/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Contributing authors:
 *     Guido Tack <tack@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2003
 *     Guido Tack, 2004
 *
 *  Last modified:
 *     $Date: 2006-08-25 10:43:21 +0200 (Fri, 25 Aug 2006) $ by $Author: schulte $
 *     $Revision: 3568 $
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
 *
 *  See the file "LICENSE" for information on usage and
 *  redistribution of this file, and for a
 *     DISCLAIMER OF ALL WARRANTIES.
 *
 */

namespace Gecode { namespace Int {

  /*
   * Range lists
   *
   */

#define GECODE_INT_RL2PD(r) reinterpret_cast<ptrdiff_t>(r)
#define GECODE_INT_PD2RL(p) reinterpret_cast<RangeList*>(p)

  forceinline
  IntVarImp::RangeList::RangeList(void) {}

  forceinline
  IntVarImp::RangeList::RangeList(int min, int max)
    : _min(min), _max(max) {}

  forceinline
  IntVarImp::RangeList::RangeList(int min, int max, RangeList* p, RangeList* n)
    : _min(min), _max(max) {
    _next = GECODE_INT_PD2RL(GECODE_INT_RL2PD(p)^GECODE_INT_RL2PD(n));
  }

  forceinline IntVarImp::RangeList*
  IntVarImp::RangeList::next(const RangeList* p) const {
    return GECODE_INT_PD2RL(GECODE_INT_RL2PD(_next)^GECODE_INT_RL2PD(p));
  }
  forceinline IntVarImp::RangeList*
  IntVarImp::RangeList::prev(const RangeList* n) const {
    return GECODE_INT_PD2RL(GECODE_INT_RL2PD(_next)^GECODE_INT_RL2PD(n));
  }
  forceinline void
  IntVarImp::RangeList::prevnext(RangeList* p, RangeList* n) {
    _next = GECODE_INT_PD2RL(GECODE_INT_RL2PD(p)^GECODE_INT_RL2PD(n));
  }
  forceinline void
  IntVarImp::RangeList::next(RangeList* o, RangeList* n) {
    _next = GECODE_INT_PD2RL(GECODE_INT_RL2PD(_next)^
			     (GECODE_INT_RL2PD(o)^GECODE_INT_RL2PD(n)));
  }
  forceinline void
  IntVarImp::RangeList::prev(RangeList* o, RangeList* n) {
    _next = GECODE_INT_PD2RL(GECODE_INT_RL2PD(_next)^
			     (GECODE_INT_RL2PD(o)^GECODE_INT_RL2PD(n)));
  }
  forceinline void
  IntVarImp::RangeList::fix(RangeList* n) {
    _next = n;
  }

  forceinline void
  IntVarImp::RangeList::min(int n) {
    _min = n;
  }
  forceinline void
  IntVarImp::RangeList::max(int n) {
    _max = n;
  }

  forceinline int
  IntVarImp::RangeList::min(void) const {
    return _min;
  }
  forceinline int
  IntVarImp::RangeList::max(void) const {
    return _max;
  }
  forceinline unsigned int
  IntVarImp::RangeList::width(void) const {
    return _max - _min + 1;
  }


  forceinline void
  IntVarImp::RangeList::operator delete(void*) {}

  forceinline void
  IntVarImp::RangeList::operator delete(void*, Space*) {
    GECODE_NEVER;
  }

  forceinline void*
  IntVarImp::RangeList::operator new(size_t s, Space* home) {
    assert(s == sizeof(RangeList));
    return home->fl_alloc<sizeof(RangeList)>();
  }

  forceinline void
  IntVarImp::RangeList::dispose(Space* home, RangeList* p, RangeList* l) {
    RangeList* c = this;
    while (c != l) {
      RangeList* n = c->next(p);
      c->fix(n);
      p=c; c=n;
    }
    home->fl_dispose<sizeof(RangeList)>(this,l);
  }

  forceinline void
  IntVarImp::RangeList::dispose(Space* home, RangeList* l) {
    home->fl_dispose<sizeof(RangeList)>(this,l);
  }

  forceinline void
  IntVarImp::RangeList::dispose(Space* home) {
    home->fl_dispose<sizeof(RangeList)>(this,this);
  }

