/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Guido Tack <tack@gecode.org>
 *
 *  Contributing authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2013
 *     Guido Tack, 2013
 *
 *  Last modified:
 *     $Date: 2013-10-30 13:25:29 +0100 (Wed, 30 Oct 2013) $ by $Author: schulte $
 *     $Revision: 14036 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  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.
 *
 */

#include <gecode/search.hh>

namespace Gecode { namespace Search {

  forceinline
  CutoffConstant::CutoffConstant(unsigned long int c0) 
    : c(c0) {}
  unsigned long int 
  CutoffConstant::operator ()(void) {
    return c;
  }
  
  
  forceinline
  CutoffLinear::CutoffLinear(unsigned long int s) 
    : scale(s), n(0) {}
  unsigned long int 
  CutoffLinear::operator ()(void) {
    n += scale;
    return n;
  }
  
  
  unsigned long int
  CutoffLuby::start[CutoffLuby::n_start] = {
    1,1,2,1,1,2,4,1,1,2,1,1,2,4,8,1,1,2,1,1,2,4,1,1,2,1,1,2,4,8,16,
    1,1,2,1,1,2,4,1,1,2,1,1,2,4,8,1,1,2,1,1,2,4,1,1,2,1,1,2,4,8,16,32
  };
  forceinline
  CutoffLuby::CutoffLuby(unsigned long int scale0) 
    : i(1U), scale(scale0) {}
  forceinline unsigned long int 
  CutoffLuby::log(unsigned long int i) {
    if (i == 1U)
      return 0U;
    unsigned long int exp = 0U;
    while ( (i >> (++exp)) > 1U ) {}
    return exp;
  }
  forceinline unsigned long int 
  CutoffLuby::luby(unsigned long int i) {
    while (true) {
      if (i <= n_start)
        return start[i-1];
      unsigned long int l = log(i);
      if (i == (1U<<(l+1))-1)
        return 1UL<<l;
      i=i-(1U<<l)+1;
    }
    GECODE_NEVER;
    return 0;
  }
  unsigned long int 
  CutoffLuby::operator() (void) {
    return scale*luby(i++);
  }


  forceinline
  CutoffGeometric::CutoffGeometric(unsigned long int scale, double base0) 
    : n(static_cast<double>(scale)), base(base0) {}
  unsigned long int 
  CutoffGeometric::operator ()(void) {
    unsigned long int oldn = static_cast<unsigned long int>(n);
    n *= base;
    return oldn;
  }
  
  
  forceinline
  CutoffRandom::CutoffRandom(unsigned int seed, 
                             unsigned long int min0, 
                             unsigned long int max0, 
                             unsigned long int n0)
      : rnd(seed), min(min0), n(n0 == 0 ? (max0-min+1U) : n0), 
        step(std::max(1UL,
                      static_cast<unsigned long int>((max0-min0+1U)/n))) {}
  unsigned long int 
  CutoffRandom::operator ()(void) {
    return min+step*rnd(n);
  }
  

  forceinline
  CutoffAppend::CutoffAppend(Cutoff* d1, unsigned long int n0, Cutoff* d2) 
    : c1(d1), c2(d2), n(n0) {}
  unsigned long int 
  CutoffAppend::operator ()(void) {
    if (n > 0) {
      n--;
      return (*c1)();
    } else {
      return (*c2)();
    }
  }
  forceinline
  CutoffAppend::~CutoffAppend(void) {
    delete c1; delete c2;
  }


  forceinline
  CutoffRepeat::CutoffRepeat(Cutoff* c1, unsigned long int n0)
    : c(c1), i(0), n(n0) {
    cutoff = (*c)();
  }
  unsigned long int
  CutoffRepeat::operator ()(void) {
    unsigned long int current = cutoff;
    i++;
    if (i == n) {
      cutoff = (*c)();
      i = 0;
    }
    return current;
  }
  forceinline
  CutoffRepeat::~CutoffRepeat(void) {
    delete c;
  }
  
  
  Cutoff*
  Cutoff::constant(unsigned long int scale) {
    return new CutoffConstant(scale);
  }
  Cutoff*
  Cutoff::linear(unsigned long int scale) {
    return new CutoffLinear(scale);
  }
  Cutoff*
  Cutoff::luby(unsigned long int scale) {
    return new CutoffLuby(scale);
  }
  Cutoff*
  Cutoff::geometric(unsigned long int base, double scale) {
    return new CutoffGeometric(base,scale);
  }
  Cutoff*
  Cutoff::rnd(unsigned int seed, 
              unsigned long int min, 
              unsigned long int max, 
              unsigned long int n) {
    return new CutoffRandom(seed,min,max,n);
  }
  Cutoff*
  Cutoff::append(Cutoff* c1, unsigned long int n, Cutoff* c2) {
    return new CutoffAppend(c1,n,c2);
  }
  Cutoff*
  Cutoff::repeat(Cutoff* c, unsigned long int n) {
  return new CutoffRepeat(c,n);
  }

}}

// STATISTICS: search-other
