/*
* This file is part of rasdaman community.
*
* Rasdaman community 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 3 of the License, or
* (at your option) any later version.
*
* Rasdaman community 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 rasdaman community.  If not, see <http://www.gnu.org/licenses/>.
*
* Copyright 2003, 2004, 2005, 2006, 2007, 2008, 2009 Peter Baumann /
rasdaman GmbH.
*
* For more information please see <http://www.rasdaman.org>
* or contact Peter Baumann via <baumann@rasdaman.com>.
/
/**
 * SOURCE: miter.cc
 *
 * MODULE: raslib
 * CLASS:  r_Miter
 *
*/

#include "raslib/miter.hh"
#include "raslib/minterval.hh"
#include "raslib/rmdebug.hh"

inline
r_Miter::r_Miter( const r_Minterval* newAreaIter, 
		  const r_Minterval* newAreaTile, 
		  r_Bytes newCellSize, const char* newFirstCell ) 
  : areaIter(newAreaIter), areaTile(newAreaTile), cellSize(newCellSize),
    firstCell(newFirstCell), done(false)
{
  RMDBGENTER(1, RMDebug::module_raslib, "r_Miter", "r_Miter()");
  // the following initializes incArrIter and calculates the first offset
  int tIncIter = 1;     // total increment for current dimension
  int prevTIncIter = 1; // total increment for previous dimension
  r_Bytes incIter = cellSize; // current increment
  r_Dimension i;
  int firstOff = 0;

  RMDBGMIDDLE(2, RMDebug::module_raslib, "r_Miter", "area for iteration: " << *newAreaIter);
  RMDBGMIDDLE(2, RMDebug::module_raslib, "r_Miter", "whole area: " << *newAreaTile);

  // dimensionality of both areaIter and areaTile
  r_Dimension dim = areaIter->dimension();
  // stores the increments
  incArrIter = new incArrElem[dim];

  for( i=0; i<dim; i++ ) {
    // in RasDaMan the order of dimensions is the other way round!
    int r = dim - i - 1;
    // used for counting in iteration, initialize with 0
    incArrIter[i].curr = 0;
    // how often is the increment added?
    incArrIter[i].repeat = (*areaIter)[r].high() - (*areaIter)[r].low() + 1;
    RMDBGMIDDLE(4, RMDebug::module_raslib, "r_Miter", "repeat dim " << i << ": " << incArrIter[i].repeat );
    // the increment for the result tile (higher dimensions calculated 
    // further down)
    incArrIter[i].inc = incIter;
    RMDBGMIDDLE(4, RMDebug::module_raslib, "r_Miter", "incIter dim " << i << ": " << incIter );

    // calculate starting offset and increments for higher dimensions
    // firstOff is the offset in chars of the first cell
    firstOff += ((*areaIter)[r].low()-(*areaTile)[r].low()) * prevTIncIter * cellSize;
    // tInc is the increment if the dimension would be skipped
    tIncIter = ((*areaTile)[r].high()-(*areaTile)[r].low()+1) * prevTIncIter;
    // inc is the real increment, after some cells in the dimensions
    // have been iterated through.
    incIter = (tIncIter - incArrIter[i].repeat*prevTIncIter) * cellSize;
    // remember total increment of last dimension
    prevTIncIter = tIncIter;
  }
  firstCell += firstOff;
  reset();
  RMDBGEXIT(1, RMDebug::module_raslib, "r_Miter", "r_Miter()");
}

inline
r_Miter::~r_Miter() 
{
  delete [] incArrIter;
}

inline void
r_Miter::reset()
{
  currCell = (char*)firstCell;
  done = false;
  lowCount = 0;
  for( r_Dimension i=0; i<areaIter->dimension(); i++ ) {
    incArrIter[i].curr = 0;
  }
}

inline char* 
r_Miter::nextCell()
{
  // return the current cell
  char* retVal = currCell;
  r_Dimension i = 0;

  if(done)
    return retVal;
  
  // increment adresses
  currCell += incArrIter[0].inc;
  lowCount++;
  if(lowCount == incArrIter[0].repeat) {
    lowCount = 0;
    // increment other dimensions
    for(i=1; i < areaIter->dimension(); i++) {
      incArrIter[i].curr++;
      currCell += incArrIter[i].inc;
      if(incArrIter[i].curr < incArrIter[i].repeat) {
	// no overflow in this dimension
	break;
      } else {
	// overflow in this dimension
	incArrIter[i].curr = 0;
      }
    }
    if( i == areaIter->dimension() ) {
      // overflow in last dimension
      done = true;
      currCell = retVal;
    }
  }
  return retVal;
}

bool
r_Miter::isDone()
{
  return done;
}