String Heap

[kevin]

  String Heap - Bank Version

    This code lets the user store a bunch of the string data in bank with a reference table.  So it's kind of simulating an array, except all the data is in one place,  rather than separate strings.   So if your program needs a lot of static string data, you could dump it all into the heap,  then save/reload the banks.

PlayBASIC Code: [Select]

   // alloc the heap
   Init_String_Heap()


   // make a bunhc of dummy strings and store them on heap

   t=timer()
   for lp =0 to 1000
      AddHeapString(make$("HelloWorld"+Str$(lp),(lp and 15)+1 ))
   next
   print "time:"+str$(timer()-t)
   
   print "HeapSize:"+str$(heapsize)

   ; SHow the strings on screen
   for lp =0 to heapsize
      print ReadHeapString$(lp)
   next

   
   Sync
   waitkey



   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------


   Type tStringHeapTable
         offset
         Size
   EndTYpe

   global HeapSize      =0         ; number of strings in heap
   global HeapMaxSize   =0         ; Max number of string in heap before it needs a resize
   global HeapCache      =0         ; bank used for string cache
   global HeapTable      =0         ; bank used for reference table 



Function Init_String_Heap(MinNumberOfStrings=4096)

      HeapCache   =NewBank(MinNumberOfStrings*256)
      HeapTable   =Newbank(MinNumberOfStrings*sizeof(tStringHeapTable))      
      
      HeapSize      =0
      HeapMaxSize   =MinNumberOfStrings      

EndFUnction





   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------


Function ReadHeapString$(Index)
   dim ThisString as tStringHeapTable pointer

   if Index>=0 and index<HeapSize
      ThisString = getbankptr(HeapTable)+((INdex)*sizeof(tStringHeapTable))
      // write this into the table
      s$=PeekBankString(HeapCache,ThisString.Offset,ThisString.Size)
   endif

EndFunction S$


   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------


Function AddHeapString(s$)

   ; 
   StringSize=Len(s$)

   
   if (HeapSize+1) >=HeapMaxSize
         HeapMaxSize*=2
         ResizeBank HeapTable,HeapMaxSize*sizeof(tStringHeapTable)
   endif
   
   dim PreviousString as tStringHeapTable pointer
   dim ThisString as tStringHeapTable pointer
   
   tableptr=getbankptr(HeapTable)

   if HeapSize>0
      PreviousString = tableptr+((HeapSize-1)*sizeof(tStringHeapTable))
      Offset =PreviousString.offset
      Offset+=PreviousString.Size
   endif

   ThisString = tableptr+((HeapSize)*sizeof(tStringHeapTable))

   // write this into the table
   ThisString.Offset   =Offset
   ThisString.Size   =StringSize

   // check if the heap cache is big enough for this string ??
   CacheSize=GetBankSize(HeapCache)
   if (Offset+StringSize+100)>=CacheSize
         CacheSize=(Offset+StringSize+100)*2
         resizebank heapCache,CacheSize
   endif
   
   // poke the string into the cache 
   pokebankString HeapCache,offset,s$,0

   HeapSize++
   
EndFunction

   

[kevin]

  String Heap - String Cache Version

     This is an alternative version of the previous code, where the only difference is this version holds the cached strings in a single string and lets PB manage the string memory for us.

PlayBASIC Code: [Select]

   explicit on

   // alloc the heap
   Init_String_Heap()

   // make a bunhc of dummy strings and store them on heap

   local lp,t=timer()
   for lp =0 to 1000
      AddHeapString(make$("HelloWorld"+Str$(lp),(lp and 15)+1 ))
   next
   print "time:"+str$(timer()-t)
   
   print "Strings in Heap:"+str$(GetStringHeapSize())
   print "Heap Cache Size:"+str$(GetStringCacheSize())
   
   ; SHow the strings on screen
   for lp =0 to GetStringHeapSize()
      print ReadHeapString$(lp)
   next

   
   Sync
   waitkey



   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ;  [ STRING HEAP ]----------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------

   Type tStringHeapTable
         offset
         Size
   EndTYpe

   global HeapSize         =0         ; number of strings in heap
   global HeapMaxSize      =0         ; Max number of string in heap before it needs a resize
   global HeapCacheString$   =""      ; global string used to house string fragments
   
   global HeapTable         =0         ; bank used for reference table 



Function Init_String_Heap(MinNumberOfStrings=4096)


      // fill cache with some emtpy charcters
      HeapCacheString$=make$("      ",4096)
      // trim the size to zero without releasing the buffer
      HeapCacheString$=left$(HeapCacheString$,0)
      
      // alloc table
      HeapTable   =Newbank(MinNumberOfStrings*sizeof(tStringHeapTable))      
      
      HeapSize      =0
      HeapMaxSize   =MinNumberOfStrings      

EndFUnction



Function GetStringHeapSize()
         result=HeapSize
EndFunction Result


Function GetStringCacheSize()
         result=len(HeapCacheString$)
EndFunction Result


   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------


Function ReadHeapString$(Index)
   dim ThisString as tStringHeapTable pointer

   if Index>=0 and index<HeapSize
      ThisString = getbankptr(HeapTable)+((INdex)*sizeof(tStringHeapTable))
      // grab string fragment from the cache
      s$=mid$(HeapCacheString$,ThisString.Offset,ThisString.Size)
   endif

EndFunction S$


   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------
   ; --------------------------------------------------------------------------


Function AddHeapString(s$)

   ; 
   local StringSize=Len(s$)

   if (HeapSize+1) >=HeapMaxSize
         HeapMaxSize*=2
         ResizeBank HeapTable,HeapMaxSize*sizeof(tStringHeapTable)
   endif
   dim ThisString as tStringHeapTable pointer
   
   ThisString = getbankptr(HeapTable)+((HeapSize)*sizeof(tStringHeapTable))

   // write this into the table
   ThisString.Offset   =len(HeapCacheString$)
   ThisString.Size   =StringSize

   HeapCacheString$+=s$
   
   HeapSize++
   
EndFunction