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Commit 6955404b authored by Kirill Smelkov's avatar Kirill Smelkov Committed by GitHub
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Merge pull request #8 from navytux/splitx 

splitX bugfix test + simplification

In the process of going through b code I've noticed that splitX bug fix (commit 5c732b36) handling logic was not covered by tests for edge cases and that this edge-handling logic itself can be simplified. Please find patches which add corresponding test and do the simplification attached.

The simplified logic will be handy for upcoming work.

Please see details in individual commit messages.

Thanks beforehand,
Kirill
parents aaaa43c9 9fff7486
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AUTHORS
View file @ 6955404b
......@@ -9,3 +9,4 @@
# Please keep the list sorted.
Jan Mercl <0xjnml@gmail.com>
Nexedi <jp@nexedi.com>
CONTRIBUTORS
View file @ 6955404b
......@@ -10,4 +10,5 @@ Andrey Elenskiy <andrey.elenskiy@gmail.com>
Brian Fallik <bfallik@gmail.com>
Dan Kortschak <dan.kortschak@adelaide.edu.au>
Jan Mercl <0xjnml@gmail.com>
Kirill Smelkov <kirr@nexedi.com>
Nikifor Seryakov <nikandfor@gmail.com>
all_test.go
View file @ 6955404b
......@@ -292,6 +292,71 @@ func TestPrealloc(*testing.T) {
r.Close()
}
func TestSplitXOnEdge(t *testing.T) {
// verify how splitX works when splitting X for k pointing directly at split edge
tr := TreeNew(cmp)
// one index page with 2*kx+2 elements (last has .k=∞ so x.c=2*kx+1)
// which will splitX on next Set
for i := 0; i <= (2*kx + 1) * 2*kd; i++ {
// odd keys are left to be filled in second test
tr.Set(2*i, 2*i)
}
x0 := tr.r.(*x)
if x0.c != 2*kx+1 {
t.Fatalf("x0.c: %v ; expected %v", x0.c, 2*kx+1)
}
// set element with k directly at x0[kx].k
kedge := 2 * (kx + 1) * (2*kd)
if x0.x[kx].k != kedge {
t.Fatalf("edge key before splitX: %v ; expected %v", x0.x[kx].k, kedge)
}
tr.Set(kedge, 777)
// if splitX was wrong kedge:777 would land into wrong place with Get failing
v, ok := tr.Get(kedge)
if !(v==777 && ok) {
t.Fatalf("after splitX: Get(%v) -> %v, %v ; expected 777, true", v, ok)
}
// now check the same when splitted X has parent
xr := tr.r.(*x)
if xr.c != 1 { // second x comes with k=∞ with .c index
t.Fatalf("after splitX: xr.c: %v ; expected 1", xr.c)
}
if xr.x[0].ch != x0 {
t.Fatal("xr[0].ch is not x0")
}
for i := 0; i <= (2*kx) * kd; i++ {
tr.Set(2*i+1, 2*i+1)
}
// check x0 is in pre-splitX condition and still at the right place
if x0.c != 2*kx+1 {
t.Fatalf("x0.c: %v ; expected %v", x0.c, 2*kx+1)
}
if xr.x[0].ch != x0 {
t.Fatal("xr[0].ch is not x0")
}
// set element with k directly at x0[kx].k
kedge = (kx + 1) * (2*kd)
if x0.x[kx].k != kedge {
t.Fatalf("edge key before splitX: %v ; expected %v", x0.x[kx].k, kedge)
}
tr.Set(kedge, 888)
// if splitX was wrong kedge:888 would land into wrong place
v, ok = tr.Get(kedge)
if !(v==888 && ok) {
t.Fatalf("after splitX: Get(%v) -> %v, %v ; expected 888, true", v, ok)
}
}
func BenchmarkSetSeq1e3(b *testing.B) {
