wp

qb.go

@@ -26,16 +26,18 @@ const (
 type TimestampCompressor interface {
 	// (tmp, timestamp)
 	Evaluate([]byte, uint32) TimeEvaluationReport
-	// (offset, change, timestamp)
+	// (rewindOffset, change, timestamp)
 	Append(int, []byte, uint32)
 	Size() int
 	//Chunks() [][]byte
 	//DeleteLast()
-	CaptureState() TimeDeltaCapturedState
+	CaptureState()
+	// (offset) => payload
+	Tail(int) []byte
 	CreateDecompressor() TimestampDecompressor
 	//Payload() []byte // для снапшота
 	//	Offset() int
-	Rotate([]byte)
+	ReplaceBuffer([]byte)
 	WritePayloadTo(io.Writer, *TimeDeltaCapturedState) error
 	LastTimestamp() uint32
 	ReplaceSinceWithUntil() uint32
@@ -49,25 +51,28 @@ type TimeDeltaCapturedState struct {
 }
 
 type TimeEvaluationReport struct {
-	TotalSpace int
-	Offset     int
-	ChangeSize int
+	TotalSpace   int
+	Offset       int // from payload start
+	RewindOffset int // steps to back from pos
+	ChangeSize   int
 }
 
 type ValueCompressor interface {
 	// (tmp, value)
 	Evaluate([]byte, float64) ValueEvaluationReport
-	// (offset, change, value, delta)
+	// (rewindOffset, change, value, delta)
 	Append(int, []byte, float64, uint64)
 	Size() int
 	//Chunks() [][]byte
 	//DeleteLast()
-	CaptureState() ValueDeltaCapturedState
+	CaptureState()
+	// (offset) => payload
+	Tail(int) []byte
 	// fracDigits
-	CreateDecompressor() ValueDecompressor
+	CreateDecompressor(MetricType, byte) ValueDecompressor
 	//Payload() []byte // для снапшота
 	//Offset() int
-	Rotate([]byte)
+	ReplaceBuffer([]byte)
 	WritePayloadTo(io.Writer, *ValueDeltaCapturedState) error
 	LastValue() float64
 }
@@ -79,10 +84,11 @@ type ValueDeltaCapturedState struct {
 }
 
 type ValueEvaluationReport struct {
-	TotalSpace int
-	Offset     int
-	ChangeSize int
-	Delta      uint64
+	TotalSpace   int
+	Offset       int // from payload start
+	RewindOffset int // steps to back from pos
+	ChangeSize   int
+	Delta        uint64
 }
 
 type TimestampDecompressor interface {