### 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,

	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
)

	if w.f != nil {
		if err := w.closeCurrentFile(); err != nil {
			return err
		}

		// This function is a no-op if opts.Compress is false
		// writes an error in JSON form to stderr, if we cannot
		// compress.
		if err := w.compress(); err != nil {
			msg := fmt.Sprintf("unable to compress log file %v: %v, ignoring and moving on", w.f.Name(), err)
			stdErrEnc.Encode(&log.Entry{
				Level:   ErrorKind,
				Message: msg,

	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
}

    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{}

    compressing outbound web socket messages. Configure this with 0L to always compress outbound
    messages and `Long.MAX_VALUE` to never compress outbound messages. The default is 1024L which
    compresses messages of size 1 KiB and larger. (Inbound messages are compressed or not based on
    the web socket server's configuration.)

		return io.ErrUnexpectedEOF
	}
	ver := int(b[0])
	switch ver {
	case dataUsageCacheVerV1:
		return errors.New("cache version deprecated (will autoupdate)")
	case dataUsageCacheVerV2:
		// Zstd compressed.
		dec, err := zstd.NewReader(r, zstd.WithDecoderConcurrency(2))
		if err != nil {
			return err
		}
		defer dec.Close()

		dold := &dataUsageCacheV2{}

	// Some standard content-types which we strictly dis-allow for compression.
	standardExcludeCompressContentTypes = []string{"video/*", "audio/*", "application/zip", "application/x-gzip", "application/x-zip-compressed", " application/x-compress", "application/x-spoon"}

	// AuthZ Plugin system.
	globalAuthZPlugin *polplugin.AuthZPlugin

	// Deployment ID - unique per deployment
	globalDeploymentIDPtr atomic.Pointer[string]

    // TODO: checkState open or half-closed (local) or raise STREAM_CLOSED
    val inFinished = flags and FLAG_END_STREAM != 0
    val gzipped = flags and FLAG_COMPRESSED != 0
    if (gzipped) {
      throw IOException("PROTOCOL_ERROR: FLAG_COMPRESSED without SETTINGS_COMPRESS_DATA")
    }

    val padding = if (flags and FLAG_PADDED != 0) source.readByte() and 0xff else 0
    val dataLength = lengthWithoutPadding(length, flags, padding)