deleted file mode 100644

@@ -1,27 +0,0 @@

-Copyright (c) 2009 The Go Authors. All rights reserved.

-

-Redistribution and use in source and binary forms, with or without

-modification, are permitted provided that the following conditions are

-met:

-

-   * Redistributions of source code must retain the above copyright

-notice, this list of conditions and the following disclaimer.

-   * Redistributions in binary form must reproduce the above

-copyright notice, this list of conditions and the following disclaimer

-in the documentation and/or other materials provided with the

-distribution.

-   * Neither the name of Google Inc. nor the names of its

-contributors may be used to endorse or promote products derived from

-this software without specific prior written permission.

-

-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

deleted file mode 100644

@@ -1,22 +0,0 @@

-Additional IP Rights Grant (Patents)

-

-"This implementation" means the copyrightable works distributed by

-Google as part of the Go project.

-

-Google hereby grants to You a perpetual, worldwide, non-exclusive,

-no-charge, royalty-free, irrevocable (except as stated in this section)

-patent license to make, have made, use, offer to sell, sell, import,

-transfer and otherwise run, modify and propagate the contents of this

-implementation of Go, where such license applies only to those patent

-claims, both currently owned or controlled by Google and acquired in

-the future, licensable by Google that are necessarily infringed by this

-implementation of Go.  This grant does not include claims that would be

-infringed only as a consequence of further modification of this

-implementation.  If you or your agent or exclusive licensee institute or

-order or agree to the institution of patent litigation against any

-entity (including a cross-claim or counterclaim in a lawsuit) alleging

-that this implementation of Go or any code incorporated within this

-implementation of Go constitutes direct or contributory patent

-infringement, or inducement of patent infringement, then any patent

-rights granted to you under this License for this implementation of Go

-shall terminate as of the date such litigation is filed.

deleted file mode 100644

@@ -1,27 +0,0 @@

-# Go Tools

-

-This subrepository holds the source for various packages and tools that support

-the Go programming language.

-

-Some of the tools, `godoc` and `vet` for example, are included in binary Go

-distributions.

-

-Others, including the Go `guru` and the test coverage tool, can be fetched with

-`go get`.

-

-Packages include a type-checker for Go and an implementation of the

-Static Single Assignment form (SSA) representation for Go programs.

-

-## Download/Install

-

-The easiest way to install is to run `go get -u golang.org/x/tools/...`. You can

-also manually git clone the repository to `$GOPATH/src/golang.org/x/tools`.

-

-## Report Issues / Send Patches

-

-This repository uses Gerrit for code changes. To learn how to submit changes to

-this repository, see https://golang.org/doc/contribute.html.

-

-The main issue tracker for the tools repository is located at

-https://github.com/golang/go/issues. Prefix your issue with "x/tools/(your

-subdir):" in the subject line, so it is easy to find.

deleted file mode 100644

@@ -1,20 +0,0 @@

-// Copyright 2015 The Go Authors. All rights reserved.

-// Use of this source code is governed by a BSD-style

-// license that can be found in the LICENSE file.

-

-// +build amd64,!appengine,!gccgo

-

-package intsets

-

-func popcnt(x word) int

-func havePOPCNT() bool

-

-var hasPOPCNT = havePOPCNT()

-

-// popcount returns the population count (number of set bits) of x.

-func popcount(x word) int {

-	if hasPOPCNT {

-		return popcnt(x)

-	}

-	return popcountTable(x) // faster than Hacker's Delight

-}

deleted file mode 100644

@@ -1,30 +0,0 @@

-// Copyright 2015 The Go Authors. All rights reserved.

-// Use of this source code is governed by a BSD-style

-// license that can be found in the LICENSE file.

-

-// +build amd64,!appengine,!gccgo

-

-#include "textflag.h"

-

-// func havePOPCNT() bool

-TEXT ·havePOPCNT(SB),4,$0

-	MOVQ	$1, AX

-	CPUID

-	SHRQ	$23, CX

-	ANDQ	$1, CX

-	MOVB	CX, ret+0(FP)

-	RET

-

-// func popcnt(word) int

-TEXT ·popcnt(SB),NOSPLIT,$0-8

-	XORQ	AX, AX

-	MOVQ	x+0(FP), SI

-	// POPCNT (SI), AX is not recognized by Go assembler,

-	// so we assemble it ourselves.

