// Returns RLEs for a given label where the key of the returned map is the block index
// in string format.
func (d *Data) GetLabelRLEs(v dvid.VersionID, label uint64) (dvid.BlockRLEs, error) {
	store, err := storage.SmallDataStore()
	if err != nil {
		return nil, fmt.Errorf("Data type labelvol had error initializing store: %v\n", err)
	}

	// Get the start/end indices for this body's KeyLabelSpatialMap (b + s) keys.
	begIndex := NewTKey(label, dvid.MinIndexZYX.ToIZYXString())
	endIndex := NewTKey(label, dvid.MaxIndexZYX.ToIZYXString())

	// Process all the b+s keys and their values, which contain RLE runs for that label.
	labelRLEs := dvid.BlockRLEs{}
	var f storage.ChunkFunc = func(chunk *storage.Chunk) error {
		// Get the block index where the fromLabel is present
		_, blockStr, err := DecodeTKey(chunk.K)
		if err != nil {
			return fmt.Errorf("Can't recover block index with chunk key %v: %v\n", chunk.K, err)
		}

		var blockRLEs dvid.RLEs
		if err := blockRLEs.UnmarshalBinary(chunk.V); err != nil {
			return fmt.Errorf("Unable to unmarshal RLE for label in block %v", chunk.K)
		}
		labelRLEs[blockStr] = blockRLEs
		return nil
	}
	ctx := datastore.NewVersionedCtx(d, v)
	err = store.ProcessRange(ctx, begIndex, endIndex, &storage.ChunkOp{}, f)
	if err != nil {
		return nil, err
	}
	fmt.Printf("Found %d blocks with label %d\n", len(labelRLEs), label)
	return labelRLEs, nil
}

// Alter serialized RLEs by the bounds.
func boundRLEs(b []byte, bounds *dvid.Bounds) ([]byte, error) {
	var oldRLEs dvid.RLEs
	err := oldRLEs.UnmarshalBinary(b)
	if err != nil {
		return nil, err
	}
	newRLEs := oldRLEs.FitToBounds(bounds)
	return newRLEs.MarshalBinary()
}

func getBytesRLE(t *testing.T, rles dvid.RLEs) *bytes.Buffer {
	n := len(rles)
	buf := new(bytes.Buffer)
	buf.WriteByte(dvid.EncodingBinary)
	binary.Write(buf, binary.LittleEndian, uint8(3))  // # of dimensions
	binary.Write(buf, binary.LittleEndian, byte(0))   // dimension of run (X = 0)
	buf.WriteByte(byte(0))                            // reserved for later
	binary.Write(buf, binary.LittleEndian, uint32(0)) // Placeholder for # voxels
	binary.Write(buf, binary.LittleEndian, uint32(n)) // Placeholder for # spans
	rleBytes, err := rles.MarshalBinary()
	if err != nil {
		t.Errorf("Unable to serialize RLEs: %v\n", err)
	}
	buf.Write(rleBytes)
	return buf
}

// SplitCoarseLabels splits a portion of a label's voxels into a given split label or, if the given split
// label is 0, a new label, which is returned.  The input is a binary sparse volume defined by block
// coordinates and should be the smaller portion of a labeled region-to-be-split.
//
// EVENTS
//
// labels.SplitStartEvent occurs at very start of split and transmits labels.DeltaSplitStart struct.
//
// labels.SplitBlockEvent occurs for every block of a split label and transmits labels.DeltaSplit struct.
//
// labels.SplitEndEvent occurs at end of split and transmits labels.DeltaSplitEnd struct.
//
func (d *Data) SplitCoarseLabels(v dvid.VersionID, fromLabel, splitLabel uint64, r io.ReadCloser) (toLabel uint64, err error) {
	store, err := d.GetOrderedKeyValueDB()
	if err != nil {
		err = fmt.Errorf("Data type labelvol had error initializing store: %v\n", err)
		return
	}
	batcher, ok := store.(storage.KeyValueBatcher)
	if !ok {
		err = fmt.Errorf("Data type labelvol requires batch-enabled store, which %q is not\n", store)
		return
	}

	// Create a new label id for this version that will persist to store
	if splitLabel != 0 {
		toLabel = splitLabel
		dvid.Debugf("Splitting coarse subset of label %d into given label %d ...\n", fromLabel, splitLabel)
	} else {
		toLabel, err = d.NewLabel(v)
		if err != nil {
			return
		}
		dvid.Debugf("Splitting coarse subset of label %d into new label %d ...\n", fromLabel, toLabel)
	}

	evt := datastore.SyncEvent{d.DataUUID(), labels.SplitStartEvent}
	splitOpStart := labels.DeltaSplitStart{fromLabel, toLabel}
	splitOpEnd := labels.DeltaSplitEnd{fromLabel, toLabel}

