factmngr.c

一套美国国家宇航局人工智能中心NASA的专家系统工具源代码

   /* Return TRUE to indicate that fact slot */
   /* values were successfully copied.       */
   /*========================================*/
   
   return(CLIPS_TRUE);
  }
  
/*********************************************/
/* CreateFactBySize: Allocates a fact data   */
/*   structure based on the number of slots. */
/*********************************************/
globle struct fact *CreateFactBySize(size)
  int size;
  {
   struct fact *theFact;
   int newSize;

   if (size <= 0) newSize = 1;
   else newSize = size;

   theFact = get_var_struct2(fact,sizeof(struct field) * (newSize - 1)); 
   
   theFact->depth = (unsigned) CurrentEvaluationDepth;
   theFact->garbage = CLIPS_FALSE;
   theFact->factIndex = 0L;
   theFact->factHeader.busyCount = 0;
   theFact->factHeader.theInfo = &FactInfo;
#if LOGICAL_DEPENDENCIES
   theFact->factHeader.dependents = NULL;
#endif
   theFact->whichDeftemplate = NULL;
   theFact->nextFact = NULL;
   theFact->previousFact = NULL;
   theFact->list = NULL;
   
   theFact->theProposition.multifieldLength = size;
   theFact->theProposition.depth = (short) CurrentEvaluationDepth;
   theFact->theProposition.busyCount = 0;

   return(theFact);
  }

/*********************************************/
/* ReturnFact: Returns a fact data structure */
/*   to the pool of free memory.             */
/*********************************************/
globle VOID ReturnFact(theFact)
  struct fact *theFact;
  {
   struct multifield *theSegment;
   int newSize, i;
   
   theSegment = &theFact->theProposition;
   
   for (i = 0; i < (int) theSegment->multifieldLength; i++)
     {
      if (theSegment->theFields[i].type == MULTIFIELD)
        { ReturnMultifield(theSegment->theFields[i].value); }
     }
   
   if (theFact->theProposition.multifieldLength == 0) newSize = 1;
   else newSize = theFact->theProposition.multifieldLength;
   
   rtn_var_struct2(fact,sizeof(struct field) * (newSize - 1),theFact);
  }

/*************************************************************/
/* FactInstall: Increments the fact, deftemplate, and atomic */
/*   data value busy counts associated with the fact.        */
/*************************************************************/
globle VOID FactInstall(newFact)
  struct fact *newFact;
  {
   struct multifield *theSegment;
   int i;
   
   NumberOfFacts++;
   newFact->whichDeftemplate->busyCount++;
   theSegment = &newFact->theProposition;
      
   for (i = 0 ; i < (int) theSegment->multifieldLength ; i++)
     { 
      AtomInstall(theSegment->theFields[i].type,theSegment->theFields[i].value);
     }
     
   newFact->factHeader.busyCount++; 
  }

/***************************************************************/
/* FactDeinstall: Decrements the fact, deftemplate, and atomic */
/*   data value busy counts associated with the fact.          */
/***************************************************************/
globle VOID FactDeinstall(newFact)
  struct fact *newFact;
  {
   struct multifield *theSegment;
   int i;
   
   NumberOfFacts--;
   theSegment = &newFact->theProposition;
   newFact->whichDeftemplate->busyCount--;
   
   for (i = 0 ; i < (int) theSegment->multifieldLength ; i++)
     { 
      AtomDeinstall(theSegment->theFields[i].type,theSegment->theFields[i].value);
     }
     
   newFact->factHeader.busyCount--; 
  }

/*********************************************/
/* IncrementFactCount: Increments the number */
/*   of references to a specified fact.      */
/*********************************************/
globle VOID IncrementFactCount(factPtr)
  VOID *factPtr;
  {
   ((struct fact *) factPtr)->factHeader.busyCount++;
  }

/*********************************************/
/* DecrementFactCount: Decrements the number */
/*   of references to a specified fact.      */
/*********************************************/
globle VOID DecrementFactCount(factPtr)
  VOID *factPtr;
  {
   ((struct fact *) factPtr)->factHeader.busyCount--;
  }

/************************************************************/
/* GetNextFact: If passed a NULL pointer, returns the first */
/*   fact in the fact-list. Otherwise returns the next fact */
/*   following the fact passed as an argument.              */
/************************************************************/
globle VOID *GetNextFact(factPtr)
  VOID *factPtr;
  {
   if (factPtr == NULL)
     { return((VOID *) FactList); }

   if (((struct fact *) factPtr)->garbage) return(NULL);

   return((VOID *) ((struct fact *) factPtr)->nextFact);
  }

/**************************************************/
/* GetNextFactInScope: Returns the next fact that */
/*   is in scope of the current module. Works in  */
/*   a similar fashion to GetNextFact, but skips  */
/*   facts that are out of scope.                 */
/**************************************************/
globle VOID *GetNextFactInScope(vTheFact)
  VOID *vTheFact;
  {          
   static long lastModuleIndex = -1;
   struct fact *theFact = (struct fact *) vTheFact;
   