#undef GECODE_INT_RL2PD
#undef GECODE_INT_PD2RL

  /*
   * Mainitaining range lists for variable domain
   *
   */

  forceinline IntVarImp::RangeList*
  IntVarImp::fst(void) const {
    return dom.next(NULL);
  }

  forceinline void
  IntVarImp::fst(IntVarImp::RangeList* f) {
    dom.prevnext(NULL,f);
  }

  forceinline IntVarImp::RangeList*
  IntVarImp::lst(void) const {
    return _lst;
  }

  forceinline void
  IntVarImp::lst(IntVarImp::RangeList* l) {
    _lst = l;
  }

  /*
   * Creation of new variable implementations
   *
   */

  forceinline
  IntVarImp::IntVarImp(Space* home, int min, int max)
    : IntVarImpBase(home), dom(min,max,NULL,NULL), holes(0) {}

  forceinline
  IntVarImp::IntVarImp(Space* home, const IntSet& d)
    : IntVarImpBase(home), dom(d.min(),d.max()) {
    if (d.size() > 1) {
      int n = d.size();
      RangeList* r = reinterpret_cast<RangeList*>
	(home->alloc(sizeof(RangeList)*n));
      fst(r); lst(r+n-1);
      unsigned int h = d.max()-d.min()+1;
      for (int i = n; i--; ) {
	h -= d.width(i);
	r[i].min(d.min(i)); r[i].max(d.max(i));
	r[i].prevnext(&r[i-1],&r[i+1]);
      }
      r[0].prev(&r[-1],NULL);
      r[n-1].next(&r[n],NULL);
      holes = h;
    } else {
      fst(NULL); holes = 0;
    }
  }


  /*
   * Operations on integer variable implementations
   *
   */

  forceinline int
  IntVarImp::min(void) const {
    return dom.min();
  }
  forceinline int
  IntVarImp::max(void) const {
    return dom.max();
  }
  forceinline int
  IntVarImp::val(void) const {
    assert(dom.min() == dom.max());
    return dom.min();
  }

  forceinline bool
  IntVarImp::range(void) const {
    return fst() == NULL;
  }
  forceinline bool
  IntVarImp::assigned(void) const {
    return dom.min() == dom.max();
  }


  forceinline unsigned int
  IntVarImp::width(void) const {
    return dom.width();
  }

  forceinline unsigned int
  IntVarImp::size(void) const {
    return dom.width() - holes;
  }

  forceinline unsigned int
  IntVarImp::regret_min(void) const {
    if (fst() == NULL) {
      return (dom.min() == dom.max()) ? 0 : 1;
    } else if (dom.min() == fst()->max()) {
      return fst()->next(NULL)->min()-dom.min();
    } else {
      return 1;
    }
  }
  forceinline unsigned int
  IntVarImp::regret_max(void) const {
    if (lst() == NULL) {
      return (dom.min() == dom.max()) ? 0 : 1;
    } else if (dom.max() == lst()->min()) {
      return dom.max()-lst()->prev(NULL)->max();
    } else {
      return 1;
    }
  }



  /*
   * Tests
   *
   */

  forceinline bool
  IntVarImp::in(int n) const {
    if ((n < dom.min()) || (n > dom.max()))
      return false;
    return (fst() == NULL) || in_full(n);
  }
  forceinline bool
  IntVarImp::in(double n) const {
    if ((n < dom.min()) || (n > dom.max()))
      return false;
    return (fst() == NULL) || in_full(static_cast<int>(n));
  }


  /*
   * Accessing rangelists for iteration
   *
   */

  forceinline const IntVarImp::RangeList*
  IntVarImp::ranges_fwd(void) const {
    return (fst() == NULL) ? &dom : fst();
  }

  forceinline const IntVarImp::RangeList*
  IntVarImp::ranges_bwd(void) const {
    return (fst() == NULL) ? &dom : lst();
  }



