From e1e897cd7c27d7c598de52be83e3b4764a5c7861 Mon Sep 17 00:00:00 2001 From: Dimitri Sokolyuk Date: Tue, 12 Jul 2016 20:05:13 +0200 Subject: ReadAt --- cmd/btcheck/main.go | 43 ++++++++++++++++++++++++++++++++++++++++++- meta/info.go | 21 ++++++++++++++++----- 2 files changed, 58 insertions(+), 6 deletions(-) diff --git a/cmd/btcheck/main.go b/cmd/btcheck/main.go index 38dd16d..f7c6bee 100644 --- a/cmd/btcheck/main.go +++ b/cmd/btcheck/main.go @@ -1,3 +1,44 @@ package main -func main() {} +import ( + "fmt" + "io/ioutil" + "log" + "os" + + "dim13.org/btget/bencode" + "dim13.org/btget/meta" +) + +func Open(fname string) (meta.Torrent, error) { + var tor meta.Torrent + body, err := ioutil.ReadFile(fname) + if err != nil { + return meta.Torrent{}, err + } + err = bencode.Unmarshal(body, &tor) + if err != nil { + return meta.Torrent{}, err + } + return tor, nil +} + +func main() { + if len(os.Args) != 2 { + log.Fatal("usage: ", os.Args[0], " ") + } + tor, err := Open(os.Args[1]) + if err != nil { + log.Fatal(err) + } + p := tor.Info.GetPieces() + buf := make([]byte, tor.Info.PieceLength) + for i := 0; i < tor.Info.NPieces(); i++ { + off := tor.Info.Offset(i) + n, err := tor.Info.ReadAt(buf, off) + if err != nil { + log.Fatal(err) + } + fmt.Println(i, off, n, p[i].Check(buf[:n])) + } +} diff --git a/meta/info.go b/meta/info.go index d4b19bc..4b3d28a 100644 --- a/meta/info.go +++ b/meta/info.go @@ -21,6 +21,15 @@ type Info struct { RootHash []byte `bencode:"root hash"` // BEP-0030 } +// NPieces returns number of all pieces +func (i Info) NPieces() int { + full, last := i.Full(), i.Last() + if last > 0 { + return full + 1 + } + return full +} + // Full returns count of full pieces func (i Info) Full() int { return int(i.TotalLength() / int64(i.PieceLength)) @@ -121,6 +130,9 @@ func (i Info) WriteAt(b []byte, off int64) (n int, err error) { // FIXME ReadAt ... func (i Info) ReadAt(b []byte, off int64) (n int, err error) { + if off >= i.TotalLength() { + return 0, nil + } n, foff := i.findFirstFile(off) fd, err := i.Open(n) @@ -131,18 +143,17 @@ func (i Info) ReadAt(b []byte, off int64) (n int, err error) { flen := i.FileLength(n) - // does it fit? - if int64(len(b))+foff <= flen { + // does it fit? read ahead + if int64(len(b))+foff < flen { return fd.ReadAt(b, foff) } - end := flen + foff - + end := flen - foff done, err := fd.ReadAt(b[:end], foff) if err != nil { return done, err } - next, err := i.ReadAt(b[end:], end) + next, err := i.ReadAt(b[end:], off+end) return done + next, err } -- cgit v1.2.3