(PowerBuilder) Compress Large Binary File in Blocks

Compresses a large binary file in blocks.

Note: This example requires Chilkat v11.0.0 or greater.

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

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 assumes 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 large binary file for reading.
li_Success = loo_FacSrc.OpenForRead("qa_data/bmp/big.bmp")
if li_Success = 0 then
    Write-Debug loo_FacSrc.LastErrorText
    destroy loo_FacSrc
    destroy loo_FacDest
    return
end if

// If we compress in 64K chunks, find out how many blocks there will be.
li_BlockSize = 65536
li_NumBlocks = loo_FacSrc.GetNumBlocks(li_BlockSize)

// Open an output file for the compressed data.
li_Success = loo_FacDest.OpenForWrite("c:/temp/qa_output/compressedBmp.dat")
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_FileBytes = loo_FacSrc.ReadBlock(i,li_BlockSize)
    loo_CompressedBytes = loo_Compress.CompressBytes(loo_FileBytes)

    loo_FacDest.FileWrite(loo_CompressedBytes)

    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 compressing file."


destroy loo_FacSrc
destroy loo_FacDest
destroy loo_Compress