metainfo: Remove reflection dependency for `Piece.Hash()` (#661)

`copy`  will copy exactly `HashSize` bytes here.

diff --git a/metainfo/piece.go b/metainfo/piece.go
index b204faae24db17454034038655d1c87df32ab66a..d8895384d0a1858d17bd3d08fdf89dd4672b3f99 100644 (file)
--- a/metainfo/piece.go
+++ b/metainfo/piece.go
@@ -1,9 +1,5 @@
 package metainfo
 
-import (
-       "github.com/anacrolix/missinggo/v2"
-)
-
 type Piece struct {
        Info *Info // Can we embed the fields here instead, or is it something to do with saving memory?
        i    pieceIndex
@@ -23,7 +19,7 @@ func (p Piece) Offset() int64 {
 }
 
 func (p Piece) Hash() (ret Hash) {
-       missinggo.CopyExact(&ret, p.Info.Pieces[p.i*HashSize:(p.i+1)*HashSize])
+       copy(ret[:], p.Info.Pieces[p.i*HashSize:(p.i+1)*HashSize])
        return
 }