encoding

type Batch struct {
	Timestamps [BatchSize]int64
	Values     [BatchSize]float64
	Index      int
	Length     int
}

type Chunk interface {
	// Add adds a SamplePair to the chunks, performs any necessary
	// re-encoding, and creates any necessary overflow chunk.
	// The returned Chunk is the overflow chunk if it was created.
	// The returned Chunk is nil if the sample got appended to the same chunk.
	Add(sample model.SamplePair) (Chunk, error)
	// NewIterator returns an iterator for the chunks.
	// The iterator passed as argument is for reuse. Depending on implementation,
	// the iterator can be re-used or a new iterator can be allocated.
	NewIterator(Iterator) Iterator
	Marshal(io.Writer) error
	UnmarshalFromBuf([]byte) error
	Encoding() Encoding

	// Len returns the number of samples in the chunk.  Implementations may be
	// expensive.
	Len() int

	// Equals checks if this chunk holds the same data as another.
	Equals(Chunk) (bool, error)
}

type Encoding byte

type Iterator interface {
	// Scans the next value in the chunk. Directly after the iterator has
	// been created, the next value is the first value in the
	// chunk. Otherwise, it is the value following the last value scanned or
	// found (by one of the Find... methods). Returns false if either the
	// end of the chunk is reached or an error has occurred.
	Scan() bool
	// Finds the oldest value at or after the provided time. Returns false
	// if either the chunk contains no value at or after the provided time,
	// or an error has occurred.
	FindAtOrAfter(model.Time) bool
	// Returns the last value scanned (by the scan method) or found (by one
	// of the find... methods). It returns model.ZeroSamplePair before any of
	// those methods were called.
	Value() model.SamplePair
	// Returns a batch of the provisded size; NB not idempotent!  Should only be called
	// once per Scan.
	Batch(size int) Batch
	// Returns the last error encountered. In general, an error signals data
	// corruption in the chunk and requires quarantining.
	Err() error
}