jochen
10f76cafc4
Betterbird's pinned .tar.xz failed on the build seat with "this build seat has no xz to read it": the seat's image is the catalogue's build-agent recipe, which installs git and docker-cli alone, and xz had been added only to cmd/mesh-builder/Dockerfile, which the seat does not build from. The stream is now read with github.com/ulikunitz/xz (vendored), its dictionary capped at xz's own largest preset, and what it unpacks to bounded as before; the xz line in the unused Dockerfile is taken back out.
89 lines
2.6 KiB
Markdown
89 lines
2.6 KiB
Markdown
# Package xz
|
|
|
|
This Go language package supports the reading and writing of xz
|
|
compressed streams. It includes also a gxz command for compressing and
|
|
decompressing data. The package is completely written in Go and doesn't
|
|
have any dependency on any C code.
|
|
|
|
The package is currently under development. There might be bugs and APIs
|
|
are not considered stable. At this time the package cannot compete with
|
|
the xz tool regarding compression speed and size. The algorithms there
|
|
have been developed over a long time and are highly optimized. However
|
|
there are a number of improvements planned and I'm very optimistic about
|
|
parallel compression and decompression. Stay tuned!
|
|
|
|
## Using the API
|
|
|
|
The following example program shows how to use the API.
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"bytes"
|
|
"io"
|
|
"log"
|
|
"os"
|
|
|
|
"github.com/ulikunitz/xz"
|
|
)
|
|
|
|
func main() {
|
|
const text = "The quick brown fox jumps over the lazy dog.\n"
|
|
var buf bytes.Buffer
|
|
// compress text
|
|
w, err := xz.NewWriter(&buf)
|
|
if err != nil {
|
|
log.Fatalf("xz.NewWriter error %s", err)
|
|
}
|
|
if _, err := io.WriteString(w, text); err != nil {
|
|
log.Fatalf("WriteString error %s", err)
|
|
}
|
|
if err := w.Close(); err != nil {
|
|
log.Fatalf("w.Close error %s", err)
|
|
}
|
|
// decompress buffer and write output to stdout
|
|
r, err := xz.NewReader(&buf)
|
|
if err != nil {
|
|
log.Fatalf("NewReader error %s", err)
|
|
}
|
|
if _, err = io.Copy(os.Stdout, r); err != nil {
|
|
log.Fatalf("io.Copy error %s", err)
|
|
}
|
|
}
|
|
```
|
|
|
|
## Documentation
|
|
|
|
You can find the full documentation at [pkg.go.dev](https://pkg.go.dev/github.com/ulikunitz/xz).
|
|
|
|
## Using the gxz compression tool
|
|
|
|
The package includes a gxz command line utility for compression and
|
|
decompression.
|
|
|
|
Use following command for installation:
|
|
|
|
$ go get github.com/ulikunitz/xz/cmd/gxz
|
|
|
|
To test it call the following command.
|
|
|
|
$ gxz bigfile
|
|
|
|
After some time a much smaller file bigfile.xz will replace bigfile.
|
|
To decompress it use the following command.
|
|
|
|
$ gxz -d bigfile.xz
|
|
|
|
## Security & Vulnerabilities
|
|
|
|
The security policy is documented in [SECURITY.md](SECURITY.md).
|
|
|
|
The software is not affected by the supply chain attack on the original xz
|
|
implementation, [CVE-2024-3094](https://nvd.nist.gov/vuln/detail/CVE-2024-3094).
|
|
This implementation doesn't share any files with the original xz implementation
|
|
and no patches or pull requests are accepted without a review.
|
|
|
|
All security advisories for this project are published under
|
|
[github.com/ulikunitz/xz/security/advisories](https://github.com/ulikunitz/xz/security/advisories?state=published).
|