(PureBasic) Compress and Decompress Base64

Imagine we have data represented as a base64 string. This example demonstrates how to decode, compress, and re-encode to smaller base64 representing the compressed data.

Note: This example requires Chilkat v9.5.0.66 or greater.

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IncludeFile "CkBinData.pb"
IncludeFile "CkCompression.pb"

Procedure ChilkatExample()

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

    success.i

    strBase64.s = "VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NClRoZSBxdWljayBicm93biBmb3gganVtcGVkIG92ZXIgdGhlIGxhenkgZG9nLg0KVGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NCg0K"

    compress.i = CkCompression::ckCreate()
    If compress.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCompression::setCkAlgorithm(compress, "deflate")

    binDat.i = CkBinData::ckCreate()
    If binDat.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Load the base64 data into a BinData object.
    ; This decodes the base64. The decoded bytes will be contained in the BinData.
    CkBinData::ckAppendEncoded(binDat,strBase64,"base64")

    ; Compress the BinData.
    CkCompression::ckCompressBd(compress,binDat)

    ; Get the compressed data in base64 format:
    compressedBase64.s = CkBinData::ckGetEncoded(binDat,"base64")
    Debug "compressed base64:"
    Debug compressedBase64

    ; The compressed base64 is: C8lIVSgszUzOVkgqyi/PU0jLr1DIKs0tSE1RyC9LLVIoAcrnJFZVKqTkp+vxcoUMYeW8XAA=

    ; Now decompress:
    CkBinData::ckClear(binDat)
    CkBinData::ckAppendEncoded(binDat,compressedBase64,"base64")
    CkCompression::ckDecompressBd(compress,binDat)

    decompressedBase64.s = CkBinData::ckGetEncoded(binDat,"base64")
    Debug "decompressed base64:"
    Debug decompressedBase64

    ; The output is the original data:
    ; VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NClRoZSBxdWljayBicm93biBmb3gganVtcGVkIG92ZXIgdGhlIGxhenkgZG9nLg0KVGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NCg0K


    CkCompression::ckDispose(compress)
    CkBinData::ckDispose(binDat)


    ProcedureReturn
EndProcedure