(Tcl) 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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load ./chilkat.dll

set success 0

set zip [new_CkZip]

# Open an existing ZIP archive.
set success [CkZip_OpenZip $zip "qa_data/zips/configFiles.zip"]
if {$success == 0} then {
    puts [CkZip_lastErrorText $zip]
    delete_CkZip $zip
    exit
}

# Locate the JSON file entry within the ZIP archive.
set entry [new_CkZipEntry]

set success [CkZip_EntryOf $zip "config/settings.json" $entry]
if {$success == 0} then {
    puts "ZIP entry not found."
    CkZip_CloseZip $zip
    delete_CkZip $zip
    delete_CkZipEntry $entry
    exit
}

# ------------------------------------------------------------
# Inflate the ZIP entry directly into a StringBuilder.
# 
# The uncompressed text is appended to the StringBuilder.
# 
set sb [new_CkStringBuilder]

# Leave line endings unchanged.
set lineEndingBehavior 0

# Interpret the uncompressed bytes as UTF-8 text.
set srcCharset "utf-8"

set success [CkZipEntry_UnzipToSb $entry $lineEndingBehavior $srcCharset $sb]
if {$success == 0} then {
    puts [CkZipEntry_lastErrorText $entry]
    delete_CkZip $zip
    delete_CkZipEntry $entry
    delete_CkStringBuilder $sb
    exit
}

puts "Uncompressed text:"
puts 
puts [CkStringBuilder_getAsString $sb]

CkZip_CloseZip $zip

puts "Done."

delete_CkZip $zip
delete_CkZipEntry $entry
delete_CkStringBuilder $sb