benchmarkSetSeq(b, 1e3)
}
......
btree.go
View file @ 6955404b
......@@ -547,12 +547,13 @@ func (t *Tree) Set(k interface{} /*K*/, v interface{} /*V*/) {
if ok {
switch x := q.(type) {
case *x:
i++
if x.c > 2*kx {
x, i = t.splitX(p, x, pi, i)
}
pi = i + 1
pi = i
p = x
q = x.x[i+1].ch
q = x.x[i].ch
continue
case *d:
x.d[i].v = v
......@@ -614,12 +615,13 @@ func (t *Tree) Put(k interface{} /*K*/, upd func(oldV interface{} /*V*/, exists
if ok {
switch x := q.(type) {
case *x:
i++
if x.c > 2*kx {
x, i = t.splitX(p, x, pi, i)
}
pi = i + 1
pi = i
p = x
q = x.x[i+1].ch
q = x.x[i].ch
continue
case *d:
oldV = x.d[i].v
......@@ -701,36 +703,20 @@ func (t *Tree) splitX(p *x, q *x, pi int, i int) (*x, int) {
r.c = kx
if pi >= 0 {
p.insert(pi, q.x[kx].k, r)
q.x[kx].k = zk
for i := range q.x[kx+1:] {
q.x[kx+i+1] = zxe
}
switch {
case i < kx:
return q, i
case i == kx:
return p, pi
default: // i > kx
return r, i - kx - 1
}
} else {
t.r = newX(q).insert(0, q.x[kx].k, r)
}
nr := newX(q).insert(0, q.x[kx].k, r)
t.r = nr
q.x[kx].k = zk
for i := range q.x[kx+1:] {
q.x[kx+i+1] = zxe
}
switch {
case i < kx:
return q, i
case i == kx:
return nr, 0
default: // i > kx
return r, i - kx - 1
if i > kx {
q = r
i -= kx + 1
}
return q, i
}
func (t *Tree) underflow(p *x, q *d, pi int) {
......
example/all_test.go
View file @ 6955404b
......@@ -620,13 +620,13 @@ func TestEnumeratorPrev(t *testing.T) {
hit bool
keys []int
}{
{5, false, []int{10}},
{5, false, []int{}},
{10, true, []int{10}},
{15, false, []int{20, 10}},
{15, false, []int{10}},
{20, true, []int{20, 10}},
{25, false, []int{30, 20, 10}},
{25, false, []int{20, 10}},
{30, true, []int{30, 20, 10}},
{35, false, []int{}},
{35, false, []int{30, 20, 10}},
}
for i, test := range table {
......@@ -683,6 +683,51 @@ func TestEnumeratorPrev(t *testing.T) {
}
}
func TestEnumeratorPrevSanity(t *testing.T) {
// seeking within 3 keys: 10, 20, 30
table := []struct {
k int
hit bool
kOut int
vOut int
errOut error
}{
{10, true, 10, 100, nil},
{20, true, 20, 200, nil},
{30, true, 30, 300, nil},
{35, false, 30, 300, nil},
{25, false, 20, 200, nil},
{15, false, 10, 100, nil},
{5, false, 0, 0, io.EOF},
}
for i, test := range table {
r := TreeNew(cmp)
r.Set(10, 100)
r.Set(20, 200)
r.Set(30, 300)
en, hit := r.Seek(test.k)
if g, e := hit, test.hit; g != e {
t.Fatal(i, g, e)
}
k, v, err := en.Prev()
if g, e := err, test.errOut; g != e {
t.Fatal(i, g, e)
}
if g, e := k, test.kOut; g != e {
t.Fatal(i, g, e)
}
if g, e := v, test.vOut; g != e {
t.Fatal(i, g, e)
}
}
}
func BenchmarkSeekSeq1e3(b *testing.B) {
benchmarkSeekSeq(b, 1e3)
}
......
example/int.go
View file @ 6955404b
......@@ -76,7 +76,7 @@ type (
//
// However, once an Enumerator returns io.EOF to signal "no more
// items", it does no more attempt to "resync" on tree mutation(s). In
// other words, io.EOF from an Enumaretor is "sticky" (idempotent).
// other words, io.EOF from an Enumerator is "sticky" (idempotent).
Enumerator struct {
err error
hit bool
......@@ -450,7 +450,7 @@ func (t *Tree) overflow(p *x, q *d, pi, i int, k int, v int) {
