LocToBuf() works for sliced Loc's
diff --git a/slab.go b/slab.go
index 830040d..5ab0d6e 100644
--- a/slab.go
+++ b/slab.go
@@ -40,7 +40,7 @@
var nilLoc = Loc{-1, -1, -1, -1, -1} // A sentinel.
// IsNil returns true if the Loc came from NilLoc().
-func (cl *Loc) IsNil() bool {
+func (cl Loc) IsNil() bool {
return cl.slabClassIndex < 0 && cl.slabIndex < 0 &&
cl.chunkIndex < 0 && cl.bufStart < 0 && cl.bufLen < 0
}
@@ -52,8 +52,8 @@
//
// NOTE: Many API's (such as BufToLoc) do not correctly handle Loc's
// with non-zero bufStart, so use sliced Loc's with caution.
-func (cl *Loc) Slice(bufStart, bufLen int) Loc {
- rv := *cl // Makes a copy.
+func (cl Loc) Slice(bufStart, bufLen int) Loc {
+ rv := cl // Makes a copy.
rv.bufStart = bufStart
rv.bufLen = bufLen
return rv
@@ -198,7 +198,7 @@
cNext.addRef()
- return scNext.chunkMem(cNext)[c.next.bufStart:c.next.bufLen]
+ return scNext.chunkMem(cNext)[c.next.bufStart : c.next.bufStart+c.next.bufLen]
}
// SetNext associates the next chain buf following the input buf to be
@@ -252,13 +252,14 @@
}
// LocToBuf returns a buf for an Arena-managed Loc. Does not affect
-// the reference count of the buf.
+// the reference count of the buf. The Loc may have come from
+// Loc.Slice().
func (s *Arena) LocToBuf(loc Loc) []byte {
sc, chunk := s.chunk(loc)
if sc == nil || chunk == nil {
return nil
}
- return sc.chunkMem(chunk)[loc.bufStart:loc.bufLen]
+ return sc.chunkMem(chunk)[loc.bufStart : loc.bufStart+loc.bufLen]
}
func (s *Arena) LocAddRef(loc Loc) {
@@ -442,7 +443,8 @@
sc := &(s.slabClasses[slabClassIndex])
slab := sc.slabs[slabIndex]
- chunkIndex := len(slab.chunks) - (footerDistance / sc.chunkSize)
+ chunkIndex := len(slab.chunks) -
+ int(math.Ceil(float64(footerDistance)/float64(sc.chunkSize)))
return sc, &(slab.chunks[chunkIndex])
}
diff --git a/slab_test.go b/slab_test.go
index 7aefa99..0a23886 100644
--- a/slab_test.go
+++ b/slab_test.go
@@ -628,7 +628,17 @@
func TestStats(t *testing.T) {
a := NewArena(1, 1024*1024, 2, nil)
a.Alloc(3)
- a.DecRef(a.Alloc(17))
+ aa := a.Alloc(17)
+ if len(aa) != 17 {
+ t.Errorf("expected 17")
+ }
+ aaloc := a.BufToLoc(aa)
+ aaloc45 := aaloc.Slice(4, 5)
+ bb := a.LocToBuf(aaloc45)
+ if len(bb) != 5 {
+ t.Errorf("expected 5")
+ }
+ a.DecRef(bb)
a.Alloc(4096)
stats := a.Stats(map[string]int64{})
if len(stats) == 0 {
