GeneratePiecesFromMemory

metainfo/pieces.go

@@ -1,6 +1,7 @@
 package metainfo
 
 import (
+	"bytes"
 	"crypto/sha1"
 	"io"
 )
@@ -20,3 +21,22 @@ func GeneratePieces(r io.Reader, pieceLength int64, b []byte) ([]byte, error) {
 		}
 	}
 }
+
+func GeneratePiecesFromMemory(data []byte, pieceLength int64, len int, b []byte) ([]byte, error) {
+	reader := io.NewSectionReader(bytes.NewReader(data), 0, int64(len))
+	for {
+		h := sha1.New()
+		// copy pieceLength bytes from reader to h
+		num, err := io.CopyN(h, reader, pieceLength)
+		if num > 0 {
+			b = h.Sum(b)
+		}
+		if err == io.EOF {
+			return b, nil
+		}
+		if err != nil {
+			return b, err
+		}
+	}
+
+}