VecIterator.h

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/****************************************************************/
/* Parallel Combinatorial BLAS Library (for Graph Computations) */
/* version 1.6 -------------------------------------------------*/
/* date: 6/15/2017 ---------------------------------------------*/
/* authors: Ariful Azad, Aydin Buluc  --------------------------*/
/****************************************************************/
/*
 Copyright (c) 2010-2017, The Regents of the University of California
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 */


#ifndef VEC_ITERATOR_H
#define VEC_ITERATOR_H

#include "FullyDistVec.h"
#include "FullyDistSpVec.h"

namespace combblas {

template <class IT, class NT>
class VectorLocalIterator
{
    public:
    virtual ~VectorLocalIterator() {}
    
    virtual IT LocalToGlobal(IT loc_idx) const = 0;
    virtual IT GlobalToLocal(IT gbl_idx) const = 0;
    
    virtual bool Next() = 0;
    virtual bool NextTo(IT loc_idx) = 0;
    virtual bool HasNext() = 0;
    virtual IT GetLocIndex() const = 0;
    virtual NT& GetValue() const = 0;

    virtual void Del() = 0;
    
    virtual void Set(const IT loc_idx, const NT& val) = 0;
};

template <class IT, class NT>
class DenseVectorLocalIterator: public VectorLocalIterator<IT, NT>
{
    protected:
    FullyDistVec<IT, NT>& v;
    IT iter_idx;
    
    public:
    DenseVectorLocalIterator(FullyDistVec<IT, NT>& in_v): v(in_v), iter_idx(0) {}
    
    IT LocalToGlobal(IT loc_idx) const
    {
        return v.LengthUntil() + loc_idx;
    }
    
    IT GlobalToLocal(IT gbl_idx) const
    {
        IT ret;
        v.Owner(gbl_idx, ret);
        return ret;
    }
    
    
    bool Next()
    {
        iter_idx++;
        bool exists = ((unsigned)iter_idx < v.arr.size());
        if (!exists)
            iter_idx = -1;
        return exists;
    }

    bool NextTo(IT loc_idx)
    {
        iter_idx = loc_idx;
        return iter_idx > 0 && (unsigned)iter_idx < v.arr.size();
    }

    bool HasNext()
    {
        return iter_idx >= 0 && (unsigned)iter_idx < v.arr.size();
    }
    
    IT GetLocIndex() const
    {
        if ((unsigned)iter_idx < v.arr.size())
            return iter_idx;
        else
            return -1;
    }
    
    NT& GetValue() const
    {
        return v.arr[iter_idx];
    }

    void Del()
    {
        assert(false);
    }
    
    void Set(const IT loc_idx, const NT& val)
    {
        v.arr[loc_idx] = val;
    }
};

template <class IT, class NT>
class SparseVectorLocalIterator: public VectorLocalIterator<IT, NT>
{
    protected:
    FullyDistSpVec<IT, NT>& v;
    IT iter_idx;
    
    public:
    SparseVectorLocalIterator(FullyDistSpVec<IT, NT>& in_v): v(in_v), iter_idx(0)
    {
        if (v.ind.size() == 0)
            iter_idx = -1;
    }
    
    IT LocalToGlobal(IT loc_idx) const
    {
        return v.LengthUntil() + loc_idx;
    }
    
    IT GlobalToLocal(IT gbl_idx) const
    {
        IT ret;
        v.Owner(gbl_idx, ret);
        return ret;
    }
    
    bool Next()
    {
        iter_idx++;
        bool exists = ((unsigned)iter_idx < v.ind.size());
        if (!exists)
            iter_idx = -1;
        return exists;
    }

    bool NextTo(IT loc_idx)
    {
        typename std::vector<IT>::iterator iter = std::lower_bound(v.ind.begin()+iter_idx, v.ind.end(), loc_idx);   
        if(iter == v.ind.end()) // beyond limits, insert from back
        {
            iter_idx = -1;
            return false;
        }
        else if (loc_idx < *iter)   // not found, but almost
        {
            iter_idx = iter - v.ind.begin();
            return false;
        }
        else // found
        {
            iter_idx = iter - v.ind.begin();
            return true;
        }
    }
    
    bool HasNext()
    {
        return iter_idx >= 0 && (unsigned)iter_idx < v.ind.size();
    }
    
    IT GetLocIndex() const
    {
        if (iter_idx < 0)
            return -1;
        else
            return v.ind[iter_idx];
    }
    
    NT& GetValue() const
    {
        return v.num[iter_idx];
    }

    void Del()
    {
        v.ind.erase(v.ind.begin()+iter_idx);
        v.num.erase(v.num.begin()+iter_idx);
        if ((unsigned)iter_idx >= v.ind.size())
            iter_idx = -1;
    }
    
    void Set(const IT loc_idx, const NT& val)
    {
        // see if we're just replacing the current value
        /*if (loc_idx >= 0 && loc_idx == v.ind[iter_idx])
        {
            v.num[iter_idx] = val;
            return;
        }*/
        
        // inserted elsewhere
        // This is from FullyDistSpVec::SetElement():
        typename std::vector<IT>::iterator iter = std::lower_bound(v.ind.begin(), v.ind.end(), loc_idx);    
        if(iter == v.ind.end()) // beyond limits, insert from back
        {
            v.ind.push_back(loc_idx);
            v.num.push_back(val);
        }
        else if (loc_idx < *iter)   // not found, insert in the middle
        {
            // the order of insertions is crucial
            // if we first insert to ind, then ind.begin() is invalidated !
            v.num.insert(v.num.begin() + (iter-v.ind.begin()), val);
            v.ind.insert(iter, loc_idx);
        }
        else // found
        {
            *(v.num.begin() + (iter-v.ind.begin())) = val;
        }
    }
    
    void Append(const IT loc_idx, const NT& val)
    {
        v.ind.push_back(loc_idx);
        v.num.push_back(val);
    }
};

#include "VecIterator.cpp"

}

#endif