Add BytesCompleted method for files (#347)

* Add BytesCompleted method for files

* Make sure we check limit pieces correctly

* Remove unnecessary info check

diff --git a/file.go b/file.go
index 15f5e2395b51a97fe06092ca85059c1ff454a0f9..4775b4ff0e8d55e3781971c53af5297a2958b93b 100644 (file)
--- a/file.go
+++ b/file.go
@@ -3,7 +3,10 @@ package torrent
 import (
        "strings"
 
+       "github.com/anacrolix/missinggo/bitmap"
+
        "github.com/anacrolix/torrent/metainfo"
+       pp "github.com/anacrolix/torrent/peer_protocol"
 )
 
 // Provides access to regions of torrent data that correspond to its files.
@@ -40,6 +43,46 @@ func (f *File) Length() int64 {
        return f.length
 }
 
+// Number of bytes of the entire file we have completed. This is the sum of
+// completed pieces, and dirtied chunks of incomplete pieces.
+func (f *File) BytesCompleted() int64 {
+       f.t.cl.rLock()
+       defer f.t.cl.rUnlock()
+       return f.bytesCompleted()
+}
+
+func (f *File) bytesCompleted() int64 {
+       return f.length - f.bytesLeft()
+}
+
+func (f *File) bytesLeft() (left int64) {
+       firstPieceIndex := f.firstPieceIndex()
+       endPieceIndex := f.endPieceIndex()
+       bitmap.Flip(f.t.completedPieces, firstPieceIndex, endPieceIndex+1).IterTyped(func(piece int) bool {
+               p := &f.t.pieces[piece]
+               left += int64(p.length() - p.numDirtyBytes())
+               return true
+       })
+       startPiece := f.t.piece(firstPieceIndex)
+       endChunk := int(f.offset%f.t.info.PieceLength) * int(startPiece.numChunks()) / int(startPiece.length())
+       bitmap.Flip(startPiece.dirtyChunks, 0, endChunk).IterTyped(func(chunk int) bool {
+               left -= int64(startPiece.chunkSize())
+               return true
+       })
+       endPiece := f.t.piece(endPieceIndex)
+       startChunk := int((f.offset+f.length)%f.t.info.PieceLength) * int(endPiece.numChunks()) / int(endPiece.length())
+       lastChunkIndex := int(endPiece.lastChunkIndex())
+       bitmap.Flip(endPiece.dirtyChunks, startChunk, int(endPiece.numChunks())).IterTyped(func(chunk int) bool {
+               if chunk == lastChunkIndex {
+                       left -= int64(endPiece.chunkIndexSpec(pp.Integer(chunk)).Length)
+               } else {
+                       left -= int64(endPiece.chunkSize())
+               }
+               return true
+       })
+       return
+}
+
 // The relative file path for a multi-file torrent, and the torrent name for a
 // single-file torrent.
 func (f *File) DisplayPath() string {