From c7cb1009a5cc1b503d68d5469b9dabfe77b2f959 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 20 Oct 2015 17:53:12 +1100
Subject: [PATCH] Fix #33.

---
 data/file/file.go | 15 +++++++++++----
 torrent.go        |  2 +-
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/data/file/file.go b/data/file/file.go
index a24f4ebe..4725de74 100644
--- a/data/file/file.go
+++ b/data/file/file.go
@@ -109,18 +109,25 @@ func (me data) WriteSectionTo(w io.Writer, off, n int64) (written int64, err err
 		if err != nil {
 			return
 		}
-		n1, err = io.Copy(w, io.NewSectionReader(f, off, n1))
+		var w1 int64
+		w1, err = io.Copy(w, io.NewSectionReader(f, off, n1))
 		f.Close()
-		if err != nil {
+		written += w1
+		if w1 != n1 {
+			if err == nil || err == io.EOF {
+				err = io.ErrUnexpectedEOF
+			}
 			return
+		} else {
+			err = nil
 		}
-		written += n1
 		off = 0
 		n -= n1
 		if n == 0 {
-			break
+			return
 		}
 	}
+	err = io.EOF
 	return
 }
 
diff --git a/torrent.go b/torrent.go
index e1ad41ca..7d3e235d 100644
--- a/torrent.go
+++ b/torrent.go
@@ -673,7 +673,7 @@ func (t *torrent) hashPiece(piece pp.Integer) (ps pieceSum) {
 		return
 	}
 	if n != pl {
-		panic("lame")
+		panic(fmt.Sprintf("%T: %d != %d", t.data, n, pl))
 	}
 	missinggo.CopyExact(ps[:], hash.Sum(nil))
 	return