xzwriter

README

xzwriter: a trivial Go library for compressing with XZ.

Package xzwriter provides a writer XZWriter that pipes through an external XZ compressor.

Expects the Tukaani XZ tool in $PATH. See the XZ Utils home page: http://tukaani.org/xz/

License

As this is a trivial convenience package, you should probably not import this. Anyway licensed under the Apache License, Version 2.0.

See also

https://github.com/ulikunitz/xz

Documentation

Overview

Package xzwriter provides a WriteCloser XZWriter that pipes through an external XZ compressor.

Expects the Tukaani XZ tool in $PATH. See the XZ Utils home page: <http://tukaani.org/xz/>

Index

• Constants
• Variables
• type Option
  • func WithCompressLevel(l int) Option
  • func WithExtreme() Option
  • func WithNiceness(_ int) Option
  • func WithSeparateProcessGroup() Option
  • func WithVerbose(stderr io.Writer) Option
• type XZWriter
  • func New(w io.Writer) (*XZWriter, error)
  • func NewWithContext(ctx context.Context, w io.Writer) (*XZWriter, error)
  • func NewWithOptions(ctx context.Context, w io.Writer, opts ...Option) (*XZWriter, error)
  • func (xz *XZWriter) Close() error
  • func (xz *XZWriter) Write(p []byte) (n int, err error)

Constants

const (
	Fast    = 0
	Default = 6
	Best    = 9
)

Variables

var (
	ErrOptionIllegal = errors.New("option illegal")
)

Types

type Option

type Option func(*XZWriter) error

func WithCompressLevel

func WithCompressLevel(l int) Option

WithCompressLevel sets the compression level between 0 and 9. The constants `Fast`, `Default` and `Best` correspond to the flags `--fast`, `--default` and `--best`.

func WithExtreme

func WithExtreme() Option

WithExtreme set the `--extreme` flag.

func WithNiceness

func WithNiceness(_ int) Option

func WithSeparateProcessGroup

func WithSeparateProcessGroup() Option

func WithVerbose

func WithVerbose(stderr io.Writer) Option

WithVerbose sets verbosity and takes a writer that will be connected to STDERR of the xz subprocess. This provides nice progress output to look at.

type XZWriter

type XZWriter struct {
	// contains filtered or unexported fields
}

XZWriter is a WriteCloser that wraps a writer around an XZ compressor.

func New

func New(w io.Writer) (*XZWriter, error)

New returns an XZWriter, wrapping the writer w.

func NewWithContext

func NewWithContext(ctx context.Context, w io.Writer) (*XZWriter, error)

NewWithContext returns an XZWriter, wrapping the writer w. The context may be used to cancel or timeout the external compressor process.

The context can be used to kill the external process early. You still need to call Close() to clean up resources. Alternatively you may call Close() prematurely.

func NewWithOptions

func NewWithOptions(ctx context.Context, w io.Writer, opts ...Option) (*XZWriter, error)

NewWithOptions returns an XZWriter, wrapping the writer w. The context may be used to cancel or timeout the external compressor process.

The context can be used to kill the external process early. You still need to call Close() to clean up resources. Alternatively you may call Close() prematurely.

The compressor process can be configured with options.

func (*XZWriter) Close

func (xz *XZWriter) Close() error

Close implements the io.Closer interface.

func (*XZWriter) Write

func (xz *XZWriter) Write(p []byte) (n int, err error)

Write implements the io.Writer interface.