/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2006
 *
 *  Last modified:
 *     $Date: 2006-08-08 20:36:53 +0200 (Tue, 08 Aug 2006) $ by $Author: schulte $
 *     $Revision: 3538 $
 *
 *  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 { namespace Count {

  /*
   * General baseclass
   *
   */

  template <class VX, class VY>
  forceinline
  BaseInt<VX,VY>::BaseInt(Space* home, 
			  ViewArray<VX>& x0, int n_s0, VY y0, int c0)
    : Propagator(home), x(x0), n_s(n_s0), y(y0), c(c0) {
    for (int i=n_s; i--; )
      x[i].subscribe(home,this,PC_INT_DOM);
    y.subscribe(home,this,PC_INT_DOM);
  }

  template <class VX, class VY>
  size_t
  BaseInt<VX,VY>::dispose(Space* home) {
    assert(!home->failed());
    for (int i=n_s; i--; )
      x[i].cancel(home,this,PC_INT_DOM);
    y.cancel(home,this,PC_INT_DOM);
    (void) Propagator::dispose(home);
    return sizeof(*this);
  }

  template <class VX, class VY>
  forceinline
  BaseInt<VX,VY>::BaseInt(Space* home, bool share, BaseInt<VX,VY>& p)
    : Propagator(home,share,p), n_s(p.n_s), c(p.c) {
    x.update(home,share,p.x);
    y.update(home,share,p.y);
  }

  template <class VX, class VY>
  PropCost
  BaseInt<VX,VY>::cost(void) const {
    return cost_lo(x.size(),PC_LINEAR_LO);
  }

  /*
   * Equal propagator (integer rhs)
   *
   */
  template <class VX, class VY>
  forceinline
  EqInt<VX,VY>::EqInt(Space* home, ViewArray<VX>& x, int n_s, VY y, int c)
    : BaseInt<VX,VY>(home,x,n_s,y,c) {}

  template <class VX, class VY>
  ExecStatus
  EqInt<VX,VY>::post(Space* home, ViewArray<VX>& x, VY y, int c) {
    // Eliminate decided views
    int n_x = x.size();
    for (int i=n_x; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE:
	x[i] = x[--n_x]; break;
      case RT_TRUE:
	x[i] = x[--n_x]; c--; break;
      case RT_MAYBE:
	break;
      default: 
	GECODE_NEVER;
      }
    x.size(n_x);
    // RHS too small or too large
    if ((c < 0) || (c > n_x))
      return ES_FAILED;
    // All views must be different
    if (c == 0) {
      ExecStatus es = post_false(home,x,y);
      return (es == ES_SUBSUMED) ? ES_OK : es;
    }
    // All views must be equal
    if (c == n_x) {
      ExecStatus es = post_true(home,x,y);
      return (es == ES_SUBSUMED) ? ES_OK : es;
    }
    // Compute how many subscriptions must be created
    int n_s = std::max(c,n_x-c)+1;
    assert(n_s <= n_x);
    (void) new (home) EqInt<VX,VY>(home,x,n_s,y,c);
    return ES_OK;
  }

  template <class VX, class VY>
  forceinline
  EqInt<VX,VY>::EqInt(Space* home, bool share, EqInt<VX,VY>& p)
    : BaseInt<VX,VY>(home,share,p) {}

  template <class VX, class VY>
  Actor*
  EqInt<VX,VY>::copy(Space* home, bool share) {
    return new (home) EqInt<VX,VY>(home,share,*this);
  }

