Arrays of Arrays - Any way to implement?

[Andrew Peskin]

I have run into a problem solving a problem mentioned in an earlier post (the problem with multiple instantiations). My problem is I would like to create an array of arrays (something possible with VB but apparently not in PB). I need the ability to create (dynamically) x number of arrays of unknown sizes. For Example:

I have a function which can be called an unknown number of times, and with each unique call of that function I need to set up some data storage. I would like to create a master Data-Storage array with each element being an array of actual data being stored. This approach would allow me to continually redim preserve the array allowing it to grow as needed.

	Val1 = MyFunc(5,Init)
	Val2 = MyFunc(7,Init)
	.
	.
	.
	Val9 = MyFunc(25,Init)

With each init call of this function, I would add a new element array of data to the master array.

	ReDim DataStorage(1:1)
	ReDim DataStorage(1).(1:5)

	ReDim Preserve DataStorage(1:2)
	ReDim DataStorage(2).(1:7)

	.
	.
	.

	ReDim Preserve DataStorage(1:9)
	ReDim DataStorage(9).(1:25)

My question is, what is the best (and easiest) way to implement something like this in PowerBasic? Any and all suggestions/advice is welcomed!

Thank you in advance for your help.

Best regards,

Andrew Peskin
[email protected]





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[Tim Wisseman]

How about:

DIM ArrayStart(1 to 100) As Global Long '// Where the data starts
DIM ArrayLen(1 to 100) As Global  Long   '// How much data there is
DIM ArrayData(1 To 10000) As Global  Long '// The data array
DIM g_Position As Global Long

Sub AddData(index As Long, dataPTR As Long PTR, vCount As Long)
Dim i As Long
Dim v1PTR As Long Ptr
Dim vStart As Long
Dim v As Long
   vStart = g_Position + 1
   If (vStart + vCount) > UBound(ArrayData) Then
      v = UBOUND(ArrayData) + vCount + 1000
      Redim Preserve ArrayData(1 To v)
   End If
   If index > UBound(ArrayStart) Then
      v = index + 1000
      Redim Preserve ArrayStart(1 To v)
      Redim Preserve ArrayLen(1 To v)
   End If
   v1PTR = VARPTR(ArrayData(vStart))
   For i = 1 To vCount
      @v1PTR[i - 1] = @dataPTR[i - 1]   
   Next i
   ArrayStart(index) = vStart
   ArrayLen(index) = vCount
   g_Position = g_Position + vCount
End Sub

Function ReadArray(index As Long, element As Long) As Long
   If element > ArrayLen(index) Then
      msgbox "ERROR!!! Out of bounds!"
   End If
   ReadArray = ArrayData(ArrayStart(index) + element - 1)
End Function

'////
Using the sub:
Dim temp1(1 to 777) As Long
Dim temp2(1 to 176) As Long
Dim i As Long
Dim v1PTR As Long Ptr
   For i = 1 to 777
      temp1(i) = Rnd * 3000
   Next i
   For i = 1 to 176
      temp2(i) = Rnd * 3000
   Next i

   v1PTR = VARPTR(temp1(1))
   AddData 1, v1PTR, 777

   v1PTR = VARPTR(temp2(1))
   AddData 2, v1PTR, 176

   i = ReadArray(1, 211) '// Read element 211 from array 1
   i = ReadArray(2, 122) '// Read element 122 from array 2

[This message has been edited by Tim Wisseman (edited October 03, 2000).]

[Tim Wisseman]

I made an even easier example that does not use pointers

DIM ArrayStart(1 to 100) As Global Long '// Where the data starts
DIM ArrayLen(1 to 100) As Global  Long   '// How much data there is
DIM ArrayData(1 To 10000) As Global  Long '// The data array
DIM g_Position As Global Long

Sub MakeArray(index As Long, vSize As Long)
Dim vStart As Long
Dim v As Long
   vStart = g_Position + 1
   If (vStart + vSize) > UBound(ArrayData) Then
      v = UBOUND(ArrayData) + vSize + 1000
      Redim Preserve ArrayData(1 To v)
   End If
   If index > UBound(ArrayStart) Then
      v = index + 1000
      Redim Preserve ArrayStart(1 To v)
      Redim Preserve ArrayLen(1 To v)
   End If
   ArrayStart(index) = vStart
   ArrayLen(index) = vSize
   g_Position = g_Position + vSize
End Sub

Sub WriteArray(index As Long, vElement As Long, vValue As Long)
   ArrayData(ArrayStart(index) + vElement - 1) = vValue
End Sub

Function ReadArray(index As Long, vElement As Long) As Long
   ReadArray = ArrayData(ArrayStart(index) + vElement - 1)
End Function
'//
'////Using the sub:
'// I will make 4 arrays of 4 different sizes
MakeArray 1, 177  'Array 1 has 177 elements
MakeArray 2, 188
MakeArray 3, 200
MakeArray 4, 19
'//
'//
'// I will write data to the array
WriteArray 1, 56, 13  '// Write to array 1, set element 56 to a value of 13
WriteArray 3, 199, 1
'// Read data from the array
i = ReadArray(1, 56)  '// Read array 1 element 56

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