Parameter Bucket

[kevin]

Parameter Bucket

     This example uses a bank as a type of memory bucket to hold lists of Parameter pairs.  You can alter the parameters type and add your own read/write functions, but the idea here to set up a structure than the user recreated every frame without actually destorying it.  So at the end of each frame after we write a bunch of nonsense data into the bucket we just reset the buckets internal pointer to the start and keep going..
   

PlayBASIC Code: [Select]

      // Set up the Bucket, which is just a global bank we're
      // poking directly into
      AllocParamBucket()


      // ---------------------------------------------------------
      do
      // ---------------------------------------------------------

         Cls 0

         TestCount++
         ink $ff0000
         print "Running Test #"+Str$(TestCount)
         ink -1      
         print fps()
         
         //  Allocate the FIRST item in this list
         MyList=   NewParamBucketList()

         //  Remember this offset and Set the data fields
         CurrentOffset=MyList         
         // Set the data at this offset
         SetParamToBucket(CurrentOffset,"Hello","World")

         //  Add some more dummy data to the list
         for lp =0 to rndrange(1,100)
            //   add a new item to end of this list      
            CurrentOffset =AddParamToBucket(CurrentOffset)
            //  write data into it
            SetParamToBucket(CurrentOffset,"Hello"+str$(lp),"World"+str$(lp))
         next

         // Display This List    
           ShowParamBucketList(MyList)
       

            
            // reset the Bucket to it's initial state...
            // Next frame we're over writing the same memory 
            ResetParamBucket()
            

         sync
      loop spacekey()=true      





   type tParamBucket
         Bank
         BankPtr
         BankSize
         CurrentOffset      
   EndType

   Dim ParamBucket as tParamBucket


   type tParams
         LinkOffset      ; Bytes to next item in this list
         Name$   
         Value$
   EndType   



Function AllocParamBucket()
   
   Dim ParamBucket as tParamBucket
   ParamBucket = new tParamBucket
   
   size = $10000
   Bank=newBank(Size)   
   if Bank
      
      paramBucket.bank       = Bank
      paramBucket.BankPtr    = getBankPtr(Bank)
      paramBucket.BankSize   = Size
      
      ResetParamBucket()
      
   endif   
EndFunction



Function ResetParamBucket()
      paramBucket.CurrentOffset = 16
EndFunction

Function NewParamBucketList()

   if paramBucket.bank
         ListOffset = ParamBucket.CurrentOffset

         dim Link as tparams pointer
         Link =ParamBucket.BankPtr + ListOffset

         //  Force The List to next Object to be ZERO
         Link.LinkOffset = 0
         Link.Name$   =""
         Link.Value   =""
         //  Move the current pointer past this 
         ParamBucket.CurrentOffset+=sizeof(tparams)
   endif
EndFunction ListOffset





Function AddParamToBucket(ListOffset)

   if paramBucket.bank

   // check we're within the bucket size for the entry link
   if range(ListOffset,1,ParamBucket.BankSize)
      
         // Check if this is the last lilnk ??
         dim Search as tparams pointer
         Search =ParamBucket.BankPtr + ListOffset

         // step to the end of this list
         While Search.LinkOffset <>0      
               // Move the search pointer to the next link in this list
                  Search =ParamBucket.BankPtr +Search.LinkOffset
         EndWhile
      
         //  Get the current free item from the global
         NewParamOffset       = ParamBucket.CurrentOffset

         // Point the last fragment at this new fragment
         Search.LinkOffset    = NewParamOffset
      
      
         //  Reused Search pointer to init this new fragment
         Search =ParamBucket.BankPtr +Search.LinkOffset

         //  Flush this fragment out to it's empty state         
         Search.LinkOffset   =   0         
         Search.Value   =   ""         
         Search.Name      =   ""      

         //  Move the current pointer past this 
         ParamBucket.CurrentOffset+=sizeof(tparams)
                        

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