PureBasic

Compressing StringBuilder Data Using CompressSb (Single Call and Chunked)

See more Compression Examples

This example demonstrates how to compress text stored in a StringBuilder using the CompressSb method in two ways:

1. Single-call compression, where the entire input is compressed in one operation.
2. Chunked compression, where the input is split into multiple parts and processed sequentially using the FirstChunk and LastChunk properties.

The example shows how compressed output is appended to a BinData object, and how the result can be verified by decompressing back to the original text. This is useful for both simple use cases and scenarios where data is processed incrementally (such as streaming or large inputs).

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Key Points

• CompressSb converts text to bytes using the Charset property (UTF-8 recommended).
• Compressed data is appended to a BinData object.
• When both FirstChunk and LastChunk are true, compression is done in a single call.
• For chunked processing:
  • First chunk → FirstChunk = true, LastChunk = false
  • Middle chunks → both false
  • Final chunk → LastChunk = true
• Chunked compression is useful when processing data incrementally.

PureBasic

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

Procedure ChilkatExample()

    success.i = 0

    ; This example assumes the Chilkat API has already been unlocked.
    ; See Global Unlock Sample for sample code.

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

    CkCompression::setCkAlgorithm(compress, "zlib")

    ; ================================================================
    ; 1) Single-call compression (entire data in one call)
    ; ================================================================

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

    CkStringBuilder::ckAppend(sb,"The quick brown fox jumps over the lazy dog. ")
    CkStringBuilder::ckAppend(sb,"This is a simple example using CompressSb.")

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

    ; When both FirstChunk and LastChunk are true (the defaults),
    ; the entire compression happens in a single call.
    CkCompression::setCkFirstChunk(compress, 1)
    CkCompression::setCkLastChunk(compress, 1)

    success = CkCompression::ckCompressSb(compress,sb,bdCompressed)
    If success = 0
        Debug CkCompression::ckLastErrorText(compress)
        CkCompression::ckDispose(compress)
        CkStringBuilder::ckDispose(sb)
        CkBinData::ckDispose(bdCompressed)
        ProcedureReturn
    EndIf

    compressedBase64.s = CkBinData::ckGetEncoded(bdCompressed,"base64")

    Debug "Single-call compressed (base64):"
    Debug compressedBase64

    ; ================================================================
    ; 2) Chunked compression using FirstChunk / LastChunk
    ; ================================================================

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

    ; First chunk
    CkCompression::setCkFirstChunk(compress, 1)
    CkCompression::setCkLastChunk(compress, 0)

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

    CkStringBuilder::ckAppend(sbPart,"The quick brown fox ")

    success = CkCompression::ckCompressSb(compress,sbPart,bdChunkedOut)
    If success = 0
        Debug CkCompression::ckLastErrorText(compress)
        CkCompression::ckDispose(compress)
        CkStringBuilder::ckDispose(sb)
        CkBinData::ckDispose(bdCompressed)
        CkBinData::ckDispose(bdChunkedOut)
        CkStringBuilder::ckDispose(sbPart)
        ProcedureReturn
    EndIf

    ; Middle chunk
    CkCompression::setCkFirstChunk(compress, 0)
    CkCompression::setCkLastChunk(compress, 0)

    CkStringBuilder::ckClear(sbPart)
    CkStringBuilder::ckAppend(sbPart,"jumps over the lazy dog. ")

    success = CkCompression::ckCompressSb(compress,sbPart,bdChunkedOut)
    If success = 0
        Debug CkCompression::ckLastErrorText(compress)
        CkCompression::ckDispose(compress)
        CkStringBuilder::ckDispose(sb)
        CkBinData::ckDispose(bdCompressed)
        CkBinData::ckDispose(bdChunkedOut)
        CkStringBuilder::ckDispose(sbPart)
        ProcedureReturn
    EndIf

    ; Final chunk
    CkCompression::setCkFirstChunk(compress, 0)
    CkCompression::setCkLastChunk(compress, 1)

    CkStringBuilder::ckClear(sbPart)
    CkStringBuilder::ckAppend(sbPart,"This is a chunked CompressSb example.")

    success = CkCompression::ckCompressSb(compress,sbPart,bdChunkedOut)
    If success = 0
        Debug CkCompression::ckLastErrorText(compress)
        CkCompression::ckDispose(compress)
        CkStringBuilder::ckDispose(sb)
        CkBinData::ckDispose(bdCompressed)
        CkBinData::ckDispose(bdChunkedOut)
        CkStringBuilder::ckDispose(sbPart)
        ProcedureReturn
    EndIf

    chunkedBase64.s = CkBinData::ckGetEncoded(bdChunkedOut,"base64")

    Debug "Chunked compressed (base64):"
    Debug chunkedBase64

    ; ================================================================
    ; 3) Decompress to verify correctness
    ; ================================================================

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

    ; Decompress in a single call (entire data already assembled)
    CkCompression::setCkFirstChunk(compress, 1)
    CkCompression::setCkLastChunk(compress, 1)

    success = CkCompression::ckDecompressSb(compress,bdChunkedOut,sbDecompressed)
    If success = 0
        Debug CkCompression::ckLastErrorText(compress)
        CkCompression::ckDispose(compress)
        CkStringBuilder::ckDispose(sb)
        CkBinData::ckDispose(bdCompressed)
        CkBinData::ckDispose(bdChunkedOut)
        CkStringBuilder::ckDispose(sbPart)
        CkStringBuilder::ckDispose(sbDecompressed)
        ProcedureReturn
    EndIf

    Debug "Decompressed text:"
    Debug CkStringBuilder::ckGetAsString(sbDecompressed)


    CkCompression::ckDispose(compress)
    CkStringBuilder::ckDispose(sb)
    CkBinData::ckDispose(bdCompressed)
    CkBinData::ckDispose(bdChunkedOut)
    CkStringBuilder::ckDispose(sbPart)
    CkStringBuilder::ckDispose(sbDecompressed)


    ProcedureReturn
EndProcedure