (the "LGPL") or, at your option, under the terms of the Mozilla
* Public License Version 1.1 (the "MPL"). If you do not alter this
* notice, a recipient may use your version of this file under either
* the MPL or the LGPL.
*
* You should have received a copy of the LGPL along with this library
* in the file COPYING-LGPL-2.1; if not, output to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
* You should have received a copy of the MPL along with this library
* in the file COPYING-MPL-1.1
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
* OF ANY KIND, either express or implied. See the LGPL or the MPL for
* the specific language governing rights and limitations.
*
*/
#ifndef SEEN_INTERVAL_H
#define SEEN_INTERVAL_H
#include <assert.h>
#include <2geom/coord.h>
#include <boost/optional/optional.hpp>
namespace Geom {
class Interval;
/**
* \brief This class represents a range of numbers that is never empty.
*
* The endpoints are included in the range.
*/
class Interval {
private:
Coord _b[2];
public:
/// The default constructor creates an interval [0,0] DO NOT RELY ON THIS, BEST NOT TO USE THIS CONSTRUCTOR
explicit Interval() { _b[0] = 0; _b[1] = 0; }
explicit Interval(Coord u) { _b[0] = _b[1] = u; }
/* When creating an Interval using the constructor specifying the exact range, the created interval
* will be [u,v] when u<=v ; and will be [v,u] when v < u !!!
*/
Interval(Coord u, Coord v) {
if(u < v) {
_b[0] = u; _b[1] = v;
} else {
_b[0] = v; _b[1] = u;
}
}
double operator[](unsigned i) const {
assert(i < 2);
return _b[i];
}
inline double& operator[](unsigned i) { return _b[i]; } //Trust the user...
inline Coord min() const { return _b[0]; }
inline Coord max() const { return _b[1]; }
inline Coord extent() const { return _b[1] - _b[0]; }
inline Coord middle() const { return (_b[1] + _b[0]) * 0.5; }
// inline bool isEmpty() const { return _b[0] > _b[1]; }
inline bool isSingular() const { return _b[0] == _b[1]; }
inline bool contains(Coord val) const { return _b[0] <= val && val <= _b[1]; }
bool contains(const Interval & val) const { return _b[0] <= val._b[0] && val._b[1] <= _b[1]; }
bool intersects(const Interval & val) const {
return contains(val._b[0]) || contains(val._b[1]) || val.contains(*this);
}
inline bool operator==(Interval other) const { return _b[0] == other._b[0] && _b[1] == other._b[1]; }
inline bool operator!=(Interval other) const { return _b[0] != other._b[0] || _b[1] != other._b[1]; }
//IMPL: OffsetableConcept
//TODO: rename output_type to something else in the concept
typedef Coord output_type;
inline Interval operator+(Coord amnt) {
return Interval(_b[0] + amnt, _b[1] + amnt);
}
inline Interval operator-(Coord amnt) {
return Interval(_b[0] - amnt, _b[1] - amnt);
}
inline Interval operator+=(Coord amnt) {
_b[0] += amnt; _b[1] += amnt;
return *this;
}
inline Interval operator-=(Coord amnt) {
_b[0] -= amnt; _b[1] -= amnt;
return *this;
}
//IMPL: ScalableConcept
inline Interval operator-() const { return Interval(*this); }
inline Interval operator*(Coord s) const { return Interval(_b[0]*s, _b[1]*s); }
inline Interval operator/(Coord s) const { return Interval(_b[0]/s, _b[1]/s); }
Interval operator*=(Coord s) {
if(s < 0) {
Coord temp = _b[0];
_b[0] = _b[1]*s;
_b[1] = temp*s;
} else {
_b[0] *= s;
_b[1] *= s;
}
return *this;
}
Interval operator/=(Coord s) {
//TODO: what about s=0?
if(s < 0) {
Coord temp = _b[0];
_b[0] = _b[1]/s;
_b[1] = temp/s;
} else {
_b[0] /= s;
_b[1] /= s;
}
return *this;
}
//TODO: NaN handleage for the next two?
//TODO: Evaluate if wrap behaviour is proper.