  template <class VX, class VY>
  ExecStatus
  EqInt<VX,VY>::propagate(Space* home) {
    // Eliminate decided views from subscribed views
    int n_x = x.size();
    for (int i=n_s; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE:
	x[i].cancel(home,this,PC_INT_DOM);
	x[i]=x[--n_s]; x[n_s]=x[--n_x]; 
	break;
      case RT_TRUE:
	x[i].cancel(home,this,PC_INT_DOM);
	x[i]=x[--n_s]; x[n_s]=x[--n_x]; c--; 
	break;
      case RT_MAYBE:
	break;
      default: 
	GECODE_NEVER;
      }
    x.size(n_x);
    if ((c < 0) || (c > n_x))
      return ES_FAILED;
    // Eliminate decided views from unsubscribed views
    for (int i=n_x; i-- > n_s; )
      switch (holds(x[i],y)) {
      case RT_FALSE: x[i]=x[--n_x]; break;
      case RT_TRUE:  x[i]=x[--n_x]; c--; break;
      case RT_MAYBE: break;
      default:       GECODE_NEVER;
      }
    x.size(n_x);
    if ((c < 0) || (c > n_x))
      return ES_FAILED;
    if (c == 0)
      // All views must be different
      return post_false(home,x,y);
    if (c == n_x)
      // All views must be equal
      return post_true(home,x,y);
    int m = std::max(c,n_x-c)+1;
    assert(m <= n_x);
    // Now, there must be new subscriptions from x[n_s] up to x[m-1]
    while (n_s < m)
      x[n_s++].subscribe(home,this,PC_INT_DOM,false);
    return ES_FIX;
  }

  /*
   * Greater or equal propagator (integer rhs)
   *
   */
  template <class VX, class VY>
  forceinline
  GqInt<VX,VY>::GqInt(Space* home, ViewArray<VX>& x, int n_s, VY y, int c)
    : BaseInt<VX,VY>(home,x,n_s,y,c) {}

  template <class VX, class VY>
  ExecStatus
  GqInt<VX,VY>::post(Space* home, ViewArray<VX>& x, VY y, int c) {
    // Eliminate decided views
    int n_x = x.size();
    for (int i=n_x; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE:
	x[i] = x[--n_x]; break;
      case RT_TRUE:
	x[i] = x[--n_x]; c--; break;
      case RT_MAYBE:
	break;
      default: 
	GECODE_NEVER;
      }
    x.size(n_x);
    // RHS too large
    if (n_x < c)
      return ES_FAILED;
    // Whatever the x[i] take for values, the inequality is subsumed
    if (c <= 0)
      return ES_OK;
    // All views must be equal
    if (c == n_x) {
      ExecStatus es = post_true(home,x,y);
      return (es == ES_SUBSUMED) ? ES_OK : es;
    }
    (void) new (home) GqInt<VX,VY>(home,x,c+1,y,c);
    return ES_OK;
  }

  template <class VX, class VY>
  forceinline
  GqInt<VX,VY>::GqInt(Space* home, bool share, GqInt<VX,VY>& p)
    : BaseInt<VX,VY>(home,share,p) {}

  template <class VX, class VY>
  Actor*
  GqInt<VX,VY>::copy(Space* home, bool share) {
    return new (home) GqInt<VX,VY>(home,share,*this);
  }

  template <class VX, class VY>
  ExecStatus
  GqInt<VX,VY>::propagate(Space* home) {
    // Eliminate decided views from subscribed views
    int n_x = x.size();
    for (int i=n_s; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE:
	x[i].cancel(home,this,PC_INT_DOM);
	x[i]=x[--n_s]; x[n_s]=x[--n_x]; 
	break;
      case RT_TRUE:
	x[i].cancel(home,this,PC_INT_DOM);
	x[i]=x[--n_s]; x[n_s]=x[--n_x]; c--; 
	break;
      case RT_MAYBE:
	break;
      default: 
	GECODE_NEVER;
      }
    x.size(n_x);
    if (n_x < c)
      return ES_FAILED;
    if (c <= 0)
      return ES_SUBSUMED;
    // Eliminate decided views from unsubscribed views
    for (int i=n_x; i-- > n_s; )
      switch (holds(x[i],y)) {
      case RT_FALSE: x[i]=x[--n_x]; break;
      case RT_TRUE:  x[i]=x[--n_x]; c--; break;
      case RT_MAYBE: break;
      default:       GECODE_NEVER;
      }
    x.size(n_x);
    if (n_x < c)
      return ES_FAILED;
    if (c <= 0)
      return ES_SUBSUMED;
    if (c == n_x)
      // All views must be equal
      return post_true(home,x,y);
    // Now, there must be new subscriptions from x[n_s] up to x[c+1]
    while (n_s <= c)
      x[n_s++].subscribe(home,this,PC_INT_DOM,false);
    return ES_FIX;
  }

