Quickly copy a huge string array to a UDT array

[dreammanor]

I need to copy a huge 2D string array into a 2D UDT array, and I hope the speed can be as fast as possible. I'd like to know if there is a way to increase the speed of copying data. Thanks.

[Arnoutdv]

Can you provide some additional information?
What does your 2D UDT array looks like?
What kind of 2D string array do you have?

How big is a huge 2D string array?

[dreammanor]

Hi Arnoutdv, I just deleted the attachment code and re-posted the new demo code.

[Elroy]

Dreammanor,

The way you've organized things, you've got it about as fast as it's going to get, safely.

One idea is to swap string pointers, thereby making the string array have an empty string, and the UDT's string having the actual string. However, that's not a copy. That's a swap. And, you'd have to be very careful that you did it correctly, or you'd get a crash.

If you actually want to copy the strings, and they're variable length, what you've got is about as good as it gets.

My first thought is just to organize your code such that the strings are read into the UDT in the first place. However, maybe that's not possible.

Now, if you could re-organize things and use fixed-length-strings, you could take advantage of some other things. For instance, if you re-organized your UDT such that each element within it was an array, rather than the whole thing being an array, and you made all the strings fixed length, then you could use CopyMemory to copy the whole block of strings.

Here's what I propose for your UDT:

Private Type Item_Info
    Index() As Long
    Key() As String
    Text() As String * 20
End Type

Notice that each item is an array. Rather than have the whole UDT as an array, you'd Redim each element and just keep them the same number of dimensions.

Also notice that the string (Text) item is fixed length.

Then, you'd have to do the same to your string array:

Private m_arrText() As String * 20

Then, knowing the size of the arrays, you could use CopyMemory to copy all the string data in one-fell-swoop, very quick.

I didn't flesh out every detail, but the concepts are there. The whole idea is to get your strings such that they're in contiguous memory.

Good Luck,
Elroy

[dreammanor]

Hi Elroy, it's a good idea to use fixed-length strings or UDTs, which does improve performance. Thank you very much.

[DaveDavis]

Hi Elroy, it's a good idea to use fixed-length strings or UDTs, which does improve performance. Thank you very much.

this guy is still working hard on his Spread Grid.

[dreammanor]

this guy is still working hard on his Spread Grid.

You are very ignorant and full of malice. You may never get the Spread you want, and you will never understand what I'm doing.

Malicious speculation will never improve your programming skills.

[ChrisE]

Hi,

why not use a Flat File with ADO ?

here my go with the Array -> to UDT

put this in a Modul

Option Explicit

Public Type SampleType
   mName As String * 35
   mField1 As String * 19
   mField2 As String * 15
End Type

Public SampleData() As SampleType

and this in a Class

Option Explicit

Private Sample() As SampleType

Public Sub FillUDT(v As Variant)
'fill UDT

   Dim i As Long
   Dim s() As String

      'Variant in Array
      s() = v
      
      'fill UDT from Array
      ReDim Sample(UBound(s, 2))
      For i = LBound(s, 2) To UBound(s, 2)
         Sample(i).mName = s(0, i)
         Sample(i).mField1 = s(1, i)
         Sample(i).mField2 = s(2, i)
      Next
End Sub

Public Sub PrintData(Column As Long)

 
    Debug.Print "Class Sample-Column " & Column
     Debug.Print Sample(Column).mName; Sample(Column).mField1; Sample(Column).mField2; vbCrLf;
'    Debug.Print Sample(Column).mName
'    Debug.Print Sample(Column).mField1
'    Debug.Print Sample(Column).mField2
    Debug.Print "------------------------------------------------------------------------------"


End Sub

and this in a Form

Option Explicit

'Ref. class
Private c1 As Class1


Private Sub Command1_Click()
 Dim i As Long
   
      For i = LBound(SampleData) To UBound(SampleData)
         c1.PrintData i
      Next
End Sub

Private Sub Form_Load()
  Dim s() As String
   Dim var As Variant
   Dim i As Long
   
   
    Set c1 = New Class1
      
      'fill UDT
      ReDim SampleData(1)
      SampleData(0).mName = "Name1"
      SampleData(0).mField1 = "Field1"
      SampleData(0).mField2 = 111
      SampleData(1).mName = "Name2"
      SampleData(1).mField1 = "Field2"
      SampleData(1).mField2 = 222
   
      'UDT in Array
      ReDim s(2, UBound(SampleData))
      For i = LBound(SampleData) To UBound(SampleData)
         s(0, i) = SampleData(i).mName
         s(1, i) = SampleData(i).mField1
         s(2, i) = SampleData(i).mField2
      Next
      
      'Array in Variant
      var = s()
      
      'Variant -> Class
      c1.FillUDT var
End Sub

I didn't ckeck performance

hth

[DaveDavis]

You are very ignorant and full of malice. You may never get the Spread you want, and you will never understand what I'm doing.

Malicious speculation will never improve your programming skills.

It is not Malicious speculation. People need to know what are you doing so that they can provide expertise to make your grid's Data
or specific case be manageable.

[dreammanor]

It is not Malicious speculation. People need to know what are you doing so that they can provide expertise to make your grid's Data
or specific case be manageable.

If I'm wrong about you, I apologize to you.

I'm doing something that Microsoft is not willing to do, and these things will be of interest to all VB6ers. The difficulty and the workload of these things are so great that I don't know when I can finish it or whether I can continue to do it (because my work is often interrupted by other work), so I'll not disclose my plan for the time being. I think it would be more valuable to come up with a mature product that can be used directly in the future.

But one thing I can tell you is that it's not a difficult thing for me to develop a better Spread than FarpointSpread.