//If val > max, then rather than becoming a min==max range, it 'wraps' over
void setMin(Coord val) {
if(val > _b[1]) {
_b[0] = _b[1];
_b[1] = val;
} else {
_b[0] = val;
}
}
//If val < min, then rather than becoming a min==max range, it 'wraps' over
void setMax(Coord val) {
if(val < _b[0]) {
_b[1] = _b[0];
_b[0] = val;
} else {
_b[1] = val;
}
}
inline void extendTo(Coord val) {
if(val < _b[0]) _b[0] = val;
if(val > _b[1]) _b[1] = val; //no else, as we want to handle NaN
}
static Interval fromArray(const Coord* c, int n) {
assert(n > 0);
Interval result(c[0]);
for(int i = 1; i < n; i++) result.extendTo(c[i]);
return result;
}
/** When this would create an empty interval, the interval will be the centerpoint of the old range only.
*/
inline void expandBy(double amnt) {
_b[0] -= amnt;
_b[1] += amnt;
if (_b[0] > _b[1]) {
Coord halfway = (_b[0]+_b[1])/2;
_b[0] = _b[1] = halfway;
}
}
inline void unionWith(const Interval & a) {
if(a._b[0] < _b[0]) _b[0] = a._b[0];
if(a._b[1] > _b[1]) _b[1] = a._b[1];
}
};
//IMPL: AddableConcept
inline Interval operator+(const Interval & a, const Interval & b) {
return Interval(a.min() + b.min(), a.max() + b.max());
}
inline Interval operator-(const Interval & a, const Interval & b) {
return Interval(a.min() - b.max(), a.max() - b.min());
}
inline Interval operator+=(Interval & a, const Interval & b) { a = a + b; return a; }
inline Interval operator-=(Interval & a, const Interval & b) { a = a - b; return a; }
//There might be impls of this based off sign checks
inline Interval operator*(const Interval & a, const Interval & b) {
Interval res(a.min() * b.min());
res.extendTo(a.min() * b.max());
res.extendTo(a.max() * b.min());
res.extendTo(a.max() * b.max());
return res;
}
inline Interval operator*=(Interval & a, const Interval & b) { a = a * b; return a; }
/* reinstate if useful (doesn't do the proper thing for 0 inclusion)
inline Interval operator/(const Interval & a, const Interval & b) {
Interval res(a.min() / b.min());
res.extendTo(a.min() / b.max());
res.extendTo(a.max() / b.min());
res.extendTo(a.max() / b.max());
return res;
}
inline Interval operator/=(Interval & a, const Interval & b) { a = a / b; return a; }
*/
// 'union' conflicts with C keyword
inline Interval unify(const Interval & a, const Interval & b) {
return Interval(std::min(a.min(), b.min()),
std::max(a.max(), b.max()));
}
/**
* \brief OptInterval is an Interval that can be empty.
*/
class OptInterval : public boost::optional<Interval> {
public:
OptInterval() : boost::optional<Interval>() {};
OptInterval(Interval const &a) : boost::optional<Interval>(a) {};
OptInterval(Coord u) : boost::optional<Interval>(Interval(u)) {};
OptInterval(Coord u, Coord v) : boost::optional<Interval>(Interval(u,v)) {};
/**
* Check whether this OptInterval is empty or not.
*/
inline bool isEmpty() { return (*this == false); };
/**
* If \c this is empty, copy argument \c a. Otherwise, union with it (and do nothing when \c a is empty)
*/
inline void unionWith(const OptInterval & a) {
if (a) {
if (*this) { // check that we are not empty
(*this)->unionWith(*a);
} else {
*this = a;
}
}
}
};
inline OptInterval intersect(const Interval & a, const Interval & b) {
Coord u = std::max(a.min(), b.min()),
v = std::min(a.max(), b.max());
//technically >= might be incorrect, but singulars suck
return u > v ? OptInterval()
: OptInterval(Interval(u, v));
}
#ifdef _GLIBCXX_IOSTREAM
inline std::ostream &operator<< (std::ostream &os,
const Geom::Interval &I) {
os << "Interval("<<I[0] << ", "<<I[1] << ")";
return os;
}
#endif
}
#endif //SEEN_INTERVAL_H
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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