torrent/mmap_span.go

81 lines
1.4 KiB
Go

package torrent
import (
"io"
"launchpad.net/gommap"
)
type MMap struct {
gommap.MMap
}
func (me MMap) Size() int64 {
return int64(len(me.MMap))
}
type MMapSpan []MMap
func (me MMapSpan) span() (s span) {
for _, mmap := range me {
s = append(s, mmap)
}
return
}
func (me MMapSpan) Close() {
for _, mMap := range me {
mMap.UnsafeUnmap()
}
}
func (me MMapSpan) Size() (ret int64) {
for _, mmap := range me {
ret += mmap.Size()
}
return
}
func (me MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
me.span().ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
_n := copy(p, interval.(MMap).MMap[intervalOffset:])
p = p[_n:]
n += _n
return len(p) == 0
})
if len(p) != 0 {
err = io.EOF
}
return
}
func (me MMapSpan) WriteSectionTo(w io.Writer, off, n int64) (written int64, err error) {
me.span().ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
var _n int
p := interval.(MMap).MMap[intervalOffset:]
if n < int64(len(p)) {
p = p[:n]
}
_n, err = w.Write(p)
written += int64(_n)
n -= int64(_n)
if err != nil {
return true
}
return n == 0
})
return
}
func (me MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
me.span().ApplyTo(off, func(iOff int64, i sizer) (stop bool) {
_n := copy(i.(MMap).MMap[iOff:], p)
p = p[_n:]
n += _n
return len(p) == 0
})
if len(p) != 0 {
err = io.ErrShortWrite
}
return
}