  /*
   * Tell operations (to be inlined: performing bounds checks first)
   *
   */

  forceinline ModEvent
  IntVarImp::gq(Space* home, int n) {
    if (n <= dom.min()) return ME_INT_NONE;
    if (n > dom.max())  return ME_INT_FAILED;
    gq_full(home,n);
    if (assigned())
      return ME_INT_VAL;
    return ME_INT_BND;
  }
  forceinline ModEvent
  IntVarImp::gq(Space* home, double n) {
    if (n <= dom.min()) return ME_INT_NONE;
    if (n > dom.max())  return ME_INT_FAILED;
    gq_full(home,static_cast<int>(n));
    if (assigned())
      return ME_INT_VAL;
    return ME_INT_BND;
  }


  forceinline ModEvent
  IntVarImp::lq(Space* home, int n) {
    if (n >= dom.max()) return ME_INT_NONE;
    if (n < dom.min())  return ME_INT_FAILED;
    lq_full(home,n);
    if (dom.min() == n)
      return ME_INT_VAL;
    return ME_INT_BND;
  }
  forceinline ModEvent
  IntVarImp::lq(Space* home, double n) {
    if (n >= dom.max()) return ME_INT_NONE;
    if (n < dom.min())  return ME_INT_FAILED;
    lq_full(home,static_cast<int>(n));
    if (dom.max() == n)
      return ME_INT_VAL;
    return ME_INT_BND;
  }


  forceinline ModEvent
  IntVarImp::eq(Space* home, int n) {
    if ((n < dom.min()) || (n > dom.max()))
      return ME_INT_FAILED;
    if ((n == dom.min()) && (n == dom.max()))
      return ME_INT_NONE;
    eq_full(home,n);
    if (dom.min() == Limits::Int::int_max+1)
      return ME_INT_FAILED;
    return ME_INT_VAL;
  }
  forceinline ModEvent
  IntVarImp::eq(Space* home, double n) {
    if ((n < dom.min()) || (n > dom.max()))
      return ME_INT_FAILED;
    if ((n == dom.min()) && (n == dom.max()))
      return ME_INT_NONE;
    eq_full(home,static_cast<int>(n));
    if (dom.min() == Limits::Int::int_max+1)
      return ME_INT_FAILED;
    return ME_INT_VAL;
  }


  forceinline ModEvent
  IntVarImp::nq(Space* home, int n) {
    if ((n < dom.min()) || (n > dom.max())) return ME_INT_NONE;
    return nq_full(home,n);
  }
  forceinline ModEvent
  IntVarImp::nq(Space* home, double d) {
    if ((d < dom.min()) || (d > dom.max())) return ME_INT_NONE;
    return nq_full(home,static_cast<int>(d));
  }


  /*
   * Tell operations with respect to iterators
   *
   */

  template <class I>
  forceinline ModEvent
  IntVarImp::narrow(Space* home, I& ri) {
    // Is new domain empty?
    if (!ri())
      return ME_INT_FAILED;
    int min0 = ri.min();
    int max0 = ri.max();
    ++ri;
    // Is new domain range?
    if (!ri()) {
      // Remove possible rangelist (if it was not a range, the domain
      // must have been narrowed!)
      if (fst()) {
	fst()->dispose(home,NULL,lst());
	fst(NULL); holes = 0;
      }
      const int min1 = dom.min(); dom.min(min0);
      const int max1 = dom.max(); dom.max(max0);
      if ((min0 == min1) && (max0 == max1))
	return ME_INT_NONE;
      if (min0 == max0) {
	notify(home,ME_INT_VAL);
	return ME_INT_VAL;
      }
    } else {
      // Construct new rangelist
      RangeList*   f = new (home) RangeList(min0,max0,NULL,NULL);
      RangeList*   l = f;
      unsigned int s = max0-min0+1;
      do {
	RangeList* n = new (home) RangeList(ri.min(),ri.max(),l,NULL);
	l->next(NULL,n);
	l = n;
	s += ri.width();
	++ri;
      } while (ri());
      if (fst() != NULL)
	fst()->dispose(home,NULL,lst());
      fst(f); lst(l);
      // Check for modification
      if (size() == s)
	return ME_INT_NONE;
      const int min1 = dom.min(); min0 = f->min(); dom.min(min0);
      const int max1 = dom.max(); max0 = l->max(); dom.max(max0);
      holes = width() - s;
      if ((min0 == min1) && (max0 == max1)) {
	notify(home,ME_INT_DOM);
	return ME_INT_DOM;
      }
    }
    notify(home,ME_INT_BND);
    return ME_INT_BND;
  }

