text: /***************************************************************************************[ClausesBuffer.h]
   Glucose -- Copyright (c) 2009-2014, Gilles Audemard, Laurent Simon
   CRIL - Univ. Artois, France
   LRI  - Univ. Paris Sud, France (2009-2013)
   Labri - Univ. Bordeaux, France
  
   Syrup (Glucose Parallel) -- Copyright (c) 2013-2014, Gilles Audemard, Laurent Simon
   CRIL - Univ. Artois, France
   Labri - Univ. Bordeaux, France
  
   ZIB Glucose -- Copyright (c) 2016 - 2019, Marc Hartung, Zuse Institute Berlin
  
   Glucose sources are based on MiniSat (see below MiniSat copyrights). Permissions and copyrights of
   Glucose (sources until 2013, Glucose 3.0, single core) are exactly the same as Minisat on which it
   is based on. (see below).
  
   Glucose-Syrup sources are based on another copyright. Permissions and copyrights for the parallel
   version of Glucose-Syrup (the "Software") are granted, free of charge, to deal with the Software
   without restriction, including the rights to use, copy, modify, merge, publish, distribute,
   sublicence, 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 and below copyrights notices and this permission notice shall be included in all
   copies or substantial portions of the Software;
   - The parallel version of Glucose (all files modified since Glucose 3.0 releases, 2013) cannot
   be used in any competitive event (sat competitions/evaluations) without the express permission of
   the authors (Gilles Audemard / Laurent Simon). This is also the case for any competitive event
   using Glucose Parallel as an embedded SAT engine (single core or not).
  
  
   --------------- Original Minisat Copyrights
  
   Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
   Copyright (c) 2007-2010, Niklas Sorensson
  
   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.
   **************************************************************************************************/
  
  #ifndef ClausesBuffer_h 
  #define ClausesBuffer_h
  
  #include "mtl/Vec.h"
  #include "core/SolverTypes.h"
  #include "core/Solver.h"
  #include <pthread.h>
  
  //=================================================================================================
  
  namespace Glucose {
  // index : size clause
  // index + 1 : nbSeen
  // index + 2 : threadId
  // index + 3 : .. index + 3 + size : Lit of clause
  
  struct PreventFalseSharing {
  	unsigned int id;
  	char dummy[128 - sizeof(id)];
  
  	operator const unsigned int &() const {
  		return id;
  	}
  
  	operator unsigned int &() {
  		return id;
  	}
  
  	PreventFalseSharing & operator=(const unsigned int & in)
  	{
  		id = in;
  		return *this;
  	}
  };
  
  class ClausesBuffer {
  	vec<uint32_t> elems;
  	unsigned int first;
  	unsigned int last;
  	unsigned int maxsize;
  	unsigned int queuesize; // Number of current elements (must be < maxsize !)
  	unsigned int removedClauses;
  	unsigned int forcedRemovedClauses;
  	static const int headerSize = 3;
  	int nbThreads;
  	bool whenFullRemoveOlder;
  	unsigned int fifoSizeByCore;
  	pthread_mutex_t mtx;
  	vec<PreventFalseSharing> lastOfThread; // Last value for a thread
  
  public:
  	ClausesBuffer(int _nbThreads, unsigned int _maxsize);
  	ClausesBuffer();
  
  	void setNbThreads(int _nbThreads, int numBuffers);
  	unsigned int nextIndex(unsigned int i);
  	unsigned int addIndex(unsigned int i, unsigned int a);
  	void removeLastClause();
  
  	void getLock();
  	void freeLock();
  
  	void noCheckPush(uint32_t x);
  	uint32_t noCheckPop(unsigned int & index);
  
  	// Return true if the clause was succesfully added
  	bool pushClause(int threadId, Clause & c);
  	bool pushClause(int threadId, const vec<Lit> & c);
  	bool getClause(int threadId, int & threadOrigin, vec<Lit> & resultClause,
  			bool firstFound = false);
  
  	int maxSize() const {
  		return maxsize;
  	}
  	uint32_t getCap();
  	void growTo(int size) {
  		assert(0); // Not implemented (essentially for efficiency reasons)
  		elems.growTo(size);
  		first = 0;
  		maxsize = size;
  		queuesize = 0;
  		last = 0;
  		for (int i = 0; i < size; i++)
  			elems[i] = 0;
  	}
  
  	void fastclear() {
  		first = 0;
  		last = 0;
  		queuesize = 0;
  	}
  
  	int size(void) {
  		return queuesize;
  	}
  
  	void clear(bool dealloc = false) {
  		elems.clear(dealloc);
  		first = 0;
  		maxsize = 0;
  		queuesize = 0;
  	}
  	inline int toInt(Lit p) {
  		return p.x;
  	}
  
  };
  }
  //=================================================================================================
  
  #endif
  