// 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/config"
	xioutil "github.com/minio/minio/internal/ioutil"

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.

	}
	return includes, nil
}

// 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, kvs.Get(config.Enable))
	if compress == "" {
		compress = env.Get(EnvCompress, "")
	}

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

    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