	// Make sure we can split given current merges in progress
	if err := labels.SplitStart(d.getMergeIV(v), splitOpStart); err != nil {
		return toLabel, err
	}
	defer labels.SplitStop(d.getMergeIV(v), splitOpEnd)

	// Signal that we are starting a split.
	msg := datastore.SyncMessage{labels.SplitStartEvent, v, splitOpStart}
	if err := datastore.NotifySubscribers(evt, msg); err != nil {
		return 0, err
	}

	// Read the sparse volume from reader.
	var splits dvid.RLEs
	splits, err = dvid.ReadRLEs(r)
	if err != nil {
		return
	}
	numBlocks, _ := splits.Stats()

	// Order the split blocks
	splitblks := make(dvid.IZYXSlice, numBlocks)
	n := 0
	for _, rle := range splits {
		p := rle.StartPt()
		run := rle.Length()
		for i := int32(0); i < run; i++ {
			izyx := dvid.IndexZYX{p[0] + i, p[1], p[2]}
			splitblks[n] = izyx.ToIZYXString()
			n++
		}
	}
	sort.Sort(splitblks)

	// Iterate through the split blocks, read the original block and change labels.
	// TODO: Modifications should be transactional since it's GET-PUT, therefore use
	// hash on block coord to direct it to block-specific goroutine; we serialize
	// requests to handle concurrency.
	ctx := datastore.NewVersionedCtx(d, v)
	batch := batcher.NewBatch(ctx)

	var toLabelSize uint64
	for _, splitblk := range splitblks {
		// Get original block
		tk := NewTKey(fromLabel, splitblk)
		val, err := store.Get(ctx, tk)
		if err != nil {
			return toLabel, err
		}
		if val == nil {
			return toLabel, fmt.Errorf("Split block %s is not part of original label %d", splitblk, fromLabel)
		}
		var rles dvid.RLEs
		if err := rles.UnmarshalBinary(val); err != nil {
			return toLabel, fmt.Errorf("Unable to unmarshal RLE for original labels in block %s", splitblk)
		}
		numVoxels, _ := rles.Stats()
		toLabelSize += numVoxels

		// Delete the old block and save the sparse volume but under a new label.
//.........这里部分代码省略.........

// SplitLabels splits a portion of a label's voxels into a given split label or, if the given split
// label is 0, a new label, which is returned.  The input is a binary sparse volume and should
// preferably be the smaller portion of a labeled region.  In other words, the caller should chose
// to submit for relabeling the smaller portion of any split.  It is assumed that the given split
// voxels are within the fromLabel set of voxels and will generate unspecified behavior if this is
// not the case.
//
// EVENTS
//
// labels.SplitStartEvent occurs at very start of split and transmits labels.DeltaSplitStart struct.
//
// labels.SplitBlockEvent occurs for every block of a split label and transmits labels.DeltaSplit struct.
//
// labels.SplitEndEvent occurs at end of split and transmits labels.DeltaSplitEnd struct.
//
func (d *Data) SplitLabels(v dvid.VersionID, fromLabel, splitLabel uint64, r io.ReadCloser) (toLabel uint64, err error) {
	store, err := d.GetOrderedKeyValueDB()
	if err != nil {
		err = fmt.Errorf("Data type labelvol had error initializing store: %v\n", err)
		return
	}
	batcher, ok := store.(storage.KeyValueBatcher)
	if !ok {
		err = fmt.Errorf("Data type labelvol requires batch-enabled store, which %q is not\n", store)
		return
	}

	// Create a new label id for this version that will persist to store
	if splitLabel != 0 {
		toLabel = splitLabel
		dvid.Debugf("Splitting subset of label %d into given label %d ...\n", fromLabel, splitLabel)
	} else {
		toLabel, err = d.NewLabel(v)
		if err != nil {
			return
		}
		dvid.Debugf("Splitting subset of label %d into new label %d ...\n", fromLabel, toLabel)
	}

	evt := datastore.SyncEvent{d.DataUUID(), labels.SplitStartEvent}
	splitOpStart := labels.DeltaSplitStart{fromLabel, toLabel}
	splitOpEnd := labels.DeltaSplitEnd{fromLabel, toLabel}

	// Make sure we can split given current merges in progress
	if err := labels.SplitStart(d.getMergeIV(v), splitOpStart); err != nil {
		return toLabel, err
	}
	defer labels.SplitStop(d.getMergeIV(v), splitOpEnd)

	// Signal that we are starting a split.
	msg := datastore.SyncMessage{labels.SplitStartEvent, v, splitOpStart}
	if err := datastore.NotifySubscribers(evt, msg); err != nil {
		return 0, err
	}

	// Read the sparse volume from reader.
	var split dvid.RLEs
	split, err = dvid.ReadRLEs(r)
	if err != nil {
		return
	}
	toLabelSize, _ := split.Stats()

