PartioIterator.h

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/*
PARTIO SOFTWARE
Copyright 2010 Disney Enterprises, Inc. All rights reserved
 
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modification, are permitted provided that the following conditions are
met:
 
* Redistributions of source code must retain the above copyright
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* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
 
* The names "Disney", "Walt Disney Pictures", "Walt Disney Animation
Studios" or the names of its contributors may NOT be used to
endorse or promote products derived from this software without
specific prior written permission from Walt Disney Pictures.
 
Disclaimer: THIS SOFTWARE IS PROVIDED BY WALT DISNEY PICTURES AND
CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
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*/
#ifndef _PartioParticleIterator_h_
#define _PartioParticleIterator_h_
 
#include <cassert>
#include <vector>
#include <iostream>
#include "PartioAttribute.h"
 
namespace Partio{
 
class  ParticlesData;
struct ParticleAccessor;
 
 
template<class T,int d>
struct Data
{
    T x[d];
 
    const T& operator[](const int i) const {return x[i];}
    T& operator[](const int i) {return x[i];}
};
typedef Data<int,1> DataI;
typedef Data<float,1> DataF;
typedef Data<float,3> DataV;
 
 
template<bool constant> class ParticleIterator;
 
struct Provider
{
    virtual void setupIteratorNextBlock(ParticleIterator<true>& iterator) const=0;
    virtual void setupIteratorNextBlock(ParticleIterator<false>& iterator)=0;
    virtual void setupAccessor(ParticleIterator<true>& iterator,ParticleAccessor& accessor) const=0;
    virtual void setupAccessor(ParticleIterator<false>& iterator,ParticleAccessor& accessor)=0;
    virtual ~Provider(){}
};
 
template<bool constant>
struct PROVIDER
{
    typedef Provider TYPE;
};
template<>
struct PROVIDER<true>
{
    typedef const Provider TYPE;
};
 
// TODO: non copyable
struct ParticleAccessor
{
    int stride;
    char* basePointer;
    int attributeIndex; // index of attribute opaque, do not touch
    int count;
private:
    ParticleAttributeType type;
    
    ParticleAccessor* next;
 
public:
    ParticleAccessor(const ParticleAttribute& attr)
        :stride(0),basePointer(0),attributeIndex(attr.attributeIndex),
        count(attr.count),type(attr.type),next(0)
    {}
 
    template<class TDATA,class TITERATOR> TDATA* raw(const TITERATOR& it)
    {return reinterpret_cast<TDATA*>(basePointer+it.index*stride);}
 
    template<class TDATA,class TITERATOR> const TDATA* raw(const TITERATOR& it) const
    {return reinterpret_cast<const TDATA*>(basePointer+it.index*stride);}
 
    template<class TDATA,class TITERATOR> TDATA& data(const TITERATOR& it)
    {return *reinterpret_cast<TDATA*>(basePointer+it.index*stride);}
 
    template<class TDATA,class TITERATOR> const TDATA& data(const TITERATOR& it) const
    {return *reinterpret_cast<const TDATA*>(basePointer+it.index*stride);}
 
    friend class ParticleIterator<true>;
    friend class ParticleIterator<false>;
};
 
 
template<bool constant=false>
class ParticleIterator
{
public:
private:
    typedef typename PROVIDER<constant>::TYPE PROVIDER;
 
    PROVIDER* particles;
 
public:
    size_t index;
private:
 
    size_t indexEnd;
 
    ParticleAccessor* accessors;
 
public:
    ParticleIterator()
        :particles(0),index(0),indexEnd(0),accessors(0)
    {}
 
    ParticleIterator(const ParticleIterator& other)
                :particles(other.particles),index(other.index),indexEnd(other.indexEnd),accessors(0)
    {}
 
    ParticleIterator(PROVIDER* particles,size_t index,size_t indexEnd)
        :particles(particles),index(index),indexEnd(indexEnd)
    {}
 
    bool valid() const
    {return particles;}
 
    ParticleIterator operator++(int)
    {
        ParticleIterator newIt(*this);
        index++;
        return newIt;
    }
 
    ParticleIterator& operator++()
    {
        index++;
        // TODO: make particles==0 check unnecessary by using indexEnd=0 to signify invalid iterator
        if((index>indexEnd) && particles) particles->setupIteratorNextBlock(*this);
        return *this;
    }
 
    bool operator==(const ParticleIterator& other)
    {
        // TODO: this is really really expensive
        // TODO: this needs a block or somethingt o say which segment it is
        return particles==other.particles && index==other.index;
    }
     
    bool operator!=(const ParticleIterator& other)
    {
        if(other.particles!=particles) return true; // if not same delegate
        else if(particles==0) return false; // if both are invalid iterators
        else return !(*this==other);
    }
    
    void addAccessor(ParticleAccessor& newAccessor)
    {
        newAccessor.next=accessors;
        accessors=&newAccessor;
        if(particles) particles->setupAccessor(*this,newAccessor);
    }
 
 
    // TODO: add copy constructor that wipes out accessor linked list
 
};
 
template<class T,int d>
std::ostream& operator<<(std::ostream& output,const Data<T,d>& v)
{
    output<<v[0];
    for(int i=1;i<d;i++) output<< " " << v[i];
    return output;
}
 
 
}
 
#endif