#archive - tar / zip containers

Enable with use archive;. Bundle files into a tar or zip container and read them back, entirely over bytes - no fs dependency, value-semantic. Shares the pack / unpack verbs with compress (byte streams there, file bundles here); the container format is a string argument. Backed by Go's archive/tar + archive/zip; works on both binaries.

#Surface

format is "tar", "zip", or the gzip combo "tar.gz" (alias "tgz"). An unknown format, or corrupt input to unpack, is a positioned runtime error (catchable with try / catch).

unpack bounds untrusted input: the total decompressed payload of one call (summed across every entry) is capped at 256 MiB and the member count at 65536; past either cap it raises a normal catchable error instead of expanding a small "zip bomb" into gigabytes of memory. It also rejects any member whose name is an absolute path or escapes with .. (a "zip-slip" name), so a naive extraction loop (fs.writeBytes($dir + "/" + $e.name, $e.data)) can't be tricked into writing outside the target directory.

#archive.Entry

A struct { name as string, data as bytes, mode as int, mtime as int }:

• name - the path within the archive (subdirectories with /).
• data - the file contents.
• mode - unix permission bits (e.g. 0o644); 0 means the default 0o644.
• mtime - modification time, unix seconds.

Only regular files map to an Entry; directory members are skipped on unpack.

#Example

use io;
use archive;
use convert;

def readme as archive.Entry init archive.Entry{
    name: "README", data: convert.bytesFromString("hello", "utf-8"), mode: 0o644, mtime: 0
};
def blob as bytes init archive.pack([$readme], "tar.gz");   # one call: tar, then gzip
def back as list of archive.Entry init archive.unpack($blob, "tar.gz");
io.printf("%s = %s\n", $back[0].name, convert.stringFromBytes($back[0].data, "utf-8"));

"tar.gz" layers compress's gzip over a tar internally, so the everyday .tar.gz case is a single call rather than a tar-then-gzip pair.

#See also

• compress.md - pack / unpack for byte streams ("gzip" / "zlib" / "deflate").
• fs.md - write the packed bytes to disk, or read an archive off disk to unpack.