constrnt.c

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   /*******************************************************/
   /*      "C" Language Integrated Production System      */
   /*                                                     */
   /*             CLIPS Version 6.05  04/09/97            */
   /*                                                     */
   /*                 CONSTRAINT MODULE                   */
   /*******************************************************/

/*************************************************************/
/* Purpose: Provides functions for creating and removing     */
/*   constraint records, adding them to the contraint hash   */
/*   table, and enabling and disabling static and dynamic    */
/*   constraint checking.                                    */
/*                                                           */
/* Principal Programmer(s):                                  */
/*      Gary D. Riley                                        */
/*                                                           */
/* Contributing Programmer(s):                               */
/*      Brian Donnell                                        */
/*                                                           */
/* Revision History:                                         */
/*                                                           */
/*************************************************************/

#define _CONSTRNT_SOURCE_

#include <stdio.h>
#define _CLIPS_STDIO_
#if ANSI_COMPILER
#include <stdlib.h>
#endif

#include "setup.h"

#include "constant.h"
#include "clipsmem.h"
#include "router.h"
#include "extnfunc.h"
#include "scanner.h"
#include "multifld.h"
#include "constrnt.h"
#include "argacces.h"

/***************************************/
/* LOCAL INTERNAL FUNCTION DEFINITIONS */
/***************************************/

#if ANSI_COMPILER
#if (! RUN_TIME) && (! BLOAD_ONLY)
   static VOID                     InstallConstraintRecord(CONSTRAINT_RECORD *);
   static int                      ConstraintCompare(struct constraintRecord *,struct constraintRecord *);
#endif
#if (! RUN_TIME)
   static VOID                     ReturnConstraintRecord(CONSTRAINT_RECORD *);
   static VOID                     DeinstallConstraintRecord(CONSTRAINT_RECORD *);
#endif
#else
#if (! RUN_TIME) && (! BLOAD_ONLY)
   static VOID                     InstallConstraintRecord();
   static int                      ConstraintCompare();
#endif
#if (! RUN_TIME)
   static VOID                     ReturnConstraintRecord();
   static VOID                     DeinstallConstraintRecord();
#endif
#endif

/****************************************/
/* GLOBAL INTERNAL VARIABLE DEFINITIONS */
/****************************************/

   globle struct constraintRecord   **ConstraintHashtable;
   
/***************************************/
/* LOCAL INTERNAL VARIABLE DEFINITIONS */
/***************************************/
 
   static BOOLEAN                     StaticConstraintChecking = CLIPS_TRUE;
   static BOOLEAN                     DynamicConstraintChecking = CLIPS_FALSE;

/*****************************************************/
/* InitializeConstraints: Initializes the constraint */
/*   hash table to NULL and defines the static and   */
/*   dynamic constraint access functions.            */
/*****************************************************/
globle VOID InitializeConstraints()
   {
#if (! RUN_TIME) && (! BLOAD_ONLY)
    int i;
    
    ConstraintHashtable = (struct constraintRecord **) 
                          gm2((int) sizeof (struct constraintRecord *) * 
                                    SIZE_CONSTRAINT_HASH);

    if (ConstraintHashtable == NULL) ExitCLIPS(1);

    for (i = 0; i < SIZE_CONSTRAINT_HASH; i++) ConstraintHashtable[i] = NULL;

#endif

#if (! RUN_TIME)    
   DefineFunction2("get-dynamic-constraint-checking",'b',GDCCommand,"GDCCommand", "00");
   DefineFunction2("set-dynamic-constraint-checking",'b',SDCCommand,"SDCCommand", "11");
   
   DefineFunction2("get-static-constraint-checking",'b',GSCCommand,"GSCCommand", "00");
   DefineFunction2("set-static-constraint-checking",'b',SSCCommand,"SSCCommand", "11");
#endif
  }

#if (! RUN_TIME)

/*************************************************************/
/* ReturnConstraintRecord: Frees the data structures used by */
/*   a constraint record. If the returnOnlyFields argument   */
/*   is FALSE, then the constraint record is also freed.     */
/*************************************************************/
static VOID ReturnConstraintRecord(constraints)
  CONSTRAINT_RECORD *constraints;
  {    
   if (constraints == NULL) return;
   
   if (constraints->bucket < 0)
     {
      ReturnExpression(constraints->restrictionList);
      ReturnExpression(constraints->maxValue);
      ReturnExpression(constraints->minValue);
      ReturnExpression(constraints->minFields);
      ReturnExpression(constraints->maxFields);
     }
     
