8 "github.com/anacrolix/torrent/segments"
9 "github.com/edsrzf/mmap-go"
12 type MMapSpan struct {
15 segmentLocater segments.Index
18 func (ms *MMapSpan) Append(mMap mmap.MMap) {
19 ms.mMaps = append(ms.mMaps, mMap)
22 func (ms *MMapSpan) Close() (errs []error) {
25 for _, mMap := range ms.mMaps {
28 errs = append(errs, err)
31 // This is for issue 211.
37 func (me *MMapSpan) InitIndex() {
39 me.segmentLocater = segments.NewIndex(func() (segments.Length, bool) {
40 if i == len(me.mMaps) {
43 l := int64(len(me.mMaps[i]))
47 //log.Printf("made mmapspan index: %v", me.segmentLocater)
50 func (ms *MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
51 //log.Printf("reading %v bytes at %v", len(p), off)
54 n = ms.locateCopy(func(a, b []byte) (_, _ []byte) { return a, b }, p, off)
61 func copyBytes(dst, src []byte) int {
65 func (ms *MMapSpan) locateCopy(copyArgs func(remainingArgument, mmapped []byte) (dst, src []byte), p []byte, off int64) (n int) {
66 ms.segmentLocater.Locate(segments.Extent{off, int64(len(p))}, func(i int, e segments.Extent) bool {
67 mMapBytes := ms.mMaps[i][e.Start:]
68 //log.Printf("got segment %v: %v, copying %v, %v", i, e, len(p), len(mMapBytes))
69 _n := copyBytes(copyArgs(p, mMapBytes))
72 if segments.Int(_n) != e.Length {
73 panic(fmt.Sprintf("did %d bytes, expected to do %d", _n, e.Length))
80 func (ms *MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
81 // log.Printf("writing %v bytes at %v", len(p), off)
84 n = ms.locateCopy(func(a, b []byte) (_, _ []byte) { return b, a }, p, off)
86 err = io.ErrShortWrite