(Swift) Unzip a Text File Entry into a StringBuilder Using ZipEntry.UnzipToSb

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This example demonstrates how to use the ZipEntry.UnzipToSb method to inflate a text file entry directly into a StringBuilder object.

The ZIP entry is uncompressed entirely in memory and appended to the StringBuilder without creating a temporary file on disk.

This is useful when:

• Processing text files directly in memory
• Avoiding temporary filesystem files
• Reading configuration files, JSON, XML, CSV, or source code from ZIP archives
• Automatically converting line endings while inflating the text

The srcCharset argument specifies how the uncompressed bytes should be interpreted, such as:

• utf-8
• utf-16
• windows-1252

The lineEndingBehavior argument controls line-ending conversion:

• 0 — Leave line endings unchanged
• 1 — Convert all line endings to bare LF
• 2 — Convert all line endings to CRLF

Suppose the ZIP archive contains:

config/settings.json

The example inflates the JSON file directly into a StringBuilder.

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func chilkatTest() {
    var success: Bool = false

    let zip = CkoZip()!

    // Open an existing ZIP archive.
    success = zip.open("qa_data/zips/configFiles.zip")
    if success == false {
        print("\(zip.lastErrorText!)")
        return
    }

    // Locate the JSON file entry within the ZIP archive.
    let entry = CkoZipEntry()!

    success = zip.entry(of: "config/settings.json", entry: entry)
    if success == false {
        print("ZIP entry not found.")
        zip.close()
        return
    }

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a StringBuilder.
    // 
    // The uncompressed text is appended to the StringBuilder.
    // 
    let sb = CkoStringBuilder()!

    // Leave line endings unchanged.
    var lineEndingBehavior: Int = 0

    // Interpret the uncompressed bytes as UTF-8 text.
    var srcCharset: String? = "utf-8"

    success = entry.unzip(toSb: lineEndingBehavior, srcCharset: srcCharset, sb: sb)
    if success == false {
        print("\(entry.lastErrorText!)")
        return
    }

    print("Uncompressed text:")
    print("")
    print("\(sb.getAsString()!)")

    zip.close()

    print("Done.")

}