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x/tools/container/intsets: use root block
The root block was used as a sentinel. This means we always need to allocate a second block on the heap, even if the set has a few small elements. We now use the root block: it is always the block with the smallest offset. The logic becomes very messy if there is no sentinel; to avoid this we still use a sentinel (a special singleton block) and return it in when appropriate in the first, last, next wrappers. Also adding some benchmarks and making some optimizations: name old time/op new time/op delta Popcount-4 2.18ns ± 1% 2.21ns ± 1% +1.47% InsertProbeSparse_2_10-4 76.2ns ±23% 37.2ns ± 1% -51.21% InsertProbeSparse_10_10-4 240ns ±15% 162ns ± 4% -32.58% InsertProbeSparse_10_1000-4 419ns ± 4% 371ns ±19% -11.43% InsertProbeSparse_100_100-4 2.30µs ± 1% 1.93µs ± 1% -16.08% InsertProbeSparse_100_10000-4 2.12µs ± 3% 2.07µs ± 1% -2.11% UnionDifferenceSparse-4 165µs ±16% 170µs ± 9% ~ UnionDifferenceHashTable-4 310µs ±10% 291µs ±17% ~ AppendTo-4 11.0µs ± 0% 11.0µs ± 0% -0.35% name old alloc/op new alloc/op delta Popcount-4 0.00B ±NaN% 0.00B ±NaN% ~ InsertProbeSparse_2_10-4 64.0B ± 0% 0.0B ±NaN% -100.00% InsertProbeSparse_10_10-4 64.0B ± 0% 0.0B ±NaN% -100.00% InsertProbeSparse_10_1000-4 256B ± 0% 192B ± 0% -25.00% InsertProbeSparse_100_100-4 64.0B ± 0% 0.0B ±NaN% -100.00% InsertProbeSparse_100_10000-4 256B ± 0% 192B ± 0% -25.00% UnionDifferenceSparse-4 59.4kB ± 0% 59.2kB ± 0% -0.32% UnionDifferenceHashTable-4 138kB ± 0% 138kB ± 0% ~ AppendTo-4 0.00B ±NaN% 0.00B ±NaN% ~ name old allocs/op new allocs/op delta Popcount-4 0.00 ±NaN% 0.00 ±NaN% ~ InsertProbeSparse_2_10-4 1.00 ± 0% 0.00 ±NaN% -100.00% InsertProbeSparse_10_10-4 1.00 ± 0% 0.00 ±NaN% -100.00% InsertProbeSparse_10_1000-4 4.00 ± 0% 3.00 ± 0% -25.00% InsertProbeSparse_100_100-4 1.00 ± 0% 0.00 ±NaN% -100.00% InsertProbeSparse_100_10000-4 4.00 ± 0% 3.00 ± 0% -25.00% UnionDifferenceSparse-4 928 ± 0% 925 ± 0% -0.32% UnionDifferenceHashTable-4 271 ± 0% 271 ± 0% ~ AppendTo-4 0.00 ±NaN% 0.00 ±NaN% ~ Fixes golang/go#21311. Change-Id: Ie472a2afa269c21cb33b22ffdac8dd2594b816ac Reviewed-on: https://go-review.googlesource.com/53431 Reviewed-by: Alan Donovan <adonovan@google.com>
This commit is contained in:
Radu Berinde
Alan Donovan
parent
84a35ef54d
commit
43e94ff202
@ -21,10 +21,6 @@ package intsets // import "golang.org/x/tools/container/intsets"
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// The space usage would be proportional to Max(), not Len(), and the
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// implementation would be based upon big.Int.
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//
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// TODO(adonovan): experiment with making the root block indirect (nil
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// iff IsEmpty). This would reduce the memory usage when empty and
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// might simplify the aliasing invariants.
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//
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// TODO(adonovan): opt: make UnionWith and Difference faster.
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// These are the hot-spots for go/pointer.
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@ -45,9 +41,10 @@ type Sparse struct {
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// An uninitialized Sparse represents an empty set.
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// An empty set may also be represented by
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// root.next == root.prev == &root.
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// In a non-empty set, root.next points to the first block and
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// root.prev to the last.
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// root.offset and root.bits are unused.
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//
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// The root is always the block with the smallest offset.
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// It can be empty, but only if it is the only block; in that case, offset is
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// MaxInt (which is not a valid offset).
