Performance improvement splitting huge file

[bplus]

This is a simplified part of a more complex process to split 1 huge inFile into multiple smaller outFile() ones:

Code: (Select All)

  Dim As _Unsigned _Byte inPos, splitFiles, splitFile
  Dim As _Unsigned _Integer64 inSize, splitPos, splitSize
  Dim As _Unsigned _Byte inFile(1 To inSize), char
  Get #1, 1, inFile()
  Dim As String outFile(splitFiles)
  For splitFile = 1 To splitFiles
    outFile(splitFile) = String$(splitSize, 0)
  Next splitFile

  For splitPos = 1 To splitSize
    For splitFile = 1 To splitFiles
      inPos = inPos + 1
      If inPos <= inSize Then
        char = inFile(inPos)
        Mid$(outFile(splitFile), splitPos, 1) = Chr$(char)
      End If
    Next splitFile
  Next splitPos
  For splitFile = 1 To splitFiles
    Put #splitFile%, , outFile(splitFile)
  Next splitFile

inFile is the byte-array of the inputfile
inSize is the size in bytes of the inFile
inPos is the current characterposition of the inFile
outFile() are the strings build for the split-files
splitFiles is the number of files to split into
splitSize is the size in bytes of each outFile (e.g. roundup(inSize/splitFiles))
splitFile is current splitFile
splitPos is the current characterposition of the outFile

Above works, but variable length strings and the Mid$() command are very time-expensive (2GB inFile takes >10 minutes)

I've tried 2-dimensional byte-arrays for the out-files like outFile(files, length) , but QB64 does not support Put with one dimension like Put #x, , outFile(x)
I've also tried mapping this 2-dimensional array with _MEM but did not succeed so far.

Does anyone have a clever trick to speed this up?

Binary access, not clever but no splitting needed, just clever coding ;-)) You are not saying why you think you need to split.