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, "")
	}
	cfg.Enabled, err = config.ParseBool(compress)
	if err != nil {
		// Parsing failures happen due to empty KVS, ignore it.
		if kvs.Empty() {
			return cfg, nil
		}

### 4. Excluded Types

- Already compressed objects are not fit for compression since they do not have compressible patterns.
Such objects do not produce efficient [`LZ compression`](https://en.wikipedia.org/wiki/LZ77_and_LZ78)
which is a fitness factor for a lossless data compression.

Pre-compressed input typically compresses in excess of 2GiB/s per core,

// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package compress

import (
	"reflect"
	"testing"
)

func TestParseCompressIncludes(t *testing.T) {
	testCases := []struct {
		str              string
		expectedPatterns []string
		success          bool
	}{

	dnsDelimiter = "."
	// On compressed files bigger than this;
	compReadAheadSize = 100 << 20
	// Read this many buffers ahead.
	compReadAheadBuffers = 5
	// Size of each buffer.
	compReadAheadBufSize = 1 << 20
	// Pad Encrypted+Compressed files to a multiple of this.
	compPadEncrypted = 256
	// Disable compressed file indices below this size
	compMinIndexSize = 8 << 20
)

pkg debug/elf, const COMPRESS_HIOS = 1879048191
pkg debug/elf, const COMPRESS_HIOS CompressionType
pkg debug/elf, const COMPRESS_HIPROC = 2147483647
pkg debug/elf, const COMPRESS_HIPROC CompressionType
pkg debug/elf, const COMPRESS_LOOS = 1610612736
pkg debug/elf, const COMPRESS_LOOS CompressionType
pkg debug/elf, const COMPRESS_LOPROC = 1879048192
pkg debug/elf, const COMPRESS_LOPROC CompressionType

	return err
}

// 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 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)
}

func decompressor(method uint16) Decompressor {

}

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) {

    frame.writeByte(Http2.TYPE_DATA)
    frame.writeByte(FLAG_COMPRESSED)
    frame.writeInt(expectedStreamId and 0x7fffffff)
    zipped.readAll(frame)
    assertFailsWith<IOException> {
      reader.nextFrame(requireSettings = false, BaseTestHandler())
    }.also { expected ->
      assertThat(expected.message)
        .isEqualTo("PROTOCOL_ERROR: FLAG_COMPRESSED without SETTINGS_COMPRESS_DATA")
    }
  }

	line, col   int
	Disable     *bool   `yaml:"disable" json:"disable"`
	Batch       *int    `yaml:"batch" json:"batch"`
	InMemory    *bool   `yaml:"inmemory" json:"inmemory"`
	Compress    *bool   `yaml:"compress" json:"compress"`
	SmallerThan *string `yaml:"smallerThan" json:"smallerThan"`
	SkipErrs    *bool   `yaml:"skipErrs" json:"skipErrs"`
}

var _ yaml.Unmarshaler = &BatchJobSnowball{}