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root block
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}
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@ -144,7 +141,6 @@ func (b *block) len() int {
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// max returns the maximum element of the block.
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// The block must not be empty.
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//
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func (b *block) max() int {
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bi := b.offset + bitsPerBlock
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// Decrement bi by number of high zeros in last.bits.
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@ -161,7 +157,6 @@ func (b *block) max() int {
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// and also removes it if take is set.
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// The block must not be initially empty.
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// NB: may leave the block empty.
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//
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func (b *block) min(take bool) int {
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for i, w := range b.bits {
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if w != 0 {
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@ -204,14 +199,20 @@ func offsetAndBitIndex(x int) (int, uint) {
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// -- Sparse --------------------------------------------------------------
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// start returns the root's next block, which is the root block
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// (if s.IsEmpty()) or the first true block otherwise.
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// start has the side effect of ensuring that s is properly
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// initialized.
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//
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func (s *Sparse) start() *block {
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// none is a shared, empty, sentinel block that indicates the end of a block
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// list.
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var none block
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// Dummy type used to generate an implicit panic. This must be defined at the
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// package level; if it is defined inside a function, it prevents the inlining
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// of that function.
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type to_copy_a_sparse_you_must_call_its_Copy_method struct{}
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// init ensures s is properly initialized.
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func (s *Sparse) init() {
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root := &s.root
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if root.next == nil {
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root.offset = MaxInt
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root.next = root
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root.prev = root
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} else if root.next.prev != root {
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@ -219,21 +220,45 @@ func (s *Sparse) start() *block {
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// new Sparse y shares the old linked list, but iteration
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// on y will never encounter &y.root so it goes into a
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// loop. Fail fast before this occurs.
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panic("A Sparse has been copied without (*Sparse).Copy()")
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// We don't want to call panic here because it prevents the
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// inlining of this function.
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_ = (interface{}(nil)).(to_copy_a_sparse_you_must_call_its_Copy_method)
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}
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}
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return root.next
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func (s *Sparse) first() *block {
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s.init()
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if s.root.offset == MaxInt {
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return &none
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}
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return &s.root
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}
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// next returns the next block in the list, or end if b is the last block.
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func (s *Sparse) next(b *block) *block {
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if b.next == &s.root {
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return &none
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}
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return b.next
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}
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// prev returns the previous block in the list, or end if b is the first block.
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func (s *Sparse) prev(b *block) *block {
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if b.prev == &s.root {
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return &none
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}
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return b.prev
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}
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// IsEmpty reports whether the set s is empty.
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func (s *Sparse) IsEmpty() bool {
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return s.start() == &s.root
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return s.root.next == nil || s.root.offset == MaxInt
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}
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// Len returns the number of elements in the set s.
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func (s *Sparse) Len() int {
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var l int
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for b := s.start(); b != &s.root; b = b.next {
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for b := s.first(); b != &none; b = s.next(b) {
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l += b.len()
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}
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return l
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@ -252,19 +277,16 @@ func (s *Sparse) Min() int {
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if s.IsEmpty() {
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return MaxInt
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}
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return s.root.next.min(false)
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return s.root.min(false)
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}
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// block returns the block that would contain offset,
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// or nil if s contains no such block.
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//
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func (s *Sparse) block(offset int) *block {
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b := s.start()
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for b != &s.root && b.offset <= offset {
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for b := s.first(); b != &none && b.offset <= offset; b = s.next(b) {
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if b.offset == offset {
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return b
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}
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b = b.next
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}
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return nil
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}
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@ -272,26 +294,49 @@ func (s *Sparse) block(offset int) *block {
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// Insert adds x to the set s, and reports whether the set grew.
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func (s *Sparse) Insert(x int) bool {
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offset, i := offsetAndBitIndex(x)
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b := s.start()
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for b != &s.root && b.offset <= offset {
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b := s.first()
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for ; b != &none && b.offset <= offset; b = s.next(b) {
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if b.offset == offset {
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return b.insert(i)
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}
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b = b.next
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}
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// Insert new block before b.
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new := &block{offset: offset}
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new.next = b
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new.prev = b.prev
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new.prev.next = new
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new.next.prev = new
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new := s.insertBlockBefore(b)
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new.offset = offset
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return new.insert(i)
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}
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func (s *Sparse) removeBlock(b *block) {
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b.prev.next = b.next
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b.next.prev = b.prev
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// removeBlock removes a block and returns the block that followed it (or end if
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// it was the last block).