-	BYTE	$0xf3

-	BYTE	$0x48

-	BYTE	$0x0f

-	BYTE	$0xb8

-	BYTE	$0xc6

-	MOVQ	AX, ret+8(FP)

-	RET

deleted file mode 100644

@@ -1,9 +0,0 @@

-// Copyright 2015 The Go Authors.  All rights reserved.

-// Use of this source code is governed by a BSD-style

-// license that can be found in the LICENSE file.

-

-// +build gccgo

-

-package intsets

-

-func popcount(x word) int

deleted file mode 100644

@@ -1,19 +0,0 @@

-// Copyright 2015 The Go Authors.  All rights reserved.

-// Use of this source code is governed by a BSD-style

-// license that can be found in the LICENSE file.

-

-// +build gccgo

-

-#include <errno.h>

-#include <stdint.h>

-#include <unistd.h>

-

-#define _STRINGIFY2_(x) #x

-#define _STRINGIFY_(x) _STRINGIFY2_(x)

-#define GOSYM_PREFIX _STRINGIFY_(__USER_LABEL_PREFIX__)

-

-extern intptr_t popcount(uintptr_t x) __asm__(GOSYM_PREFIX GOPKGPATH ".popcount");

-

-intptr_t popcount(uintptr_t x) {

-	return __builtin_popcountl((unsigned long)(x));

-}

deleted file mode 100644

@@ -1,33 +0,0 @@

-// Copyright 2015 The Go Authors. All rights reserved.

-// Use of this source code is governed by a BSD-style

-// license that can be found in the LICENSE file.

-

-// +build !amd64 appengine

-// +build !gccgo

-

-package intsets

-

-import "runtime"

-

-// We compared three algorithms---Hacker's Delight, table lookup,

-// and AMD64's SSE4.1 hardware POPCNT---on a 2.67GHz Xeon X5550.

-//

-// % GOARCH=amd64 go test -run=NONE -bench=Popcount

-// POPCNT               5.12 ns/op

-// Table                8.53 ns/op

-// HackersDelight       9.96 ns/op

-//

-// % GOARCH=386 go test -run=NONE -bench=Popcount

-// Table               10.4  ns/op

-// HackersDelight       5.23 ns/op

-//

-// (AMD64's ABM1 hardware supports ntz and nlz too,

-// but they aren't critical.)

-

-// popcount returns the population count (number of set bits) of x.

-func popcount(x word) int {

-	if runtime.GOARCH == "386" {

-		return popcountHD(uint32(x))

-	}

-	return popcountTable(x)

-}

deleted file mode 100644

@@ -1,1091 +0,0 @@

-// Copyright 2014 The Go Authors. All rights reserved.

-// Use of this source code is governed by a BSD-style

-// license that can be found in the LICENSE file.

-

-// Package intsets provides Sparse, a compact and fast representation

-// for sparse sets of int values.

-//

-// The time complexity of the operations Len, Insert, Remove and Has

-// is in O(n) but in practice those methods are faster and more

-// space-efficient than equivalent operations on sets based on the Go

-// map type.  The IsEmpty, Min, Max, Clear and TakeMin operations

-// require constant time.

-//

-package intsets // import "golang.org/x/tools/container/intsets"

-

-// TODO(adonovan):

-// - Add InsertAll(...int), RemoveAll(...int)

-// - Add 'bool changed' results for {Intersection,Difference}With too.

-//

-// TODO(adonovan): implement Dense, a dense bit vector with a similar API.

-// The space usage would be proportional to Max(), not Len(), and the

-// implementation would be based upon big.Int.

-//

-// TODO(adonovan): opt: make UnionWith and Difference faster.

-// These are the hot-spots for go/pointer.

-

-import (

-	"bytes"

-	"fmt"

-)

-

-// A Sparse is a set of int values.

-// Sparse operations (even queries) are not concurrency-safe.

-//

-// The zero value for Sparse is a valid empty set.

-//

-// Sparse sets must be copied using the Copy method, not by assigning

-// a Sparse value.

-//

-type Sparse struct {

-	// An uninitialized Sparse represents an empty set.