  /*
   * Less or equal propagator (integer rhs)
   *
   */
  template <class VX, class VY>
  forceinline
  LqInt<VX,VY>::LqInt(Space* home, ViewArray<VX>& x, int n_s, VY y, int c)
    : BaseInt<VX,VY>(home,x,n_s,y,c) {}

  template <class VX, class VY>
  ExecStatus
  LqInt<VX,VY>::post(Space* home, ViewArray<VX>& x, VY y, int c) {
    // Eliminate decided views
    int n_x = x.size();
    for (int i=n_x; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE:
	x[i] = x[--n_x]; break;
      case RT_TRUE:
	x[i] = x[--n_x]; c--; break;
      case RT_MAYBE:
	break;
      default: 
	GECODE_NEVER;
      }
    x.size(n_x);
    if (c < 0)
      return ES_FAILED;
    if (c >= n_x)
      return ES_OK;
    // All views must be different
    if (c == 0) {
      ExecStatus es = post_false(home,x,y);
      return (es == ES_SUBSUMED) ? ES_OK : es;
    }
    (void) new (home) LqInt<VX,VY>(home,x,n_x-c+1,y,c);
    return ES_OK;
  }

  template <class VX, class VY>
  forceinline
  LqInt<VX,VY>::LqInt(Space* home, bool share, LqInt<VX,VY>& p)
    : BaseInt<VX,VY>(home,share,p) {}

  template <class VX, class VY>
  Actor*
  LqInt<VX,VY>::copy(Space* home, bool share) {
    return new (home) LqInt<VX,VY>(home,share,*this);
  }

  template <class VX, class VY>
  ExecStatus
  LqInt<VX,VY>::propagate(Space* home) {
    // Eliminate decided views from subscribed views
    int n_x = x.size();
    for (int i=n_s; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE:
	x[i].cancel(home,this,PC_INT_DOM);
	x[i]=x[--n_s]; x[n_s]=x[--n_x]; 
	break;
      case RT_TRUE:
	x[i].cancel(home,this,PC_INT_DOM);
	x[i]=x[--n_s]; x[n_s]=x[--n_x]; c--; 
	break;
      case RT_MAYBE:
	break;
      default: 
	GECODE_NEVER;
      }
    x.size(n_x);
    if (c < 0)
      return ES_FAILED;
    if (c >= n_x)
      return ES_SUBSUMED;
    // Eliminate decided views from unsubscribed views
    for (int i=n_x; i-- > n_s; )
      switch (holds(x[i],y)) {
      case RT_FALSE: x[i]=x[--n_x]; break;
      case RT_TRUE:  x[i]=x[--n_x]; c--; break;
      case RT_MAYBE: break;
      default:       GECODE_NEVER;
      }
    x.size(n_x);
    if (c < 0)
      return ES_FAILED;
    if (c >= n_x)
      return ES_SUBSUMED;
    if (c == 0)
      // All views must be different
      return post_false(home,x,y);
    // Now, there must be new subscriptions from x[n_s] up to x[n_x-c+1]
    int m = n_x-c;
    while (n_s <= m)
      x[n_s++].subscribe(home,this,PC_INT_DOM,false);
    return ES_FIX;
  }