   /*=======================================================*/
   /* If fact passed as an argument is a NULL pointer, then */
   /* we're just beginning a traversal of the fact list. If */
   /* the module index has changed since that last time the */
   /* fact list was traversed by this routine, then         */
   /* determine all of the deftemplates that are in scope   */
   /* of the current module.                                */
   /*=======================================================*/
   
   if (theFact == NULL)
     { 
      theFact = FactList;
      if (lastModuleIndex != ModuleChangeIndex)
        {
         UpdateDeftemplateScope();
         lastModuleIndex = ModuleChangeIndex;
        }
     }
     
   /*==================================================*/
   /* Otherwise, if the fact passed as an argument has */
   /* been retracted, then there's no way to determine */
   /* the next fact, so return a NULL pointer.         */
   /*==================================================*/
   
   else if (((struct fact *) theFact)->garbage) 
     { return(NULL); }
     
   /*==================================================*/
   /* Otherwise, start the search for the next fact in */
   /* scope with the fact immediately following the    */
   /* fact passed as an argument.                      */
   /*==================================================*/
   
   else
     { theFact = theFact->nextFact; }
     
   /*================================================*/
   /* Continue traversing the fact-list until a fact */
   /* is found that's associated with a deftemplate  */
   /* that's in scope.                               */
   /*================================================*/
                          
   while (theFact != NULL)
     {
      if (theFact->whichDeftemplate->inScope) return((VOID *) theFact);
        
      theFact = theFact->nextFact;
     }
     
   return(NULL);
  }

/*******************************************/
/* GetFactPPForm: Returns the pretty print */
/*   representation of a fact.             */
/*******************************************/
globle VOID GetFactPPForm(buffer,bufferLength,theFact)
  char *buffer;
  int bufferLength;
  VOID *theFact;
  {
   OpenStringDestination("FactPPForm",buffer,bufferLength);
   PrintFactWithIdentifier("FactPPForm",(struct fact *) theFact);
   CloseStringDestination("FactPPForm");
  }

/***********************************/
/* FactIndex: C access routine for */
/*   the fact-index function.      */
/***********************************/
globle long int FactIndex(factPtr)
  VOID *factPtr;
  {
   return(((struct fact *) factPtr)->factIndex);
  }

/**************************************/
/* AssertString: C access routine for */
/*   the assert-string function.      */
/**************************************/
globle VOID *AssertString(theString)
  char *theString;
  {
   struct fact *theFact;

   if ((theFact = StringToFact(theString)) == NULL) return(NULL);

   return((VOID *) Assert((VOID *) theFact));
  }

/******************************************************/
/* GetFactListChanged: Returns the flag indicating    */
/*   whether a change to the fact-list has been made. */
/******************************************************/
globle int GetFactListChanged()
  { return(ChangeToFactList); }

/********************************************************/
/* SetFactListChanged: Sets the flag indicating whether */
/*   a change to the fact-list has been made.           */
/********************************************************/
globle VOID SetFactListChanged(value)
  int value;
  {
   ChangeToFactList = value;
  }

/****************************************/
/* GetNumberOfFacts: Returns the number */
/* of facts in the fact-list.           */
/****************************************/
globle long int GetNumberOfFacts()
  { return(NumberOfFacts); }

/***********************************************************/
/* ResetFacts: Reset function for facts. Sets the starting */
/*   fact index to zero and removes all facts.             */
/***********************************************************/
static VOID ResetFacts()
  {
   /*====================================*/
   /* Initialize the fact index to zero. */
   /*====================================*/

   NextFactIndex = 0L;

   /*======================================*/
   /* Remove all facts from the fact list. */
   /*======================================*/

   RemoveAllFacts();
  }
  
/************************************************************/
/* ClearFactsReady: Clear ready function for facts. Returns */
/*   TRUE if facts were successfully removed and the clear  */
/*   command can continue, otherwise FALSE.                 */
/************************************************************/
static int ClearFactsReady()
  {
   /*====================================*/
   /* Initialize the fact index to zero. */
   /*====================================*/

   NextFactIndex = 0L;

   /*======================================*/
   /* Remove all facts from the fact list. */
   /*======================================*/

   RemoveAllFacts();
   
   /*==============================================*/
   /* If for some reason there are any facts still */
   /* remaining, don't continue with the clear.    */
   /*==============================================*/
                    
   if (GetNextFact(NULL) != NULL) return(CLIPS_FALSE);
   
   /*=============================*/
   /* Return TRUE to indicate the */
   /* clear command can continue. */
   /*=============================*/
   
   return(CLIPS_TRUE);
  }

/***************************************************/
/* FindIndexedFact: Returns a pointer to a fact in */
/*   the fact list with the specified fact index.  */
/***************************************************/
globle struct fact *FindIndexedFact(factIndexSought)
  long int factIndexSought;
  {
   struct fact *theFact;

   for (theFact = (struct fact *) GetNextFact(NULL);
        theFact != NULL;
        theFact = (struct fact *) GetNextFact(theFact))
     {
      if (theFact->factIndex == factIndexSought)
        { return(theFact); }
     }

   return(NULL);
  }
  
#endif /* DEFTEMPLATE_CONSTRUCT && DEFRULE_CONSTRUCT */