// The common methods [Store] and [Deflate] are built in.
func RegisterCompressor(method uint16, comp Compressor) {
	if _, dup := compressors.LoadOrStore(method, comp); dup {
		panic("compressor already registered")
	}
}

func compressor(method uint16) Compressor {
	ci, ok := compressors.Load(method)
	if !ok {
		return nil
	}
	return ci.(Compressor)
}

}

// RegisterCompressor registers or overrides a custom compressor for a specific
// method ID. If a compressor for a given method is not found, [Writer] will
// default to looking up the compressor at the package level.
func (w *Writer) RegisterCompressor(method uint16, comp Compressor) {
	if w.compressors == nil {
		w.compressors = make(map[uint16]Compressor)
	}
	w.compressors[method] = comp
}

}

func ExampleWriter_RegisterCompressor() {
	// Override the default Deflate compressor with a higher compression level.

	// Create a buffer to write our archive to.
	buf := new(bytes.Buffer)

	// Create a new zip archive.
	w := zip.NewWriter(buf)

	// Register a custom Deflate compressor.
	w.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package s3select

import (
	"bufio"
	"bytes"
	"compress/bzip2"
	"encoding/xml"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strings"
	"sync"

	"github.com/klauspost/compress/s2"
	"github.com/klauspost/compress/zstd"
	gzip "github.com/klauspost/pgzip"
	"github.com/minio/minio/internal/bpool"
	"github.com/minio/minio/internal/config"

pkg archive/zip, method (*ReadCloser) RegisterDecompressor(uint16, Decompressor)
pkg archive/zip, method (*Reader) RegisterDecompressor(uint16, Decompressor)
pkg archive/zip, method (*Writer) RegisterCompressor(uint16, Compressor)
pkg bufio, method (*Scanner) Buffer([]uint8, int)
pkg bufio, var ErrFinalToken error
pkg crypto/tls, const TLS_RSA_WITH_AES_128_GCM_SHA256 = 156
pkg crypto/tls, const TLS_RSA_WITH_AES_128_GCM_SHA256 uint16

// IsCompressed returns true if the object is marked as compressed.
func (o *ObjectInfo) IsCompressed() bool {
	_, ok := o.UserDefined[ReservedMetadataPrefix+"compression"]
	return ok
}

// IsCompressedOK returns whether the object is compressed and can be decompressed.
func (o *ObjectInfo) IsCompressedOK() (bool, error) {
	scheme, ok := o.UserDefined[ReservedMetadataPrefix+"compression"]
	if !ok {
		return false, nil
	}

# Compression Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io)

MinIO server allows streaming compression to ensure efficient disk space usage.
Compression happens inflight, i.e objects are compressed before being written to disk(s).
MinIO uses [`klauspost/compress/s2`](https://github.com/klauspost/compress/tree/master/s2)
streaming compression due to its stability and performance.

}

// LookupConfig - lookup compression config.
func LookupConfig(kvs config.KVS) (Config, error) {
	var err error
	cfg := Config{}
	if err = config.CheckValidKeys(config.CompressionSubSys, kvs, DefaultKVS); err != nil {
		return cfg, err
	}

	compress := env.Get(EnvCompressState, "")
	if compress == "" {
		compress = env.Get(EnvCompressEnableLegacy, "")
		if compress == "" {

    memory if web socket compression is negotiated but not used.


## Version 4.5.0-RC1

_2020-03-17_

**This release candidate turns on web socket compression.**

The [spec][rfc_7692] includes a sophisticated mechanism for client and server to negotiate
compression features. We strive to offer great performance in our default configuration and so we're

Interceptors can be chained. Suppose you have both a compressing interceptor and a checksumming interceptor: you'll need to decide whether data is compressed and then checksummed, or checksummed and then compressed. OkHttp uses lists to track interceptors, and interceptors are called in order.

![Interceptors Diagram](../assets/images/******@****.***)

### Application Interceptors