   ReturnConstraintRecord(constraints->multifield); 
   
   rtn_struct(constraintRecord,constraints);
  }

/***************************************************/
/* DeinstallConstraintRecord: Decrements the count */
/*   values of all occurrences of primitive data   */
/*   types found in a constraint record.           */
/***************************************************/
static VOID DeinstallConstraintRecord(constraints)
  CONSTRAINT_RECORD *constraints;
  {   
   if (constraints->bucket >= 0)
     {
      RemoveHashedExpression(constraints->restrictionList);
      RemoveHashedExpression(constraints->maxValue);
      RemoveHashedExpression(constraints->minValue);
      RemoveHashedExpression(constraints->minFields);
      RemoveHashedExpression(constraints->maxFields);
     }
   else
     {
      ExpressionDeinstall(constraints->restrictionList);
      ExpressionDeinstall(constraints->maxValue);
      ExpressionDeinstall(constraints->minValue);
      ExpressionDeinstall(constraints->minFields);
      ExpressionDeinstall(constraints->maxFields);
     }
     
   if (constraints->multifield != NULL)                             
     { DeinstallConstraintRecord(constraints->multifield); }
  }

/******************************************/
/* RemoveConstraint: Removes a constraint */
/*   from the constraint hash table.      */
/******************************************/
globle VOID RemoveConstraint(theConstraint)
  struct constraintRecord *theConstraint;
  {
   struct constraintRecord *tmpPtr, *prevPtr = NULL;

   if (theConstraint == NULL) return;
   
   /*========================================*/
   /* If the bucket value is less than zero, */
   /* then the constraint wasn't stored in   */
   /* the hash table.                        */
   /*========================================*/
   
   if (theConstraint->bucket < 0)
     {
      ReturnConstraintRecord(theConstraint);
      return;
     }
   
   /*================================*/
   /* Find and remove the constraint */
   /* from the contraint hash table. */
   /*================================*/
   
   tmpPtr = ConstraintHashtable[theConstraint->bucket];
   while (tmpPtr != NULL)
     {
      if (tmpPtr == theConstraint)
        {
         theConstraint->count--;
         if (theConstraint->count == 0)
           {
            if (prevPtr == NULL) 
              { ConstraintHashtable[theConstraint->bucket] = theConstraint->next; }
            else
              { prevPtr->next = theConstraint->next; }
            DeinstallConstraintRecord(theConstraint);
            ReturnConstraintRecord(theConstraint);
           }
         return;
        }
        
      prevPtr = tmpPtr;
      tmpPtr = tmpPtr->next;
     }
     
   return;
  }
  
#endif /* (! RUN_TIME) */
  
#if (! RUN_TIME) && (! BLOAD_ONLY)    

/***********************************/
/* HashConstraint: Returns a hash  */
/*   value for a given constraint. */
/***********************************/
globle int HashConstraint(theConstraint)
  struct constraintRecord *theConstraint;
  {
   int i = 0;
   unsigned int count = 0;
   int hashValue;
   struct expr *tmpPtr;

   count +=       
      (theConstraint->anyAllowed * 17) +
      (theConstraint->symbolsAllowed * 5) +
      (theConstraint->stringsAllowed * 23) +
      (theConstraint->floatsAllowed * 19) +
      (theConstraint->integersAllowed * 29) +
      (theConstraint->instanceNamesAllowed * 31) +
      (theConstraint->instanceAddressesAllowed * 17);
      
   count +=
      (theConstraint->externalAddressesAllowed * 29) +
      (theConstraint->multifieldsAllowed * 29) +
      (theConstraint->factAddressesAllowed * 79) +
      (theConstraint->anyRestriction * 59) +
      (theConstraint->symbolRestriction * 61);
   count +=
      (theConstraint->stringRestriction * 3) +
      (theConstraint->floatRestriction * 37) +
      (theConstraint->integerRestriction * 9) +
      (theConstraint->instanceNameRestriction * 7);
   
   for (tmpPtr = theConstraint->restrictionList; tmpPtr != NULL; tmpPtr = tmpPtr->nextArg)
     { count += GetAtomicHashValue(tmpPtr->type,tmpPtr->value,i++); }
     
   for (tmpPtr = theConstraint->minValue; tmpPtr != NULL; tmpPtr = tmpPtr->nextArg)
     { count += GetAtomicHashValue(tmpPtr->type,tmpPtr->value,i++); }
     
   for (tmpPtr = theConstraint->maxValue; tmpPtr != NULL; tmpPtr = tmpPtr->nextArg)
     { count += GetAtomicHashValue(tmpPtr->type,tmpPtr->value,i++); }
     
   for (tmpPtr = theConstraint->minFields; tmpPtr != NULL; tmpPtr = tmpPtr->nextArg)
     { count += GetAtomicHashValue(tmpPtr->type,tmpPtr->value,i++); }
     
   for (tmpPtr = theConstraint->maxFields; tmpPtr != NULL; tmpPtr = tmpPtr->nextArg)
     { count += GetAtomicHashValue(tmpPtr->type,tmpPtr->value,i++); }
   
   if (theConstraint->multifield != NULL)           
     { count += HashConstraint(theConstraint->multifield); }
     
   hashValue = (int) (count % SIZE_CONSTRAINT_HASH);
   if (hashValue < 0) hashValue = - hashValue;
   return(hashValue);
  }