wp

enc/time_delta.go

@@ -1,6 +1,7 @@
 package enc
 
 import (
+	"fmt"
 	"io"
 	"log"
 
@@ -159,7 +160,7 @@ func (s *TimeDeltaCompressor) Evaluate(tmp []byte, timestamp uint32) qb.TimeEval
 	}
 	return qb.TimeEvaluationReport{
 		RewindOffset: rewindOffset,
-		Offset:       s.pos + rewindOffset,
+		Offset:       len(s.buf) - s.pos - rewindOffset,
 		ChangeSize:   i,
 		TotalSpace:   s.pos - rewindOffset + i,
 	}
@@ -185,13 +186,21 @@ func (s *TimeDeltaCompressor) Append(rewindOffset int, change []byte, timestamp
 // }
 
 func (s *TimeDeltaCompressor) getState() qb.TimeDeltaCapturedState {
-	bound := s.pos + 1 + bin.CountVarUint64(uint64(s.lastDelta))
-	return qb.TimeDeltaCapturedState{
-		H:            s.buf[s.pos],
+	state := qb.TimeDeltaCapturedState{
 		LastUnixtime: s.lastUnixtime,
 		LastDelta:    s.lastDelta,
-		Payload:      s.buf[bound:],
 	}
+	if s.pos < len(s.buf) {
+		var bound int
+		if s.lastDelta > 0 {
+			state.H = s.buf[s.pos]
+			bound = s.pos + 1 + bin.CountVarUint64(uint64(s.lastDelta))
+		} else {
+			bound = s.pos // only since encoded
+		}
+		state.Payload = s.buf[bound:]
+	}
+	return state
 }
 
 func (s *TimeDeltaCompressor) CaptureState() {
@@ -204,6 +213,7 @@ func (s *TimeDeltaCompressor) ForgetCapturedState() {
 }
 
 func (s *TimeDeltaCompressor) Tail(offset int) []byte {
+	fmt.Println("time tail:", s.pos, len(s.buf), offset)
 	return s.buf[s.pos : len(s.buf)-offset]
 }
 
@@ -220,11 +230,19 @@ func (s *TimeDeltaCompressor) Size() int {
 	return len(s.buf) - s.pos
 }
 
-func (s *TimeDeltaCompressor) StoredSize() int {
+func (s *TimeDeltaCompressor) CommitedSize() int {
 	if s.state == nil {
 		return len(s.buf) - s.pos
 	} else {
-		return bin.CountVarUint64(uint64(s.state.LastDelta)) + 1 + len(s.state.Payload)
+		if len(s.state.Payload) > 0 {
+			if s.state.LastDelta > 0 {
+				return bin.CountVarUint64(uint64(s.state.LastDelta)) + 1 + len(s.state.Payload)
+			} else {
+				return 4 // since
+			}
+		} else {
+			return 0
+		}
 	}
 }
 
@@ -240,9 +258,9 @@ func (s *TimeDeltaCompressor) StoredSize() int {
 // 	}
 // }
 
-func (s *TimeDeltaCompressor) WriteStoredTo(w io.Writer) (err error) {
+func (s *TimeDeltaCompressor) WriteCommitedTo(w io.Writer) (err error) {
 	if s.state == nil {
-		_, err = w.Write(s.buf[:s.pos])
+		_, err = w.Write(s.buf[s.pos:])
 		return
 	} else {
 		_, err = w.Write(s.state.Payload)
@@ -308,14 +326,18 @@ func NewTimeDeltaDecompressor() *TimeDeltaDecompressor {
 // викликається для повних сторінок
 func (s *TimeDeltaDecompressor) RestoreFromEnd(buf []byte) {
 	s.buf = buf
-	var err error
-	s.lastUnixtime, err = bin.GetUint32(buf[len(buf)-4:])
-	if err != nil {
-		log.Fatalf("bug: get last unixtime: %s", err)
-	}
-	if len(buf) > 4 {
-		s.readHeader()
-		s.readDelta()
+	if len(s.buf) > 0 {
+		var err error
+		s.lastUnixtime, err = bin.GetUint32(buf[len(buf)-4:])
+		if err != nil {
+			log.Fatalf("bug: get last unixtime: %s", err)
+		}
+		if len(buf) > 4 {
+			s.readHeader()
+			s.readDelta()
+		}
+	} else {
+		s.done = true
 	}
 	// fmt.Printf("h: % x\n", s.buf[s.pos])
 	// fmt.Printf("lastUnixtime: %d\n", s.lastUnixtime)
@@ -326,10 +348,14 @@ func (s *TimeDeltaDecompressor) RestoreFromEnd(buf []byte) {
 // викликається для data level tail
 func (s *TimeDeltaDecompressor) RestoreFromState(state qb.TimeDeltaCapturedState) {
 	s.buf = state.Payload
-	s.lastUnixtime = state.LastUnixtime
-	if state.LastDelta > 0 {
-		s.lastDelta = state.LastDelta
-		s.decodeHeaderByte(state.H)
+	if len(s.buf) > 0 {
+		s.lastUnixtime = state.LastUnixtime
+		if state.LastDelta > 0 {
+			s.lastDelta = state.LastDelta
+			s.decodeHeaderByte(state.H)
+		}
+	} else {
+		s.done = true
 	}
 }