-	// An empty set may also be represented by

-	//  root.next == root.prev == &root.

-	//

-	// The root is always the block with the smallest offset.

-	// It can be empty, but only if it is the only block; in that case, offset is

-	// MaxInt (which is not a valid offset).

-	root block

-}

-

-type word uintptr

-

-const (

-	_m            = ^word(0)

-	bitsPerWord   = 8 << (_m>>8&1 + _m>>16&1 + _m>>32&1)

-	bitsPerBlock  = 256 // optimal value for go/pointer solver performance

-	wordsPerBlock = bitsPerBlock / bitsPerWord

-)

-

-// Limit values of implementation-specific int type.

-const (

-	MaxInt = int(^uint(0) >> 1)

-	MinInt = -MaxInt - 1

-)

-

-// -- block ------------------------------------------------------------

-

-// A set is represented as a circular doubly-linked list of blocks,

-// each containing an offset and a bit array of fixed size

-// bitsPerBlock; the blocks are ordered by increasing offset.

-//

-// The set contains an element x iff the block whose offset is x - (x

-// mod bitsPerBlock) has the bit (x mod bitsPerBlock) set, where mod

-// is the Euclidean remainder.

-//

-// A block may only be empty transiently.

-//

-type block struct {

-	offset     int                 // offset mod bitsPerBlock == 0

-	bits       [wordsPerBlock]word // contains at least one set bit

-	next, prev *block              // doubly-linked list of blocks

-}

-

-// wordMask returns the word index (in block.bits)

-// and single-bit mask for the block's ith bit.

-func wordMask(i uint) (w uint, mask word) {

-	w = i / bitsPerWord

-	mask = 1 << (i % bitsPerWord)

-	return

-}

-

-// insert sets the block b's ith bit and

-// returns true if it was not already set.

-//

-func (b *block) insert(i uint) bool {

-	w, mask := wordMask(i)

-	if b.bits[w]&mask == 0 {

-		b.bits[w] |= mask

-		return true

-	}

-	return false

-}

-

-// remove clears the block's ith bit and

-// returns true if the bit was previously set.

-// NB: may leave the block empty.

-//

-func (b *block) remove(i uint) bool {

-	w, mask := wordMask(i)

-	if b.bits[w]&mask != 0 {

-		b.bits[w] &^= mask

-		return true

-	}

-	return false

-}

-

-// has reports whether the block's ith bit is set.

-func (b *block) has(i uint) bool {

-	w, mask := wordMask(i)

-	return b.bits[w]&mask != 0

-}

-

-// empty reports whether b.len()==0, but more efficiently.

-func (b *block) empty() bool {

-	for _, w := range b.bits {

-		if w != 0 {

-			return false

-		}

-	}

-	return true

-}

-

-// len returns the number of set bits in block b.

-func (b *block) len() int {

-	var l int

-	for _, w := range b.bits {

-		l += popcount(w)

-	}

-	return l

-}

-

-// max returns the maximum element of the block.

-// The block must not be empty.

-func (b *block) max() int {

-	bi := b.offset + bitsPerBlock

-	// Decrement bi by number of high zeros in last.bits.

-	for i := len(b.bits) - 1; i >= 0; i-- {

-		if w := b.bits[i]; w != 0 {

-			return bi - nlz(w) - 1

-		}

-		bi -= bitsPerWord

-	}

-	panic("BUG: empty block")

-}

-

-// min returns the minimum element of the block,

-// and also removes it if take is set.

-// The block must not be initially empty.

-// NB: may leave the block empty.

-func (b *block) min(take bool) int {

-	for i, w := range b.bits {

-		if w != 0 {

-			tz := ntz(w)

-			if take {

-				b.bits[i] = w &^ (1 << uint(tz))

-			}

-			return b.offset + int(i*bitsPerWord) + tz

-		}

-	}

-	panic("BUG: empty block")

-}

-

-// lowerBound returns the smallest element of the block that is greater than or

-// equal to the element corresponding to the ith bit. If there is no such

-// element, the second return value is false.

