mmap_span: Avoid allocating the span slice on every use

[btrtrc.git] / mmap_span / mmap_span.go

diff --git a/mmap_span/mmap_span.go b/mmap_span/mmap_span.go
index 66635a128c918b77739019bedfb4cecdeba04dc7..37e63af58970f1383979ad883407c5adf775f36c 100644 (file)
--- a/mmap_span/mmap_span.go
+++ b/mmap_span/mmap_span.go
@@ -14,30 +14,29 @@ func (me segment) Size() int64 {
        return int64(len(me.MMap))
 }
 
-type MMapSpan []gommap.MMap
+type MMapSpan struct {
+       span
+}
 
-func (me MMapSpan) span() (s span) {
-       for _, mmap := range me {
-               s = append(s, segment{mmap})
-       }
-       return
+func (me *MMapSpan) Append(mmap gommap.MMap) {
+       me.span = append(me.span, segment{mmap})
 }
 
 func (me MMapSpan) Close() {
-       for _, mMap := range me {
-               mMap.UnsafeUnmap()
+       for _, mMap := range me.span {
+               mMap.(segment).UnsafeUnmap()
        }
 }
 
 func (me MMapSpan) Size() (ret int64) {
-       for _, seg := range me.span() {
+       for _, seg := range me.span {
                ret += seg.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) {
+       me.ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
                _n := copy(p, interval.(segment).MMap[intervalOffset:])
                p = p[_n:]
                n += _n
@@ -50,7 +49,7 @@ func (me MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
 }
 
 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) {
+       me.ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
                var _n int
                p := interval.(segment).MMap[intervalOffset:]
                if n < int64(len(p)) {
@@ -68,7 +67,7 @@ func (me MMapSpan) WriteSectionTo(w io.Writer, off, n int64) (written int64, err
 }
 
 func (me MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
-       me.span().ApplyTo(off, func(iOff int64, i sizer) (stop bool) {
+       me.ApplyTo(off, func(iOff int64, i sizer) (stop bool) {
                mMap := i.(segment)
                _n := copy(mMap.MMap[iOff:], p)
                // err = mMap.Sync(gommap.MS_ASYNC)