t.ver++
l, r := p.siblings(pi)
if l != nil && l.c < 2*kd {
if l != nil && l.c < 2*kd && i != 0 {
l.mvL(q, 1)
t.insert(q, i-1, k, v)
p.x[pi-1].k = q.d[0].k
......@@ -473,9 +473,9 @@ func (t *Tree) overflow(p *x, q *d, pi, i int, k int, v int) {
t.split(p, q, pi, i, k, v)
}
// Seek returns an Enumerator positioned on a an item such that k >= item's
// key. ok reports if k == item.key The Enumerator's position is possibly
// after the last item in the tree.
// Seek returns an Enumerator positioned on an item such that k >= item's key.
// ok reports if k == item.key The Enumerator's position is possibly after the
// last item in the tree.
func (t *Tree) Seek(k int) (e *Enumerator, ok bool) {
q := t.r
if q == nil {
......@@ -547,12 +547,13 @@ func (t *Tree) Set(k int, v int) {
if ok {
switch x := q.(type) {
case *x:
i++
if x.c > 2*kx {
x, i = t.splitX(p, x, pi, i)
}
pi = i + 1
pi = i
p = x
q = x.x[i+1].ch
q = x.x[i].ch
continue
case *d:
x.d[i].v = v
......@@ -614,12 +615,13 @@ func (t *Tree) Put(k int, upd func(oldV int, exists bool) (newV int, write bool)
if ok {
switch x := q.(type) {
case *x:
i++
if x.c > 2*kx {
x, i = t.splitX(p, x, pi, i)
}
pi = i + 1
pi = i
p = x
q = x.x[i+1].ch
q = x.x[i].ch
continue
case *d:
oldV = x.d[i].v
......@@ -701,36 +703,20 @@ func (t *Tree) splitX(p *x, q *x, pi int, i int) (*x, int) {
r.c = kx
if pi >= 0 {
p.insert(pi, q.x[kx].k, r)
q.x[kx].k = zk
for i := range q.x[kx+1:] {
q.x[kx+i+1] = zxe
}
switch {
case i < kx:
return q, i
case i == kx:
return p, pi
default: // i > kx
return r, i - kx - 1
}
} else {
t.r = newX(q).insert(0, q.x[kx].k, r)
}
nr := newX(q).insert(0, q.x[kx].k, r)
t.r = nr
q.x[kx].k = zk
for i := range q.x[kx+1:] {
q.x[kx+i+1] = zxe
}
switch {
case i < kx:
return q, i
case i == kx:
return nr, 0
default: // i > kx
return r, i - kx - 1
if i > kx {
q = r
i -= kx + 1
}
return q, i
}
func (t *Tree) underflow(p *x, q *d, pi int) {
......@@ -826,13 +812,7 @@ func (e *Enumerator) Next() (k int, v int, err error) {
}
if e.ver != e.t.ver {
f, hit := e.t.Seek(e.k)
if !e.hit && hit {
if err = f.next(); err != nil {
return
}
}
f, _ := e.t.Seek(e.k)
*e = *f
f.Close()
}
......@@ -849,7 +829,7 @@ func (e *Enumerator) Next() (k int, v int, err error) {
i := e.q.d[e.i]
k, v = i.k, i.v
e.k, e.hit = k, false
e.k, e.hit = k, true
e.next()
return
}
......@@ -880,13 +860,7 @@ func (e *Enumerator) Prev() (k int, v int, err error) {
}
if e.ver != e.t.ver {
f, hit := e.t.Seek(e.k)
if !e.hit && hit {
if err = f.prev(); err != nil {
return
}
}
f, _ := e.t.Seek(e.k)
*e = *f
f.Close()
}
......@@ -895,15 +869,22 @@ func (e *Enumerator) Prev() (k int, v int, err error) {
return
}
if !e.hit {
// move to previous because Seek overshoots if there's no hit
if err = e.prev(); err != nil {
return
}
}
if e.i >= e.q.c {
if err = e.next(); err != nil {
if err = e.prev(); err != nil {
return
}
}
i := e.q.d[e.i]
k, v = i.k, i.v
e.k, e.hit = k, false
e.k, e.hit = k, true
e.prev()
return
}
......
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