-func (b *block) lowerBound(i uint) (int, bool) {

-	w := i / bitsPerWord

-	bit := i % bitsPerWord

-

-	if val := b.bits[w] >> bit; val != 0 {

-		return b.offset + int(i) + ntz(val), true

-	}

-

-	for w++; w < wordsPerBlock; w++ {

-		if val := b.bits[w]; val != 0 {

-			return b.offset + int(w*bitsPerWord) + ntz(val), true

-		}

-	}

-

-	return 0, false

-}

-

-// forEach calls f for each element of block b.

-// f must not mutate b's enclosing Sparse.

-func (b *block) forEach(f func(int)) {

-	for i, w := range b.bits {

-		offset := b.offset + i*bitsPerWord

-		for bi := 0; w != 0 && bi < bitsPerWord; bi++ {

-			if w&1 != 0 {

-				f(offset)

-			}

-			offset++

-			w >>= 1

-		}

-	}

-}

-

-// offsetAndBitIndex returns the offset of the block that would

-// contain x and the bit index of x within that block.

-//

-func offsetAndBitIndex(x int) (int, uint) {

-	mod := x % bitsPerBlock

-	if mod < 0 {

-		// Euclidean (non-negative) remainder

-		mod += bitsPerBlock

-	}

-	return x - mod, uint(mod)

-}

-

-// -- Sparse --------------------------------------------------------------

-

-// none is a shared, empty, sentinel block that indicates the end of a block

-// list.

-var none block

-

-// Dummy type used to generate an implicit panic. This must be defined at the

-// package level; if it is defined inside a function, it prevents the inlining

-// of that function.

-type to_copy_a_sparse_you_must_call_its_Copy_method struct{}

-

-// init ensures s is properly initialized.

-func (s *Sparse) init() {

-	root := &s.root

-	if root.next == nil {

-		root.offset = MaxInt

-		root.next = root

-		root.prev = root

-	} else if root.next.prev != root {

-		// Copying a Sparse x leads to pernicious corruption: the

-		// new Sparse y shares the old linked list, but iteration

-		// on y will never encounter &y.root so it goes into a

-		// loop.  Fail fast before this occurs.

-		// We don't want to call panic here because it prevents the

-		// inlining of this function.

-		_ = (interface{}(nil)).(to_copy_a_sparse_you_must_call_its_Copy_method)

-	}

-}

-

-func (s *Sparse) first() *block {

-	s.init()

-	if s.root.offset == MaxInt {

-		return &none

-	}

-	return &s.root

-}

-

-// next returns the next block in the list, or end if b is the last block.

-func (s *Sparse) next(b *block) *block {

-	if b.next == &s.root {

-		return &none

-	}

-	return b.next

-}

-

-// prev returns the previous block in the list, or end if b is the first block.

-func (s *Sparse) prev(b *block) *block {

-	if b.prev == &s.root {

-		return &none

-	}

-	return b.prev

-}

-

-// IsEmpty reports whether the set s is empty.

-func (s *Sparse) IsEmpty() bool {

-	return s.root.next == nil || s.root.offset == MaxInt

-}

-

-// Len returns the number of elements in the set s.

-func (s *Sparse) Len() int {

-	var l int

-	for b := s.first(); b != &none; b = s.next(b) {

-		l += b.len()

-	}

-	return l

-}

-

-// Max returns the maximum element of the set s, or MinInt if s is empty.

-func (s *Sparse) Max() int {

-	if s.IsEmpty() {

-		return MinInt

-	}

-	return s.root.prev.max()

-}

-

-// Min returns the minimum element of the set s, or MaxInt if s is empty.

-func (s *Sparse) Min() int {

-	if s.IsEmpty() {

-		return MaxInt

-	}

-	return s.root.min(false)

-}

-

-// LowerBound returns the smallest element >= x, or MaxInt if there is no such

-// element.

-func (s *Sparse) LowerBound(x int) int {

-	offset, i := offsetAndBitIndex(x)

-	for b := s.first(); b != &none; b = s.next(b) {

-		if b.offset > offset {

-			return b.min(false)

-		}

-		if b.offset == offset {

-			if y, ok := b.lowerBound(i); ok {

-				return y

-			}

-		}

-	}

-	return MaxInt

-}

-

-// block returns the block that would contain offset,

-// or nil if s contains no such block.

-// Precondition: offset is a multiple of bitsPerBlock.

