compression

Documentation

Index

• Constants
• type Algorithm
  • func (a Algorithm) String() string
• type Compressor
  • func GetCompressor(a Algorithm) Compressor
• type Decompressor
  • func GetDecompressor(a Algorithm) Decompressor

Constants

const UseStandardZstdLib = true

UseStandardZstdLib indicates whether the zstd implementation is a port of the official one in the facebook/zstd repository.

This constant is only used in tests. Some tests rely on reproducibility of SST files, but a custom implementation of zstd will produce different compression result. So those tests have to be disabled in such cases.

We cannot always use the official facebook/zstd implementation since it relies on CGo.

Types

type Algorithm

type Algorithm uint8

const (
	None Algorithm = iota
	Snappy
	Zstd
	MinLZ
)

The available compression types.

func (Algorithm) String

func (a Algorithm) String() string

String implements fmt.Stringer, returning a human-readable name for the compression algorithm.

type Compressor

type Compressor interface {
	// Compress a block, appending the compressed data to dst[:0].
	Compress(dst, src []byte) []byte

	// Close must be called when the Compressor is no longer needed.
	// After Close is called, the Compressor must not be used again.
	Close()
}

func GetCompressor

func GetCompressor(a Algorithm) Compressor

type Decompressor

type Decompressor interface {
	// DecompressInto decompresses compressed into buf. The buf slice must have the
	// exact size as the decompressed value. Callers may use DecompressedLen to
	// determine the correct size.
	DecompressInto(buf, compressed []byte) error

	// DecompressedLen returns the length of the provided block once decompressed,
	// allowing the caller to allocate a buffer exactly sized to the decompressed
	// payload.
	DecompressedLen(b []byte) (decompressedLen int, err error)

	// Close must be called when the Decompressor is no longer needed.
	// After Close is called, the Decompressor must not be used again.
	Close()
}

func GetDecompressor

func GetDecompressor(a Algorithm) Decompressor