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) Flush() (errs []error) {
25 for _, mMap := range ms.mMaps {
28 errs = append(errs, err)
34 func (ms *MMapSpan) Close() (errs []error) {
37 for _, mMap := range ms.mMaps {
40 errs = append(errs, err)
43 // This is for issue 211.
49 func (me *MMapSpan) InitIndex() {
51 me.segmentLocater = segments.NewIndex(func() (segments.Length, bool) {
52 if i == len(me.mMaps) {
55 l := int64(len(me.mMaps[i]))
59 // log.Printf("made mmapspan index: %v", me.segmentLocater)
62 func (ms *MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
63 // log.Printf("reading %v bytes at %v", len(p), off)
66 n = ms.locateCopy(func(a, b []byte) (_, _ []byte) { return a, b }, p, off)
73 func copyBytes(dst, src []byte) int {
77 func (ms *MMapSpan) locateCopy(copyArgs func(remainingArgument, mmapped []byte) (dst, src []byte), p []byte, off int64) (n int) {
78 ms.segmentLocater.Locate(segments.Extent{off, int64(len(p))}, func(i int, e segments.Extent) bool {
79 mMapBytes := ms.mMaps[i][e.Start:]
80 // log.Printf("got segment %v: %v, copying %v, %v", i, e, len(p), len(mMapBytes))
81 _n := copyBytes(copyArgs(p, mMapBytes))
85 if segments.Int(_n) != e.Length {
86 panic(fmt.Sprintf("did %d bytes, expected to do %d", _n, e.Length))
93 func (ms *MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
94 // log.Printf("writing %v bytes at %v", len(p), off)
97 n = ms.locateCopy(func(a, b []byte) (_, _ []byte) { return b, a }, p, off)
99 err = io.ErrShortWrite