-func (s *Sparse) block(offset int) *block {

-	for b := s.first(); b != &none && b.offset <= offset; b = s.next(b) {

-		if b.offset == offset {

-			return b

-		}

-	}

-	return nil

-}

-

-// Insert adds x to the set s, and reports whether the set grew.

-func (s *Sparse) Insert(x int) bool {

-	offset, i := offsetAndBitIndex(x)

-

-	b := s.first()

-	for ; b != &none && b.offset <= offset; b = s.next(b) {

-		if b.offset == offset {

-			return b.insert(i)

-		}

-	}

-

-	// Insert new block before b.

-	new := s.insertBlockBefore(b)

-	new.offset = offset

-	return new.insert(i)

-}

-

-// removeBlock removes a block and returns the block that followed it (or end if

-// it was the last block).

-func (s *Sparse) removeBlock(b *block) *block {

-	if b != &s.root {

-		b.prev.next = b.next

-		b.next.prev = b.prev

-		if b.next == &s.root {

-			return &none

-		}

-		return b.next

-	}

-

-	first := s.root.next

-	if first == &s.root {

-		// This was the only block.

-		s.Clear()

-		return &none

-	}

-	s.root.offset = first.offset

-	s.root.bits = first.bits

-	if first.next == &s.root {

-		// Single block remaining.

-		s.root.next = &s.root

-		s.root.prev = &s.root

-	} else {

-		s.root.next = first.next

-		first.next.prev = &s.root

-	}

-	return &s.root

-}

-

-// Remove removes x from the set s, and reports whether the set shrank.

-func (s *Sparse) Remove(x int) bool {

-	offset, i := offsetAndBitIndex(x)

-	if b := s.block(offset); b != nil {

-		if !b.remove(i) {

-			return false

-		}

-		if b.empty() {

-			s.removeBlock(b)

-		}

-		return true

-	}

-	return false

-}

-

-// Clear removes all elements from the set s.

-func (s *Sparse) Clear() {

-	s.root = block{

-		offset: MaxInt,

-		next:   &s.root,

-		prev:   &s.root,

-	}

-}

-

-// If set s is non-empty, TakeMin sets *p to the minimum element of

-// the set s, removes that element from the set and returns true.

-// Otherwise, it returns false and *p is undefined.

-//

-// This method may be used for iteration over a worklist like so:

-//

-// 	var x int

-// 	for worklist.TakeMin(&x) { use(x) }

-//

-func (s *Sparse) TakeMin(p *int) bool {

-	if s.IsEmpty() {

-		return false

-	}

-	*p = s.root.min(true)

-	if s.root.empty() {

-		s.removeBlock(&s.root)

-	}

-	return true

-}

-

-// Has reports whether x is an element of the set s.

-func (s *Sparse) Has(x int) bool {

-	offset, i := offsetAndBitIndex(x)

-	if b := s.block(offset); b != nil {

-		return b.has(i)

-	}

-	return false

-}

-

-// forEach applies function f to each element of the set s in order.

-//

-// f must not mutate s.  Consequently, forEach is not safe to expose

-// to clients.  In any case, using "range s.AppendTo()" allows more

-// natural control flow with continue/break/return.

-//

-func (s *Sparse) forEach(f func(int)) {

-	for b := s.first(); b != &none; b = s.next(b) {

-		b.forEach(f)

-	}

-}

-

-// Copy sets s to the value of x.

-func (s *Sparse) Copy(x *Sparse) {

-	if s == x {

-		return

-	}

-

-	xb := x.first()

-	sb := s.first()

-	for xb != &none {

-		if sb == &none {

-			sb = s.insertBlockBefore(sb)

-		}

-		sb.offset = xb.offset

-		sb.bits = xb.bits

-		xb = x.next(xb)

-		sb = s.next(sb)

-	}

-	s.discardTail(sb)

-}

-

-// insertBlockBefore returns a new block, inserting it before next.

-// If next is the root, the root is replaced. If next is end, the block is

-// inserted at the end.

-func (s *Sparse) insertBlockBefore(next *block) *block {

-	if s.IsEmpty() {

-		if next != &none {

-			panic("BUG: passed block with empty set")

-		}

-		return &s.root

-	}

-

-	if next == &s.root {

-		// Special case: we need to create a new block that will become the root

-		// block.The old root block becomes the second block.