	// Partition the split spans into blocks.
	var splitmap dvid.BlockRLEs
	splitmap, err = split.Partition(d.BlockSize)
	if err != nil {
		return
	}

	// Get a sorted list of blocks that cover split.
	splitblks := splitmap.SortedKeys()

	// Iterate through the split blocks, read the original block.  If the RLEs
	// are identical, just delete the original.  If not, modify the original.
	// TODO: Modifications should be transactional since it's GET-PUT, therefore use
	// hash on block coord to direct it to blockLabel, splitLabel-specific goroutine; we serialize
	// requests to handle concurrency.
	ctx := datastore.NewVersionedCtx(d, v)
	batch := batcher.NewBatch(ctx)

	for _, splitblk := range splitblks {

		// Get original block
		tk := NewTKey(fromLabel, splitblk)
		val, err := store.Get(ctx, tk)
		if err != nil {
			return toLabel, err
		}

		if val == nil {
			return toLabel, fmt.Errorf("Split RLEs at block %s are not part of original label %d", splitblk, fromLabel)
		}
		var rles dvid.RLEs
		if err := rles.UnmarshalBinary(val); err != nil {
			return toLabel, fmt.Errorf("Unable to unmarshal RLE for original labels in block %s", splitblk)
		}

		// Compare and process based on modifications required.
		remain, err := rles.Split(splitmap[splitblk])
//.........这里部分代码省略.........

// PutSparseVol stores an encoded sparse volume that stays within a given forward label.
// Note that this encoded sparse volume is added to any existing sparse volume for
// a body rather than replace it.  To carve out a part of an existing sparse volume,
// use the SplitLabels().
//
// This function handles modification/deletion of all denormalized data touched by this
// sparse label volume.
//
// EVENTS
//
//
func (d *Data) PutSparseVol(v dvid.VersionID, label uint64, r io.Reader) error {
	store, err := storage.SmallDataStore()
	if err != nil {
		return fmt.Errorf("Data type labelvol had error initializing store: %v\n", err)
	}
	batcher, ok := store.(storage.KeyValueBatcher)
	if !ok {
		return fmt.Errorf("Data type labelvol requires batch-enabled store, which %q is not\n", store)
	}

	// Mark the label as dirty until done.
	iv := dvid.InstanceVersion{d.DataName(), v}
	dirtyLabels.Incr(iv, label)
	defer dirtyLabels.Decr(iv, label)

	// TODO -- Signal that we are starting a label modification.

	// Read the sparse volume from reader.
	header := make([]byte, 8)
	if _, err = io.ReadFull(r, header); err != nil {
		return err
	}
	if header[0] != dvid.EncodingBinary {
		return fmt.Errorf("sparse vol for split has unknown encoding format: %v", header[0])
	}
	var numSpans uint32
	if err = binary.Read(r, binary.LittleEndian, &numSpans); err != nil {
		return err
	}
	var mods dvid.RLEs
	if err = mods.UnmarshalBinaryReader(r, numSpans); err != nil {
		return err
	}

	// Partition the mods spans into blocks.
	var modmap dvid.BlockRLEs
	modmap, err = mods.Partition(d.BlockSize)
	if err != nil {
		return err
	}

	// Publish sparsevol mod event
	evt := datastore.SyncEvent{d.DataName(), labels.SparsevolModEvent}
	msg := datastore.SyncMessage{v, labels.DeltaSparsevol{label, modmap}}
	if err := datastore.NotifySubscribers(evt, msg); err != nil {
		return err
	}

	// Get a sorted list of blocks that cover mods.
	modblks := modmap.SortedKeys()

	ctx := datastore.NewVersionedCtx(d, v)
	batch := batcher.NewBatch(ctx)
	var voxelsAdded int64

	for _, modblk := range modblks {

		// Get original block
		tk := NewTKey(label, modblk)
		val, err := store.Get(ctx, tk)
		if err != nil {
			return err
		}

		// If there's no original block, just write the mod block.
		if val == nil || len(val) == 0 {
			numVoxels, _ := modmap[modblk].Stats()
			voxelsAdded += int64(numVoxels)
			rleBytes, err := modmap[modblk].MarshalBinary()
			if err != nil {
				return fmt.Errorf("can't serialize modified RLEs for %d: %v\n", label, err)
			}
			batch.Put(tk, rleBytes)
			continue
		}

		// if there's an original, integrate and write merged RLE.
		var rles dvid.RLEs
		if err := rles.UnmarshalBinary(val); err != nil {
			return fmt.Errorf("Unable to unmarshal RLE for original labels in block %s", modblk.Print())
		}
		voxelsAdded += rles.Add(modmap[modblk])
		rleBytes, err := rles.MarshalBinary()
		if err != nil {
			return fmt.Errorf("can't serialize modified RLEs of %d: %v\n", label, err)
		}
		batch.Put(tk, rleBytes)
	}

//.........这里部分代码省略.........