(Lianja) File Read Blocks

Demonstrates how to read a file in fixed-size blocks (except for the very last block).

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// Demonstrates how to read a file in blocks,
// which can be useful when uploading to cloud storage
// services such as Azure, S3, Google, etc.

// For this example, we're simply writing the blocks
// to an output file, and then checking to see if the
// resulting file contents equals the original file contents.

loFacSrc = createobject("CkFileAccess")
loFacDest = createobject("CkFileAccess")

lcSrcPath = "qa_data/xml/hamlet.xml"
lcDestPath = "qa_output/hamletOut.xml"

llSuccess = loFacSrc.OpenForRead(lcSrcPath)
llSuccess = loFacDest.OpenForWrite(lcDestPath)
// Assuming success for the example..

// How many 1024-byte blocks?  (Including 1 for the last partial block)
lnNumBlocks = loFacSrc.GetNumBlocks(1024)

i = 0
do while (i < lnNumBlocks)
    loDataBlock = loFacSrc.ReadBlock(i,1024)
    if (loFacSrc.LastMethodSuccess <> .T.) then
        ? loFacSrc.LastErrorText
        release loFacSrc
        release loFacDest
        return
    endif

    llSuccess = loFacDest.FileWrite(loDataBlock)
    if (llSuccess <> .T.) then
        ? loFacDest.LastErrorText
        release loFacSrc
        release loFacDest
        return
    endif

    i = i + 1
enddo

loFacSrc.FileClose()
loFacDest.FileClose()

llBEqual = loFacSrc.FileContentsEqual(lcSrcPath,lcDestPath)
if (llBEqual <> .T.) then
    ? "Something went wrong!"
    release loFacSrc
    release loFacDest
    return
endif

? "File successfully copied by blocks."


release loFacSrc
release loFacDest