/***********************************************************************
 * Software License Agreement (BSD License)
 *
 * Copyright 2008-2009  Marius Muja (mariusm@cs.ubc.ca). All rights reserved.
 * Copyright 2008-2009  David G. Lowe (lowe@cs.ubc.ca). All rights reserved.
 *
 * THE BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *************************************************************************/

#ifndef DATASET_H
#define DATASET_H

#include <stdio.h>
#include <random.h>


namespace cvflann
{
/**
* Class implementing a generic rectangular dataset.
*/
template <typename T>
class Matrix {

    /**
    * Flag showing if the class owns its data storage.
    */
    bool ownData;

    void shallow_copy(const Matrix& rhs)
    {
        data = rhs.data;
        rows = rhs.rows;
        cols = rhs.cols;
        ownData = false;
    }

public:
    long rows;
    long cols;
    T* data;


    Matrix(long rows_, long cols_, T* data_ = NULL) :
    	 ownData(false), rows(rows_), cols(cols_), data(data_)
	{
        if (data_==NULL) {
		    data = new T[rows*cols];
            ownData = true;
        }
	}

    Matrix(const Matrix& d)
    {
        shallow_copy(d);
    }

    const Matrix& operator=(const Matrix& rhs)
    {
        if (this!=&rhs) {
            shallow_copy(rhs);
        }
        return *this;
    }

	~Matrix()
	{
        if (ownData) {
		  delete[] data;
        }
	}

    /**
    * Operator that return a (pointer to a) row of the data.
    */
    T* operator[](long index)
    {
        return data+index*cols;
    }

    T* operator[](long index) const
    {
        return data+index*cols;
    }



    Matrix<T>* sample(long size, bool remove = false)
    {
        UniqueRandom rand(rows);
        Matrix<T> *newSet = new Matrix<T>(size,cols);

        T *src,*dest;
        for (long i=0;i<size;++i) {
            long r = rand.next();
            dest = (*newSet)[i];
            src = (*this)[r];
            for (long j=0;j<cols;++j) {
                dest[j] = src[j];
            }
            if (remove) {
                dest = (*this)[rows-i-1];
                src = (*this)[r];
                for (long j=0;j<cols;++j) {
                    swap(*src,*dest);
                    src++;
                    dest++;
                }
            }
        }

        if (remove) {
            rows -= size;
        }

        return newSet;
    }

    Matrix<T>* sample(long size) const
    {
        UniqueRandom rand(rows);
        Matrix<T> *newSet = new Matrix<T>(size,cols);

        T *src,*dest;
        for (long i=0;i<size;++i) {
            long r = rand.next();
            dest = (*newSet)[i];
            src = (*this)[r];
            for (long j=0;j<cols;++j) {
                dest[j] = src[j];
            }
        }

        return newSet;
    }

};


}

#endif //DATASET_H