subsumption.hpp

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/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
/*
 *  Main authors:
 *     Christian Schulte <schulte@gecode.org>
 *
 *  Copyright:
 *     Christian Schulte, 2015
 *
 *  This file is part of Gecode, the generic constraint
 *  development environment:
 *     http://www.gecode.org
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namespace Gecode { namespace Int { namespace Cumulative {

  template<class Task>
  forceinline ExecStatus
  subsumed(Space& home, Propagator& p, int c, TaskArray<Task>& t) {
    Region r;

    if (Event* e = Event::events(r,t)) {
      // Process events, use ccur as the capacity that is still free
      do {
        // Current time
        int time = e->time();
        // Process events for completion of required part
        for ( ; (e->type() == Event::LRT) && (e->time() == time); e++)
          c += t[e->idx()].c();
        // Process events for zero-length task
        for ( ; (e->type() == Event::ZRO) && (e->time() == time); e++)
          if (c < t[e->idx()].c())
            return ES_FAILED;
        // Process events for start of required part
        for ( ;  (e->type() == Event::ERT) && (e->time() == time); e++) {
          c -= t[e->idx()].c();
          if (c < 0)
            return ES_FAILED;
        }
      } while (e->type() != Event::END);
    } else {
      return ES_OK;
    }

    return home.ES_SUBSUMED(p);
  }

}}}

// STATISTICS: int-prop