Extract files from a zip whose central directory is damaged

Last resort in extract_zip_files(). Some IRS zips cannot be opened by index; reading them front to back from the local file headers works for entries compressed with ordinary Deflate. The zip is piped through libarchive's bsdtar in streaming mode and only the wanted files are extracted. On Deflate64 entries bsdtar writes zero-filled files, which is why the caller validates the output.

Usage

stream_unzip(zf, files, dest)

Arguments

zf

Path to the zip file.

files

File names (no folder) to extract.

dest

Folder to put them in, without the zip's internal folders.

Value

The base names of the files extracted.

Details

Needs bsdtar. It ships with Windows 10+ as %SystemRoot%\System32\tar.exe, and with macOS as tar. GNU tar cannot read zip files. A large zip takes a few minutes, because it is read in full.