-		second := s.root

-		s.root = block{

-			next: &second,

-		}

-		if second.next == &s.root {

-			s.root.prev = &second

-		} else {

-			s.root.prev = second.prev

-			second.next.prev = &second

-			second.prev = &s.root

-		}

-		return &s.root

-	}

-	if next == &none {

-		// Insert before root.

-		next = &s.root

-	}

-	b := new(block)

-	b.next = next

-	b.prev = next.prev

-	b.prev.next = b

-	next.prev = b

-	return b

-}

-

-// discardTail removes block b and all its successors from s.

-func (s *Sparse) discardTail(b *block) {

-	if b != &none {

-		if b == &s.root {

-			s.Clear()

-		} else {

-			b.prev.next = &s.root

-			s.root.prev = b.prev

-		}

-	}

-}

-

-// IntersectionWith sets s to the intersection s ∩ x.

-func (s *Sparse) IntersectionWith(x *Sparse) {

-	if s == x {

-		return

-	}

-

-	xb := x.first()

-	sb := s.first()

-	for xb != &none && sb != &none {

-		switch {

-		case xb.offset < sb.offset:

-			xb = x.next(xb)

-

-		case xb.offset > sb.offset:

-			sb = s.removeBlock(sb)

-

-		default:

-			var sum word

-			for i := range sb.bits {

-				r := xb.bits[i] & sb.bits[i]

-				sb.bits[i] = r

-				sum |= r

-			}

-			if sum != 0 {

-				sb = s.next(sb)

-			} else {

-				// sb will be overwritten or removed

-			}

-

-			xb = x.next(xb)

-		}

-	}

-

-	s.discardTail(sb)

-}

-

-// Intersection sets s to the intersection x ∩ y.

-func (s *Sparse) Intersection(x, y *Sparse) {

-	switch {

-	case s == x:

-		s.IntersectionWith(y)

-		return

-	case s == y:

-		s.IntersectionWith(x)

-		return

-	case x == y:

-		s.Copy(x)

-		return

-	}

-

-	xb := x.first()

-	yb := y.first()

-	sb := s.first()

-	for xb != &none && yb != &none {

-		switch {

-		case xb.offset < yb.offset:

-			xb = x.next(xb)

-			continue

-		case xb.offset > yb.offset:

-			yb = y.next(yb)

-			continue

-		}

-

-		if sb == &none {

-			sb = s.insertBlockBefore(sb)

-		}

-		sb.offset = xb.offset

-

-		var sum word

-		for i := range sb.bits {

-			r := xb.bits[i] & yb.bits[i]

-			sb.bits[i] = r

-			sum |= r

-		}

-		if sum != 0 {

-			sb = s.next(sb)

-		} else {

-			// sb will be overwritten or removed

-		}

-

-		xb = x.next(xb)

-		yb = y.next(yb)

-	}

-

-	s.discardTail(sb)

-}

-

-// Intersects reports whether s ∩ x ≠ ∅.

-func (s *Sparse) Intersects(x *Sparse) bool {

-	sb := s.first()

-	xb := x.first()

-	for sb != &none && xb != &none {

-		switch {

-		case xb.offset < sb.offset:

-			xb = x.next(xb)

-		case xb.offset > sb.offset:

-			sb = s.next(sb)

-		default:

-			for i := range sb.bits {

-				if sb.bits[i]&xb.bits[i] != 0 {

-					return true

-				}

-			}

-			sb = s.next(sb)

-			xb = x.next(xb)

-		}

-	}

-	return false

-}

-

-// UnionWith sets s to the union s ∪ x, and reports whether s grew.

-func (s *Sparse) UnionWith(x *Sparse) bool {

-	if s == x {

-		return false

-	}

-

-	var changed bool

-	xb := x.first()

-	sb := s.first()

-	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 = 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 = x.next(xb)

-		}

-		sb = s.next(sb)

-	}

-	return changed

-}

-

-// Union sets s to the union x ∪ y.

-func (s *Sparse) Union(x, y *Sparse) {

-	switch {

-	case x == y:

-		s.Copy(x)

-		return

-	case s == x:

-		s.UnionWith(y)