  /*
   * Copying a variable
   *
   */

  forceinline IntVarImp*
  IntVarImp::copy(Space* home, bool share) {
    return copied() ? static_cast<IntVarImp*>(forward())
      : perform_copy(home,share);
  }
  forceinline IntVarImp*
  IntVarImp::copy_bool(Space* home, bool share) {
    return copied() ? static_cast<IntVarImp*>(forward())
      : perform_copy_bool(home,share);
  }



  /*
   * Boolean tell operations (assume not yet assigned 0/1 variable)
   *
   */

  forceinline void
  IntVarImp::t_zero_none(Space* home) {
    assert((dom.min() == 0) && (dom.max() == 1));
    dom.max(0);
    notify(home,ME_INT_VAL);
  }

  forceinline void
  IntVarImp::t_one_none(Space* home) {
    assert((dom.min() == 0) && (dom.max() == 1));
    dom.min(1);
    notify(home,ME_INT_VAL);
  }


  /*
   * Forward range iterator for rangelists
   *
   */

  forceinline
  IntVarImpFwd::IntVarImpFwd(void) {}
  forceinline
  IntVarImpFwd::IntVarImpFwd(const IntVarImp* x)
    : p(NULL), c(x->ranges_fwd()) {}
  forceinline void
  IntVarImpFwd::init(const IntVarImp* x) {
    p=NULL; c=x->ranges_fwd();
  }

  forceinline bool
  IntVarImpFwd::operator()(void) const {
    return c != NULL;
  }
  forceinline void
  IntVarImpFwd::operator++(void) {
    const IntVarImp::RangeList* n=c->next(p); p=c; c=n;
  }

  forceinline int
  IntVarImpFwd::min(void) const {
    return c->min();
  }
  forceinline int
  IntVarImpFwd::max(void) const {
    return c->max();
  }
  forceinline unsigned int
  IntVarImpFwd::width(void) const {
    return c->width();
  }


  /*
   * Backward range iterator for rangelists
   *
   */

  forceinline
  IntVarImpBwd::IntVarImpBwd(void) {}
  forceinline
  IntVarImpBwd::IntVarImpBwd(const IntVarImp* x)
    : n(NULL), c(x->ranges_bwd()) {}
  forceinline void
  IntVarImpBwd::init(const IntVarImp* x) {
    n=NULL; c=x->ranges_bwd();
  }

  forceinline bool
  IntVarImpBwd::operator()(void) const {
    return c != NULL;
  }
  forceinline void
  IntVarImpBwd::operator++(void) {
    const IntVarImp::RangeList* p=c->prev(n); n=c; c=p;
  }

  forceinline int
  IntVarImpBwd::min(void) const {
    return c->min();
  }
  forceinline int
  IntVarImpBwd::max(void) const {
    return c->max();
  }
  forceinline unsigned int
  IntVarImpBwd::width(void) const {
    return c->width();
  }


  /*
   * More domain operations
   *
   */
  template <class I>
  forceinline ModEvent
  IntVarImp::inter(Space* home, I& i) {
    IntVarImpFwd j(this);
    Iter::Ranges::Inter<I,IntVarImpFwd> ij(i,j);
    return narrow(home,ij);
  }

  template <class I>
  forceinline ModEvent
  IntVarImp::minus(Space* home, I& i) {
    IntVarImpFwd j(this);
    Iter::Ranges::Diff<IntVarImpFwd,I> ij(j,i);
    return narrow(home,ij);
  }

  /*
   * Subscribing to variables
   *
   */
  forceinline void
  IntVarImp::subscribe(Space* home, Propagator* p, PropCond pc, bool process) {
    IntVarImpBase::subscribe(home,p,pc,dom.min()==dom.max(),process);
  }

}}

// STATISTICS: int-var