(PowerBuilder) Decompress Large Binary File in Blocks

Decompresses a large binary file in blocks. This example uses BeginDecompressBytes, MoreDecompressBytes, and EndDecompressBytes.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

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

loo_FacSrc = create oleobject
// Use "Chilkat_9_5_0.FileAccess" for versions of Chilkat < 10.0.0
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
// Use "Chilkat_9_5_0.FileAccess" for versions of Chilkat < 10.0.0
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("qa_data/bmp/compressedBmp.dat")
if li_Success <> 1 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("qa_output/decompressed.bmp")
if li_Success <> 1 then
    Write-Debug loo_FacDest.LastErrorText
    destroy loo_FacSrc
    destroy loo_FacDest
    return
end if

loo_Compress = create oleobject
// Use "Chilkat_9_5_0.Compression" for versions of Chilkat < 10.0.0
li_rc = loo_Compress.ConnectToNewObject("Chilkat.Compression")

loo_Compress.Algorithm = "deflate"

i = 0
do while i < li_NumBlocks
    loo_CompressedBytes = loo_FacSrc.ReadBlock(i,li_BlockSize)
    if i = 0 then
        loo_DecompressedBytes = loo_Compress.BeginDecompressBytes(loo_CompressedBytes)
    else
        loo_DecompressedBytes = loo_Compress.MoreDecompressBytes(loo_CompressedBytes)
    end if

    loo_FacDest.FileWrite(loo_DecompressedBytes)

    i = i + 1
loop

// At the very end, flush any remaining decompressed bytes, if any.
loo_DecompressedBytes = loo_Compress.EndDecompressBytes()
loo_FacDest.FileWrite(loo_DecompressedBytes)

loo_FacSrc.FileClose()
loo_FacDest.FileClose()

Write-Debug "Finished decompressing file."


destroy loo_FacSrc
destroy loo_FacDest
destroy loo_Compress