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func (s *Sparse) removeBlock(b *block) *block {
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if b != &s.root {
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b.prev.next = b.next
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b.next.prev = b.prev
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if b.next == &s.root {
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return &none
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}
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return b.next
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}
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first := s.root.next
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if first == &s.root {
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// This was the only block.
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s.Clear()
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return &none
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}
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s.root.offset = first.offset
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s.root.bits = first.bits
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if first.next == &s.root {
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// Single block remaining.
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s.root.next = &s.root
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s.root.prev = &s.root
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} else {
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s.root.next = first.next
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first.next.prev = &s.root
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}
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return &s.root
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}
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// Remove removes x from the set s, and reports whether the set shrank.
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@ -311,8 +356,11 @@ func (s *Sparse) Remove(x int) bool {
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// Clear removes all elements from the set s.
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func (s *Sparse) Clear() {
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s.root.next = &s.root
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s.root.prev = &s.root
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s.root = block{
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offset: MaxInt,
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next: &s.root,
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prev: &s.root,
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}
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}
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// If set s is non-empty, TakeMin sets *p to the minimum element of
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@ -325,13 +373,12 @@ func (s *Sparse) Clear() {
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// for worklist.TakeMin(&x) { use(x) }
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//
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func (s *Sparse) TakeMin(p *int) bool {
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head := s.start()
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if head == &s.root {
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if s.IsEmpty() {
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return false
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}
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*p = head.min(true)
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if head.empty() {
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s.removeBlock(head)
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*p = s.root.min(true)
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if s.root.empty() {
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s.removeBlock(&s.root)
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}
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return true
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}
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@ -352,7 +399,7 @@ func (s *Sparse) Has(x int) bool {
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// natural control flow with continue/break/return.
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//
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func (s *Sparse) forEach(f func(int)) {
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for b := s.start(); b != &s.root; b = b.next {
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for b := s.first(); b != &none; b = s.next(b) {
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b.forEach(f)
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}
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}
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@ -363,22 +410,51 @@ func (s *Sparse) Copy(x *Sparse) {
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return
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}
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xb := x.start()
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sb := s.start()
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for xb != &x.root {
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if sb == &s.root {
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xb := x.first()
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sb := s.first()
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for xb != &none {
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if sb == &none {
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sb = s.insertBlockBefore(sb)
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}
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sb.offset = xb.offset
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sb.bits = xb.bits
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xb = xb.next
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sb = sb.next
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xb = x.next(xb)
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sb = s.next(sb)
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}
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s.discardTail(sb)
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}
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// insertBlockBefore returns a new block, inserting it before next.
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// If next is the root, the root is replaced. If next is end, the block is
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// inserted at the end.
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func (s *Sparse) insertBlockBefore(next *block) *block {
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if s.IsEmpty() {
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if next != &none {
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panic("BUG: passed block with empty set")
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}
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return &s.root
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}
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if next == &s.root {
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// Special case: we need to create a new block that will become the root
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// block.The old root block becomes the second block.
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second := s.root
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s.root = block{
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next: &second,
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}
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if second.next == &s.root {
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s.root.prev = &second
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} else {
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s.root.prev = second.prev
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second.next.prev = &second
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second.prev = &s.root
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}
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return &s.root
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}
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if next == &none {
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// Insert before root.
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next = &s.root
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}
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b := new(block)
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b.next = next
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b.prev = next.prev
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@ -389,9 +465,13 @@ func (s *Sparse) insertBlockBefore(next *block) *block {
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// discardTail removes block b and all its successors from s.
