(C#) Compressing StringBuilder Data Using CompressSb (Single Call and Chunked)

See more Compression Examples

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).

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.

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bool success = false;

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

Chilkat.Compression compress = new Chilkat.Compression();
compress.Algorithm = "zlib";

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

Chilkat.StringBuilder sb = new Chilkat.StringBuilder();
sb.Append("The quick brown fox jumps over the lazy dog. ");
sb.Append("This is a simple example using CompressSb.");

Chilkat.BinData bdCompressed = new Chilkat.BinData();

// When both FirstChunk and LastChunk are true (the defaults),
// the entire compression happens in a single call.
compress.FirstChunk = true;
compress.LastChunk = true;

success = compress.CompressSb(sb,bdCompressed);
if (success == false) {
    Debug.WriteLine(compress.LastErrorText);
    return;
}

string compressedBase64 = bdCompressed.GetEncoded("base64");

Debug.WriteLine("Single-call compressed (base64):");
Debug.WriteLine(compressedBase64);

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

Chilkat.BinData bdChunkedOut = new Chilkat.BinData();

// First chunk
compress.FirstChunk = true;
compress.LastChunk = false;

Chilkat.StringBuilder sbPart = new Chilkat.StringBuilder();
sbPart.Append("The quick brown fox ");

success = compress.CompressSb(sbPart,bdChunkedOut);
if (success == false) {
    Debug.WriteLine(compress.LastErrorText);
    return;
}

// Middle chunk
compress.FirstChunk = false;
compress.LastChunk = false;

sbPart.Clear();
sbPart.Append("jumps over the lazy dog. ");

success = compress.CompressSb(sbPart,bdChunkedOut);
if (success == false) {
    Debug.WriteLine(compress.LastErrorText);
    return;
}

// Final chunk
compress.FirstChunk = false;
compress.LastChunk = true;

sbPart.Clear();
sbPart.Append("This is a chunked CompressSb example.");

success = compress.CompressSb(sbPart,bdChunkedOut);
if (success == false) {
    Debug.WriteLine(compress.LastErrorText);
    return;
}

string chunkedBase64 = bdChunkedOut.GetEncoded("base64");

Debug.WriteLine("Chunked compressed (base64):");
Debug.WriteLine(chunkedBase64);

// ================================================================
// 3) Decompress to verify correctness
// ================================================================

Chilkat.StringBuilder sbDecompressed = new Chilkat.StringBuilder();

// Decompress in a single call (entire data already assembled)
compress.FirstChunk = true;
compress.LastChunk = true;

success = compress.DecompressSb(bdChunkedOut,sbDecompressed);
if (success == false) {
    Debug.WriteLine(compress.LastErrorText);
    return;
}

Debug.WriteLine("Decompressed text:");
Debug.WriteLine(sbDecompressed.GetAsString());