4 files changed, 29 insertions, 21 deletions

diff --git a/weed/storage/erasure_coding/ec_locate.go b/weed/storage/erasure_coding/ec_locate.go
index ee8af3382..562966f8f 100644
--- a/weed/storage/erasure_coding/ec_locate.go
+++ b/weed/storage/erasure_coding/ec_locate.go
@@ -69,3 +69,15 @@ func locateOffsetWithinBlocks(blockLength int64, offset int64) (blockIndex int,
 	innerBlockOffset = offset % blockLength
 	return
 }
+
+func (interval Interval) ToShardIdAndOffset(largeBlockSize, smallBlockSize int64) (ShardId, int64) {
+	ecFileOffset := interval.InnerBlockOffset
+	rowIndex := interval.BlockIndex / DataShardsCount
+	if interval.IsLargeBlock {
+		ecFileOffset += int64(rowIndex) * largeBlockSize
+	} else {
+		ecFileOffset += int64(interval.LargeBlockRowsCount)*largeBlockSize + int64(rowIndex)*smallBlockSize
+	}
+	ecFileIndex := interval.BlockIndex % DataShardsCount
+	return ShardId(ecFileIndex), ecFileOffset
+}
diff --git a/weed/storage/erasure_coding/ec_shard.go b/weed/storage/erasure_coding/ec_shard.go
index 084d3f03b..fa4bfcecd 100644
--- a/weed/storage/erasure_coding/ec_shard.go
+++ b/weed/storage/erasure_coding/ec_shard.go
@@ -105,3 +105,9 @@ func (shard *EcVolumeShard) findNeedleFromEcx(needleId types.NeedleId) (offset t
 	err = fmt.Errorf("needle id %d not found", needleId)
 	return
 }
+
+func (shard *EcVolumeShard) ReadAt(buf []byte, offset int64) (int, error) {
+
+	return shard.ecdFile.ReadAt(buf, offset)
+
+}
diff --git a/weed/storage/erasure_coding/ec_test.go b/weed/storage/erasure_coding/ec_test.go
index 83b0bc23a..e2e872dbe 100644
--- a/weed/storage/erasure_coding/ec_test.go
+++ b/weed/storage/erasure_coding/ec_test.go
@@ -105,10 +105,8 @@ func readEcFile(datSize int64, ecFiles []*os.File, offset types.Offset, size uin
 
 	intervals := LocateData(largeBlockSize, smallBlockSize, datSize, offset.ToAcutalOffset(), size)
 
-	nLargeBlockRows := int(datSize / (largeBlockSize * DataShardsCount))
-
 	for i, interval := range intervals {
-		if d, e := readOneInterval(interval, ecFiles, nLargeBlockRows); e != nil {
+		if d, e := readOneInterval(interval, ecFiles); e != nil {
 			return nil, e
 		} else {
 			if i == 0 {
@@ -122,21 +120,14 @@ func readEcFile(datSize int64, ecFiles []*os.File, offset types.Offset, size uin
 	return data, nil
 }
 
-func readOneInterval(interval Interval, ecFiles []*os.File, nLargeBlockRows int) (data []byte, err error) {
-	ecFileOffset := interval.InnerBlockOffset
-	rowIndex := interval.BlockIndex / DataShardsCount
-	if interval.IsLargeBlock {
-		ecFileOffset += int64(rowIndex) * largeBlockSize
-	} else {
-		ecFileOffset += int64(nLargeBlockRows)*largeBlockSize + int64(rowIndex)*smallBlockSize
-	}
+func readOneInterval(interval Interval, ecFiles []*os.File) (data []byte, err error) {
 
-	ecFileIndex := interval.BlockIndex % DataShardsCount
+	ecFileOffset, ecFileIndex := interval.ToShardIdAndOffset(largeBlockSize, smallBlockSize)
 
 	data = make([]byte, interval.Size)
 	err = readFromFile(ecFiles[ecFileIndex], data, ecFileOffset)
 	{ // do some ec testing
-		ecData, err := readFromOtherEcFiles(ecFiles, ecFileIndex, ecFileOffset, interval.Size)
+		ecData, err := readFromOtherEcFiles(ecFiles, int(ecFileIndex), ecFileOffset, interval.Size)
 		if err != nil {
 			return nil, fmt.Errorf("ec reconstruct error: %v", err)
 		}
@@ -198,7 +189,7 @@ func TestLocateData(t *testing.T) {
 	if len(intervals) != 1 {
 		t.Errorf("unexpected interval size %d", len(intervals))
 	}
-	if !intervals[0].sameAs(Interval{0, 0, 1, false}) {
+	if !intervals[0].sameAs(Interval{0, 0, 1, false, 1}) {
 		t.Errorf("unexpected interval %+v", intervals[0])
 	}
 
diff --git a/weed/storage/erasure_coding/ec_volume.go b/weed/storage/erasure_coding/ec_volume.go
index d57a28449..881e88d5f 100644
--- a/weed/storage/erasure_coding/ec_volume.go
+++ b/weed/storage/erasure_coding/ec_volume.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
 	"github.com/chrislusf/seaweedfs/weed/storage/needle"
+	"github.com/chrislusf/seaweedfs/weed/storage/types"
 )
 
 type EcVolumeShards []*EcVolumeShard
@@ -71,19 +72,17 @@ func (shards *EcVolumeShards) ToVolumeEcShardInformationMessage() (messages []*m
 	return
 }
 
-func (shards *EcVolumeShards) ReadEcShardNeedle(n *needle.Needle) (int, error) {
+func (shards *EcVolumeShards) LocateEcShardNeedle(n *needle.Needle) (offset types.Offset, size uint32, intervals []Interval, err error) {
 
 	shard := (*shards)[0]
 	// find the needle from ecx file
-	offset, size, err := shard.findNeedleFromEcx(n.Id)
+	offset, size, err = shard.findNeedleFromEcx(n.Id)
 	if err != nil {
-		return 0, err
+		return types.Offset{}, 0, nil, err
 	}
 
 	// calculate the locations in the ec shards
-	intervals := LocateData(ErasureCodingLargeBlockSize, ErasureCodingSmallBlockSize, shard.ecxFileSize, offset.ToAcutalOffset(), size)
+	intervals = LocateData(ErasureCodingLargeBlockSize, ErasureCodingSmallBlockSize, shard.ecxFileSize, offset.ToAcutalOffset(), size)
 
-	// TODO read the intervals
-
-	return len(intervals), nil
+	return
 }