chunkenc

Documentation

Index

• type Appender
• type Chunk
  • func FromData(e Encoding, d []byte) (Chunk, error)
• type Encoding
  • func (e Encoding) String() string
• type Iterator
  • func NewNopIterator() Iterator
• type Pool
  • func NewPool() Pool
• type XORChunk
  • func NewXORChunk() *XORChunk
  • func (c *XORChunk) Appender() (Appender, error)
  • func (c *XORChunk) Bytes() []byte
  • func (c *XORChunk) Compact()
  • func (c *XORChunk) Encoding() Encoding
  • func (c *XORChunk) Iterator(it Iterator) Iterator
  • func (c *XORChunk) NumSamples() int

Types

type Appender

type Appender interface {
	Append(int64, float64)
}

Appender adds sample pairs to a chunk.

type Chunk

type Chunk interface {
	// Bytes returns the underlying byte slice of the chunk.
	Bytes() []byte

	// Encoding returns the encoding type of the chunk.
	Encoding() Encoding

	// Appender returns an appender to append samples to the chunk.
	Appender() (Appender, error)

	// The iterator passed as argument is for re-use.
	// Depending on implementation, the iterator can
	// be re-used or a new iterator can be allocated.
	Iterator(Iterator) Iterator

	// NumSamples returns the number of samples in the chunk.
	NumSamples() int

	// Compact is called whenever a chunk is expected to be complete (no more
	// samples appended) and the underlying implementation can eventually
	// optimize the chunk.
	// There's no strong guarantee that no samples will be appended once
	// Compact() is called. Implementing this function is optional.
	Compact()
}

Chunk holds a sequence of sample pairs that can be iterated over and appended to.

func FromData

func FromData(e Encoding, d []byte) (Chunk, error)

FromData returns a chunk from a byte slice of chunk data. This is there so that users of the library can easily create chunks from bytes.

type Encoding

type Encoding uint8

Encoding is the identifier for a chunk encoding.

const (
	EncNone Encoding = iota
	EncXOR
)

The different available chunk encodings.

func (Encoding) String

func (e Encoding) String() string

type Iterator

type Iterator interface {
	// Next advances the iterator by one.
	Next() bool
	// Seek advances the iterator forward to the first sample with the timestamp equal or greater than t.
	// If current sample found by previous `Next` or `Seek` operation already has this property, Seek has no effect.
	// Seek returns true, if such sample exists, false otherwise.
	// Iterator is exhausted when the Seek returns false.
	Seek(t int64) bool
	// At returns the current timestamp/value pair.
	// Before the iterator has advanced At behaviour is unspecified.
	At() (int64, float64)
	// Err returns the current error. It should be used only after iterator is
	// exhausted, that is `Next` or `Seek` returns false.
	Err() error
}

Iterator is a simple iterator that can only get the next value. Iterator iterates over the samples of a time series, in timestamp-increasing order.

func NewNopIterator

func NewNopIterator() Iterator

NewNopIterator returns a new chunk iterator that does not hold any data.

type Pool

type Pool interface {
	Put(Chunk) error
	Get(e Encoding, b []byte) (Chunk, error)
}

Pool is used to create and reuse chunk references to avoid allocations.

func NewPool

func NewPool() Pool

NewPool returns a new pool.

type XORChunk

type XORChunk struct {
	// contains filtered or unexported fields
}

XORChunk holds XOR encoded sample data.

func NewXORChunk

func NewXORChunk() *XORChunk

NewXORChunk returns a new chunk with XOR encoding of the given size.

func (*XORChunk) Appender

func (c *XORChunk) Appender() (Appender, error)

Appender implements the Chunk interface.

func (*XORChunk) Bytes

func (c *XORChunk) Bytes() []byte

Bytes returns the underlying byte slice of the chunk.

func (*XORChunk) Compact

func (c *XORChunk) Compact()

func (*XORChunk) Encoding

func (c *XORChunk) Encoding() Encoding

Encoding returns the encoding type.

func (*XORChunk) Iterator

func (c *XORChunk) Iterator(it Iterator) Iterator

Iterator implements the Chunk interface.

func (*XORChunk) NumSamples

func (c *XORChunk) NumSamples() int

NumSamples returns the number of samples in the chunk.