env

type FrameOffsetEntry struct {
	// ID is the is the sequence number of the frame in the index.
	ID int64

	// CompOffset is the offset within compressed stream.
	CompOffset uint64
	// DecompOffset is the offset within decompressed stream.
	DecompOffset uint64
	// CompSize is the size of the compressed frame.
	CompSize uint32
	// DecompSize is the size of the original data.
	DecompSize uint32

	// Checksum is the lower 32 bits of the XXH64 hash of the uncompressed data.
	Checksum uint32
}

type REnvironment interface {
	// GetFrameByIndex returns the compressed frame by its index.
	GetFrameByIndex(index FrameOffsetEntry) ([]byte, error)
	// ReadFooter returns buffer whose last 9 bytes are interpreted as a `Seek_Table_Footer`.
	ReadFooter() ([]byte, error)
	// ReadSkipFrame returns the full Seek Table Skippable frame
	// including the `Skippable_Magic_Number` and `Frame_Size`.
	ReadSkipFrame(skippableFrameOffset int64) ([]byte, error)
}

type WEnvironment interface {
	// WriteFrame is called each time frame is encoded and needs to be written upstream.
	WriteFrame(p []byte) (n int, err error)
	// WriteSeekTable is called on Close to flush the seek table.
	WriteSeekTable(p []byte) (n int, err error)
}