Add some checks to TorrentReadAt for 0 byte reads

diff --git a/client.go b/client.go
index 2a20b263385c0b802bd7b26e3708f45b8b777581..86f908818c1fe354900964d6faae75997a1c429f 100644 (file)
--- a/client.go
+++ b/client.go
@@ -161,10 +161,14 @@ func (cl *Client) TorrentReadAt(ih InfoHash, off int64, p []byte) (n int, err er
                return
        }
        piece := t.Pieces[index]
-       pieceOff := pp.Integer(off % int64(t.PieceLength(0)))
-       high := int(t.PieceLength(index) - pieceOff)
-       if high < len(p) {
-               p = p[:high]
+       pieceOff := pp.Integer(off % int64(t.UsualPieceSize()))
+       pieceLeft := int(t.PieceLength(index) - pieceOff)
+       if pieceLeft <= 0 {
+               err = io.EOF
+               return
+       }
+       if len(p) > pieceLeft {
+               p = p[:pieceLeft]
        }
        for cs, _ := range piece.PendingChunkSpecs {
                chunkOff := int64(pieceOff) - int64(cs.Begin)
@@ -181,6 +185,9 @@ func (cl *Client) TorrentReadAt(ih InfoHash, off int64, p []byte) (n int, err er
                        p = p[:-chunkOff]
                }
        }
+       if len(p) == 0 {
+               panic(len(p))
+       }
        return t.Data.ReadAt(p, off)
 }