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func (s *Sparse) discardTail(b *block) {
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if b != &s.root {
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b.prev.next = &s.root
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s.root.prev = b.prev
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if b != &none {
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if b == &s.root {
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s.Clear()
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} else {
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b.prev.next = &s.root
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s.root.prev = b.prev
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}
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}
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}
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@ -401,16 +481,15 @@ func (s *Sparse) IntersectionWith(x *Sparse) {
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return
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}
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xb := x.start()
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sb := s.start()
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for xb != &x.root && sb != &s.root {
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xb := x.first()
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sb := s.first()
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for xb != &none && sb != &none {
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switch {
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case xb.offset < sb.offset:
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xb = xb.next
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xb = x.next(xb)
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case xb.offset > sb.offset:
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sb = sb.next
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s.removeBlock(sb.prev)
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sb = s.removeBlock(sb)
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default:
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var sum word
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@ -420,12 +499,12 @@ func (s *Sparse) IntersectionWith(x *Sparse) {
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sum |= r
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}
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if sum != 0 {
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sb = sb.next
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sb = s.next(sb)
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} else {
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// sb will be overwritten or removed
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}
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xb = xb.next
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xb = x.next(xb)
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}
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}
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@ -446,20 +525,20 @@ func (s *Sparse) Intersection(x, y *Sparse) {
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return
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}
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xb := x.start()
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yb := y.start()
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sb := s.start()
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for xb != &x.root && yb != &y.root {
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xb := x.first()
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yb := y.first()
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sb := s.first()
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for xb != &none && yb != &none {
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switch {
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case xb.offset < yb.offset:
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xb = xb.next
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xb = x.next(xb)
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continue
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case xb.offset > yb.offset:
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yb = yb.next
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yb = y.next(yb)
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continue
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}
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if sb == &s.root {
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if sb == &none {
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sb = s.insertBlockBefore(sb)
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}
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sb.offset = xb.offset
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@ -471,13 +550,13 @@ func (s *Sparse) Intersection(x, y *Sparse) {
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sum |= r
