PowerBuilder Requires Chilkat v11.0.0+

Decompress Large Binary File in Blocks

See more Compression Examples

Decompresses a large binary file in blocks. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_FacSrc
oleobject loo_FacDest
integer li_BlockSize
integer li_NumBlocks
oleobject loo_Compress
integer i

li_Success = 0

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

loo_FacSrc = create oleobject
li_rc = loo_FacSrc.ConnectToNewObject("Chilkat.FileAccess")
if li_rc < 0 then
    destroy loo_FacSrc
    MessageBox("Error","Connecting to COM object failed")
    return
end if
loo_FacDest = create oleobject
li_rc = loo_FacDest.ConnectToNewObject("Chilkat.FileAccess")

//  Open a previously compressed file for decompressing.
//  See Compress Large File in Blocks

li_Success = loo_FacSrc.OpenForRead("c:/temp/qa_output/compressedBmp.dat")
if li_Success = 0 then
    Write-Debug loo_FacSrc.LastErrorText
    destroy loo_FacSrc
    destroy loo_FacDest
    return
end if

//  If we compress in 32K chunks, find out how many blocks there will be.
li_BlockSize = 32768
li_NumBlocks = loo_FacSrc.GetNumBlocks(li_BlockSize)

//  Open an output file for the decompressed data.
li_Success = loo_FacDest.OpenForWrite("c:/temp/qa_output/decompressed.bmp")
if li_Success = 0 then
    Write-Debug loo_FacDest.LastErrorText
    destroy loo_FacSrc
    destroy loo_FacDest
    return
end if

loo_Compress = create oleobject
li_rc = loo_Compress.ConnectToNewObject("Chilkat.Compression")

loo_Compress.Algorithm = "deflate"

//  Assuming numBlocks > 1
loo_Compress.FirstChunk = 1
loo_Compress.LastChunk = 0

i = 0
do while i < li_NumBlocks
    loo_CompressedBytes = loo_FacSrc.ReadBlock(i,li_BlockSize)

    loo_DecompressedBytes = loo_Compress.DecompressBytes(loo_CompressedBytes)
    loo_FacDest.FileWrite(loo_DecompressedBytes)

    i = i + 1

    loo_Compress.FirstChunk = 0
    if i = (li_NumBlocks - 1) then
        loo_Compress.LastChunk = 1
    end if

loop

loo_FacSrc.FileClose()
loo_FacDest.FileClose()

Write-Debug "Finished decompressing file."


destroy loo_FacSrc
destroy loo_FacDest
destroy loo_Compress