  /*
   * Not-equal propagator (integer rhs)
   *
   */
  template<class VX, class VY>
  forceinline
  NqInt<VX,VY>::NqInt(Space* home, ViewArray<VX>& x0, VY y0, int c0)
    : BinaryPropagator<VX,PC_INT_DOM>(home,
				      x0[x0.size()-2],
				      x0[x0.size()-1]), x(x0), y(y0), c(c0) {
    assert(x.size() >= 2);
    x.size(x.size()-2);
    y.subscribe(home,this,PC_INT_DOM);
  }

  template <class VX, class VY>
  size_t
  NqInt<VX,VY>::dispose(Space* home) {
    assert(!home->failed());
    y.cancel(home,this,PC_INT_DOM);
    (void) BinaryPropagator<VX,PC_INT_DOM>::dispose(home);
    return sizeof(*this);
  }

  template<class VX, class VY>
  forceinline
  NqInt<VX,VY>::NqInt(Space* home, bool share, NqInt<VX,VY>& p)
    : BinaryPropagator<VX,PC_INT_DOM>(home,share,p), c(p.c) {
    x.update(home,share,p.x);
    y.update(home,share,p.y);
  }

  template<class VX, class VY>
  forceinline ExecStatus
  NqInt<VX,VY>::post(Space* home, ViewArray<VX>& x, VY y, int c) {
    int n = x.size();
    for (int i=n; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE: x[i]=x[--n]; break;
      case RT_TRUE:  x[i]=x[--n]; c--; break;
      case RT_MAYBE: break;
      default:       GECODE_NEVER;
      }
    x.size(n);
    if ((n < c) || (c < 0))
      return ES_OK;
    if (n == 0)
      return (c == 0) ? ES_FAILED : ES_OK;
    if (n == 1) {
      ExecStatus es = (c == 1) ?
	post_false(home,x[0],y) : post_true(home,x[0],y);
      return (es == ES_SUBSUMED) ? ES_OK : es;
    }
    (void) new (home) NqInt(home,x,y,c);
    return ES_OK;
  }

  template<class VX, class VY>
  Actor*
  NqInt<VX,VY>::copy(Space* home, bool share) {
    return new (home) NqInt<VX,VY>(home,share,*this);
  }

  template<class VX, class VY>
  PropCost
  NqInt<VX,VY>::cost(void) const {
    return PC_LINEAR_LO;
  }

  template<class VX, class VY>
  forceinline bool
  NqInt<VX,VY>::resubscribe(Space* home, VX& z) {
    switch (holds(z,y)) {
    case RT_FALSE: break;
    case RT_TRUE:  c--; break;
    case RT_MAYBE: return true;
    default:       GECODE_NEVER;
    }
    int n = x.size();
    for (int i=n; i--; )
      switch (holds(x[i],y)) {
      case RT_FALSE: 
	x[i]=x[--n]; 
	break;
      case RT_TRUE:  
	x[i]=x[--n]; c--; 
	break;
      case RT_MAYBE: 
	// New undecided view found
	z.cancel(home,this,PC_INT_DOM);
	z=x[i]; x[i]=x[--n]; 
	x.size(n);
	z.subscribe(home,this,PC_INT_DOM,false);
	return true;
      default:       
	GECODE_NEVER;
      }
    // All views have been decided
    x.size(0);
    return false;
  }

  template<class VX, class VY>
  ExecStatus
  NqInt<VX,VY>::propagate(Space* home) {
    bool s0 = resubscribe(home,x0);
    bool s1 = resubscribe(home,x1);
    int n = x.size() + s0 + s1;
    if ((n < c) || (c < 0))
      return ES_SUBSUMED;
    if (n == 0)
      return (c == 0) ? ES_FAILED : ES_SUBSUMED;
    if (n == 1) {
      if (s0) {
	return (c == 1) ? 
	  post_false(home,x0,y) : post_true(home,x0,y);
      } else {
	assert(s1);
	return (c == 1) ? 
	  post_false(home,x1,y) : post_true(home,x1,y);
      }
      return ES_SUBSUMED;
    }
    return ES_FIX;
  }

}}}

// STATISTICS: int-prop