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}
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if sum != 0 {
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sb = sb.next
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sb = s.next(sb)
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} else {
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// sb will be overwritten or removed
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}
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xb = xb.next
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yb = yb.next
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xb = x.next(xb)
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yb = y.next(yb)
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}
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s.discardTail(sb)
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@ -485,22 +564,22 @@ func (s *Sparse) Intersection(x, y *Sparse) {
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// Intersects reports whether s ∩ x ≠ ∅.
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func (s *Sparse) Intersects(x *Sparse) bool {
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sb := s.start()
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xb := x.start()
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for sb != &s.root && xb != &x.root {
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sb := s.first()
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xb := x.first()
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for sb != &none && xb != &none {
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switch {
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case xb.offset < sb.offset:
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xb = xb.next
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xb = x.next(xb)
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case xb.offset > sb.offset:
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sb = sb.next
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sb = s.next(sb)
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default:
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for i := range sb.bits {
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if sb.bits[i]&xb.bits[i] != 0 {
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return true
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}
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}
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sb = sb.next
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xb = xb.next
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sb = s.next(sb)
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xb = x.next(xb)
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}
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}
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return false
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@ -513,26 +592,26 @@ func (s *Sparse) UnionWith(x *Sparse) bool {
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}
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var changed bool
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xb := x.start()
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sb := s.start()
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for xb != &x.root {
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if sb != &s.root && sb.offset == xb.offset {
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xb := x.first()
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sb := s.first()
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for xb != &none {
|
||||
if sb != &none && sb.offset == xb.offset {
|
||||
for i := range xb.bits {
|
||||
if sb.bits[i] != xb.bits[i] {
|
||||
sb.bits[i] |= xb.bits[i]
|
||||
changed = true
|
||||
}
|
||||
}
|
||||
xb = xb.next
|
||||
} else if sb == &s.root || sb.offset > xb.offset {
|
||||
xb = x.next(xb)
|
||||
} else if sb == &none || sb.offset > xb.offset {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
sb.offset = xb.offset
|
||||
sb.bits = xb.bits
|
||||
changed = true
|
||||
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
}
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
}
|
||||
return changed
|
||||
}
|
||||
@ -551,33 +630,33 @@ func (s *Sparse) Union(x, y *Sparse) {
|
||||
return
|
||||
}
|
||||
|
||||
xb := x.start()
|
||||
yb := y.start()
|
||||
sb := s.start()
|
||||
for xb != &x.root || yb != &y.root {
|
||||
if sb == &s.root {
|
||||
xb := x.first()
|
||||
yb := y.first()
|
||||
sb := s.first()
|
||||
for xb != &none || yb != &none {
|
||||
if sb == &none {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
}
|
||||
switch {
|
||||
case yb == &y.root || (xb != &x.root && xb.offset < yb.offset):
|
||||
case yb == &none || (xb != &none && xb.offset < yb.offset):
|
||||
sb.offset = xb.offset
|
||||
sb.bits = xb.bits
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
|
||||
case xb == &x.root || (yb != &y.root && yb.offset < xb.offset):
|
||||
case xb == &none || (yb != &none && yb.offset < xb.offset):
|
||||
sb.offset = yb.offset
