func NewIterator(roiName dvid.InstanceName, versionID dvid.VersionID, b dvid.Bounder) (*Iterator, error) {
dataservice, err := datastore.GetDataByVersion(versionID, roiName)
if err != nil {
return nil, fmt.Errorf("Can't get ROI with name %q: %v", roiName, err)
}
data, ok := dataservice.(*Data)
if !ok {
return nil, fmt.Errorf("Data name %q was not of roi data type\n", roiName)
}
// Convert voxel extents to block Z extents
minPt := b.StartPoint().(dvid.Chunkable)
maxPt := b.EndPoint().(dvid.Chunkable)
minBlockCoord := minPt.Chunk(data.BlockSize)
maxBlockCoord := maxPt.Chunk(data.BlockSize)
minIndex := minIndexByBlockZ(minBlockCoord.Value(2))
maxIndex := maxIndexByBlockZ(maxBlockCoord.Value(2))
ctx := datastore.NewVersionedCtx(data, versionID)
it := new(Iterator)
it.spans, err = getSpans(ctx, minIndex, maxIndex)
return it, err
}
// GetByVersion returns a pointer to labelblk data given a UUID and data name.
func GetByVersion(v dvid.VersionID, name dvid.InstanceName) (*Data, error) {
source, err := datastore.GetDataByVersion(v, name)
if err != nil {
return nil, err
}
data, ok := source.(*Data)
if !ok {
return nil, fmt.Errorf("Instance '%s' is not a labelblk datatype!", name)
}
return data, nil
}