9 "github.com/anacrolix/torrent/segments"
10 "github.com/edsrzf/mmap-go"
13 type MMapSpan struct {
16 segmentLocater segments.Index
19 func (ms *MMapSpan) Append(mMap mmap.MMap) {
20 ms.mMaps = append(ms.mMaps, mMap)
23 func (ms *MMapSpan) Close() (errs []error) {
26 for _, mMap := range ms.mMaps {
29 errs = append(errs, err)
32 // This is for issue 211.
38 func (me *MMapSpan) InitIndex() {
40 me.segmentLocater = segments.NewIndex(func() (segments.Length, bool) {
41 if i == len(me.mMaps) {
44 l := int64(len(me.mMaps[i]))
48 //log.Printf("made mmapspan index: %v", me.segmentLocater)
51 func (ms *MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
52 //log.Printf("reading %v bytes at %v", len(p), off)
55 n = ms.locateCopy(func(a, b []byte) (_, _ []byte) { return a, b }, p, off)
62 func copyBytes(dst, src []byte) int {
66 func (ms *MMapSpan) locateCopy(copyArgs func(remainingArgument, mmapped []byte) (dst, src []byte), p []byte, off int64) (n int) {
67 ms.segmentLocater.Locate(segments.Extent{off, int64(len(p))}, func(i int, e segments.Extent) bool {
68 mMapBytes := ms.mMaps[i][e.Start:]
69 //log.Printf("got segment %v: %v, copying %v, %v", i, e, len(p), len(mMapBytes))
70 _n := copyBytes(copyArgs(p, mMapBytes))
73 if segments.Int(_n) != e.Length {
74 panic(fmt.Sprintf("did %d bytes, expected to do %d", _n, e.Length))
81 func (ms *MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
82 log.Printf("writing %v bytes at %v", len(p), off)
85 n = ms.locateCopy(func(a, b []byte) (_, _ []byte) { return b, a }, p, off)
87 err = io.ErrShortWrite