|
||||
sb.bits = yb.bits
|
||||
yb = yb.next
|
||||
yb = y.next(yb)
|
||||
|
||||
default:
|
||||
sb.offset = xb.offset
|
||||
for i := range xb.bits {
|
||||
sb.bits[i] = xb.bits[i] | yb.bits[i]
|
||||
}
|
||||
xb = xb.next
|
||||
yb = yb.next
|
||||
xb = x.next(xb)
|
||||
yb = y.next(yb)
|
||||
}
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
}
|
||||
|
||||
s.discardTail(sb)
|
||||
@ -590,15 +669,15 @@ func (s *Sparse) DifferenceWith(x *Sparse) {
|
||||
return
|
||||
}
|
||||
|
||||
xb := x.start()
|
||||
sb := s.start()
|
||||
for xb != &x.root && sb != &s.root {
|
||||
xb := x.first()
|
||||
sb := s.first()
|
||||
for xb != &none && sb != &none {
|
||||
switch {
|
||||
case xb.offset > sb.offset:
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
|
||||
case xb.offset < sb.offset:
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
|
||||
default:
|
||||
var sum word
|
||||
@ -607,12 +686,12 @@ func (s *Sparse) DifferenceWith(x *Sparse) {
|
||||
sb.bits[i] = r
|
||||
sum |= r
|
||||
}
|
||||
sb = sb.next
|
||||
xb = xb.next
|
||||
|
||||
if sum == 0 {
|
||||
s.removeBlock(sb.prev)
|
||||
sb = s.removeBlock(sb)
|
||||
} else {
|
||||
sb = s.next(sb)
|
||||
}
|
||||
xb = x.next(xb)
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -633,27 +712,27 @@ func (s *Sparse) Difference(x, y *Sparse) {
|
||||
return
|
||||
}
|
||||
|
||||
xb := x.start()
|
||||
yb := y.start()
|
||||
sb := s.start()
|
||||
for xb != &x.root && yb != &y.root {
|
||||
xb := x.first()
|
||||
yb := y.first()
|
||||
sb := s.first()
|
||||
for xb != &none && yb != &none {
|
||||
if xb.offset > yb.offset {
|
||||
// y has block, x has none
|
||||
yb = yb.next
|
||||
// y has block, x has &none
|
||||
yb = y.next(yb)
|
||||
continue
|
||||
}
|
||||
|
||||
if sb == &s.root {
|
||||
if sb == &none {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
}
|
||||
sb.offset = xb.offset
|
||||
|
||||
switch {
|
||||
case xb.offset < yb.offset:
|
||||
// x has block, y has none
|
||||
// x has block, y has &none
|
||||
sb.bits = xb.bits
|
||||
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
|
||||
default:
|
||||
// x and y have corresponding blocks
|
||||
@ -664,25 +743,25 @@ func (s *Sparse) Difference(x, y *Sparse) {
|
||||
sum |= r
|
||||
}
|
||||
if sum != 0 {
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
} else {
|
||||
// sb will be overwritten or removed
|
||||
}
|
||||
|
||||
yb = yb.next
|
||||
yb = y.next(yb)
|
||||
}
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
}
|
||||
|
||||
for xb != &x.root {
|
||||
if sb == &s.root {
|
||||
for xb != &none {
|
||||
if sb == &none {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
}
|
||||
sb.offset = xb.offset
|
||||
sb.bits = xb.bits
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
}
|
||||
|
||||
s.discardTail(sb)
|
||||
@ -695,17 +774,17 @@ func (s *Sparse) SymmetricDifferenceWith(x *Sparse) {
|
||||
return
|
||||
}
|
||||
|
||||
sb := s.start()
|
||||
xb := x.start()
|
||||
for xb != &x.root && sb != &s.root {
|
||||
sb := s.first()
|
||||
xb := x.first()
|
||||
for xb != &none && sb != &none {
|
||||
switch {
|
||||
case sb.offset < xb.offset:
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
case xb.offset < sb.offset:
|
||||
nb := s.insertBlockBefore(sb)
|
||||
nb.offset = xb.offset
|
||||
nb.bits = xb.bits
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
default:
|
||||
var sum word
|
||||
for i := range sb.bits {
|
||||
@ -713,20 +792,21 @@ func (s *Sparse) SymmetricDifferenceWith(x *Sparse) {
|
||||
sb.bits[i] = r
|
||||
sum |= r
|
||||
}
|
||||
sb = sb.next
|
||||
xb = xb.next
|
||||
if sum == 0 {
|
||||
s.removeBlock(sb.prev)
|
||||
sb = s.removeBlock(sb)
|
||||
} else {
|
||||
sb = s.next(sb)
|
||||
}
|
||||
xb = x.next(xb)
|
||||
}
|
||||
}
|
||||
|
||||
for xb != &x.root { // append the tail of x to s
|
||||
for xb != &none { // append the tail of x to s
|
||||
sb = s.insertBlockBefore(sb)
|
||||
sb.offset = xb.offset
|
||||
sb.bits = xb.bits
|
||||
sb = sb.next
|
||||
xb = xb.next
|
||||
sb = s.next(sb)
|
||||
xb = x.next(xb)
|
||||
}
|
||||
}
|
||||
|
||||
@ -744,24 +824,24 @@ func (s *Sparse) SymmetricDifference(x, y *Sparse) {
|
||||
return
|
||||
}
|
||||
|
||||
sb := s.start()
|
||||
xb := x.start()
|
||||
yb := y.start()
|
||||
for xb != &x.root && yb != &y.root {
|
||||
if sb == &s.root {
|
||||
sb := s.first()
|
||||
xb := x.first()
|
||||
yb := y.first()
|
||||
for xb != &none && yb != &none {
|
||||
if sb == &none {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
}
|
||||
switch {
|
||||
case yb.offset < xb.offset:
|
||||
sb.offset = yb.offset
|
||||
sb.bits = yb.bits
|
||||
sb = sb.next
|
||||
yb = yb.next
|
||||
sb = s.next(sb)
|
||||
yb = y.next(yb)
|
||||
case xb.offset < yb.offset:
|
||||
sb.offset = xb.offset
|
||||
sb.bits = xb.bits
|
||||
sb = sb.next
|
||||
xb = xb.next
|
||||
sb = s.next(sb)
|
||||
xb = x.next(xb)
|
||||
default:
|
||||
var sum word
|
||||
for i := range sb.bits {
|
||||
@ -771,31 +851,31 @@ func (s *Sparse) SymmetricDifference(x, y *Sparse) {
|
||||
}
|
||||
if sum != 0 {
|
||||
sb.offset = xb.offset
|
||||
sb = sb.next
|
||||
sb = s.next(sb)
|
||||
}
|
||||
xb = xb.next
|
||||
yb = yb.next
|
||||
xb = x.next(xb)
|
||||
yb = y.next(yb)
|
||||
}
|
||||
}
|
||||
|
||||
for xb != &x.root { // append the tail of x to s
|
||||
if sb == &s.root {
|
||||
for xb != &none { // append the tail of x to s
|
||||
if sb == &none {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
}
|
||||
sb.offset = xb.offset
|
||||
sb.bits = xb.bits
|
||||
sb = sb.next
|
||||
xb = xb.next
|
||||
sb = s.next(sb)
|
||||
xb = x.next(xb)
|
||||
}
|
||||
|
||||
for yb != &y.root { // append the tail of y to s
|
||||
if sb == &s.root {
|
||||
for yb != &none { // append the tail of y to s
|
||||
if sb == &none {
|
||||
sb = s.insertBlockBefore(sb)
|
||||
}
|
||||
sb.offset = yb.offset
|
||||
sb.bits = yb.bits
|
||||
sb = sb.next
|
||||
yb = yb.next
|
||||
sb = s.next(sb)
|
||||
yb = y.next(yb)
|
||||
}
|
||||
|
||||
s.discardTail(sb)
|
||||
@ -807,22 +887,22 @@ func (s *Sparse) SubsetOf(x *Sparse) bool {
|
||||
return true
|
||||
}
|
||||
|
||||
sb := s.start()
|
||||
xb := x.start()
|
||||
for sb != &s.root {
|
||||
sb := s.first()
|
||||
xb := x.first()
|
||||
for sb != &none {
|
||||
switch {
|
||||
case xb == &x.root || xb.offset > sb.offset:
|
||||
case xb == &none || xb.offset > sb.offset:
|
||||
return false
|
||||
case xb.offset < sb.offset:
|
||||
xb = xb.next
|
||||
xb = x.next(xb)
|
||||
default:
|
||||
for i := range sb.bits {
|
||||
if sb.bits[i]&^xb.bits[i] != 0 {
|
||||
return false
|
||||
}
|
||||
}
|
||||
sb = sb.next
|
||||
xb = xb.next
|
||||
sb = s.next(sb)
|
||||
xb = x.next(xb)
|
||||
}
|
||||
}
|
||||
return true
|
||||
@ -833,13 +913,13 @@ func (s *Sparse) Equals(t *Sparse) bool {
|
||||
if s == t {
|
||||
return true
|
||||
}
|
||||
sb := s.start()
|
||||
tb := t.start()
|
||||
sb := s.first()
|
||||
tb := t.first()
|
||||
for {
|
||||
switch {
|
||||
case sb == &s.root && tb == &t.root:
|
||||
case sb == &none && tb == &none:
|
||||
return true
|
||||
case sb == &s.root || tb == &t.root:
|
||||
case sb == &none || tb == &none:
|
||||
return false
|
||||
case sb.offset != tb.offset:
|
||||
return false
|
||||
@ -847,8 +927,8 @@ func (s *Sparse) Equals(t *Sparse) bool {
|
||||
return false
|
||||
}
|
||||
|
||||
sb = sb.next
|
||||
tb = tb.next
|
||||
sb = s.next(sb)
|
||||
tb = t.next(tb)
|
||||
}
|
||||
}
|
||||
|
||||
@ -913,7 +993,7 @@ func (s *Sparse) BitString() string {
|
||||
//
|
||||
func (s *Sparse) GoString() string {
|
||||
var buf bytes.Buffer
|
||||
for b := s.start(); b != &s.root; b = b.next {
|
||||
for b := s.first(); b != &none; b = s.next(b) {
|
||||
fmt.Fprintf(&buf, "block %p {offset=%d next=%p prev=%p",
|
||||
b, b.offset, b.next, b.prev)
|
||||
for _, w := range b.bits {
|
||||
@ -937,13 +1017,18 @@ func (s *Sparse) AppendTo(slice []int) []int {
|
||||
|
||||
// check returns an error if the representation invariants of s are violated.
|
||||
func (s *Sparse) check() error {
|
||||
if !s.root.empty() {
|
||||
return fmt.Errorf("non-empty root block")
|
||||
s.init()
|
||||
if s.root.empty() {
|
||||
// An empty set must have only the root block with offset MaxInt.
|
||||
if s.root.next != &s.root {
|
||||
return fmt.Errorf("multiple blocks with empty root block")
|
||||
}
|
||||
if s.root.offset != MaxInt {
|
||||
return fmt.Errorf("empty set has offset %d, should be MaxInt", s.root.offset)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
if s.root.offset != 0 {
|
||||
return fmt.Errorf("root block has non-zero offset %d", s.root.offset)
|
||||
}
|
||||
for b := s.start(); b != &s.root; b = b.next {
|
||||
for b := s.first(); ; b = s.next(b) {
|
||||
if b.offset%bitsPerBlock != 0 {
|
||||
return fmt.Errorf("bad offset modulo: %d", b.offset)
|
||||
}
|
||||
@ -956,11 +1041,12 @@ func (s *Sparse) check() error {
|
||||
if b.next.prev != b {
|
||||
return fmt.Errorf("bad next.prev link")
|
||||
}
|
||||
if b.prev != &s.root {
|
||||
if b.offset <= b.prev.offset {
|
||||
return fmt.Errorf("bad offset order: b.offset=%d, prev.offset=%d",
|
||||
b.offset, b.prev.offset)
|
||||
}
|
||||
if b.next == &s.root {
|
||||
break
|
||||
}
|
||||
if b.offset >= b.next.offset {
|
||||
return fmt.Errorf("bad offset order: b.offset=%d, b.next.offset=%d",
|
||||
b.offset, b.next.offset)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
|
||||
@ -471,7 +471,7 @@ func TestIntersects(t *testing.T) {
|
||||
z.IntersectionWith(y)
|
||||
|
||||
if got, want := x.Intersects(y), !z.IsEmpty(); got != want {
|
||||
t.Errorf("Intersects: got %v, want %v", got, want)
|
||||
t.Errorf("Intersects(%s, %s): got %v, want %v (%s)", x, y, got, want, &z)
|
||||
}
|
||||
|
||||
// make it false
|
||||
@ -563,7 +563,7 @@ func TestFailFastOnShallowCopy(t *testing.T) {
|
||||
y := x // shallow copy (breaks representation invariants)
|
||||
defer func() {
|
||||
got := fmt.Sprint(recover())
|
||||
want := "A Sparse has been copied without (*Sparse).Copy()"
|
||||
want := "interface conversion: interface {} is nil, not intsets.to_copy_a_sparse_you_must_call_its_Copy_method"
|
||||
if got != want {
|
||||
t.Errorf("shallow copy: recover() = %q, want %q", got, want)
|
||||
}
|
||||
@ -579,7 +579,60 @@ func TestFailFastOnShallowCopy(t *testing.T) {
|
||||
// - Gather set distributions from pointer analysis.
|
||||
// - Measure memory usage.
|
||||
|
||||
func BenchmarkSparseBitVector(b *testing.B) {
|
||||
func benchmarkInsertProbeSparse(b *testing.B, size, spread int) {
|
||||
prng := rand.New(rand.NewSource(0))
|
||||
// Generate our insertions and probes beforehand (we don't want to benchmark
|
||||
// the prng).
|
||||
insert := make([]int, size)
|
||||
probe := make([]int, size*2)
|
||||
for i := range insert {
|
||||
insert[i] = prng.Int() % spread
|
||||
}
|
||||
for i := range probe {
|
||||
probe[i] = prng.Int() % spread
|
||||
}
|
||||
|
||||
b.ResetTimer()
|
||||
var x intsets.Sparse
|
||||
for tries := 0; tries < b.N; tries++ {
|
||||
x.Clear()
|
||||
for _, n := range insert {
|
||||
x.Insert(n)
|
||||
}
|
||||
hits := 0
|
||||
for _, n := range probe {
|
||||
if x.Has(n) {
|
||||
hits++
|
||||
}
|
||||
}
|
||||
// Use the variable so it doesn't get optimized away.
|
||||
if hits > len(probe) {
|
||||
b.Fatalf("%d hits, only %d probes", hits, len(probe))
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkInsertProbeSparse_2_10(b *testing.B) {
|
||||
benchmarkInsertProbeSparse(b, 2, 10)
|
||||
}
|
||||
|
||||
func BenchmarkInsertProbeSparse_10_10(b *testing.B) {
|
||||
benchmarkInsertProbeSparse(b, 10, 10)
|
||||
}
|
||||
|
||||
func BenchmarkInsertProbeSparse_10_1000(b *testing.B) {
|
||||
benchmarkInsertProbeSparse(b, 10, 1000)
|
||||
}
|
||||
|
||||
func BenchmarkInsertProbeSparse_100_100(b *testing.B) {
|
||||
benchmarkInsertProbeSparse(b, 100, 100)
|
||||
}
|
||||
|
||||
func BenchmarkInsertProbeSparse_100_10000(b *testing.B) {
|
||||
benchmarkInsertProbeSparse(b, 100, 1000)
|
||||
}
|
||||
|
||||
func BenchmarkUnionDifferenceSparse(b *testing.B) {
|
||||
prng := rand.New(rand.NewSource(0))
|
||||
for tries := 0; tries < b.N; tries++ {
|
||||
var x, y, z intsets.Sparse
|
||||
@ -596,7 +649,7 @@ func BenchmarkSparseBitVector(b *testing.B) {
|
||||
}
|
||||
}
|
||||
|
||||
func BenchmarkHashTable(b *testing.B) {
|
||||
func BenchmarkUnionDifferenceHashTable(b *testing.B) {
|
||||
prng := rand.New(rand.NewSource(0))
|
||||
for tries := 0; tries < b.N; tries++ {
|
||||
x, y, z := make(map[int]bool), make(map[int]bool), make(map[int]bool)
|
||||
|
||||
Loading…
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Reference in New Issue
Block a user